JPH0653177A - Plasma generator, surface treatment apparatus and surface treatment method - Google Patents

Abstract

(57) [Summary] (Modified) [Objective] The present invention aims to maintain a uniform high-density plasma over the entire wafer surface by forming a uniform and strong magnetic field over a wide area of the electrode surface. An object of the present invention is to provide a surface treatment apparatus and a surface treatment method that can be performed. A vacuum container 1 having a first electrode 7 and a second electrode 2 arranged so as to face the first electrode, and gas supply means for introducing a predetermined gas into the vacuum container. Vacuum evacuation means for maintaining the inside of the vacuum container under reduced pressure, electric field generation means for generating an electric field between the first and second electrodes, and magnetic field generation means for generating a magnetic field in the vacuum container. And the magnetic field generating means includes different magnets that are annular on the outer circumference and are arranged so that the magnetization direction can rotate once around the half circumference of the ring, and are configured to generate plasma. .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma generator, a surface treatment apparatus and a surface treatment method, and more particularly to a surface treatment apparatus used for forming a thin film by a vapor phase growth method, etching a thin film and the like.

[0002]

2. Description of the Related Art Reactive ion etching (RIE) is one of the dry etching methods that have been widely used in the microfabrication in the semiconductor device manufacturing process. Further, there is a magnetron RIE method which uses the magnetic field for the plasma to increase the density of the plasma, increase the etching rate, and improve the precision of fine processing.

An example of the apparatus used in this magnetron RIE method is, as shown in FIG. 39, an anode 3 mounted on a first electrode 2 on an upper inner wall of a vacuum container 1.
And a second electrode (cathode) 4 arranged opposite thereto and also serving as a substrate support, and the power generated by the high frequency power source 5 is applied between the anode 3 and the cathode 4 via the matching circuit 14. Is configured to. Then, the electric field formed thereby forms plasma between the electrodes, and the self-bias electric field induced on the surface of the cathode 3 causes the reactive ions accelerated from the plasma to collide with each other to cause the etching reaction to proceed. . In the magnetron RIE, a magnetic field is further applied from the magnet 10 in the direction orthogonal to this self-bias electric field. Magnetic field line 1 in the figure
The state of No. 1 is schematically shown. Thus, the electric field E and the magnetic field B
The electrons in the plasma can be caused to drift in the E × B direction by the Lorentz force by making them orthogonal to each other. By causing the electrons to travel a long distance in the plasma as described above, the frequency with which the electrons collide with neutral molecules and atoms increases, and the plasma density increases. Further, as a result of confining the electrons in the plasma by applying the magnetic field itself and prolonging its life (the time until it collides with the chamber side wall, the electrode, and the wafer), the plasma density can be further improved.

By increasing the density of the plasma as described above, in addition to simply increasing the etching rate, the directionality of ions is enhanced and the reaction between the neutral species and the film to be etched (isotropic reaction) is suppressed. Therefore, even if the gas pressure is lowered, it is possible to keep the ion energy, which causes damage and a reduction in the selection ratio, sufficiently low.

As described above, the magnetron RIE apparatus has excellent characteristics and is currently used for processing various thin films. However, in the conventional magnet, the uniformity of the etching rate is lowered due to the non-uniformity of the strength and direction of the magnetic field. In addition, there is a problem that the directionality of the ions incident on the wafer is disturbed, the ions are obliquely incident on the surface of the substrate to be processed, and etching with high anisotropy or the etching rate of a pattern with a narrow frontage, that is, a high aspect ratio is reduced. It was

For example, as shown in FIG. 40, in the central portion B of the wafer 3 of the etching apparatus shown in FIG. 39, a good etching shape can be obtained as shown in FIG. In C, etching is performed obliquely reflecting the incident direction of plasma, resulting in a tilted shape with poor anisotropy.

Although the cause of such a processed shape is not exactly clear, the following mechanism is considered.

That is, the magnetic lines of force formed in the peripheral portion of the wafer 3 are not formed parallel to the surface of the wafer 3, but are curved and formed obliquely with respect to the wafer, as shown in FIG. Since the electric field is relatively small in plasma, the electrons are strongly influenced by the magnetic field and perform a spiral motion with a radius of about 1 mm so as to surround the magnetic field lines. Therefore, when the line of magnetic force intersects with the wafer 3, electrons are obliquely incident along the line of magnetic force. On the other hand, since the ions directly involved in the etching reaction have a large mass, the effect of directly bending the movement direction by the magnetic field is small. However, when the electrons are obliquely incident on the groove of the substrate being processed, the electrons hit only one wall, so that the charges accumulated on the left and right walls are not equal. When the charges are asymmetrical to the left and right in this way, it is considered that the electric field newly generated in the left-right direction of the wall acts on the ions to bend the movement direction and deteriorate the shape anisotropy.

Further, such non-uniformity of charging on the wafer surface causes dielectric breakdown or leakage in a thin insulating film such as a gate oxide film when a substrate having an MOS structure is formed on the surface of the substrate. It is known that deterioration such as increase in current occurs (Sekine et al .: Proc. 13th Dry Process Symposium p99-103 The Institute of Electrical Engineers of Japan (1991)
Year Tokyo)).

Further, in the above apparatus, since the stray magnetic field is used, in order to obtain the required magnetic field strength on the substrate to be processed, a magnet having an extremely large magnetic field strength must be used.
Further, when the magnetic field strength is increased, the weight of the magnet becomes very large, which makes the device configuration difficult. Further, when it is necessary to change the magnetic field distribution or strength depending on the material of the substrate to be processed, it is necessary to replace the magnet each time. In addition, since a strong magnetic field extends beyond the space where a magnetic field is required, electronic devices that are sensitive to magnetism cannot be used in the vicinity of this processing device, and a single chamber has multiple reaction chambers. In the method, the leakage magnetic fields from the individual magnets interfere with each other and disturb the magnetic field, which greatly affects the process, and it is extremely difficult to use in the multi-chamber method.

Further, in place of the permanent magnet 10, a device has been proposed in which coil-shaped electromagnets are arranged at both ends of the side of the vacuum processing chamber. This device is characterized in that the direction of the magnetic field can be rotated by passing alternating currents whose phases are shifted by 90 degrees in two sets of coils which are orthogonal to each other. However, the magnetic field strength and distribution change with rotation, the distortion becomes large, and the impedance increases as the frequency increases in alternating current, so there is a limit to increasing the rotation speed. In order to supply a uniform magnetic field over the entire wafer, the coil spacing, that is, the size of the container,
It is necessary to make the diameter of the coil sufficiently large, and the larger the diameter of the wafer, the larger the coil must be. At the same time, the current flowing through the coil also increases, the power supply also increases, and the power supply also increases in size.

Further, since a strong magnetic field extends to unnecessary portions inside and outside the container, electro-mechanical parts which are sensitive to magnetism cannot be used and magnetic shielding to the outside of the device is also necessary.

This problem is not limited to etching, but also in terms of uniformity, precision, damage, etc., in general techniques for performing surface treatment using plasma, such as deposition techniques such as sputtering and CVD, impurity addition techniques, and surface modification techniques. It also becomes a problem.

[0014]

As described above, in the conventional magnetron RIE apparatus, since the strength and direction of the magnetic field are nonuniform, the uniformity of etching is deteriorated and the directionality of ions is disturbed. As a result, it is difficult to perform etching with high anisotropy because it is obliquely incident on the surface of the substrate to be processed. Further, when the magnetic field strength is increased, the weight of the magnet becomes large, which makes it difficult to construct the device. There is also a problem that the magnet must be replaced each time the magnetic field distribution or strength is changed. Furthermore, the leakage magnetic field is strong,
There is also a problem that a plurality of reaction chambers cannot be installed close to each other.

The present invention has been made in view of the above circumstances, and it is possible to maintain a uniform high density plasma over the entire surface of a wafer by forming a uniform and strong magnetic field over a wide range of the electrode surface. An object of the present invention is to provide a surface treatment apparatus and a surface treatment method that can be performed.

[0016]

Therefore, in the first aspect of the present invention, a vacuum container having a first electrode and a second electrode disposed so as to face the first electrode, and the vacuum container. Gas supply means for introducing a predetermined gas therein, vacuum evacuation means for maintaining the inside of the vacuum container under reduced pressure, and electric field generation means for generating an electric field between the first and second electrodes, And a magnetic field generating means for generating a magnetic field in the vacuum container,
The magnetic field generating means has a ring shape on the outer circumference and includes different magnets arranged so that the magnetizing direction can rotate once around the half circumference of the ring, and is configured to generate plasma. The first electrode may be used separately from the wall surface of the vacuum container, or may be provided separately.

According to a second aspect of the present invention, a vacuum container provided with a first electrode and a second electrode on which a substrate to be processed is disposed facing the first electrode, and the vacuum container. Gas supply means for introducing a predetermined gas into the inside, vacuum exhaust means for maintaining the inside of the vacuum vessel at a reduced pressure, electric field generating means for generating an electric field between the first and second electrodes, and the vacuum vessel A magnetic field generating means for generating a magnetic field therein, wherein the magnetic field generating means has a ring shape and includes a plurality of magnets arranged so that the magnetizing direction can rotate once around the half circumference of the ring. .

Desirably, there is provided rotating means for rotating the magnetic field generating means relative to the substrate to be processed with the central axis of the magnetic field generating means as the center.

Preferably, the magnetic field generating means changes the magnetizing direction of at least one of the magnets,
A magnetic field strength control means for adjusting the magnetic field strength is provided.

Preferably, the magnetic field generating means is provided with a transfer means capable of transferring the magnetic field in the vertical direction.

Preferably, the magnetic field generating means is divided into at least two parts in the vertical direction so as to have the same central axis, and at least one of them is configured to be movable in the vertical direction.

Preferably, the magnetic field generating means is divided into at least two parts in the vertical direction so as to have the same central axis, and the width of the interval can be adjusted.

Preferably, the magnetic field generating means is vertically divided into at least two parts so as to have the same central axis, and the phase of the magnet element can be adjusted between the upper and lower parts.

Preferably, the magnets are arranged so that their magnetizing directions are shifted by a predetermined phase, so that the magnets are individually rotated.

In the third aspect of the present invention, a vacuum container having a plurality of reaction chambers, a first electrode provided in at least one of the reaction chambers, and a first electrode provided opposite to the first electrode. A second electrode, a gas supply means for introducing a predetermined gas into the reaction chamber, a vacuum evacuation means for maintaining the reaction chamber under reduced pressure, and an electric field are generated between the first and second electrodes. An electric field generating means and a magnetic field generating means for generating a magnetic field in the reaction chamber are provided, and the magnetic field generating means forms an annular shape on the outer periphery of the reaction chamber, and the magnetizing direction can rotate once around the half circumference of the ring. A plurality of magnets arranged in such a manner are included. According to a fourth aspect of the present invention, a first electrode,
A predetermined gas is introduced into a vacuum container having a second electrode provided opposite to the second electrode, a substrate to be processed is placed on the second electrode, and the first and second electrodes are connected to each other. They are arranged to form an electric field between them and form a ring,
A plurality of different magnets whose magnetizing directions are configured to rotate on the ring form a unidirectional magnetic field that is substantially parallel to the surface of the second electrode and induce plasma in the vacuum chamber. Thus, the surface of the substrate to be processed is processed.

In the fifth aspect of the present invention, a vacuum container having a first electrode, a second electrode arranged so as to face the first electrode, and a predetermined gas is introduced into the vacuum container. Gas supply means, vacuum evacuation means for maintaining the inside of the vacuum container under reduced pressure, electric field generating means for generating an electric field between the first and second electrodes, and a magnetic field in the vacuum container. A magnetic field generating means for biasing the magnetic field generating means, wherein the magnetic field generating means includes a plurality of magnet elements that are annularly formed on the outer circumference and are arranged so that the magnetization direction can rotate once around the half circumference of the ring. It is characterized by comprising an electrode position setting means for making the position of the second electrode movable within a synthetic magnetic field created by the magnet element and for varying the distance from the first electrode. Here, the first electrode may be used by insulating the wall surface of the vacuum container from the other, or may be provided separately.

In the sixth aspect of the present invention, the first electrode,
A vacuum container provided with a second electrode on which a substrate to be processed is placed facing the first electrode, a gas supply unit for introducing a predetermined gas into the vacuum container, and the vacuum container. Vacuum evacuation means for maintaining a reduced pressure inside, and the first and second
An electric field generating means for generating an electric field between the electrodes and a magnetic field generating means for generating a magnetic field in the vacuum container, wherein the magnetic field generating means forms a ring and the magnetizing direction is a half circumference of the ring. It is characterized in that it comprises a plurality of magnet elements arranged so as to be rotatable once, and provided with a changing means for varying the diameter of the ring formed by the plurality of magnet elements.

Desirably, there is provided a rotating means for rotating the magnetic field generating means relative to the substrate to be processed about the central axis of the magnetic field generating means.

Preferably, the magnetic field generating means is divided into at least two parts in the vertical direction so as to have the same central axis, and at least one of them is configured to be movable in the vertical direction.

Preferably, the magnetic field generating means is divided into at least two parts in the vertical direction so as to have the same central axis, and the width of the interval can be adjusted.

Preferably, the magnetic field generating means is divided into at least two parts in the vertical direction so as to have the same central axis, and the phase of the magnet element can be adjusted between the upper and lower parts.

Preferably, the magnets are arranged so that their magnetization directions are shifted by a predetermined phase so that the magnets are individually rotated.

According to a seventh aspect of the present invention, the first electrode,
A vacuum container provided with a second electrode on which a substrate to be processed is placed facing the first electrode, a gas supply unit for introducing a predetermined gas into the vacuum container, and the vacuum container. Vacuum evacuation means for maintaining a reduced pressure inside, and the first and second
And an electric field generating means for generating an electric field between the electrodes of the vacuum container and a magnetic field generating means for generating a magnetic field in the vacuum container. The magnetic field generating means forms an annular shape and is perpendicular to the central axis of the annulus. At least one set of magnet elements facing each other among the plurality of magnet elements includes a plurality of magnet elements arranged such that the magnetization direction of the component at the time of magnetization in the plane can rotate once around the half circumference of the ring. It is characterized in that it has a magnetized component in the direction of the central axis of the ring, and that the sizes of the components are substantially equal and their directions are opposite to each other.

Desirably, the magnitude of the magnetization component in the central axis direction is made variable.

According to an eighth aspect of the present invention, a vacuum container having a first electrode and a second electrode on which a substrate to be processed is placed facing the first electrode, and the vacuum container. Gas supply means for introducing a predetermined gas therein, vacuum evacuation means for maintaining the inside of the vacuum container under reduced pressure, electric field generation means for generating an electric field between the first and second electrodes, and Magnetic field generating means for generating a magnetic field between the first and second electrodes, wherein the magnetic field generating means forms an annular shape on the outer circumference, and the magnetizing direction is such that it can make one rotation on a half circumference of the ring. A dividing member that includes a plurality of magnet elements arranged in a circle and that is provided on the outer periphery of the substrate to be processed and divides the space inside the vacuum container into a region including the substrate to be processed and a region not including the substrate in the radial direction of the ring. And is provided.

[0036]

According to the first structure, high density plasma can be generated.

According to the second aspect, a plurality of magnet elements are sequentially arranged in an annular shape and have different magnetizing directions so as to make one rotation around a half of the circle, and the magnet elements are provided on the surface of the first electrode. Since a unidirectional magnetic field that is substantially parallel to the unidirectional magnetic field is formed, a remarkably uniform magnetic field can be formed, and the plasma potential and the self-bias can be uniformed.
It is possible to perform uniform etching with high anisotropy. Further, the damage due to charge-up on the surface of the substrate to be processed is small. The first electrode may be formed as a part of the upper wall of the vacuum container or may be provided inside the vacuum container.

Further, in the conventional apparatus, since the magnetic field was curved, it was not possible to obtain a completely uniform magnetic field even by rotation. It is possible to form a completely uniform magnetic field.

Further, the magnetic field strength is extremely higher than that of the conventional apparatus, and it is possible to realize high strength (several kG) while maintaining uniformity. Therefore, even in a high speed process, ion energy can be lowered and damage can be reduced.

Furthermore, since the magnet is light, the peripheral mechanism can be downsized, and the device can be downsized.

Since it is an inner magnet type, the leakage magnetic field to the outside is small, so that it does not adversely affect other devices. Therefore, even in a multi-chamber system in which a plurality of reaction chambers are installed in one apparatus, the processing can be performed without affecting each other, which is extremely effective.

Furthermore, since it is not necessary to provide a magnet on the anode side, the space on the anode side can be used for other devices such as a monitor (measuring the surface condition of plasma and substrate) or an upper exhaust mechanism. It is also effective when applying high-frequency power to the side.

Desirably, the magnetic field can be further homogenized by rotating the magnetic field generating means. Further, even when rotating the magnetic field generating means, there is no limit like a coil and the like, and since it is a concentric rotationally symmetric type, it is possible to rotate at a significantly higher speed than in the past, and the device configuration is simple. .

Also preferably, by changing at least one magnetizing direction of each magnet element of the magnetic field generating means,
The magnetic field strength can be easily adjusted without replacing the magnet.

More preferably, if the magnetic field generating means or the electrode on which the substrate to be processed is placed can be vertically moved, the substrate to be processed can be easily carried in and out.

Desirably, since the slit is formed in a part of the height direction of the magnetic field generating means, the substrate to be processed can be easily carried in and out through the slit. This was done by paying attention to the fact that, as a result of various experiments, the parallel magnetic field can be maintained without adversely affecting the magnetic field direction due to the formation of the slit.

Preferably, the magnetic field generating means is vertically divided into at least two parts so as to have the same central axis,
If at least one of them is configured to be movable in the vertical direction, it becomes easy to carry in and carry out the substrate to be processed.

Desirably, the magnetic field generating means is divided into at least two parts in the vertical direction so as to have the same central axis, and the width of the interval is adjustable, so that the magnetic field strength can be easily adjusted without replacing the magnet. Can be adjusted.

Preferably, the magnetic field generating means is divided into at least two parts in the vertical direction so as to have the same central axis, and the phase of the magnet element is adjusted between the upper and lower parts of the magnetic field generating means without replacing the magnet. The magnetic field strength can be easily adjusted.

Desirably, the magnetic field generating means is divided into at least two parts in the vertical direction so as to have the same central axis, and the magnets are replaced by rotating them so that the rotation directions are opposite to each other. It is possible to easily adjust the magnetic field strength.

Desirably, each magnet, which is a constituent element of the magnetic field generating means, is arranged with its magnetization direction shifted by a predetermined phase, and each magnet is individually rotated to generate a magnetic field equivalent to that of rotating the entire magnet. Can be formed.

According to the third aspect of the present invention, if a plurality of reaction vessels are provided so that plasma can be generated in each of the reaction vessels and the surface treatment can be performed independently, the leakage magnetic field to the outside can be reduced. Since they do not exist, the respective processing can be performed well without being affected by each other.

In the fourth aspect of the present invention, a predetermined gas is introduced into the vacuum container, and the first electrode and the second electrode in the vacuum container in which the substrate to be processed is installed so as to face the first electrode. A plurality of different magnet elements that generate an electric field and are sequentially arranged in an outer circumference of the vacuum container so as to form an annular shape, and the magnetizing direction is configured to rotate once around the half circumference of the annular shape. An etching rate is set because a unidirectional magnetic field that is almost parallel to the surface of the second electrode is formed, and active species are generated by the plasma induced on the surface of the substrate to be processed to process the surface of the substrate to be processed. In addition, the uniformity of the shape can be improved, and electrostatic damage such as gate destruction caused by the plasma density distribution can be reduced. Further, the strong magnetic field on the order of kG can further increase the density of magnetron plasma and lower the energy of ions.

According to the present invention, in the surface treatment of the substrate to be processed on which the electric component is formed, a unidirectional magnetic field which is substantially parallel to the surface of the second electrode is formed, and the plasma is induced on the surface of the substrate to be processed. It is particularly effective when surface treatment is performed by generating active species. That is, here, the surface of the substrate to be processed is charged because it is exposed to plasma, but if the charging is uniform within the surface of the substrate to be processed, a large voltage will not be applied to the top and bottom of the thin insulating film, and gate breakdown will occur. In this way, stable thin film formation and etching with extremely good directionality can be performed. In the substrate processing apparatus using the dipole ring magnet described above, the substrate to be processed-center and the substrate to be processed-
The difference in the magnetic field strength created by the ruling magnet can be kept less than 20%, and the inclination of the XY plane can be kept uniform within 5 degrees. As described above, the dipole ring magnet has excellent magnetic field characteristics, but the pressure is 5 mTorr, which is considerably lower than the pressure currently used for ordinary etching.
In this region, when used in the actual magnetron RIE, the etching rate may decrease in the substrate to be processed-the most peripheral part. In addition, when this is used to process a substrate on which an element having a MOS structure is formed, a gate is used.
Dielectric breakdown may occur in thin insulating films such as oxide films. 42 and 43 show in-plane distributions of the etching rate of a magnetron RIE using a conventional magnet and a magnetron RIE oxide film using a dipole ring magnet. Although the cause of the decrease in the etching rate at the peripheral portion of the substrate to be processed is not clear, the following mechanism is considered. That is, as shown by a curve a in FIG. 42 (curve b indicates a magnetic field strength distribution formed by a conventional magnet), the magnetic field strength distribution formed by the dipole ring magnet has an area on the substrate to be processed or more. , It is uniform, but the magnetic field strength drops sharply in the vicinity of the magnet. Therefore, even at a pressure of 5 mTorr, which is considerably lower than the pressure currently used for normal etching, it is more uniform over the entire surface of the substrate to be processed than the conventional magnetron RIE, but the etching rate sharply increases at the outermost periphery. Is seen to decrease. The reason for this is considered to be that there is almost no Miller effect that forms a Miller magnetic field as compared with the conventional magnet, and therefore electrons are easily eliminated in the peripheral portion, that is, the plasma density is reduced. Further, the substrate to be processed is exposed to plasma and charged, but if the plasma densities are different, charging is non-uniform, and a large voltage is applied above and below the thin insulating film, which may cause dielectric breakdown.

Further, in the construction of this dipole ring magnet, the target substrate is transferred from the load chamber to the etching chamber or the target substrate is transferred from the etching chamber to the unload chamber because it is arranged in an actual etching apparatus. A load lock transfer system is installed, and the structure of the dipole ring magnet is vertically divided into two parts with the transfer system as the center, and each dipole ring magnet is moved vertically. However, even if both magnets are closest to each other, it is impossible to get closer than the width of the transport system, and although a parallel and uniform magnetic field can be obtained, it will weaken the magnetic field in the peripheral part. . The fall of the magnetic field strength in the peripheral part applies an auxiliary magnetic field to the peripheral part, particularly in the vicinity of the NS pole, or slightly rotates the magnetizing direction of the magnet element around the NS pole to the magnetizing direction side of the dipole ring magnet. It is possible to configure the peripheral part in the NS direction to be equal to or stronger than the central part, and actually generate a uniform parallel magnetic field in the vacuum container.
Plasma can be confined, surface treatment such as stable thin film formation with small ion damage and extremely good directivity can be performed, but the device configuration is complicated to correspond to the actual mass production process. become.

