JP3438003B2 - Plasma processing equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a plasma processing apparatus.

[0002]

2. Description of the Related Art Regarding a plasma processing apparatus, for example, it has been widely used for the surface treatment of a semiconductor wafer (hereinafter referred to as a "wafer") in the semiconductor manufacturing process. A so-called parallel plate type plasma processing apparatus is used in large numbers because it has advantages such as excellent uniformity and processing of a large-diameter wafer, and the apparatus configuration is relatively simple.

In the conventional general parallel plate type plasma processing apparatus, electrodes are provided parallel to each other in the upper and lower parts of a processing chamber, and a wafer to be processed is mounted on, for example, a lower electrode. In the case of etching treatment, for example, an etching gas is introduced into this treatment chamber, and high-frequency power is applied to the electrodes to generate plasma between the electrodes, and etchant ions generated by dissociation of the etching gas It is configured to etch the wafer. In such a case, the etching gas is directly discharged toward the wafer from a large number of holes of a gas diffusion plate which constitutes a discharge portion provided on the surface of the upper electrode facing the wafer.

By the way, the processing by plasma processing is
With higher integration of semiconductor devices, finer processing, higher processing speed, and more uniform processing are required.
Therefore, it is necessary to increase the density of the plasma generated between the electrodes. Furthermore, the silicon oxide film (S
When forming a contact hole in iO ₂ ), extremely high selectivity is required.

With respect to the above points, for example, JP-A-57-15
No. 9026 “Dry etching method” discloses a magnetron type plasma processing apparatus using a magnetron as a new plasma generation method, and Japanese Patent Publication No. 58-12346 “Plasma etching apparatus” discloses a normal electrode. Besides, a configuration in which a common anode electrode having a grid shape or the like is adopted between the upper and lower electrodes is disclosed. The lower electrode of the conventional electrode of this type of device is generally made of aluminum, while the upper electrode is made of carbon.

[0006]

However, in the above-mentioned magnetron type plasma processing apparatus, it is possible to obtain a high density plasma in a relatively high vacuum, but the magnetic field changes considerably slower than the frequency of the high frequency electric field. Therefore, the plasma state changes in accordance with the change in the magnetic field, and this change causes changes in the energy and directionality of the ions, which may cause element damage or deterioration of the processed shape.
In addition, the common anode configuration has an advantage that the ion energy and the current density can be controlled independently, but the plasma diffuses through the grid, the ion current density incident on the wafer decreases, and the processing rate decreases. There was a risk of loosening or uneven processing. When high-frequency, high-vacuum atmosphere is created due to high fine processing, the impedance between the electrode and the inner wall of the processing vessel is lowered, and the environment in which plasma is more likely to diffuse becomes.

When the plasma diffuses in the processing chamber as described above, not only the plasma density is lowered but also metal contamination occurs on the inner wall of the processing chamber to contaminate the wafer to be processed. I will end up. Such a tendency becomes more remarkable in the plasma processing under the high decompression degree necessary for high fine processing which will be required more and more in the future.

The present invention has been made in view of the above points, and in order to satisfactorily perform high-precision plasma processing as described above, plasma is adopted while adopting a relatively simple parallel plate type apparatus configuration. Does not diffuse into the processing chamber,
The purpose is to confine it in the space between the electrodes to achieve a high plasma density and to prevent contamination on the inner wall of the processing chamber.

[0009]

According to a first aspect of the present invention, in order to achieve the above object, plasma is generated by high frequency power in a processing chamber, and an object to be processed on a susceptor in the processing chamber is processed. In the configured plasma processing apparatus, an annular first magnetic field forming unit arranged concentrically with the susceptor is provided around the susceptor, and a second magnetic field forming unit is provided between the first magnetic field forming unit and the second magnetic field forming unit via a gap. Magnetic field forming means are arranged to face each other, and the first magnetic field forming means and
The second magnetic field forming means has a plurality of magnets arranged in an annular shape.
The magnet is provided inside the insulator, and
A plasma processing apparatus is provided, wherein a magnetic body is provided inside the insulator .

The first magnetic field forming means and the second magnetic field forming means each have a plurality of magnets arranged annularly, and the magnetic poles of the facing magnets are different from each other .
A magnetic body is provided on the upper end of the magnet forming the magnetic field forming means of FIG.
Only it may be. The first magnetic field forming means and the second magnetic field forming means each have a plurality of magnets arranged annularly,
The magnetic poles of the facing portions of the facing magnets may be different from each other, and the magnetic poles of the facing portions of the adjacent magnets may also be different from each other.

When the magnets are arranged in a substantially annular shape, the magnetic field strength at the peripheral portion of the object to be processed generated by the magnets is 1
It is preferably 0 Gauss or less. Further, in each plasma processing apparatus configured as described above, high frequency power for generating plasma may be applied to the first electrode and the second electrode, respectively.

In each of the above plasma processing apparatuses,
The output of the high frequency power may be configured to be modulated periodically, and the output modulation width in such a case is such that the output at the minimum is in the range of 1/2 to 1/5 of the output at the maximum. It is possible to obtain a more preferable result by setting.

In the plasma processing apparatus described above, the first electrode constitutes an upper electrode and the second electrode constitutes a lower electrode, relative high frequency power is applied to the upper electrode, and the lower electrode is applied to the lower electrode. Relative low frequency power may be applied, and the gap length between the upper electrode and the lower electrode may be set to 10 to 40 mm.

Relative high frequency power means a frequency of 10 to 4
The power of 0 MHz is referred to, and the relative low frequency power refers to the power having a frequency of 300 kHz to 3 MHz.

Further, in the case of applying to both upper and lower sides,
It is preferable to configure the upper electrode so that it is applied before the lower electrode, or to stop the power application, if the lower electrode is configured so as to be stopped before the upper electrode. can get.

In each of the above plasma processing apparatuses, the processing chamber pressure may be freely set to 5 mTorr to 100 mTorr.

According to the plasma processing apparatus of the present invention, the first
In order to generate a local magnetic field between the peripheral edge of the second electrode and the peripheral edge of the second electrode, magnetic field generating means are provided at the peripheral edge of the first electrode and the peripheral edge of the second electrode, respectively. So the first,
A local magnetic field is formed around the space between the second electrodes, which traps charged particles in the plasma and prevents the diffusion of the plasma. In addition, a plurality of magnets are arranged in a substantially annular shape in the vicinity of the first and second electrodes, respectively, and a magnet arranged on the first electrode side and a magnet arranged on the second electrode side are opposed to each other. By making the magnetic poles of the opposing magnets different from each other, a local magnetic field is formed in the peripheral portion of the space between the circumferences of the first and second electrodes, which causes charging in the plasma. It becomes possible to trap particles and prevent plasma diffusion.

Further, regarding the arrangement of the magnets described above, the magnetic poles between the adjacent magnets are not limited to the opposing side of the magnets arranged on the first electrode side and the magnets arranged on the second electrode side. Since they are also different from each other, the trap system of charged particles by the magnetic field becomes dense, and a higher plasma diffusion prevention effect can be obtained.

The magnetic field strength of the peripheral portion of the object to be processed generated by the magnets respectively arranged as described above is 10 Gauss.
When the following settings are made, the desired plasma processing can be performed without affecting the plasma in the plasma processing region of the object to be processed such as a wafer.

If the high frequency power is applied to the first electrode and the second electrode in each plasma processing apparatus, it is easy to independently change the voltage of each high frequency power. .

Further, in each of the above plasma processing apparatuses, if the output of high frequency power is periodically modulated,
It is possible to repeat high and low plasma densities and control dissociation of gas components in plasma. For example, in etching processing of contact holes, the etching progresses at high output, while at the time of low output It is possible to adopt a process of discharging the etching reaction product of. Therefore, it is possible to perform etching with excellent vertical anisotropy while increasing the etching rate and suppressing the difference in size between the hole bottom and the hole entrance.

In such output modulation, if the output at the minimum is set to be in the range of 1/2 to 1/5 of the output at the maximum, the plasma reaction state is maintained and the etching reaction product is maintained as such. Can be in a preferable state for discharging.

If the gap length between the upper electrode and the lower electrode is set to 10 to 40 mm and relative high frequency power and relative low frequency power are applied to the vertically opposed electrodes respectively to generate plasma, It is possible to perform a process that is well balanced with respect to etching rate, uniformity, and plasma stability. Also, the gap length is 15 to 30 mm,
Especially, if it is set to around 25 mm, a more preferable result can be obtained.

When applying to both the upper electrode and the lower electrode, the upper electrode is applied first, and the lower electrode is applied later than that to generate the plasma. An excessive voltage is not applied to the object to be processed placed on the electrode, plasma is easily generated, and there is little risk of damaging the object to be processed.

Also, when the plasma is extinguished, if the applied power on the lower electrode side is stopped first, and then the applied power on the upper electrode side is stopped with a delay, the deposition does not proceed and the object to be processed is not advanced. It becomes possible to prevent damage. In short, if such an application and stop sequence is adopted, the condition in which a voltage is applied only to the lower electrode on which the object to be processed is placed is avoided, so that the object to be processed can be protected from excessive voltage. is there. If the timing for delaying is set to, for example, 1 second or less, the desired effect can be obtained.

If the matching means is constructed so as to control the impedance and the phase independently of each other, it becomes difficult to be affected by the disturbance and it is easy to match the load fluctuation.

The pressure in the processing chamber is set to 5 mTorr-100
Highly fine processing is possible under a high degree of vacuum by configuring mTorr freely.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings, which schematically shows a cross section of an etching processing apparatus 1 which is a premise of the embodiment. , The so-called parallel plate type etching device in which the electrode plates face each other in parallel.

The etching processing apparatus 1 has a processing container 2 which is formed into a cylindrical shape and is made of, for example, aluminum whose surface is anodized, and which is grounded. At the bottom of the processing chamber formed in the processing container 2, a substantially columnar shape for mounting an object to be processed, for example, a semiconductor wafer (hereinafter referred to as “wafer”) W via an insulating plate 3 made of ceramic or the like. The susceptor support base 4 is housed therein, and the susceptor 5 constituting a lower electrode is provided on the upper part of the susceptor support base 4.

A coolant chamber 6 is provided inside the susceptor support 4, and a coolant for temperature control such as perfluoropolyether can be introduced into the coolant chamber 6 through a coolant introduction pipe 7. The introduced cooling medium circulates in the cooling medium chamber 6, and the cold heat generated during the cooling medium is transferred from the cooling medium chamber 6 to the wafer W through the susceptor 5, and a desired processing surface of the wafer W is obtained. It is possible to cool to temperature.

The central portion of the upper surface of the susceptor 5 is formed in a convex disk shape, and an electrostatic chuck 11 having substantially the same shape as the wafer W is provided thereon. This electrostatic chuck 11
Has a structure in which a conductive layer 12 is sandwiched between two polymer polyimide films, and for this conductive layer 12, a DC high voltage power supply 13 installed outside the processing container 2 By applying a DC high voltage of 0.5 kV, the wafer W placed on the upper surface of the electrostatic chuck 11 is attracted and held at that position by the Coulomb force.

An annular focus ring 15 is arranged around the upper end of the susceptor 5 so as to surround the wafer W placed on the electrostatic chuck 11. The focus ring 15 is made of an insulating material that does not attract reactive ions, and is configured so that the reactive ions generated by the plasma are effectively incident only on the wafer W inside thereof.

Above the susceptor 5, the upper electrode 21 is opposed to the susceptor 5 in parallel with the susceptor 5 at a position separated from the susceptor 5 by about 15 to 20 mm, and the insulating material 22 is interposed between the upper electrode 21 and the upper electrode 21. It is supported at the top. The upper electrode 21 has a large number of diffusion holes 2 on the surface facing the susceptor 5.
3, an electrode plate 24 made of, for example, SiC or amorphous carbon, and an electrode support 25 made of a conductive material supporting the electrode plate 24, for example, aluminum whose surface is anodized.

A ground electrode 27, which serves as a third electrode as shown in FIG. 2, is provided on the outer periphery of the electrode support 25 via an annular insulating material 26. As shown in FIG. 1, the ground electrode 27 is installed with its lower end holding a gap through which the wafer W can pass between the lower end and the upper end of the focus ring 15 described above. 1, as shown in FIG. 2, it has a form protruding inward.
The ground electrode 27 is the same as the susceptor 5 and the electrode plate 2.
4 is arranged so as to surround the space area between the side and the side.

A gas introduction port 28 is provided at the center of the support plate 25 in the upper electrode 21, and a gas introduction pipe 29 is connected to the gas introduction port 28. A gas supply pipe 30 is connected to the gas introduction pipe 29,
Further, the gas supply pipe 30 is branched into three and communicates with the corresponding process gas supply sources 37, 38 and 39 via valves 31, 32 and 33 and mass flow controllers 34, 35 and 36, respectively. .

In this embodiment, CF ₄ gas is supplied from the processing gas supply source 37 and Cl is supplied from the processing gas supply source 38.
The gas and processing gas supply source 39 is set to supply N ₂ gas which is an inert purge gas.

An exhaust pipe 41 is connected to the lower portion of the processing container 2, and an exhaust pipe 44 of a load lock chamber 43 adjacent to the processing container 2 via a gate valve 42, a turbo molecular pump or the like. It communicates with the vacuum evacuation means 45, and is constructed so that it can be evacuated to a predetermined reduced pressure atmosphere. The wafer W, which is an object to be processed, is transferred between the processing container 2 and the load lock chamber 43 by the transfer means 46 such as a transfer arm provided in the load lock chamber 43. ing.

The high frequency power for generating plasma in the processing container 2 of the etching processing apparatus 1 is supplied by two high frequency power supplies 51, 52 which oscillate a high frequency of 13.56 MHz, for example. That is, high frequency power source 5
1 is configured to apply high frequency power to the upper electrode 21 via the matching unit 53, and the high frequency power supply 52 is configured to apply high frequency power to the susceptor 5 via the matching unit 54. There is. Note that the upper electrode 21,
Since high frequency power is applied to the susceptor 5 by independent high frequency power supplies, the voltages applied to the upper electrode 21 and the susceptor 5 are independently variable.

Further, between the matching unit 53 and the upper electrode 21, and between the matching unit 54 and the susceptor 5, phase detecting means 55, 56 for detecting the phase signals of the high-frequency power currents respectively applied. Are provided respectively. The phase signals detected by the phase detecting means 55 and 56 are input to the phase controller 57, and the phase controller 57 supplies the high-frequency power sources 51 and 52 described above based on the detected phase signals. On the other hand, they are so controlled as to oscillate high frequencies whose phases are different by 180 °.

The etching processing apparatus 1 is configured as described above. For example, in the case where the etching processing apparatus 1 is used to etch a silicon oxide film (SiO ₂ ) on a wafer W having a silicon substrate. To explain, first, the wafer W, which is the object to be processed, is loaded into the processing container 2 from the load lock chamber 43 by the transfer means 46 after the gate valve 42 is opened, and placed on the electrostatic chuck 11. . The wafer W is adsorbed and held on the electrostatic chuck 11 by the application of the high voltage DC power supply 13. After that, the transport means 46 moves the load lock chamber 43
After retracting inward, the inside of the processing container 2 is evacuated by the exhaust means 45.

On the other hand, the valve 31 is opened and the flow rate thereof is adjusted by the mass flow controller 34, while the CF ₄ gas is supplied from the processing gas supply source 37 to the gas supply pipes 30 and
The upper electrode 21 through the gas introduction pipe 29 and the gas introduction port 28
And is uniformly ejected onto the wafer W through the diffusion holes 23 of the electrode plate 24, as shown by the arrow in FIG.

The pressure inside the processing container 2 is, for example, 1 Pa.
After being set and maintained at a high frequency, the high frequency power supplies 51 and 52 are activated, and high frequency powers having current phases different from each other by 180 ° are applied to the upper electrode 21 and the susceptor 5, respectively, and the upper electrode 21 and the susceptor 5 are Plasma is generated between
The wafer W is subjected to predetermined etching by radical components generated by dissociating the CF ₄ gas introduced into the processing container 2.

The plasma in the etching process is generated between the upper electrode 21 and the susceptor 5 as described above. As described above, the ground electrode 27 forms the space region between the upper electrode 21 and the susceptor 5. Are arranged so as to surround from the side, so that the ions that try to diffuse from the space area are attracted by the ground electrode and do not diffuse to the outside of the space area, for example, the inner wall of the processing container 2. Therefore, the plasma density in the space area, that is, the processing area for the wafer W can be maintained high, which enables highly fine processing of the wafer W.

Moreover, since the diffusion of ions to the inner wall of the processing container 2 is suppressed, during the processing, the processing container 2
The inner wall is not etched and the reaction product is attached, so that the inner wall is not contaminated and the inside of the processing container 2 is not contaminated. Therefore, the yield does not decrease from this point.

The high-frequency power applied to the upper electrode 21 and the susceptor 5 to generate plasma is
Since the current phases are different by 180 °, high-frequency power can be applied to the plasma regardless of the type of processing gas and the degree of pressure reduction, and the ion current density incident on the wafer W can be increased.

That is, when the phase difference of the frequency of the high frequency power applied between the electrodes facing each other is changed, the plasma state changes (for example, Japanese Patent Laid-Open No. 2-224239). For example, when the voltage phases of the two high frequency powers are almost the same, the plasma spreads, the density becomes low, and the processing speed decreases. On the other hand, when the voltage phase difference is shifted by 180 °, the plasma density becomes high. However, for example, when the frequencies are 380 kHz and 13.56 MHz, the voltage phase difference at which the plasma density becomes highest is different. It is considered that this is because the impedance of plasma changes.

Similarly, when the composition of the processing gas is changed,
The characteristic of the ionization cross section of the gas or the characteristic difference of the dissociation also changes the impedance of the plasma and changes the optimum voltage phase difference. Therefore, in the conventional method of controlling the voltage phase and applying high-frequency power, there is a voltage relationship in which the current flowing from one electrode due to such a change in plasma impedance flows into the counter electrode due to the phase difference. If it is not present, it is difficult to realize the state with the highest plasma density, because it diffuses to the inner wall of the processing container other than the counter electrode.

In this respect, by controlling the current phases different by 180 ° as described above, one electrode, for example, the upper electrode 21 is changed from the upper electrode 21 to the susceptor 5 which is the other counter electrode, regardless of the change in the plasma impedance. When attempting to flow in, the phase of the susceptor 5 has a relation that the current can flow, so the current flows efficiently, and as a result, the plasma is confined between the upper electrode 21 and the susceptor 5 and its density is high. It will be.

Moreover, in the etching apparatus 1, since the plasma is confined by the ground electrode 27 as described above, it is possible to realize an extremely high plasma density in cooperation with each other, and to perform high fine processing. It is possible.

The ground electrode 27 used in the etching apparatus 1 had a shape that was convexly formed inward, but instead of this, for example, as shown in FIG. 3, a simple cylindrical ground electrode is used. 61, through the insulating material 62,
It may be arranged such that it is arranged on the outer periphery of the electrode support 25 and the processing container 2 which is grounded and the ground electrode 61 are fixed to each other.

Further, in order to make the space between the opposing electrodes a more closed space, the height of the ground electrode may be further increased to form a cylindrical shape. In such a case, a plurality of through holes 64 are formed around the ground electrode 63 as shown in FIG. 4 in order to ensure sufficient exhaust of the processing gas introduced into the space between the counter electrodes. Preferably.

Further, as another example of the ground electrode which confines the plasma between the opposed electrodes and does not diffuse it to the surroundings, the ground electrodes 65 and 66 as shown in FIG. 5 may be used.
As can be seen from the figure, the ground electrodes 65 and 66 each have a substantially ring shape, and the ground electrode 65 is arranged on the outer circumference of the upper electrode 21, and the ground electrode 66 is arranged on the outer circumference near the upper end of the susceptor 5. It is arranged (in this case, the structure above the so-called exhaust ring may be provided). As a result, charged particles that try to diffuse from the upper electrode 21 are attracted to the ground electrode 66, and charged particles that try to diffuse from the susceptor 5 are attracted to the ground electrode 65. As a result, the upper electrode 21 and the susceptor 5 are The plasma generated during this time does not diffuse to the inner wall of the processing container 2.

Further, the ground electrodes 67 and 68 shown in FIG.
Instead of the shape of the electrode, the electrode has a ring shape and the cross section is formed into a substantially triangular shape so as to form an inclined surface. According to the ground electrodes 67 and 68 having such a configuration, for example, the upper ground electrode 67 has an inner sloped surface facing the direction of the susceptor 5, so that it is better than the ground electrode 65 shown in FIG. Can attract charged particles efficiently,
Further, the plasma diffusion preventing effect is improved.

The ground electrode shown in FIGS. 5 and 6 is
Both of them have a vertically opposed structure, but the plasma diffusion prevention effect can be obtained without necessarily having such a structure.

In the above-mentioned example, as the means for preventing the plasma diffusion, the upper electrode 21 and the third electrode other than the susceptor 5 are provided, but instead of this, for example, FIG.
As shown in, the magnets may be arranged to face each other around the vicinity of the upper electrode 21 and the susceptor 5. That is, the upper electrode 21 has an annular insulating member 7 on the outer periphery of the lower end of the electrode support 25.
1 is provided, and substantially cylindrical permanent magnets 72 shown in FIG. 8 are provided inside the insulating member 71 in an annular shape at equal intervals. In this embodiment, as shown in FIG. 7, the N poles of all the permanent magnets 72 are located on the lower surface side, that is, the susceptor 5 side, and the intervals for annular arrangement are shown in FIG. As described above, the central angle θ formed by another adjacent permanent magnet
Is set to be 10 °.

On the other hand, as shown in FIG. 7, an annular insulating member 73 is also provided on the outer periphery of the upper end of the susceptor 5, and the insulating member 73 has the same shape, the same size, and the same magnetic force as the permanent magnet 72. The permanent magnets 74 are provided in the same number and at the same intervals so as to face the permanent magnets 72. The magnetic poles of the permanent magnets 74 arranged on the susceptor 5 side are different from the magnetic poles of the facing portion of the permanent magnet 72, that is, the S poles are located on the upper electrode 21 side. Therefore, the relationship between the magnetic poles of the permanent magnets 72 and 74 is
It is as shown in FIG.

By arranging the magnets in this way, a local magnetic field is generated between the peripheral portion of the upper electrode 21 and the peripheral portion of the susceptor 5, and the magnetic field causes charging in the space between the upper electrode 5 and the susceptor 5. Particles can be trapped from jumping out, and the plasma can be confined in the inter-electrode space. If the strength of the magnetic field is too large, the plasma itself may be biased and may affect the plasma processing itself. Therefore, the magnetic field strength in the peripheral portion of the wafer W, which is the object to be processed, should be 10 Gauss or less. It is desirable to set.

In order to make the above-mentioned local magnetic field form more preferable, as shown in FIG.
For example, a magnetic body 75 may be provided on the upper end of the permanent magnet 72 so that the magnetic body 75 can be used together with the permanent magnet 72.

Further, in the example shown in FIGS. 7 and 10, the permanent magnet 72 arranged on the upper electrode 21 side and the permanent magnet 74 arranged on the susceptor 5 side are different from each other in the vertical direction. Although the magnetic poles have the same magnetic poles, the adjacent magnets have the same magnetic poles. Instead, as shown in FIG. 12, the adjacent magnets are arranged so that the magnetic poles are different from each other. If so, a further preferable effect can be obtained. That is, by arranging as shown in FIG. 12, magnetic flux is generated not only in the vertically opposing portions but also in the adjacent opposing portions,
This makes the trap system for charged particles more dense.
Therefore, the plasma confinement action is further improved as compared with the case of FIG.

By the way, as described above, finer processing is now required in the manufacturing process of semiconductor devices as they are highly integrated. For example, even when a contact hole is formed by etching, fine processing is required so that the hole diameter is 0.3 μm and the hole depth is 1 to 2 μm.

However, in the conventional parallel plate type plasma apparatus, since the high frequency power having a constant output is always applied, when the hole diameter becomes small as shown in FIG. 13, as shown in FIG. It becomes difficult for Z to be discharged, and Z is deposited on the bottom of the hole 81 and in the vicinity of the bottom, and the replacement with the etching gas cannot be performed smoothly. As a result, as shown in FIG.
However, there was a problem that the shape of was a truncated cone shape or the etching rate decreased, and it was not possible to perform fine processing corresponding to high integration.

In order to deal with such a problem, for example, by controlling the outputs of the high frequency power supplies 51 and 52 in the plasma processing apparatus 1, as shown in the graph of FIG.
The output may be applied to the upper electrode 21 and the susceptor 5 by repeating the magnitude of the output every 10 ms. In FIG. 14, the maximum output is controlled to 1000 w, and the minimum output is controlled to ⅕ that of 200 w. By controlling in this way, the plasma density is increased when the power is high to advance the etching, and the plasma density is decreased when the power is low to discharge the etching reaction products generated in the holes 82 shown in FIG. This facilitates the replacement with the etching gas and makes it possible to form a hole having the same diameter at the inlet and the bottom of the hole 82 as shown in FIG. The maximum and minimum of the power and the cycle thereof may be appropriately selected according to the size of the target hole, the material, the type of processing gas, and the like.

The above etching processing apparatus 1 uses two high-frequency power sources for generating plasma, and uses the upper electrode 21.
And a high frequency is applied to the susceptor 5, but if it is configured so that one of the electrodes is always grounded and only the other electrode is applied by switching, one device The configuration makes it possible to carry out two different modes of etching.

It is also possible to perform such switching using one high frequency power source. The example shown in FIG. 16 is an etching processing apparatus 9 capable of performing such two different modes of etching processing using one high frequency power supply 91.
2, the upper electrode 94 and the lower electrode 95 are vertically opposed to each other in the grounded processing container 93 which can be decompressed. And, in the upper part of this processing container 93,
The first vacuum relay 96 is housed in the shield box 97, and is responsible for switching connection between the upper electrode 94 and the high frequency power supply 91 or the processing container 93.

In the matching box 98, the second
A vacuum relay 99 is housed therein, and is responsible for switching the lower electrode 95 to the high frequency power supply 91 or the ground side and switching the path of the high frequency power supply 91 leading to the first vacuum relay 96 between ON and OFF.

Etching processing apparatus 9 having such a configuration
According to 2, R in which the DC bias is large in the state of FIG.
In the IE (reactive ion etching) mode, the upper electrode 94 is grounded, and the high frequency power from the high frequency power source 91 is applied to the lower electrode 95, so that the object to be processed such as a wafer existing between the electrodes is processed. It is possible to perform fine processing in a high vacuum region and etching with high controllability for vertical shapes.

When the first vacuum relay 96 and the second vacuum relay 99 are switched to the PE (plasma etching) mode with a small DC bias shown in FIG. 17, the lower electrode 95 is grounded and the upper electrode 94 is supplied with a high frequency power source. By applying the high frequency power from 91, it is possible to perform an etching process with high dimensional control with little damage to the object to be processed such as a wafer existing between the electrodes. Therefore, the first
By simply switching between the vacuum relay 96 and the second vacuum relay 99, it is possible to continuously perform two different etching processes on the same object to be processed in the same processing chamber, thereby expanding the application of the process. Can be achieved.

In the above-described embodiment, the case where the object to be processed is a semiconductor wafer has been described, but the present invention is not limited to this, and the present invention can also be applied to an apparatus configuration in which an LCD substrate is an object to be processed.

[0069]

According to the present invention, the plasma can be prevented from diffusing to the surroundings from the inter-electrode space in the processing chamber, the plasma density in the processing region can be increased, and the contamination on the inner wall of the processing chamber can be prevented. Nation does not occur. A local magnetic field is formed around the space between the first and second electrodes, which traps charged particles in the plasma and prevents the diffusion of the plasma. Moreover, since the magnetic bodies are provided in the first and second magnetic field forming means for forming the magnetic field, the form of the magnetic field can be made more preferable.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view of an etching processing apparatus which is a premise of an embodiment of the present invention.

FIG. 2 is a partially cutaway perspective view of a ground electrode used in the etching processing apparatus of FIG.

FIG. 3 is a cross-sectional explanatory view of a processing container using a ground electrode having another structure.

FIG. 4 is a perspective view of a ground electrode having a through hole.

FIG. 5 is a cross-sectional explanatory view of a processing container using a facing type ground electrode.

FIG. 6 is a cross-sectional explanatory view of a processing container that uses a facing-type ground electrode having a sloped portion inside.

FIG. 7 is an enlarged cross-sectional view of essential parts near an upper electrode and a susceptor when a permanent magnet is used as a plasma diffusion preventing means.

FIG. 8 is a perspective view of the permanent magnet shown in FIG.

9 is a bottom view of the insulating member showing how the permanent magnets of FIG. 7 are arranged.

10 is an explanatory diagram showing a state of magnetic pole arrangement of the permanent magnet of FIG. 7. FIG.

11 is a cross-sectional explanatory view showing a state in which a magnetic body is attached to the permanent magnet of FIG.

FIG. 12 is an explanatory diagram showing another magnetic pole arrangement state of a permanent magnet.

FIG. 13 is a cross-sectional explanatory view of a contact hole formed by etching according to a conventional technique.

FIG. 14 is a graph showing a state of output modulation of high-frequency power applied in another embodiment.

FIG. 15 is an explanatory cross-sectional view of a contact hole formed according to the embodiment of the present invention.

FIG. 16 is an explanatory diagram of another embodiment of the present invention in the RIE mode.

FIG. 17 is an explanatory diagram of another embodiment of the present invention in the PE mode.

[Explanation of symbols] 1 Etching processing equipment 2 processing vessels 5 susceptor 15 Focus ring 21 upper electrode 27 Ground electrode 51,52 High frequency power supply 55,56 Phase detection means 57 Phase Controller 72 Permanent magnet 75 Magnetic W wafer

Front page continuation (31) Priority claim number Japanese Patent Application No. 6-252963 (32) Priority date September 20, 1994 (September 20, 1994) (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 7-29940 (32) Priority date January 25, 1995 (January 25, 1995) (33) Priority claiming country Japan (JP) (72) Inventor Hiroshi Tsuchiya Nirasaki, Yamanashi Prefecture City, Fujii-machi, 2381, Kitashitajo, Tokyo Electron Yamanashi Co., Ltd. (72) Inventor Masayuki Tomoyasu, Yamanashi, 1 Narasaki, Fujii, 1-3, Kitashitajo, Tokyo Electron Yamanashi, Ltd. (72) Inventor, Yukio Naito Yamanashi 1 2381 Kitashitajo Kitajojo, Fujii-cho, Nirasaki Tokyo Electron Yamanashi Co., Ltd. (72) Inventor Kazuya Nagaseki 1238-1 Kitashitajo Kitashitajo, Fujii-cho, Narasaki City, Yamanashi Prefecture Tokyo Electron Yamanashi Co., Ltd. (72) Inventor Ryu Nonaka No. 2381 Kitashitajo, Fujii-cho, Nirasaki-shi, Yamanashi Tokyo Electron Yamanashi Corporation (72) Inventor Keizo Hirose Kitashitajo, Fujii-cho, Nirasaki-shi, Yamanashi No. 2381 1 In Tokyo Electron Yamanashi Co., Ltd. (72) Inventor Yoshio Fukasawa Kitashitajo Fujii-cho, Nirasaki City, Yamanashi Prefecture 2381 No. 1 Tokyo Electron Yamanashi Co., Ltd. (72) Inventor Koshiishi Kitashitajo Fujii-cho, Narasaki City Yamanashi Prefecture No. 2381 No. 1 Tokyo Electron Yamanashi Co., Ltd. (72) Inventor Isao Kobayashi No. 2381 Kitashitajo, Fujii-cho, Nirasaki City, Yamanashi No. 1 No. 1 Tokyo Electron Yamanashi Co., Ltd. (56) Reference JP-A-5-211137 (JP, A) ) JP-A-3-4528 (JP, A) JP-A-62-69621 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/3065 H05H 1/46

Claims (3)

(57) [Claims] 1. A plasma processing apparatus configured to generate plasma by high-frequency power in a processing chamber to process an object to be processed on a susceptor in the processing chamber, wherein the susceptor is concentric with a periphery of the susceptor. provided with a first magnetic field forming means disposed Jo annular, second magnetic field generator placed opposite through the first magnetic field generator and the gap, the first magnetic field forming means and the second The magnetic field forming means of
A plasma processing apparatus comprising a plurality of magnets arranged in an annular shape, the magnets being provided inside an insulator, and a magnetic material being provided inside the insulator . 2. Plasma is generated in the processing chamber by high frequency power.
To the object to be processed on the susceptor in the processing chamber
In a plasma processing apparatus configured to perform processing, the plasma processing apparatus is arranged around the vicinity of the susceptor in a concentric pattern with the susceptor.
And a first annular magnetic field forming means arranged in
A second magnetic field forming means through the first magnetic field forming means and the air gap.
The steps are arranged to face each other, and the first magnetic field forming means and the second magnetic field forming means are
A plurality of magnets are arranged in a ring, and
The magnetic poles on the opposite side of the stone should be different from each other.
A magnetic body is provided on the upper end of the magnet forming the magnetic field forming means of FIG.
A plasma processing apparatus characterized by the fact that 3. The first magnetic field formation of the opposed magnets.
The means and the second magnetic field forming means are the facing portions of adjacent magnets.
The magnetic poles on the side are also different from each other.
The plasma processing apparatus according to claim 2, further comprising: