TWI390065B - Sputtering device - Google Patents

Description

Sputtering device

The present invention relates to a sputtering apparatus that can perform film formation on a surface of a substrate to be processed, and more particularly, relates to a sputtering apparatus using an alternating current power source.

The sputtering method corresponds to the composition of the film formed on the surface of the substrate, so that the ions in the plasma environment are accelerated to impact on the target of the specific shape, and the target atoms are scattered to form a film on the surface of the substrate. At this time, a voltage is applied to a target of the cathode via a sputtering power source such as a DC power source or an AC power source to generate a glow discharge between the cathode and the anode or the ground electrode to form a plasma environment. However, especially an AC power source is used. At the same time, the phase voltage opposite to the charge accumulated on the surface of the cathode can be offset, so that a stable discharge can be obtained.

For the above reasons, a pair of targets are arranged in the vacuum chamber, and a voltage is applied to the pair of targets at a specific frequency by an alternating current power source to apply a voltage, and the targets are alternately switched between an anode and a cathode, and between the anode and the cathode. A sputtering process is performed to form a plasma environment, and sputtering of each target is known (for example, Patent Document 1).

[Patent Document 1] International Publication No. WO2003/14410 (for example, refer to the first item of the patent application scope).

The above technology is built-in to exchange output for 1 pair of targets. The AC power supply of the oscillation unit for the purpose of power (turning on the power). In general, the AC power source and each target are connected, for example, via a known AC power cable that twists a plurality of wires. At this time, by using the surface effect when the alternating current flows, the frequency of the alternating current power source can be increased, and the effective cross section of the conductor can be reduced to increase the alternating current resistance, thereby increasing the conductor loss, so that it is easy to cause the pair to be aligned from the alternating current power source. The loss of the target input power, in addition to the influence of noise, is also likely to cause a disturbance in the power waveform of the input power to the pair of targets. In this case, the longer the distance between the installation place of the sputtering apparatus main body and the installation place of the AC power supply, the more remarkable the problem arises. As a result, there is a problem that electric power cannot be input to one pair of targets with good precision.

In view of the above circumstances, an object of the present invention is to provide a sputtering apparatus which can perform electric power input with high precision without being affected by the distance between the installation place of the sputtering apparatus main body and the installation place of the AC power supply.

In order to solve the above problems, the sputtering device of the present invention is characterized in that: a pair of targets disposed in a vacuum chamber; and an alternating current power source that applies a voltage by alternately changing polarity with respect to the pair of targets at a specific frequency; The configuration of the AC power source is divided into: a power supply unit that can supply power; and an oscillation unit that has an oscillation switch circuit connected to the power line from the power supply unit; and the oscillation unit and the target are connected by a bus bar. target.

According to the present invention, since the configuration is divided into the power supply unit and the oscillation unit, it is possible to arrange only the oscillation unit that outputs the AC power so as to maintain the distance from the pair of targets at a predetermined short distance. In addition, since the oscillating portion and the respective targets are connected by the bus bar, the surface area of the portion through which the alternating current flows is large, and a large current can be flown without being affected by the surface effect. . As a result, it is less likely to cause a loss of input power than a known thing using an AC power cable, and is less susceptible to noise, and secondly, an AC power source can perform power input to a pair of targets with good accuracy.

In this case, when the surface of the bus bar is covered with a film of Au or Ag, and AC power is supplied, the material having a high conductivity can be used as long as the alternating current flows, so that the cost can be reduced.

Further, if the bus bar is freely expandable and contractible, when the bus bar is installed, the interval error between the oscillating portion and the target can be absorbed, and the bus bar can be easily mounted.

Further, since the distance between the oscillating portion for outputting the alternating current power and each of the targets is kept at a predetermined short distance, the frame of the oscillating portion may be attached to the outer wall of the vacuum chamber.

Further, a plurality of pairs of targets are disposed in the vacuum chamber, and an AC power source is disposed for each pair of targets, and magnetic fluxes are formed in front of the targets, respectively. When a magnet assembly composed of a plurality of magnets that are alternately converted in polarity is disposed after the target, since the AC power supply can directly input power to each pair of targets, it is possible to perform equalization on each target. Sputtering gives a good film formation.

In this case, when the magnetic flux is moved in parallel with the target, and the driving means for integrally driving each of the magnet assemblies is disposed, it is preferable to uniformly etch the respective targets.

As described above, the sputtering apparatus of the present invention is less prone to loss of input power and is less susceptible to noise, and can perform power input to the target with good precision, and does not require an expensive AC power cable. Can reduce the cost effect.

Referring to Fig. 1, reference numeral 1 denotes a magnetron sputtering apparatus (hereinafter simply referred to as "sputtering apparatus") of the present invention. In order to obtain a stable discharge by applying a phase voltage opposite to the charge accumulated on the surface of the target as described later, the sputtering apparatus 1 uses a line type of an alternating current power source. The sputtering apparatus 1 has a vacuum chamber 11 held at a specific degree of vacuum via a vacuum exhausting means (not shown) such as a rotary pump or a turbo molecular pump. A substrate transfer means is disposed above the vacuum chamber 11. The substrate transfer means has a known structure. For example, it has a carrier 2 on which the process substrate S is placed, and drives the drive means intermittently, and sequentially transports the process substrate S to a position facing the target.

A gas introduction means 3 is disposed in the vacuum chamber 11. The gas introduction means 3 communicates with the gas source 33 through the gas pipe 32 in which the mass flow controller 31 is disposed, and the O ₂ and H ₂ O used in the sputtering of Ar and the like and the reactive sputtering at a constant flow rate. The reaction gas of H ₂ , N ₂ or the like is introduced into the vacuum chamber 11 . On the lower side of the vacuum chamber 11, a cathode C is disposed.

The cathode C has a pair of targets 41a and 41b disposed opposite to the processing substrate S. Each of the targets 41a and 41b is formed by a known method using Al, Ti, Mo, ITO, or the like in accordance with the composition of the film formed on the processing substrate S to form a substantially rectangular parallelepiped (a rectangular shape when viewed from above) ). Each of the targets 41a, 41b is bonded to the support plate 42 for cooling the targets 41a, 41b via a bonding material such as indium or tin, and is mounted on the frame of the cathode C via an insulating material not shown. It is disposed in the vacuum chamber 11 in a suspended state.

At this time, the targets 41a and 41b are disposed on the same plane parallel to the processed substrate S of the unused sputtering surface 411, and no anode is disposed between the opposite sides 412 of the respective targets 41a and 41b. Or a component such as a shadow. The external dimensions of the respective targets 41a and 41b are set such that the respective targets 41a and 41b are larger than the size of the processing substrate S.

Further, the cathode C includes a magnet assembly 5 located behind each of the targets 41a and 41b. The magnet assembly 5 has a support plate 51 disposed in parallel with each of the targets 41a and 41b. The support plate 51 is formed of a rectangular plate which is smaller than the lateral width of each of the targets 41a and 41b and has two sides extending along the longitudinal direction of the targets 41a and 41b, and is made of a magnetic material for expanding the adsorption force of the magnet. . On the support plate 51, a rod-shaped central magnet 52 extending in the longitudinal direction of the targets 41a and 41b and a peripheral magnet 53 disposed along the outer edge of the support plate 51 are disposed in a mutually interchangeable polarity manner. In this case, the volume when the same magnetization is converted into the central magnet 52 is equal to, for example, the sum of the volumes converted to the same magnetization of the peripheral magnet 52 (peripheral magnet: center magnet: peripheral magnet = 1:2:1). Design.

Thereby, a closed-loop tunnel-shaped magnetic flux is formed in front of each of the targets 41a and 41b, and electrons that are free in front of the targets 41a and 41b and secondary electrons generated by sputtering are captured to improve each. The electron density in front of the targets 41a, 41b increases the plasma density. Further, the AC power source E is disposed such that the voltage can be applied to the pair of targets 41a and 41b by a specific frequency (1 to 400 kHz) to alternately change the polarity.

However, when the power is supplied to the pair of targets 41a and 41b by the AC power source E, it is necessary to not lose the input power, and it is less susceptible to noise, and the set power can be input with good precision. In the present embodiment, the configuration of the AC power source E is divided into a power supply unit 6 that can supply electric power, and an oscillation unit 7 that outputs a voltage to each of the targets 41a and 41b by alternately changing the polarity at a specific frequency, and the oscillation unit 7 The casing 70 is mounted on the bottom wall of the vacuum chamber 11, and the oscillating portion 7 and the targets 41a, 41b are connected by a bus bar 8 having a specific length as will be described later. At this time, the waveform of the output voltage is a sine wave, however, it is not limited thereto, and may be, for example, a square wave.

As shown in Fig. 2, the power supply unit 6 has a box-shaped housing 60, and the housing 60 has a first CPU circuit 61 for controlling the operation thereof and input commercial AC power (3-phase AC 200V or 400V). The input unit 62 and the six diodes 63 that rectify the input AC power and convert them into DC power have a function of outputting DC power to the oscillation unit 7 via the DC power lines 64a and 64b.

Further, a switching transistor 65 is disposed between the DC power lines 64a and 64b, and is communicably connected to the first CPU circuit 61, and is provided with a switch for controlling the on/off of the switching transistor 65. 1 driver circuit 66a and first PMW control circuit 66b. In this case, a current detecting sensor and a voltage detecting transformer are provided, and a detecting circuit 67a and an AD converting circuit 67b for detecting current and voltage between the DC power lines 64a and 64b are provided, and the detecting circuit 67a and the AD converting circuit are provided. 67b inputs the CPU circuit 61.

On the other hand, the oscillating portion 7 has a box-shaped frame body 70 and is attached to the outer wall of the lower side of the vacuum chamber 11. In the housing 70, a second CPU circuit 71 that is communicably connected to the first CPU circuit 61 is provided, and four oscillation switching circuits 72 that are disposed between the DC power lines 64a and 64b are disposed. 1 to 4th switch switching transistors 72a, 72b, 72c, and 72d; and 2nd to be communicatively coupled to the second CPU circuit 71 for controlling the on/off of each of the switch switching transistors 72a, 72b, 72c, and 72d The driver circuit 73a and the second PMW control circuit 73b.

Next, the second driver circuit 73a and the second PMW control circuit 73b are used to turn on and off, for example, the first and fourth switch switching transistors 72a and 72d and the second and third switching transistor 72b and 72c. The operation of the switching switching transistors 72a, 72b, 72c, and 72d is controlled by the timing inversion, and the AC power of the sine wave is outputted via the AC power lines 74a and 74b from the oscillation switching circuit 72. At this time, the detection circuit 75a and the AD conversion circuit 75b for detecting the oscillation voltage and the oscillation current are provided, and the second CPU circuit 71 is input via the detection circuit 75a and the AD conversion circuit 75b.

The AC power lines 74a, 74b are connected to the output transformer 76 having a known configuration via LC circuits of series or parallel or a combination thereof, and the output terminals 76a, 76b from the output transformer 76 and the pair of targets 41a, 41b are used for convergence. Article 8 is linked. In this case, the current detecting sensor and the voltage detecting transformer are provided with a detecting circuit 77a and an AD converting circuit 77b for detecting the output voltage and output current of the pair of targets 41a and 41b, and the detecting circuit 77a and The AD conversion circuit 77b inputs the second CPU circuit 71. Thereby, in the sputtering, a certain voltage can be applied to the pair of targets 41a and 41b via the AC power source E at a constant frequency and alternately changing the polarity.

Further, the output from the detection circuit 77a is connected to the detection circuit 78a for detecting the output phase and frequency of the output voltage and the output current, and is connected to the output phase frequency control circuit 78b of the detection circuit 78a via a controllable connection. The phase and frequency of the output voltage and the output current are input to the second CPU circuit 71. Thereby, the second driver circuit 73a controls the on/off of each of the switch switching transistors 72a, 72b, 72c, and 73d of the oscillation switching circuit 72 by the control signal from the second CPU circuit 71 to output voltage and output. The phases of the currents are controlled in substantially the same manner.

As shown in Fig. 3, in the configuration of the bus bar 8, the mounting portions 81 and 82 are attached to the two sides of the central portion 81 of the plate shape via the connecting means including the bolt B and the nut N, respectively. The central portion 81 and each of the mounting portions 82 and 83 should be made of the same material having a high electrical conductivity, for example, Cu, Au, Ag or an aluminum alloy.

In this case, the surface area and the thickness of the center portion 81 should be set in consideration of the material of the plate material constituting the center portion 81 and the frequency of inputting electric power and AC power to the targets 41a and 41b when the film forming process is performed by the sputtering apparatus 1. For example (for example, when the length of the central portion 81 is about 300 mm and the width is 40 mm, the thickness thereof is set to 6 mm). On the other hand, in the configuration of the mounting portions 82 and 83, it is conceivable to install the output terminals 76a and 76b and the respective targets 41a and 41b disposed on the output side of the output transformer 76 of the oscillating portion 7, and the width is larger than The plate material of the plate portion of the center portion 81 is bent into a substantially zigzag shape, and is fixed to the output terminal 76a by a connecting means (not shown) such as a bolt through a mounting hole 82a, 83a disposed at one end thereof. 76b and each of the targets 41a, 41b.

Further, at the both ends of the center portion 81 and the other ends of the respective mounting portions 82 and 83, two through holes 81a, 82b, and 83b are formed, and the through holes 81a, 82b, and 83b are aligned in the vertical direction. Both ends of the central portion 81 overlap with one end of each of the mounting portions 82 and 83, and the shaft portion of the bolt B is inserted into each of the through holes 81a, 82b, and 83b, and the nut N is locked at the other end. Connected to each other. At this time, the through hole 82b of one of the mounting portions 82 is a long hole, and the length of the bus bar 8 itself can be adjusted corresponding to the distance between the output terminals 76a and 76b and the respective targets 41a and 41b, that is, the bus bar 8 can be freely Ground expansion and contraction. Thereby, the interval error between the oscillation portion 7 and the targets 41a and 41b can be absorbed, and the installation work of the bus bar 8 can be made easier.

When the bus bar 8 is mounted between the output terminals 76a and 76b and the respective targets 41a and 41b, since the central portion 81 of the through-supporting plate 51 is exposed, the central portion 81 is covered with a known insulating material 9 such as ceramics. .

Thereby, the surface area through which the alternating current flows is large, and a large current can flow without being affected by the surface effect. As a result, compared with the case of using a known AC power cable, it is less likely to cause loss of input power, and it is less susceptible to noise, and secondly, the AC power source E can input power to the pair of targets 41a and 41b with good precision.

Next, the processing substrate S is transported to a position facing the pair of targets 41a and 41b by the substrate transfer means, and the specific sputtering gas is introduced through the gas introduction means 3. An AC voltage is applied to the pair of targets 41a and 41b via the AC power source E, and the targets 41a and 41b are alternately switched to an anode and a cathode, and a glow discharge is generated between the anode and the cathode to form a plasma environment. Thereby, the ions in the plasma environment are acceleratedly impacted toward the targets 41a and 41b on the cathode side, and the target atoms are scattered, and a thin film is formed on the surface of the substrate S.

At this time, in the magnet assembly 5, a driving means such as a motor (not shown) is disposed, and the driving means is used to perform paralleling between two positions along the horizontal direction of the targets 41a, 41b. The speed is moved back and forth to obtain an equal erosion field in the targets 41a, 41b.

In the present embodiment, the configuration in which the bus bars 8 of the two mounting portions 82 and 83 are connected to both sides of the center portion 81 will be described. However, the present invention is not limited thereto, and may be integrally formed. In addition, it is explained in the case of manufacturing a material having high conductivity. However, when AC power is supplied, a high conductivity material such as Au or Ag may be used as long as the part of the alternating current flows, that is, Au or Ag is used. The film covers the surface of the bus bar 8 to reduce the cost.

Further, in the present embodiment, a pair of targets 41a and 41b are disposed in the vacuum chamber 11, but the present invention is not limited thereto, and as shown in Fig. 4, in the vacuum chamber 11a. And the plurality of targets 41a to 41f are set, and the AC power sources E1 to E3 having the same structure are designated for the adjacent targets 41a to 41f, and the pair of the AC power sources E1, E2, and E3 are paired with each other. The present invention can also be applied to the configuration of the sputtering device in which the targets 41a to 41f are powered. At this time, AC power is supplied to each of the targets 41a to 41f by using different AC power sources E1 to E3, and the AC power sources E1 to E3 can respectively input power to each of the pair of targets 41a to 41f with good precision (the respective AC power sources can be used). The input power is substantially uniform. It is possible to perform uniform sputtering on each of the targets 41a to 41f to obtain a good film formation.

1. . . Sputtering device

11. . . Vacuum chamber

41a, 41b. . . Target

6. . . Power supply department

7. . . Oscillation section

8. . . Bus bar

E. . . AC power

Fig. 1 is a schematic explanatory view of a sputtering apparatus of the present invention.

Fig. 2 is an explanatory diagram of the configuration of an AC power source.

Fig. 3 is an exploded perspective view showing the constitution of the bus bar.

Fig. 4 is a schematic explanatory view showing a modification of the sputtering apparatus of the present invention.

1. . . Sputtering device

2. . . Carrier

3. . . Gas introduction means

5. . . Magnet assembly

6. . . Power supply department

7. . . Oscillation section

8. . . Bus bar

11. . . Vacuum chamber

31. . . Mass flow controller

32. . . trachea

33. . . Gas source

41a. . . Target

41b. . . Target

42. . . Support plate

51. . . Support board

52. . . Central magnet

53. . . Peripheral magnet

64a. . . DC power line

64b. . . DC power line

411. . . Sputtered surface

412. . . side

E. . . AC power

Claims (6)

A sputtering apparatus characterized by comprising: a pair of targets disposed in a vacuum chamber; and an alternating current power source that alternately converts polarity to a pair of targets to apply a voltage at a specific frequency; and the composition of the alternating current power source And an electric power supply unit that can supply electric power; and an oscillation unit that has an oscillation switching circuit connected to the electric power line from the electric power supply unit; and the oscillation unit and each target are connected by a bus bar. The sputtering apparatus according to claim 1, wherein the bus bar covers the surface of the film of Au or Ag. The sputtering apparatus according to claim 1 or 2, wherein the bus bar is freely expandable and contractible. The sputtering apparatus according to any one of the preceding claims, wherein the frame of the oscillating portion is mounted on an outer wall of the vacuum chamber. The sputtering apparatus according to any one of claims 1 to 2, wherein a plurality of pairs of targets are provided in the vacuum chamber, and an AC power source is provided for each pair of targets. Further, a magnet assembly including a plurality of magnets provided by alternately changing the polarity is disposed behind each of the targets so that magnetic fluxes are formed in front of the respective targets. The sputtering apparatus according to claim 5, wherein a driving means for integrally driving each of the magnet assemblies is provided, and the magnetic flux is freely moved in parallel with respect to the target.