Therefore, according to the fifth aspect of the present invention, the generation of the magnetic field generating means including a plurality of magnet elements which are sequentially arranged in an annular shape and have different magnetization directions so as to make one rotation about half the circumference of the circle. When the substrate to be processed is transported into the magnetic field, the substrate is transported into the magnetic field by the vertical movement of the substrate to be processed, so that it is not necessary to divide the magnetic field generating means by a load lock mechanism or the like. For this reason, there is no need to provide a magnetic field drop due to division or to provide an auxiliary magnetic field to prevent it, and it is possible to form a uniform high-density magnetic field with a simple device configuration and to make the plasma potential and self-bias uniform. Therefore, it is possible to perform uniform surface treatment with high anisotropy within the surface of the substrate to be treated.

Further, the height of the cathode electrode, which is the second electrode on which the substrate to be processed is installed, can be set to an arbitrary position, the electrode interval during plasma processing can be arbitrarily changed, and the material and gas can be changed. , The optimum interval can be set depending on the pressure, and the processing characteristics can be changed.

According to the sixth aspect of the present invention, the magnetic field strength generated in the ring can be arbitrarily changed by changing the diameter of the ring of the annular magnet element, and the ion energy is controlled. This makes it possible to change the processing characteristics.

Therefore, for example, when the surface treatment of the substrate to be treated is performed, or when the optimum magnetic field strength varies depending on the material or the gas, it is not necessary to replace the magnet with the optimum magnetic field strength each time, and the sequential processing or the like is required. It is possible to efficiently perform processing with optimum magnetic field strength.

Further, according to the seventh aspect of the present invention, the magnetic field generating means has an annular shape, and the direction of the magnetized component in the plane perpendicular to the central axis of the annulus can rotate once in a half circumference of the annulus. At least one set of magnet elements facing each other out of the plurality of magnet elements has a magnetizing component in the central axis direction of the ring and the magnitude of the component is large. Since the directions are substantially equal and the directions are opposite to each other, the height at which the parallel magnetic field is formed can be unevenly distributed from the center of the magnetic field generating means.

Desirably, by varying the magnitude of the magnetization component in the central axis direction, a space parallel to the magnetic field can be formed at an arbitrary height position in the ring.

Therefore, when the substrate to be processed is subjected to the plasma treatment in the parallel magnetic field, it is not necessary to convey the substrate to the vicinity of the center of the magnet, which is the parallel magnetic field space formed by the dipole ring magnet, and the moving distance of the lower electrode is reduced. It is short and the moving mechanism is simple.

Further, it is possible to easily change the magnitude of this vertical component in order to change the magnetic field strength during the processing.

According to the eighth aspect of the present invention, the vacuum container is provided by disposing the dividing member which divides the inner space of the container in the radial direction of the ring into a region containing the substrate to be treated and a region not containing it. By configuring the internal container so that discharge can be performed only in a limited region including the substrate to be processed, it becomes possible to generate magnetized plasma only in the space above the substrate to be processed in the vacuum container.

Further, by disposing the inner container so that it can be divided into a region containing the substrate to be treated and a peripheral region within the discharge space in the vacuum container, the inner container is disposed inside the vacuum container. The magnetized plasma in the space above the substrate to be processed can be generated without being affected by the magnetized plasma outside the inner container.

[0066]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a diagram showing an etching apparatus according to an embodiment of the present invention.

This etching apparatus is provided with a first electrode 7 on the inner wall of the upper end of the vacuum chamber 1 and a second electrode 2 which is arranged so as to face the first electrode 7 and also serves as a substrate support base. Is applied between the first electrode 7 and the second electrode 2 via the matching circuit 14, and the electric field formed thereby and the dipole ring disposed on the outer surface of the vacuum container 1 are applied. A reactive gas is supplied from a gas inlet 4 into a space formed by 13 and orthogonal to a magnetic field parallel to the surface of the wafer 3, plasma is formed by discharge, and the self-bias electric field induced on the wafer surface The ions accelerated from the plasma collide with the wafer to promote the etching reaction.

This dipole ring 13 is shown in FIG.
As shown in an enlarged explanatory view seen from above, it is composed of a magnet element 30 arranged on the side wall of the cylindrical vacuum container 1 so as to concentrically surround the same, and is magnetized in the magnetic field direction 35. The magnet element at the position of θ from the magnet element 30 ₀ is magnetized in the direction rotated by 2θ with respect to the magnetic field direction 35, and the magnet element at the position of 180 degrees from the magnet element 30 ₀ is again in the magnetic field direction. They are arranged in a ring shape so as to face 35. Here, since a force that causes a twist acts on each of the individual magnet elements as constituent elements, it is fixed to a robust non-magnetic yoke (not shown). As for the yoke, it is possible to use a magnetic yoke in order to further reduce the leakage magnetic field.

3 (a) and 3 (b) show the magnetic field distribution formed by this dipole ring. As is clear from this figure, the difference in the magnetic field strength created by the dipole magnets between the wafer center and the wafer periphery can be less than 20%, and the inclination within the XY plane can be achieved within ± 5 degrees.
In the height direction, the strength was ± 5% and the magnetic field inclination could be suppressed within ± 6 degrees in the central 1/3 of the height of the dipole magnet. For this uniformity, a more uniform magnetic field can be formed by making the cross-sectional shape of the magnet elements circular or increasing the number of magnet elements. On the other hand, in the conventional device shown in FIG. 33, the magnetic field strength ratio reaches twice in the central portion and the peripheral portion. Similarly, in the conventional type as well, in the upper part of the wafer, that is, in the region where plasma is formed, the magnetic field strength in the vertical direction is increased particularly in the peripheral portion, which causes the plasma distribution to be disturbed. Such a dipole ring is a polarizer or MRI originally used in SOR (synchrotron radiation facility).
(Magnetic Resonance imaging) and other medical devices (K.Mi
yata et al: The Internayional Journal for Computati
on and Mathematics in Electrical and ElectronicEng
ineering, Vol. 9 (1990), Supplement A, 115-118, H. Zijls
tra: Philips J.Res.40,259-288,1985). However, as shown in the present invention, it was found that an extremely effective action can be obtained by applying it to a device that forms a magnetized plasma.

By thus making the electric field E and the magnetic field B orthogonal to each other, the electrons in the plasma can be drifted in the E × B direction by the Lorentz force. The electrons in the plasma formed by this magnetron discharge cause a drift motion and run for a long distance, so that the electrons collide with neutral molecules and atoms more frequently, and the plasma density rises. Further, by applying the magnetic field itself, the electrons are confined in the plasma, and their life (the time until they collide with the chamber side wall, the electrode, and the wafer) is lengthened, and as a result, the plasma density can be improved. By increasing the plasma density in this way, in addition to simply increasing the etching rate, the directionality of ions is improved and the reaction between the neutral species and the film to be etched (isotropic reaction) is suppressed. Even if the gas pressure is lowered, it is possible to keep the ion energy, which causes damage and a reduction in the selection ratio, sufficiently low.

Further, a liquid is passed through the inside of the second electrode 2 serving as the substrate support table via the cooling pipe 17 so that the substrate temperature is efficiently controlled. This is because the magnetron plasma according to the present invention has a high density, and the heat given to the substrate by the plasma is larger than that in the conventional apparatus.

Further, the inner wall of the vacuum chamber is constructed so as to insulate and separate from the lower part via an insulator 11 arranged in the vicinity of the first electrode 7. Reference numeral 4 is a supply system for introducing a reaction gas, and 6 is an exhaust system. 20 is also an insulator for insulating and separating the second electrode. Further, a protective ring 16 is placed on the second electrode 2 so that the peripheral portion of the wafer is not directly exposed to the plasma. This material is SiC, alumina, A
Ceramics such as 1N and BN, carbon of various structures, Si,
Organic substances, metals, alloys, etc. are selected according to the film to be etched and the gas.

In the above embodiment, the neodymium type (Nd-
Fe) magnet was used, but other examples such as Sm-Co
It is preferable to select and use a permanent magnet material such as a system, ferrite, or alnico in consideration of a necessary magnetic field, resistance, weight, and the like.

Further, in the conventional device, the magnet was formed above the vacuum container, but in the present invention, since the dipole ring 13 is formed on the side, the back surface of the first electrode is used for a monitor device or the like. Therefore, a monitor device 52 for monitoring the state of the wafer surface through the quartz window 50 and the etching depth through the laser light detector 51 is formed above the vacuum container.

Further, the dipole ring 13 is movable in the vertical direction, and the wafer is taken in and out of the vacuum container by raising the dipole ring 13 (shown by a dotted line) through a gate valve 12 and a load lock mechanism and a transfer mechanism. Done by

Furthermore, a mechanism for moving the second electrode up and down may be provided, a gate valve may be provided at a position where the electrode is lowered, a wafer may be taken in and out, and the electrode may be lowered to perform processing at the position of the dipole ring. On the contrary, a mechanism for loading / unloading the wafer may be provided at a position where the electrode is raised above the dipole ring.

As described above, the structure of this dipole ring magnet forms a remarkably uniform magnetic field between the opposed electrodes forming plasma, and its strength is higher than that of the conventional device.
It can be realized up to several kG. Therefore, the plasma density is improved, and the processing speed and characteristics can be improved. Further, although particularly remarkable when a large diameter wafer is used, the in-plane uniformity of the wafer in the process is improved. Furthermore, there is an effect such that the electrostatic breakdown of the MOS structure caused by the nonuniformity of plasma is eliminated. On the other hand, since a magnet is formed on the side surface of the reaction container, the upper part (anode side) of the vacuum container that needs to be opened during maintenance is open, and process monitoring and rf power application to the anode side are performed. Sometimes effective. Even if the magnet and the wafer are rotated relative to each other in order to obtain evenness, there is no need to move them for maintenance as in the conventional arrangement of the magnet in the anode, so the side surface of the reaction vessel It can be rigidly fixed by a method such as providing a rail on it, and the operation becomes simple.

Next, a method of actually etching a polycrystalline silicon film formed on a thin oxide film using this apparatus will be described.

First, as shown in FIG. 4 (a), a wafer is obtained by forming a 10 nm thin silicon oxide film and a polycrystalline silicon film 301 on the surface of a silicon substrate 300 and further forming a resist pattern 302 on this surface. The dipole ring 13 is lifted up and is transferred onto the second electrode 2 of the vacuum container 1 by using a load lock mechanism and a transfer mechanism and fixed by an electrostatic chuck (not shown), -3
It is controlled to be 0 ° C.

Then, the dipole ring 13 is returned to its original position, the inside of the vacuum vessel 1 is evacuated to about 10 ^-6 Torr by the exhaust system 6, and then chlorine gas is supplied from the supply system 4 to 100 cc / m 2.
Introduced in between the first electrode 7 and the second electrode 2.
250 W of high frequency power (rf) of 56 MHz is applied.
At this time, the power density per unit area of the susceptor is 0.6.
W / cm ² . Then, set the dipole ring 13 to 20
Rotate at 0 rpm. At this time, the magnetic field strength inside the dipole ring 13 is set to 200G. Here, the gas is exhausted by a vacuum pump through a baffle plate whose opening is covered with a metal mesh to prevent plasma from flowing around, an exhaust system 6 and a conductance valve (a valve whose opening ratio is variable and whose exhaust speed can be adjusted). The pressure inside the chamber was set to 25 mTorr by adjusting this conductance valve.

For the etching monitor, the emission of plasma is examined through a quartz window, the change in the concentration of chlorine atoms, which is the etching species, is monitored, and the etching end point of the phosphorus-doped polycrystalline silicon layer is detected. After performing a predetermined over-etching (lengthening the etching time by 20 to 100% so that the etching residue does not occur even if there is variation in the film pressure of the film to be etched), turn off the high frequency power, After the etching gas is stopped and the gas remaining in the chamber is discarded, the load lock mechanism is also used and the gas is taken out of the chamber.

At this time, the etching rate is 345 nm / min, and the etching selection ratio to the underlying silicon oxide film is 5
2, etching selection ratio with photoresist 7, uniformity ±
It is 3%, and as shown in FIG. 4 (b), it is possible to obtain an etching shape having a vertical section and good dimensional accuracy.

In this way, machining with no dimensional conversion difference can be realized. Furthermore, since the plasma density can be kept extremely high, the energy of ions can be kept low, the selection ratio can be made high, and the damage can be made small.

Although the dipole ring is rotated in the above embodiment, the same effect can be obtained by rotating the second electrode and rotating the wafer.

In the above embodiment, the dipole ring is divided into 16 parts, but it may be divided into 12 parts or 8 parts as shown in FIGS. 5 (a) and 5 (b).

Further, a gas containing, for example, fluorocarbon (CF) is used for etching the silicon oxide film, a gas mainly containing oxygen for directional processing of the resist, and chlorine is mainly used for aluminum or the like used for wiring. It was possible to perform high-performance processing using the above gas, and the effect of the present invention was confirmed. Other materials can also be etched using at least halogen or a gas containing a reactive gas such as oxygen, hydrogen or nitrogen.

Furthermore, the magnetic field strength is not limited to 200 Gauss, and is appropriately selected according to the material to be etched and the gas used. For example, in the above-mentioned etching of phosphorus-doped polycrystalline silicon, an experiment was conducted by increasing the magnetic field strength up to 1600 gauss, and it was found that the selectivity with respect to the underlying oxide film increased to 74 although the etching rate hardly changed. It was Further, when such a strong magnetic field is used, in the conventional device, the pressure region in which the magnetron discharge effectively acts is about 1 × 10 ⁻³ Torr to 100 mTorr, but the pressure region is 1 × 10 ⁻⁴ Torr to several hundred mTorr. It turned out that it will be expanded to. Furthermore, when the conventional electrode interval is narrowed to about 20 mm, the efficiency of discharge is reduced, but it is 160
With 0 gauss, it can be narrowed down to 8 mm, and the tolerance for the required apparatus configuration can be increased due to the gas flow. Furthermore, regarding the high frequency, 13.56
The frequency is not limited to MHz, but a relatively low frequency of about 100 kHz to 1 MHz is effective for etching an oxide film system that requires high ion energy depending on the material to be etched. On the other hand, 20 MHz is used for materials that require a selective ratio with respect to masks and underlying materials, such as the above-mentioned phosphorus-doped polycrystalline silicon or aluminum alloy.
It is effective to use a high frequency of about 1 to several hundred MHz and reduce the ion energy. In either case,
Ion energy and plasma density, as well as other plasma parameters, can be controlled in combination with the strength of the magnetic field.

As described above, the present invention is not limited to the above embodiment, but can be applied to various devices.

Next, as a second embodiment of the present invention, an example in which a dipole ring is vertically divided into two will be described.

In this example, as shown in FIG. 6, the dipole ring is composed of an upper dipole ring 44 and a lower dipole ring 45, and a wafer connected to the gate valve 12 opened and closed by the gate valve opening / closing mechanism 41 in this gap. The load lock chamber 42 via the transfer path 43
Are connected to each other so that the wafer can be loaded and unloaded from the gap between the upper dipole ring 44 and the lower dipole ring 45. Here, 47 is a vacuum seal, 4
Reference numeral 6 is a gate valve drive shaft.

The other parts are formed in exactly the same manner as in the above embodiment. The same parts as in Example 1 are designated by the same reference numerals.

Next, an etching method for actually forming a groove in silicon using this apparatus will be described.

First, the mask 102 of the example shown in FIG.
Was directly formed on a Si substrate as a sample, which was placed in the load lock chamber 42 and evacuated to about 10 ⁻⁶ Torr, and then the gate valve opening / closing mechanism 41 raised the gate valve drive shaft 46 to raise the gate valve 12 The wafer is transferred onto the second electrode 2 serving as a substrate support via the open wafer transfer path 43 and fixed by an electrostatic chuck (not shown).
Control so that the temperature becomes ℃. Then, the gate valve opening / closing mechanism 41 lowers the gate valve drive shaft 46 to close the gate valve 12, and the exhaust system 6 ^{moves the} inside of the vacuum container 1 to 10 ⁻⁶ To.
After evacuation to rr, the HBr gas from the supply system 4 is reduced to 20
A high frequency power (800 W) is applied between the first electrode 7 and the second electrode 2 by introducing 0 cc / min. Then, the dipole rings 44 and 45 rotate in synchronization with each other at 120 rpm. At this time, the magnetic field strength inside the dipole rings 44 and 45 is 1600G.

At this time, the etching rate is 850 nm / min, and the etching shape of the Si trench having a vertical cross section and good dimensional accuracy can be obtained.

In this way, machining with no dimensional conversion difference can be realized. Furthermore, since the plasma density can be kept extremely high, the energy of ions can be kept low and damage can be reduced.
It was also found that by providing a gap that divides the upper and lower portions in the center of the dipole ring magnet, it becomes easy to transfer the wafer into the chamber, and the gap has a function of enhancing the uniformity of the magnetic field.

In this example, the upper and lower dipole rings rotated in synchronization with two sets having the same magnetization direction, but as shown in FIG. 7, a phase difference was formed between the upper and lower dipole rings. The direction of the magnetic field may be one direction by combining. FIG. 8 shows the result of measurement of the relationship between the phase difference in the magnetization directions of the upper and lower magnets and the magnetic field strength. In this way, the magnetic field strength can be adjusted by forming the phase difference between the upper and lower dipole rings. The required magnetic field strength varies depending on the process, but by controlling the phase difference with one set of magnets, it is possible to form a magnetic field as needed.

A mechanism for controlling rotation between the upper and lower dipole rings is shown in FIG. Here, the upper and lower dipole rings each have a gear 873 formed on the outer peripheral surface of a yoke 872 for fixing a magnet element 871, and are linked by a gear 874 that meshes with both the gear 873 of the upper and lower dipole rings. It is designed to rotate. Where magnet element 871
Has a prismatic shape. Gear 874 is the size of its magnet,
It will be installed in several places in consideration of the weight. Here, a cross-sectional view of FIG. 9B is shown. The gear 873 attached to the shaft 875 is rotated by a drive mechanism (not shown), and the force is applied to the gear 873.
Pass to the dipole ring magnet through 4. The die pole ring is a rail 87 with wheels 876 attached to bearings 879.
It can be rotated over 7 so that there is less friction. Ray
The ring 877 is formed in a ring shape under the die pole ring and is connected to the vacuum container via the vertical drive mechanism 96 (see FIG. 10). By adopting such a configuration,
High-speed rotation of the ruling is possible. In the drawings of this embodiment, small parts such as bearings are omitted. Also,
On the upper die pole ring divided into two, rail 87
Instead of holding the lower part by 7, it is better to hold it by hanging the upper surface. Further, since the divided die pole rings individually exert complicated forces, it is preferable to fix the gears driving the upper and lower rings to one shaft and rotate them in perfect synchronization.

Also, the meshing position with this gear may be changed,
It is also possible to change the rotational speed or shift the phase of the two by making a plurality of gears that move coaxially detachable. Further, if the magnetic element is divided into two and the phases of the magnet elements are adjusted between the upper and lower sides, the magnetic field strength can be easily adjusted without replacing the magnet.
Furthermore, the dipole ring is divided into at least two parts in the vertical direction so that they have the same central axis, and they are rotated so that the directions of rotation are opposite between the upper and lower parts of the dipole ring, so that the magnets can be easily alternated without replacing the magnet. It is also possible to create a magnetic field.

For example, each magnet element is provided with a motor,
Synchronizing with electric control or intentionally rotating asynchronously, not just rotating the magnetic field, but forming an alternating magnetic field and further rotating it, changing the magnetic field strength, changing the distribution Is also possible.

Further, in order to rotate the magnetic field at high speed, the magnetic field may be weakened by an eddy current generated by the magnetic field traversing the conductor. Therefore, in a device requiring high magnetic field strength and high speed rotation, it is preferable that the side surface of the vacuum container is made of a material having a high resistivity or an insulator. Furthermore, if a part or all of the first electrode or the second electrode is made of paramagnetic material, the magnetic lines of force easily penetrate through the paramagnetic material, and as a result, correction is performed at a portion where the magnetic field is easily disturbed, such as the electrode peripheral portion. It can be performed.

Next, as a third embodiment of the present invention, an apparatus equipped with a magnet assembly incorporating a high-speed rotating mechanism and an up-and-down mechanism thereof will be described.

In this example, as shown in FIG. 10, upper and lower dipole ring assemblies 92, 91 which can rotate at high speed are installed on the outer peripheral surface of the vacuum container through a vertical position and space adjusting mechanism 96. A duct hose 97 is installed in the rotating mechanism to prevent particles due to rotation from being emitted to the outside. Further, a gas injection nozzle 93 and an exhaust nozzle 94 are formed above the vacuum container, and the gas is exhausted upward from the exhaust port 6. The other parts are formed similarly to the second embodiment.

In addition, as a fourth embodiment of the present invention, each magnet, which is a constituent element of the magnetic field generating means, is arranged with its magnetization direction shifted by a predetermined phase, and individually rotated, whereby the entire magnet is rotated. It is possible to form a magnetic field equivalent to that of rotating.

In this example, as shown in FIG. 11, 16 small gears 102 are formed so as to mesh with the inside of a ring 103 having teeth on both sides, and the lower surface of this gear serves as a cylindrical magnet element 101. ing. Here, 104 is a rotary drive mechanism, and 105 is a gear connected to the rotary drive mechanism.
Further, 106 is a pedestal, and 107 is a bearing.

In this example, the ring is rotated around B by the rotation of the rotary drive mechanism 104, and the combined magnetic field is rotated by the rotation of each magnet element 101. Now turn the drive motor clockwise and the ring 10
3 rotates counterclockwise, and the magnet element 101 also rotates counterclockwise, so that the composite magnetic field 108 rotates clockwise.

Thus, the position of each magnet element does not change,
It is also possible to rotate (rotate) the magnet element to rotate the magnetic field that is synthesized as a dipole ring. That is, FIG. 12 (a) is the same as the magnetic field arrangement shown in FIG. 2, and only the shapes of the element magnets are different. Next, when the individual magnets are rotated clockwise at the same speed, the combined magnetic field as shown in Fig. 12 (b), Fig. 12 (c), ... rotates counterclockwise and the element magnets are rotated. It can be seen that the rotation angle of and the rotation angle of the synthetic magnetic field match. With such a structure, the same effect can be obtained without rotating the structure of the large die pole ring.

Next, a sputtering apparatus will be described as a fifth embodiment of the present invention.

As shown in FIG. 13, this sputtering apparatus includes a target plate 61 mounted on the first electrode 7 on the inner wall of the upper end of the vacuum container 1, and a first plate which is arranged so as to face the target plate 61 and also serves as a substrate support base. Two electrodes 2 are provided, and the power generated by the high frequency power source 5 is applied to the target plate 61 by the DC power source 64 via the matching circuit 14 to the target plate 61 and the second electrode 2. Gas is supplied from the gas supply system 4 into the space orthogonal to the electric field formed by these and the magnetic field formed by the upper dipole ring 44 and the lower dipole ring 45 arranged on the outer surface of the vacuum container 1. Then, a plasma is formed by the discharge, and the ions in the plasma are made to collide with the target plate 61 so that the sputtered particles from the target are vertically guided onto the wafer 3 on the second electrode 2. It is a thing. Here, the distance between the target plate 61 and the second electrode 2 was 3 cm.

This dipole ring is formed in the same manner as shown in FIG. 6 in the second embodiment of the present invention,
A parallel magnetic field is formed on the wafer surface, and the action of E × B due to this magnetic field and the electric field formed on the surface of the target plate maintains the magnetron discharge. Then, the electrons in the plasma formed by this magnetron discharge drift and increase the ionization efficiency, and it is possible to generate high-density plasma even under the condition of relatively low pressure.

Further, a temperature adjusting mechanism 62 for controlling the substrate temperature, such as embedding a heater, is installed inside the second electrode 2 as the substrate support.

Further, the inner wall of the vacuum container is configured to insulate and separate from the lower part through an insulator 65 arranged near the first electrode 7. 6 is an exhaust system, 63 is a temperature adjusting mechanism for cooling the target, and 64 is a power source for adjusting the potential of the target.

Further, the loading / unloading of the wafer into / from the vacuum container is performed by a load lock mechanism (not shown) and a transfer mechanism (not shown).

Next, a method of actually forming a deposited film using this apparatus will be described.

First, as shown in FIG. 14 (a), a silicon substrate 68 whose surface is made uneven by a pattern 67 formed on the surface is used as a wafer, and this is used as a wafer by using a load lock mechanism and a transfer mechanism. It is conveyed onto the second electrode 2, fixed by an electrostatic chuck (not shown), and controlled to a desired temperature (250 ° C.).

Then, the inside of the vacuum vessel 1 is evacuated by the exhaust system 6, and then 100 cc of argon gas is supplied from the supply system 4.
In order to remove contaminants such as surface oxide film and hydrocarbons on the electrode portion of the wafer surface, the first electrode on the second electrode side was first introduced at a flow rate of / m to a pressure of about 10 ^-3 Torr. High frequency power is applied, plasma is formed, and cleaning is performed by sputtering. Next, a large electric power is applied to the target side to sputter the aluminum alloy. DC power (400V, 3.5) is applied to the target plate 61 (first electrode 7).
A) is applied to the second electrode 2 with high frequency power. Then, the argon gas is discharged to form plasma. Then, the magnetic field confines the electrons between the electrodes. As a result, the life is extended, the travel distance of electrons is increased, the frequency of collision with molecules and atoms is increased, the ionization efficiency is increased, and high density plasma is formed even under a low gas pressure. The rotation of the magnetic field was set to 200 rpm in this embodiment for the same reason as in the etching embodiment.

A cathode drop voltage Vdc is generated on the surface of the target plate 61, argon ions in the plasma are irradiated to the surface of the target plate 61, and the target plate material, that is, the deposited material such as aluminum is released into the plasma by the sputtering action. Deposit on top.

A bias voltage is generated in the substrate by the high frequency power applied to the second electrode 2, and the deposition and sputtering actions occur simultaneously on the surface. As a result, as shown in FIG. 14 (b), it is efficiently guided to the bottom of the groove. It is possible to form a uniform and excellent thin film over the entire surface without the occurrence of "soo". This is because the magnetic field can be formed completely parallel and strong, and the reduction of the target becomes uniform. Here, the deposition rate was 1.7 μm / min, and the uniformity was ± 3%.

In this embodiment, the region where high density plasma is formed extends over the entire target plate. When high-density plasma is localized as in conventional equipment, part of the target plate is sputtered at high speed, which shortens the life of the target.
Although there were problems such as poor uniformity of film formation and the shape of the film formed depending on the position within the wafer, the target device is uniformly sputtered in the device of the present invention, improving the performance of the device. To do. Needless to say, the damage was reduced.

Then, by performing etch back as shown in FIG. 14C, it becomes possible to form the buried layer 69 having a good film quality even in the fine groove.

As described above, high-density plasma can be generated even under a relatively low pressure condition of about 10 ^-3 Torr, the amount of impurities taken into the film is extremely reduced, and the film quality is improved. Moreover, the deposition rate can be increased, and the mean free path of the particles is increased under low pressure, which is convenient for increasing the directionality in transporting the deposition species.

This device is not limited to aluminum thin films, but also high melting point thin films such as tungsten and molybdenum, aluminum oxide, tantalum pentoxide, aluminum nitride,
It can be applied to various thin film formation and etching such as insulating films such as silicon oxide and silicon nitride films.

In addition, the structure and material of the device are not limited to the embodiments, and can be appropriately modified without departing from the scope of the present invention.

Next, a cold wall type plasma CVD apparatus will be described as a sixth embodiment of the present invention.

As shown in FIG. 15, this CVD apparatus is characterized in that a multi-divided dipole ring 51 consisting of first to fourth dipole rings is arranged on the outer peripheral surface of the vacuum container 1.

The first electrode 7 is provided on the vacuum container 1.
And a second electrode 2 which is disposed so as to face the first electrode 7 and also serves as a substrate support, and the gas introduction port 4 to the second electrode formed in the vicinity of the first electrode 7. Wafer 3 on 2
While supplying gas toward the target, electric power generated by the high-frequency power source 5 is applied between the first electrode 7 and the second electrode 2 via the matching circuit 14 to generate a self-bias electric field. , High-density plasma is formed in a space orthogonal to a magnetic field parallel to the surface of the wafer 3 formed by the multi-divided dipole ring 51 arranged on the outer surface of the vacuum container 1, and self-induced plasma is generated on the wafer surface. Ions accelerated from the plasma by the bias electric field collide with the wafer to cause a thin film forming reaction to proceed.

Furthermore, a temperature adjusting mechanism 53 for adjusting the temperature of the first electrode, a matching circuit 58 connected to the first electrode 7, and a power source 59 are arranged above the vacuum container. In the figure, 54 is a quartz window, 55 is a photodetector, 56 is an optical fiber, and 57 is a spectroscope for spectroscopically analyzing the light from the plasma to examine the state in the gas phase.

Next, thin film formation using this apparatus will be described.

In this embodiment, the deposition gas SiH is used.
₄ (200 cc / min) and O ₂ (200 cc / min) are introduced and discharged at a pressure of 8 × 10 ⁻⁴ Torr to form a SiO ₂ thin film. The wafer transfer is exactly the same as in the above-described embodiment, but the load lock mechanism is not shown. The first electrode is provided separately from the vacuum container 1 and is independently connected to the power source 59. Gas is uniformly supplied toward the wafer from the gas introduction nozzle 52 through the inside of the first electrode. The basic operation procedure is the same as that of the device described above. The feature here is that the deposited species formed in the plasma are deposited on the wafer like snow and are adsorbed on the surface, and are further reacted by the impact of ions accelerated by the bias voltage induced by the high frequency power supplied from the power supply 5. In the end, a film close to a thermal oxide film with few impurities and a small refractive index is formed. Here, a very strong magnetic field with a magnetic field strength of 2000 gauss was applied. The high frequency power was 1.2 kW, and the deposition rate at this time was 0.3 μm / min.

When the absolute value of the magnetic field strength is high as described above, the absolute value of the strength difference between the high magnetic field portion and the low magnetic field portion becomes large no matter how highly uniform the magnet is. Therefore, in this embodiment, a dipole ring of a four-divided type was used. The magnetic field strength and distribution can be finely adjusted by adjusting the position of the uppermost magnet or the lowermost magnet. Further, when the size of the apparatus is increased due to the increase in the diameter of the wafer, the distance between the central portion of the electrode and the peripheral portion of the chamber is greatly different, and the plasma characteristics are different. Therefore, while keeping the magnetic field near the wafer uniform,
By intentionally disturbing the magnetic field at the periphery of the electrode and the second electrode, it is possible to enhance the uniformity of the plasma itself.
The multi-divided magnet structure enables such an application.

As described above, by implementing the present invention in a CVD apparatus, it is possible to improve the film formation rate, uniformity, reduce damage, and to form high density plasma. Since the decomposition and reaction of gas in the gas phase proceeded, the quality of the formed film was also improved.

Next, as a seventh embodiment of the present invention, a hot wall type plasma CVD apparatus will be described.

As shown in FIG. 16, in this CVD apparatus, a heater 78, a cooling plate 75, and a cooling pipe 79 are provided on the outer peripheral surface of a vacuum container 71 made of a quartz tube, and a dipole ring 80 is provided on the outside thereof. It is characterized by being present. Generally, the Curie point of a magnetic material exists at several hundreds of degrees Celsius, but in many cases, the coercive force decreases from about 100 degrees Celsius, and the temperature rise causes deterioration of characteristics. Therefore, in a device that generates heat, such as a CVD device or an etching device that heats a chamber, a cooling means is provided as necessary.

The gas inlet 74 and the gas outlet 76 are installed at both ends of the vacuum container so as to face each other, and the wafers 73 are arranged perpendicularly to the gas flow. A first electrode 72 is supported by an electrode support rod 82. Reference numeral 77 is the first electrode, which is also the first electrode.
The electrodes are supported by the electrode support rods 82 so as to face the electrodes. 5 is a power supply.

As an eighth embodiment of the present invention, a MOSFET manufacturing process using the etching apparatus shown in FIG. 1 will be described.

As shown in FIG. 17A, the silicon substrate 1
After forming an element isolation region 122 on the surface 21, a gate insulating film 123 is formed and an n + polycrystalline silicon film 124 is further formed by a CVD method. Then, a resist pattern 125 is formed on this upper layer. After that, this silicon substrate is set in the etching apparatus shown in FIG. 1 and, as shown in FIG.
The polycrystalline silicon film 124 was anisotropically etched. At this time, a mixed gas of Cl ₂ + H ₂ was used as the etching gas, the pressure was 30 mTorr, and the applied power was 200 W.
By using this device, the wafer surface is exposed to plasma, so it is charged, but the voltage (charge) is generated within the wafer surface.
Is uniform, no large voltage is applied across the gate oxide film, so that gate breakdown can be prevented. In this way, a sufficient selection ratio can be obtained and a pattern with high dimensional accuracy can be formed.

Thereafter, using this gate electrode as a mask,
Ion implantation is performed to form a source / drain region 126, and the resist pattern 125 is peeled off to form a MOSFET. As described above, according to the method of the present invention, a fine and highly reliable MOSFET without causing gate breakdown.
Can be obtained.

Next, a ninth embodiment of the present invention will be described.

18 and 19 are views showing the etching apparatus of the embodiment of the present invention. In these drawings, the same parts as those in FIG. 1 are designated by the same reference numerals and detailed description thereof will be omitted.

This etching apparatus is characterized in that the diameter of the ring of the dipole ring 13 is made variable and the lower electrode 2 can be moved up and down by the electrode position level setting means 30. That is, when the substrate 3 to be processed is transferred into the magnetic field generated by the dipole ring 13 including a plurality of magnet elements that are sequentially arranged in an annular shape and have different magnetizing directions so that the magnetizing direction makes one rotation around one half of the circle. The vertical movement of the substrate to be processed allows the substrate to be easily transported into the magnetic field.

That is, as shown in the overall schematic view of FIG. 18, this etching apparatus has the first inner wall of the upper end of the vacuum chamber 1.
And an up-and-down movable second electrode 2 facing the first electrode 7 and also serving as a substrate support, are arranged.
Applied between the second electrode 2 and the second electrode 7 and a magnetic field parallel to the surface of the wafer 3 formed by the dipole ring 13 arranged on the outer surface of the vacuum container 1. A reactive gas is supplied from the gas introduction port 4 into the space orthogonal to, and the plasma is confined by the discharge,
Ions accelerated in the plasma by the self-bias electric field induced on the surface of the wafer collide with the wafer to promote the etching reaction.

The dipole ring 13 is shown in FIG. 19 which is an enlarged explanatory view of an essential part viewed from above in FIG. 18, and FIG.
As shown in the general explanatory view in FIG. 1, a cylindrical vacuum chamber 1 is provided with a magnetic element 30 which is supported on a side wall of the vacuum container 1 so as to be concentrically surrounded and has a variable diameter, and is attached in a magnetic field direction 35. magnet elements at position θ from magnetic and magnetic elements 30 ₀ were are magnetized in a direction rotated by 2θ with respect to the magnetic field direction 35, the magnet element in the magnet elements 30 ₀ to 180 degree position again field They are arranged annularly so as to face the direction 35. Here, since a force that causes a twist acts on each of the individual magnet elements as constituent elements, it is fixed to a robust non-magnetic yoke (not shown). As for the yoke, it is possible to use a magnetic yoke in order to further reduce the leakage magnetic field.

According to this structure, since the second electrode can be moved in the vertical direction, the substrate to be processed can be easily lowered and transported. Therefore, it is not necessary to divide the magnetic field generating means, so that it is not necessary to provide a magnetic field drop due to the division or an auxiliary magnetic field for preventing it, and it is possible to form a uniform high-density magnetic field with a simple device configuration. Therefore, the plasma potential and the self-bias can be made uniform, and it is possible to perform uniform surface treatment with high anisotropy in the plane of the substrate to be treated.

Further, the height of the cathode electrode, which is the second electrode 2 on which the substrate 3 to be processed is installed, can be set to an arbitrary position, the electrode interval during plasma processing can be arbitrarily changed, and the material The optimum interval can be set depending on the gas, the gas, and the pressure, and the processing characteristics can be changed.

Further, by changing the diameter of the ring of the annular magnet element, it is possible to arbitrarily change the strength of the magnetic field generated in the ring, and it is possible to change the processing characteristics by controlling the ion energy. It will be possible.

21 (a) and 21 (b) show the radial movement amount x of this dipole ring and the magnetic field distribution formed thereby. As is clear from this figure, the magnetic field strength can be easily changed by moving the magnet element in the radial direction of the ring of the dipole ring.

In order to explain the operation of the present invention, FIG.
FIG. 4 shows the magnetic field distribution formed by the dipole ring magnet in the case where a slit is provided at a position ½ in the height direction on the assumption that the substrate to be processed is transported. As is clear from this figure, the difference in the magnetic field strength created by the dipole magnets between the wafer center and the wafer periphery can be less than 20%, and the inclination within the XY plane can be achieved within ± 5 degrees.
In the height direction, the strength was ± 5% and the magnetic field inclination could be suppressed within ± 6 degrees in the central 1/3 of the height of the dipole magnet. For this uniformity, a more uniform magnetic field can be formed by making the cross-sectional shape of the magnet elements circular or increasing the number of magnet elements. However, the magnetic field strength is reduced by forming the slit around the wall surface of the chamber. In order to prevent this, it is necessary to add an auxiliary magnet or the like to make a correction, and the device configuration becomes very complicated. However, by making the second electrode movable up and down as in the configuration of the above embodiment, It is not necessary to add an auxiliary magnet or the like for correction, and the device configuration becomes very simple.

By thus making the electric field E and the magnetic field B orthogonal to each other, the electrons in the plasma can be drifted in the E × B direction by the Lorentz force. The electrons in the plasma formed by this magnetron discharge cause a drift motion and run for a long distance, so that the electrons collide with neutral molecules and atoms more frequently, and the plasma density rises. Furthermore, by applying a magnetic field itself, the electrons are confined in the plasma, their life (the time until they collide with the chamber side wall, electrode, and wafer) is lengthened, and the plasma magnetic field strength is increased at the end in the NS direction to enhance the plasma. Can be contained, and as a result, the plasma density can be further improved. By increasing the plasma density in this way, in addition to simply increasing the etching rate, the directionality of ions is improved and the reaction between the neutral species and the film to be etched (isotropic reaction) is suppressed. Even if the gas pressure is lowered, it is possible to keep the ion energy, which causes damage and a reduction in the selection ratio, sufficiently low.

Further, a liquid is passed through the inside of the second electrode 2 serving as the substrate support table via the cooling pipe 17 so that the substrate temperature is efficiently controlled. This is because the magnetron plasma according to the present invention has a high density, and the heat given to the substrate by the plasma is larger than that in the conventional apparatus.

Further, the inner wall of the vacuum container is constructed so as to be insulated and separated from the lower part via an insulator 11 arranged near the first electrode 7. Reference numeral 4 is a supply system for introducing a reaction gas, and 6 is an exhaust system. 20 is also an insulator for insulating and separating the second electrode. Further, a protective ring 16 is placed on the second electrode 2 so that the peripheral portion of the wafer is not directly exposed to the plasma. This material is SiC, alumina, A
Ceramics such as 1N and BN, carbon of various structures, Si,
Organic substances, metals, alloys, etc. are selected according to the film to be etched and the gas.

In the above embodiment, the neodymium type (Nd-
Fe) magnet was used, but other examples such as Sm-Co
It is preferable to select and use a permanent magnet material such as a system, ferrite, or alnico in consideration of a necessary magnetic field, resistance, weight, and the like.

As described above, the structure of this dipole ring magnet forms a remarkably uniform magnetic field between the opposed electrodes forming plasma, and its strength is higher than that of the conventional device.
It can be realized up to several kG. Therefore, the plasma density is improved, and the processing speed and characteristics can be improved. Further, although particularly remarkable when a large diameter wafer is used, the in-plane uniformity of the wafer in the process is improved. Furthermore, there is an effect such that the electrostatic breakdown of the MOS structure caused by the nonuniformity of plasma is eliminated. On the other hand, since a magnet is formed on the side surface of the reaction container, the upper part (anode side) of the vacuum container that needs to be opened during maintenance is open, and process monitoring and rf power application to the anode side are performed. Sometimes effective. Even if the magnet and the wafer are rotated relative to each other in order to obtain evenness, there is no need to move them for maintenance as in the conventional arrangement of the magnet in the anode, so the side surface of the reaction vessel It can be rigidly fixed by a method such as providing a rail on it, and the operation becomes simple.

Next, a method of actually etching a silicon oxide film formed on a silicon substrate using this apparatus will be described.

First, as shown in FIG. 23A, a silicon oxide film 30 having a film thickness of 1000 nm is formed on the surface of a silicon substrate 300.
1 and further having a resist pattern 302 formed on the surface thereof is used as a wafer, and is transferred onto the second electrode 2 of the vacuum container 1 by using the load lock mechanism and the transfer mechanism.
It is fixed by an electrostatic chuck (not shown), and is raised as it is up to a point 27 mm from the first electrode on the central axis of the dipole ring magnet.

Then, the inside of the vacuum container 1 is adjusted to 10 by the exhaust system 6.
After evacuating to about ^-6 Torr, CF ₄ gas is introduced from the supply system 4 at 50 cc / min, and a high frequency power (rf) of 13.56 MHz is applied between the first electrode 7 and the second electrode 2 for 200 times.
Apply W. At this time, the power density per unit area of the susceptor is 0.6 W / cm ² . Here, the dipole ring 13 does not rotate, but may rotate. At this time, the magnetic field strength inside the dipole ring 13 is set to 200G.

After the etching is completed, the high frequency power is turned off, the etching gas is stopped, the gas remaining in the chamber is discarded, and then the second electrode is lowered to return it to its original position, again using the load lock mechanism. Then, it is taken out of the chamber, and as shown in FIG. 24 (b), an etching shape having a vertical cross section and good dimensional accuracy can be obtained.

In this way, machining with no dimensional conversion difference can be realized. Furthermore, since the plasma density can be kept extremely high, the energy of ions can be kept low, the selection ratio can be made high, and the damage can be made small.

Although the dipole ring is divided into 16 in the above-mentioned embodiment, it may be divided into 12 or 8 as shown in FIG.

For etching the silicon oxide film,
Although a gas containing fluorocarbon (CF) was used, a high-performance processing using a gas mainly containing oxygen for directional processing of the resist and a gas mainly containing chlorine such as aluminum used for wiring. It was possible and the effect of the present invention was confirmed. Other materials can also be etched using at least halogen or a gas containing a reactive gas such as oxygen, hydrogen or nitrogen.

Furthermore, the magnetic field strength is not limited to 200 Gauss, and is appropriately selected according to the material to be etched and the gas used.

Further, when the conventional electrode interval is narrowed to about 20 mm, it is recognized that the discharge efficiency is reduced, but at 1600 gauss, it can be narrowed to 8 mm, and the tolerance to the device configuration required from the gas flow etc. is increased. be able to. Furthermore, regarding the high frequency, 13.56 MH
Not limited to z, a relatively low frequency of about 100 kHz to 1 MHz is effective for etching an oxide film system that requires a high ion energy, depending on the material to be etched. On the other hand, for materials such as phosphorus-doped polycrystalline silicon or aluminum alloys that require a selective ratio with respect to the mask and the underlying material, 20 MHz to several 1
It is effective to use a high frequency of about 00 MHz and reduce the ion energy. In either case, the ion energy, plasma density, and other plasma parameters can be controlled in combination with the magnetic field strength.

Further, by using this apparatus, the vertical distance of the second electrode 2 is changed, thereby making the electrode interval 27 mm,
The thickness was changed to 40 mm and 55 mm, and the silicon oxide film actually formed on the silicon substrate was etched. The result is shown in FIG. As is clear from this figure, the etching rate and uniformity are changed by changing the electrode spacing. Thus, by changing the electrode interval depending on the material to be etched, etching with less damage or high-speed etching can be selected.

Further, it is possible to change the electrode interval during etching and perform the etching sequentially.

As described above, the present invention is not limited to the above embodiment, but can be applied to various devices.

For example, when an insulating film is formed on the electrodes of a MOS device by an etching apparatus using a conventional magnet and etch back is performed for flattening, the charge on the wafer surface is uneven due to the uneven magnetic field. As a result, dielectric breakdown may occur in the peripheral portion of the wafer, but by using this device, the surface of the wafer is uniformly charged and the occurrence of dielectric breakdown can be prevented. This example will be described.

Using this apparatus, as shown in FIG. 25, an insulating film 304 is formed on a silicon substrate 303, and a polycrystalline silicon film 305 is deposited to deposit a CVD oxide film 306 on the gate electrode of the MOS structure formed. Then, a process of anisotropically etching the entire surface to leave the insulating film 304 in the gate electrode recess will be described.

It is carried onto the second electrode 2 of the vacuum container 1 by using the load lock mechanism and the carrying mechanism, fixed by an electrostatic chuck (not shown), and then, directly from the first electrode which is the center of the dipole ring magnet. Raise upwards to the 27 mm point.

Then, the inside of the vacuum container 1 is adjusted to 10 by the exhaust system 6.
After evacuating to about ^-6 Torr, CF ₄ gas is introduced from the supply system 4 at 50 cc / min, and high frequency power (rf) of 13.56 MHz is supplied between the first electrode 7 and the second electrode 2.
7 W (2.7 W / cm ² ) was applied to etch the CVD oxide film, and after the etching was completed, the high frequency power was turned off, the etching gas was stopped, and the gas remaining in the chamber was discarded. Lower it back to its original position,
The rod lock mechanism is also used, and the rod is taken out of the chamber to obtain an etching shape as shown in FIG. 25 (b).

The device thus obtained is shown in FIG.
As shown in 6 (a) and (b), the breakdown frequency and the gate breakdown on the wafer surface when an electric field of 8 MV / cm was applied, no applied electric field was observed up to 15 MV / cm,
None of them caused gate destruction up to m. On the other hand, when the same process is performed by the conventional etching apparatus using the magnet, the breakdown frequency in FIGS. 26 (c) and 26 (d) and the gate on the wafer surface when an electric field of 8 MV / cm is applied. As shown by the breakdown, breakdown occurs even at an applied electric field of 5 MV / cm or less, and gate breakdown occurs at a ratio of 10/82 in the peripheral portion of the wafer up to 8 MV / cm.

FIG. 27 is a diagram showing the results of measuring the magnetic field strength, the oxide film etching rate, and the self-bias voltage when etching was performed under the same conditions. From this result, it is understood that the etching rate increases and the self-bias voltage decreases as the magnetic field strength increases.

Next, as still another embodiment, the diameter of the ring formed by this dipole ring magnet is changed,
An example in which the magnetic field strength is changed will be described. FIG. 28 shows
The etching rate of p-silicon when the diameter is changed under the same conditions as in the eighth embodiment and the magnetic field strength is changed to perform etching is shown. Here, the etching gas is C
150 W of 13.56 MHz high frequency power using L ₂
(0.5 W / cm ² ) was applied, and the pressure was 50 mtorr. The etching rate does not increase monotonically as the magnetic field strength increases, but becomes highest at a magnetic field strength of about 400G. Further, when the etching rate of a similar oxide film is measured and the selection ratio is obtained, the selection ratio can be obtained when the magnetic field strength is 500.
It was time for G.

Sequential etching was performed using these magnetic field strengths. A silicon oxide film 308 is deposited on a silicon substrate 307, a p-silicon film 309 is deposited to a thickness of 400 nm by a CVD method, and a photoresist 310 is patterned to prepare a wafer (FIG. 29 (a)).

This wafer is transferred onto the second electrode 2 of the vacuum container 1 by using the load lock mechanism and the transfer mechanism, fixed by an electrostatic chuck (not shown), and is directly used as the center of the dipole ring magnet. 27 from 1 electrode
Raise upwards to mm point. Then, the inside of the vacuum vessel 1 is evacuated to about 10 ^-6 Torr by the exhaust system 6, and then 50 cc / min of CF ₄ gas is introduced from the supply system 4 to connect between the first electrode 7 and the second electrode 2. 150 W (0.5 W / cm ² ) of 13.56 MHz high frequency power (rf) was applied to the
The diameter of the ring of the dipole ring magnet is adjusted so that the magnetic field strength is 0 G, and the p-silicon film is etched.

Immediately before the underlying silicon oxide film 308 is exposed, the diameter of the circular ring of the dipole ring magnet is reduced and adjusted to 500 G, and overetching is performed.

After the etching is completed, the high frequency power is turned off, the etching gas is stopped, the gas remaining in the chamber is discarded, and then the second electrode is lowered to return it to its original position. It is used and taken out of the chamber, and a good etching shape can be obtained as shown in FIG. 29 (b).

By thus increasing the etching rate at the beginning and increasing the magnetic field strength midway to perform etching with a high selection ratio, it is possible to perform high-speed etching while maintaining a high selection ratio.

Next, as a tenth embodiment of the present invention, an example in which the height of the space parallel to the magnetic field is changed will be described.
In this example, a plurality of dipole rings 13 shown in FIGS. 18 and 20 are arranged in an annular shape and in a plane perpendicular to the central axis of the dipole ring 13 so that the magnetizing direction can rotate once around a half circumference of the ring. Magnet elements M1 to M16 of the plurality of magnet elements M3,
As shown in FIG. 30, M1, M2 and M8, M9, M10 have a magnetizing component in the direction of the central axis of the ring, and have substantially the same size but opposite directions. Figure 3
As shown in FIG. 1 (a), this configuration allows the height at which the parallel magnetic field is formed to be unevenly distributed from the center of the dipole ring 13. For comparison, FIG. 31 (b) shows the height of the parallel magnetic field in the configuration shown in FIG. 18, that is, when the direction component perpendicular to the ring is not included.

In this way, a parallel magnetic field space can be formed at a position 5 cm lower than the center of the dipole ring 13. Thus, even at a position 5 cm lower than the center, the magnetic field distribution in the XY space is within 15%, and the vertical component distribution is within 4%, and it is possible to obtain uniformity equivalent to the magnetic field distribution at the center of the conventional dipole ring. .

Also in this apparatus, as shown in FIG. 32, it is possible to obtain the same uniformity as in the case where the conventional dipole ring magnet is used. In this way, the parallel magnetic field space can be created anywhere in the ring,
Maintaining the characteristics of conventional dipole ring magnets,
Further, the vertical driving distance of the wafer can be greatly shortened, and the transfer mechanism is much simpler than the conventional one.

Also, the magnitude of the vertical component may be changed during the etching.

Next, as an eleventh embodiment of the present invention, an example will be described in which a magnetron RIE layer provided with a dipole ring magnet capable of varying the slit spacing is used and etching is performed while varying the slit spacing. . FIG. 33 is a sectional view showing the device configuration of this magnetron RIE device. As shown in this figure, the dipole rings 401 and 402 can move up and down, and the interval between them can be set to an arbitrary value. Next, an example in which the substrate to be processed is etched using this apparatus will be described. First, as shown in FIG. 34, a substrate to be processed in which an oxide film 502 having a thickness of 1100 nm is formed on a silicon substrate 501 is introduced into an etching chamber (vacuum container) 1 using a load lock mechanism (not shown), and is placed on the cathode electrode 2. Placed and fixed using electrostatic chunk. Next, after the slit intervals of the dipole ring magnets 401 and 402 are arbitrarily set, CF in the etching chamber 1 is set.
₄ was introduced at a flow rate of 100 SCCM, the pressure was adjusted to 0.5 mTorr, high frequency power of 13.56 MHz was applied at an output of 2.7 W / cm ² with respect to the area of the cathode, and etching was performed for 60 seconds. went. After that, the wafer was taken out of the chamber using a load lock mechanism, and the etching rate distribution in the wafer surface was measured. As a result, the slit spacing of the dipole ring magnet and the wafer surface uniformity of the etching rate were as follows. 35 and 3
6 is a characteristic diagram showing the result. FIG. 35A shows the uniformity of the etching rate distribution in the wafer surface when the slit spacing is zero. At this time, since the magnetic field strength in the chamber is a mirror magnetic field, the etching rate at the central portion of the wafer is extremely higher than that at the peripheral portion. (b)
Indicates the uniformity when the slit spacing is 5 mm. Although the slit spacing is slightly increased, the mirror weakens, the concentration on the wafer central portion weakens, and the uneven etching rate is better than when the slit spacing is 0, but it also becomes faster in the central portion. There is. In Fig. 36 (a), the slit spacing is 15
The uniformity was shown in mm, the magnetic field strength in the etching chamber was almost uniform, and the uniformity of the etching rate was very good. In Fig. 36 (b), when the slit spacing is 30 mm, the magnetic field strength is uniform just above the wafer, but drops near the chamber side wall, and the effect of this is that the etching rate decreases at the wafer periphery. . The slit spacing for uniformizing the magnetic field in the chamber changes depending on the inner diameter of the chamber or the inner diameter of the dipole ring magnet, or the strength and shape of the individual magnets that make up the dipole ring, and can be selected as necessary. It becomes possible to perform very uniform etching.

Next, as a twelfth embodiment of the present invention, an example in which a dividing member for dividing the space in the vacuum container is installed on the outer periphery of the substrate to be processed will be described.

FIG. 37 is a sectional view showing the structure of a magnetron RIE apparatus incorporating the above members. The shape of the dividing member 601 is a cylindrical shape in this embodiment, and is installed so as to surround the target substrate installation portion (cathode) 3. That is, the dividing member 601 is a vacuum container in which the target substrate 60 is processed in the radial direction of the target substrate 602.
2 is arranged so as to be divided into a space 603a in which 2 exists and a space 603b that does not exist. Here, the dividing member 6
A large number of holes 601a having a diameter of about 5 mm are opened in 01, so that gas can be efficiently exhausted from the space 603a. It should be noted that this dividing member may be formed of a mesh having a mesh size of about 1 mm. As for the material, a metal such as aluminum whose surface is anodized or an insulator such as ceramic can be appropriately selected.
Further, when a metal is used, it is possible to maintain a ground potential or a predetermined potential.

Next, an example in which the substrate 602 to be processed is etched using this apparatus will be described. First, as shown in FIG. 34, an oxide film 502 is formed on a silicon substrate 501.
The substrate 602 to be processed having a thickness of 100 nm was introduced from a load lock chamber (not shown) into the etching chamber (vacuum container) 1, placed on the cathode electrode 2, and fixed using an electrostatic chunk. Next, after setting the slit spacing of the dipole ring magnets 401 and 402 arbitrarily, CF ₄ 100 SCC is placed in the etching chamber 1.
It was introduced at a flow rate of M, the pressure was adjusted to 0.5 mTorr, high frequency power of 13.56 MHz was applied at an output of 2.7 W / cm ² with respect to the area of the cathode, and etching was performed for 60 seconds. . After that, the wafer was taken out of the chamber using a load lock mechanism, and the etching rate distribution in the wafer surface was measured. FIG. 38 is a characteristic diagram showing the result. FIG. 38 (a) shows a case where the dipole ring 604 has a configuration without slits, and since the magnetic field strength in the chamber is a mirror magnetic field, the plasma density at the wafer center portion becomes high and the wafer center portion becomes high. The etching rate of the area is extremely higher than that of the peripheral area. FIG. 38 (b) shows a structure in which a slit is formed in the center of the dipole ring in order to improve the wafer transfer and the uniformity of the magnetic field. A mirror magnetic field is not formed and a uniform etching rate distribution is obtained in the central part of the wafer. The magnetic field strength sharply drops due to the slits formed near the inner wall of the chamber, and the etching rate around the wafer drops due to the effect.

Therefore, as shown in FIG. 37, the substrate 602 to be processed was etched by using a magnetron RIE apparatus equipped with a dipole ring having a slit and a dividing member 601. A dividing member 601 was attached so that discharge could be performed only in a limited region where the magnetic field formed by the dipole ring was uniform just above the wafer in the chamber 1. FIG. 38 (c) is a characteristic diagram showing the distribution of the etching rate in the wafer surface in this etching. As shown in this figure, even when etching at a low pressure of about 0.5 mmTorr, it is generated only in the space that forms a uniform magnetic field, and is not affected by the magnetic field drop near the inner wall of the chamber due to the slits. is there. Although the magnetic field generating means such as the dipole ring is installed outside the vacuum container in the above embodiment, it may be installed inside the vacuum container.

As described above, when film formation or surface treatment is performed on an already formed electric component other than the process of directly processing the electric component, or when the electric component exists in the lower layer but the wiring electrode or the like connected to it is processed or The present invention is also effective in the case of film formation and surface treatment. The electrical parts are not limited to the MOS structure, and are applicable to all those having an electrical function such as a pn junction, transistors of various structures, capacitors, etc., which are deteriorated by voltage or current.

Still another application is a technique of implanting impurities into a substrate. As an apparatus, a BF ₃ gas containing, for example, boron, which is an impurity, is introduced into a parallel plate type plasma apparatus to form plasma. The gas dissociates in the plasma, and B atoms therein are implanted into the substrate. At the same time, there are many F atoms, so here the gas pressure is 1
Down to 0 ^-5 Torr stand, be prevented from being etched. By applying a magnetic field as in the present invention, plasma can be generated even at such a low gas pressure, and the ion energy at that time can be suppressed to about several tens to 300 eV, and a very shallow impurity layer is formed. You can Also in this embodiment, effects such as uniformity and reduction of damage can be similarly realized.

Although the embodiment of the magnetron plasma processing apparatus and method using the die pole ring has been described above focusing on etching, CVD, sputtering film formation, and impurity addition, the present invention is not limited to this. It can be applied to other processes and devices using magnetized plasma. For example, the magnetic field strength is selected according to the process in the range from several tens of Gauss to several thousand Gauss.

Further, surface modification by plasma CVD equipment or plasma, plasma ion source of ion implantation equipment, EC
It can also be used in a device that forms R or Whistler wave (helicon wave) plasma and uses it as a source of plasma, electrons, ions, and neutral active species.

Further, regarding the device configuration, high frequency or DC power may be applied individually to the first and second electrodes. The high frequency is 13.56 MH in the embodiment.
Although a large amount of z is used, it is possible to select a low frequency of about 100 kHz to a high frequency of several 100 MHz according to the application, and adjust the ion energy together with the strength of the magnetic field.

[0191]

As described above, according to the present invention, it is possible to generate a uniform parallel magnetic field having an arbitrary strength in a vacuum container and confine a plasma, and to reduce ion damage, and to make it uniform and stable. Surface treatment such as thin film formation and etching with extremely good directivity can be performed.

[Brief description of drawings]

FIG. 1 is a diagram showing an etching apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a dipole ring of the etching apparatus.

FIG. 3 is a diagram showing a magnetic field distribution of the etching apparatus.

FIG. 4 is a diagram showing an etching method using the same etching apparatus.

FIG. 5 is a view showing a modified example of the dipole ring.

FIG. 6 is a diagram showing an etching apparatus according to a second embodiment of the present invention.

FIG. 7 is a diagram showing a relationship between a phase difference between upper and lower dipole rings of the etching apparatus and a synthetic magnetic field.

FIG. 8 is a diagram showing the relationship between the phase difference between the upper and lower magnets and the magnetic field strength.

FIG. 9 is a diagram showing a rotary drive device for upper and lower magnets.

FIG. 10 is a diagram showing an etching apparatus according to a third embodiment of the present invention.

FIG. 11 is a diagram showing a driving device for a dipole ring of an etching apparatus according to a fourth embodiment of the present invention.

FIG. 12 is a diagram showing rotation of a magnetic element of a dipole ring and a magnetic field direction.

FIG. 13 is a diagram showing a sputtering apparatus according to a fifth embodiment of the present invention.

FIG. 14 is a view showing a sputtering process according to the fifth embodiment of the present invention.

FIG. 15 is a diagram showing a CVD apparatus according to a sixth embodiment of the present invention.

FIG. 16 is a diagram showing a CVD apparatus according to a seventh embodiment of the present invention.

FIG. 17 is a view showing a manufacturing process of the MOSFET according to the eighth embodiment of the present invention.

FIG. 18 is a diagram showing an etching apparatus according to a ninth embodiment of the present invention.

FIG. 19 is an enlarged explanatory view of a main part of a dipole ring of the etching apparatus.

FIG. 20 is an explanatory diagram of a dipole ring of the etching apparatus.

FIG. 21 is a diagram showing a magnetic field distribution when the radius of the dipole ring is changed in the etching apparatus.

FIG. 22 is a diagram showing the results of measuring the relationship between the distance from the center of the wafer and the etching rate.

FIG. 23 is a diagram showing an etching process using the same apparatus.

FIG. 24 is a diagram showing a relationship between an electrode interval and an etching rate.

FIG. 25 is an etching process diagram when the apparatus of the present invention is used for etch back.

FIG. 26 is a comparative diagram showing the breakdown frequency when the process of FIG. 25 is performed using the device of the present invention and the device using a conventional magnet.

FIG. 27 is a diagram showing the relationship between magnetic field strength and etching rate.

FIG. 28 is a diagram showing the relationship between magnetic field strength, etching rate, and etching selection ratio.

FIG. 29 is a diagram showing an etching process according to another embodiment of the present invention.

FIG. 30 is an explanatory view of a main part of a dipole ring of an etching apparatus according to a tenth embodiment of the present invention.

FIG. 31 is a diagram showing positions of parallel magnetic fields of the etching apparatus of FIG. 29 and a normal etching apparatus.

FIG. 32 is a diagram showing the relationship between the distance from the wafer center and the etching rate when etching is performed using the dipole ring according to the tenth embodiment of the present invention.

FIG. 33 is a diagram showing an etching apparatus of an eleventh embodiment of the present invention.

FIG. 34 is a diagram showing a substrate to be processed which is etched using the etching apparatus of FIG. 33.

FIG. 35 is a characteristic diagram showing the in-plane distribution of the etching rate when etching is performed using the etching apparatus of FIG. 33.

FIG. 36 is a characteristic diagram showing a wafer in-plane distribution of the same etching rate.

FIG. 37 is a diagram showing an etching apparatus according to a twelfth embodiment of the present invention.

38 is a characteristic diagram showing the in-plane distribution of the etching rate in the wafer when etching is performed using the etching apparatus of FIG. 37 in comparison with the conventional case.

FIG. 39 is a diagram showing a conventional magnetron etching apparatus.

FIG. 40 is a view showing an etched shape using the same device.

FIG. 41 is a diagram showing a magnetic field distribution of the device.

FIG. 42 is a diagram showing the relationship between the distance from the center of the wafer and the etching rate in the conventional etching apparatus using a magnet.

FIG. 43 is a diagram showing the relationship between the distance from the wafer center and the etching rate in an etching apparatus using a dipole ring.

[Explanation of symbols]

 1 Vacuum Container 2 Second Electrode 3 Wafer, 4 Gas Inlet 5 High Frequency Power Supply 6 Outlet 7 Second Electrode 11 Insulator 12 Gate Valve 13 Dipole Ring 14 Matching Circuit 16 Protective Ring 17 Cooling Tube 50 Quartz Window 51 Optical Detection Device 52 Monitor device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Haruo Okano 1 Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Toshiba Research & Development Center Co., Ltd. Toshiba Research and Development Center Co., Ltd. (72) Inventor Norihiro Hasegawa Komukai Toshiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa 1 Toshiba Research and Development Center Co., Ltd.

Claims (15)

[Claims] 1. A vacuum container comprising a first electrode, a second electrode arranged so as to face the first electrode, and a gas supply means for introducing a predetermined gas into the vacuum container. Vacuum evacuation means for maintaining a reduced pressure in the vacuum container, electric field generation means for generating an electric field between the first and second electrodes, and magnetic field generation means for generating a magnetic field in the vacuum container. The magnetic field generating means includes a different magnet that is annular on the outer circumference and is arranged so that the magnetizing direction can rotate once around the half circumference of the annulus, and is configured to generate plasma. A plasma generation device characterized by the above. 2. A vacuum container having a first electrode and a second electrode on which a substrate to be processed, which is arranged so as to face the first electrode, is installed, and a predetermined gas in the vacuum container. A gas supply means for introducing a gas, a vacuum evacuation means for maintaining a reduced pressure in the vacuum container, an electric field generating means for generating an electric field between the first and second electrodes, and a magnetic field in the vacuum container. And a magnetic field generating means for biasing the magnetic field, wherein the magnetic field generating means includes a plurality of magnets that are annular and are arranged so that the magnetization direction can rotate once around a half of the ring. apparatus. 3. The surface according to claim 2, further comprising rotating means for rotating the magnetic field generating means about a central axis of the magnetic field generating means relative to a substrate to be processed. Processing equipment. 4. The magnetic field generation means comprises magnetic field strength control means for adjusting the magnetic field strength by changing at least one magnetizing direction of each of the magnets. Surface treatment equipment. 5. The surface treatment apparatus according to claim 2, wherein the magnetic field generating means includes a transfer means capable of moving the magnetic field in the vertical direction. 6. The magnetic field generating means is divided into at least two parts in the vertical direction so as to have the same central axis, and at least one of them is configured to be movable in the vertical direction. The surface treatment apparatus according to claim 2. 7. The magnetic field generating means is divided into at least two parts in the vertical direction so as to have the same central axis, and the width of the interval between them is adjustable. The surface treatment apparatus according to item (2). 8. The magnetic field generating means is vertically divided into at least two parts so as to have the same central axis, and the phase of the magnet element can be adjusted between the upper and lower parts. The surface treatment device according to claim 3. 9. The surface treatment apparatus according to claim 2, wherein each of the magnets is arranged with its magnetization direction shifted by a predetermined phase, and rotation means is provided for individually rotating the magnet. . 10. A vacuum container having a plurality of reaction chambers, a first electrode provided in at least one of the reaction chambers, a second electrode provided opposite to the first electrode, and the reaction. Gas supply means for introducing a predetermined gas into the chamber, vacuum evacuation means for maintaining the reaction chamber under reduced pressure, electric field generation means for generating an electric field between the first and second electrodes, and the reaction A plurality of magnetic field generating means for generating a magnetic field in the chamber, wherein the magnetic field generating means forms a ring on the outer periphery of the reaction chamber and is arranged so that the magnetization direction can rotate once around the half circumference of the ring. A surface treatment apparatus including the magnet of. 11. A predetermined gas is introduced into a vacuum container provided with a first electrode and a second electrode provided so as to face the first electrode, and a substrate to be processed is placed on the second electrode. A plurality of different magnets that generate an electric field between the first and second electrodes and that are arranged in an annular shape and that are magnetized in such a manner that they rotate on the annulus. A surface treatment method characterized in that a substantially parallel unidirectional magnetic field is formed along the surface of the second electrode and plasma is induced in the vacuum container to treat the surface of the substrate to be treated. 12. A vacuum container provided with a first electrode and a second electrode on which a substrate to be processed, which is arranged so as to face the first electrode, is installed, and a predetermined gas in the vacuum container. A gas supply means for introducing a gas, a vacuum evacuation means for maintaining the inside of the vacuum container under reduced pressure, an electric field generation means for generating an electric field between the first and second electrodes, and the first and second Magnetic field generating means for generating a magnetic field between the magnetic field generating means and the electrode of the plurality of magnetic field generating means, the magnetic field generating means forming an annular shape on the outer circumference, and the magnetizing direction is arranged so as to be rotatable once around the half circumference of the ring. An electrode position setting means that includes the magnet element and that makes it possible to move the position of the second electrode within a combined magnetic field created by the plurality of magnet elements and that makes the distance from the first electrode variable. A characteristic substrate processing apparatus. 13. A vacuum container provided with a first electrode and a second electrode, which is arranged facing the first electrode and on which a substrate to be processed is installed, and a predetermined gas in the vacuum container. A gas supply means for introducing a gas, a vacuum evacuation means for maintaining a reduced pressure in the vacuum container, an electric field generation means for generating an electric field between the first and second electrodes, and the first and second electrodes And a magnetic field generating means for generating a magnetic field between the magnetic field generating means and the magnetic field generating means, the magnetic field generating means forms a ring, and a plurality of magnet elements arranged so that the magnetizing direction can rotate once around a half circumference of the ring. A substrate processing apparatus comprising: a diameter changing means for changing a diameter of the ring formed by the plurality of magnet elements. 14. A vacuum container provided with a first electrode and a second electrode on which a substrate to be processed, which is arranged facing the first electrode, is installed; and a predetermined gas in the vacuum container. A gas supply means for introducing a gas, a vacuum evacuation means for maintaining a reduced pressure in the vacuum container, an electric field generation means for generating an electric field between the first and second electrodes, and the first and second electrodes And a magnetic field generating means for generating a magnetic field between the magnetic field generating means and the magnetic field generating means, and the magnetic field generating means forms a ring, and the direction of the magnetization component in a plane perpendicular to the central axis of the ring is equal to one half of the ring. At least one of the plurality of magnet elements facing each other includes a plurality of magnet elements arranged so as to be rotatable.
A substrate processing apparatus, characterized in that a pair of magnet elements have a magnetization component in the direction of the central axis of the ring, and the sizes of the components are substantially equal and their directions are opposite to each other. 15. A vacuum container provided with a first electrode and a second electrode on which a substrate to be processed is arranged facing the first electrode, and a predetermined gas in the vacuum container. A gas supply means for introducing a gas, a vacuum evacuation means for maintaining the inside of the vacuum container under reduced pressure, an electric field generation means for generating an electric field between the first and second electrodes, and the first and second Magnetic field generating means for generating a magnetic field between the magnetic field generating means and the electrode of the plurality of magnetic field generating means, the magnetic field generating means forming an annular shape on the outer circumference, and the magnetizing direction is arranged so as to be rotatable once around the half circumference of the ring. And a dividing member that is provided on the outer periphery of the substrate to be processed and divides the space inside the vacuum container into a region including the substrate to be processed and a region not including the substrate in the radial direction of the ring. A substrate processing apparatus characterized by: