JP2835323B2 - Power supply for sputtering equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to electronic components, semiconductors,
The present invention relates to a power supply device for a sputtering apparatus for forming a thin film on an optical disk or the like.

[0002]

2. Description of the Related Art A technique for forming a thin film on a semiconductor, an electronic component, a decorative component, or the like by a sputtering apparatus using a sputtering source having a magnet disposed on the back surface of a target has been widely used. In such a sputtering apparatus, for example, an inert gas such as Ar is introduced as a discharge gas into a vacuum chamber, and a sputtering source is arranged in the vacuum chamber.
A magnetron discharge is generated by applying a negative voltage to the sputter source, ionizing the discharge gas introduced into the vacuum chamber, and the ionized argon positive ions are accelerated and collide with the target surface of the sputter source. And
The target surface is sputter evaporated. The sputtered particles are deposited on a substrate to form a thin film made of a target material, which is called sputtering.

[0003] During this sputtering,
The magnetron discharge may change to an arc discharge. As described above, when the magnetron discharge shifts to the arc discharge, sputtering cannot be performed.

Therefore, immediately after the occurrence of the arc discharge, a reverse voltage pulse for maintaining the sputtering source at a slightly positive potential is applied to suppress the occurrence of the arc discharge. Conventionally, the time interval for applying this reverse voltage pulse is 3
0 μs or more.

[0005]

By the way, the time interval for applying the reverse voltage pulse needs to be a certain time interval due to a problem such as protection against destruction due to power loss of the switching element.

However, as described above, even when a reverse voltage pulse is applied at a time interval of 30 μs or more, an arc discharge may immediately and continuously occur, and a continuous arc discharge may occur.
There is a problem that the probability of occurrence of discharge is high.

[0007] When a reverse voltage pulse is applied, a positive voltage is applied to the sputter source, and arc discharge may occur in a reverse direction, for example, from a substrate or the like. When a continuous arc discharge occurs due to the arc discharge in the reverse direction, there is a problem that the substrate is damaged.

The present invention has been made in view of the above points, and an object of the present invention is to set a time interval for applying a reverse voltage pulse to prevent generation of a continuous arc discharge. The object of the present invention is to provide a power supply device for a sputtering apparatus capable of detecting the occurrence of a reverse arc discharge by the reverse voltage pulse within a range of 1 to 10 .mu.s.

[0009]

According to a first aspect of the present invention, there is provided a power supply apparatus for a sputtering apparatus, wherein an inert gas is introduced into a grounded vacuum chamber, and a negative voltage is applied to a sputtering source arranged in the vacuum chamber. In a sputtering apparatus for performing sputtering, a DC power supply for applying a DC voltage to the sputtering source and a reverse voltage for applying a reverse voltage to the sputtering source to stop generation of arc discharge generated during the sputtering. Reverse voltage generating means, a switch means for applying a reverse voltage generated by the reverse voltage generating means to the sputtering source, and an arc discharge detection for detecting the occurrence of arc discharge in the vacuum chamber. When the occurrence of an arc discharge is detected by the means and the arc discharge detection means, the switch means is turned on for a set time, and the arc voltage is generated by the reverse voltage generation means. A reverse voltage generating means for applying a voltage to the sputter source; and a reverse voltage generated by the reverse voltage generating means when the arc discharge is detected by the arc discharge detecting means. Is applied to the sputtering source for a set time, and after the application is completed, if the occurrence of arc discharge is detected again by the arc discharge detection means, the reverse voltage generation means is applied within 1 to 10 μS. And a reverse voltage application control means for applying the reverse voltage generated in (1) to the sputtering source.

[0010] Therefore, the interval between application of the reverse voltage pulse is detected at a time interval of 1 to 10 µs or less when the arc discharge is detected, so that the probability of occurrence of the continuous arc discharge can be extremely reduced. .

According to a second aspect of the present invention, there is provided a power supply apparatus for a sputtering apparatus, comprising: a forward impedance connected between a reverse voltage generating means according to the first aspect and the sputtering source in a direction in which a current of a sputtering discharge flows; A reverse arc discharge prevention circuit having a reverse impedance that is larger than the forward impedance and that is connected in parallel and that prevents the occurrence of a reverse arc discharge is provided.

Therefore, the same operation as in the first aspect can be performed, and when the reverse voltage pulse is applied, the arc discharge current is suppressed so as to suppress the arc discharge current when the reverse arc discharge occurs. Since the reverse impedance is provided in parallel with the directional impedance, the occurrence of the arc discharge in the reverse direction can be suppressed, and the probability of occurrence of the continuous arc discharge can be extremely reduced.

According to a third aspect of the present invention, there is provided a power supply device for a sputtering apparatus according to the second aspect, wherein the forward impedance is a diode and the reverse impedance is a resistor.

Therefore, the same operation as the power supply device for a sputtering apparatus according to the second aspect can be performed. A power supply device for a sputtering apparatus according to claim 4 is provided in claim 2.
A second source connected between the sputter source side of the reverse arc discharge prevention circuit and the positive electrode side of the DC power supply so as to flow current from the anode side of the diode toward the positive electrode side of the DC power supply; And a resistor connected in series to the second diode.

Therefore, the same operation as the power supply device for a sputtering apparatus according to the second aspect can be performed, and when a reverse voltage pulse is applied, the current flowing through the vacuum chamber (sputter source) side and the diode D11 The current flowing on the side can be adjusted by the resistance value r11, so that damage to the substrate due to substrate arc discharge can be prevented.

According to a fifth aspect of the present invention, there is provided a power supply apparatus for a sputtering apparatus, wherein the reverse voltage generating means according to any one of the first to fourth aspects is configured such that the DC power supply is connected to a primary side and the sputtering side is connected to a secondary side. A pulse transformer connected to a power source, wherein a turn ratio between a primary side and a secondary side of the pulse transformer is 1: 1.1 to 1: 1.3.

Therefore, a reverse voltage pulse of 0.1 to 0.3 times the DC power supply can be output from the transformer. According to a sixth aspect of the present invention, in the power supply device for a sputtering apparatus, the reverse voltage generating means according to any one of the first to fourth aspects is configured such that the DC power supply is connected to a primary side and the secondary side is connected to the sputter source. The primary to secondary winding ratio of the auto transformer is 1: 1.1.
１1: 1.3.

Therefore, a reverse voltage pulse of 0.1 to 0.3 times the DC power supply can be output from the transformer. A power supply device for a sputtering apparatus according to claim 7 eliminates the generation of continuous arc discharge of two or more pulses in the vacuum chamber by the reverse arc discharge prevention circuit according to any one of claims 2 to 6. In addition, the transformer is not magnetically saturated by setting the voltage-time product of the transformer as the reverse voltage generating means to four pulses or more.

Therefore, by designing the voltage-time product of the transformer for generating the reverse voltage pulse to be four pulses or more, it is possible to eliminate the magnetic saturation of the transformer for generating the reverse voltage pulse, thereby preventing control failure. be able to.

[0020]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention;
An embodiment will be described. FIG. 1 is a circuit diagram showing a power supply device for a sputtering apparatus. In the figure, reference numeral 11 denotes, for example, an 800 V DC power supply for a sputtering apparatus. The negative electrode of the DC power source 11 is connected to one input terminal of the primary coil 12 ₁ and secondary coil 12 ₂ of the pulse transformer 12 as the reverse voltage generating means. Turns ratio of the primary coil 12 ₁ and secondary coil 12 ₂ 1: 1.1 to 1: is set to 1.3.

The other end of the primary coil 12 ₁ is connected to the emitter of the transistor Q1 as a switching means. The collector of the transistor Q1 is connected to the positive terminal of the DC power supply 11.

Furthermore, between the primary coil 12 ₁ at both ends,
A circuit in which a resistor r1 and a diode D1 are connected in series is connected in parallel. The resistance r1 is for surge absorption,
D1 is for a flywheel.

Furthermore, between the collector of the primary coil 12 ₁ of the one end and the transistor Q1 (or between both electrodes of the DC power supply 11), the capacitor C1 of a large capacity is connected in parallel. Therefore, a voltage equal to the DC power supply 11 is charged at both ends of the capacitor C1.

[0024] In addition, the other end of the secondary coil 12 ₂ is output to case -
Source 1 via _one line 131 in the cable 13
4 is connected. Reference numeral 15 denotes a vacuum chamber in which the sputtering source 14 is disposed. A substrate 16 is provided in the vacuum chamber 15 at a position facing the target of the sputtering source 14. An inert gas such as an argon gas is introduced into the vacuum chamber 15.

Reference numeral 21 denotes a DC power supply for a control circuit. A resistor r is connected between both poles of the control circuit DC power supply 21.
2, a circuit in which a diode D2 connected in the opposite direction is connected in series is connected in parallel. Further, a resistor r3 is connected between the negative electrode of the DC power supply 11 and a connection point between the resistor r2 and the diode D2.

The connection point between the resistor r2 and the diode D2 is connected to the signal input terminal of the control CPU 22 (central processing unit) via the resistor r2a. This CPU 22
Has a built-in counter 22c for timing processing.

Further, between both poles of the DC power supply 21,
A circuit in which a diode D3 connected in the opposite direction to the resistor r4 is connected in series is connected in parallel. Further, the output and the other end of the secondary coil of the pulse transformer 12 Quai - a point on one of the lines 13 ₁ at one end is connected lines Bull 13 A
Is connected to the connection point between the resistor r4 and the diode D3 via the resistor r5.

The connection point between the resistor r4 and the diode D3 is connected to the Schmitt trigger circuit 23 via the resistor r6.
Connected to the input of When the voltage at the point A drops, the output of the Schmitt trigger circuit 23 changes from the “0” level to the “1” level. This is because, when an arc discharge occurs in the vacuum chamber 15, the voltage at the point A drops. The Schmitt trigger circuit 23 constitutes an arc discharge detecting means.

The output of the Schmitt trigger circuit 23 is
The signal is input to the interrupt terminal INT of the CPU 22 and is also input to one input terminal of the AND circuit 24. A gate control signal a is input from the CPU 22 to the other input terminal of the AND circuit 24.

Further, the control signal b of the CPU 22 is input to one input terminal of the OR circuit 25, and the output of the AND circuit 24 is input to the other input terminal of the OR circuit 25. The gate control signal a outputs "1" level in the normal state, and the control signal b outputs "0" level in the normal state.

The output signal c of the OR circuit 25 outputs a "1" level when outputting a reverse voltage pulse, and outputs a "0" level when not outputting a reverse voltage pulse. The output signal c of the OR circuit 25 is the switching FET Q2
Is input to the gate. The source of the FET Q2 is connected to the negative electrode of the DC power supply 21.

Furthermore, FET Q2 Seo - scan the diode - via the de D4 and resistor r7 is connected to one terminal of the primary coil 26 ₁ of the pulse transformer 26. The other end of the primary coil 26 ₁ is connected to the drain of the FET Q2.

The positive terminal of the DC power supply 21 is connected to the source of the FET Q2 via a resistor r8 and a capacitor C2. Connection point between the resistor r8 and capacitor C2 is connected to an intermediate point of the primary coil 26 _1.

Further, between both ends of the secondary coil 26 ₂ of the transformer 26, resistors r9 capacitor C3 in series are connected in parallel. One end of the capacitor C3 is connected to the base of the transistor Q1, and the other end is connected to the emitter of the transistor Q1.

The positive electrode of the DC power supply 11 is grounded, and the other line 13 ₂ (ground side) of the output cable 13 is connected to the tank of the vacuum chamber 15. Next, the operation of the first embodiment configured as described above will be described. First, the vacuum chamber 15 is evacuated by a vacuum pump (not shown). Then, an Ar gas pulse is introduced into the vacuum chamber 15, and a negative voltage of the DC power supply 11 is applied to the sputtering source 14 to generate a magnetron discharge. By this magnetron discharge, an argon plasma is formed in the discharge space. Argon positive ions in this plasma are accelerated by a negative voltage difference and collide with the surface of the target of the sputtering source 14. This collision causes the aluminum atoms in the target to evaporate. Then, a part of the sputter-evaporated aluminum atoms is deposited on the substrate 16, and sputter deposition for forming a thin film of aluminum is performed.

If the magnetron discharge generated in the vacuum chamber 15 does not shift to the arc discharge, sputter deposition is performed continuously. By the way, when the magnetron discharge generated in the vacuum chamber 15 shifts to arc discharge,
As shown in FIG. 2A, the voltage at point A drops. Since the voltage at the point A is divided by the resistors r5 and r4 and input to the Schmitt trigger circuit 23 via the resistor r6, the Schmitt trigger circuit 23 changes to “0” level when the voltage at the point A exceeds 300V, for example. , 150 V or less, the "1" level is output to the interrupt terminal INT of the CPU 22 and
The signal is also output to the AND circuit 24.

Since the gate control signal a input to the other input terminal of the AND circuit 24 is "1" level in a normal state, the output of the AND circuit 24 is "1".
Stand up to the level. This signal is input to the gate of the FET Q2 via the OR circuit 25. Therefore, the FET Q
2 turns on.

Then, a pulse voltage is applied to the primary coil 26 ₁ of the pulse transformer 26 and its secondary coil 26 ₂
Is applied to the gate of the transistor Q1.

[0039] The primary coil 12 ₁ of the transformer 12 is the same voltage is applied between the DC power supply 11 which is charged in the capacitor C1, the primary coil 1 of the transformer 12 to provisionally
2 ₁ and the turns ratio of the secondary coil 12 ₂ 1: If 1.1, the secondary coil 12 ₂ of the transformer 12, 1.1 E
(E is the voltage of the DC power supply 11).

Therefore, a positive voltage of 0.1 E is applied to the sputtering source 14. That is, the reverse voltage pulse p1 is applied from time t1. This reverse voltage pulse p1
Is applied, the sputter source 14 is maintained at a positive voltage, so that the arc discharge is extinguished.

The CPU 22 determines that the voltage of the DC power supply 11 exceeds 300 V, for example, from the divided voltages of the resistors r3 and r2, and when it determines that the voltage exceeds 300 V, sets the gate control signal a to "1". Output at "" level (Fig. 2
(E)). On the other hand, when it is determined that the voltage is 300 V or less, the gate control signal a is output at the “0” level.

The CPU 22 detects the occurrence of arc discharge by monitoring the voltage at the point A. The voltage at point A indicates, for example, 300 V or more during normal discharge and 150 V or less during arc discharge.

The Schmitt trigger circuit 23 compares the voltage obtained by dividing the voltage at the point A by the resistors r4 and r5 with the internal operating voltage. If an arc discharge has occurred, for example, the voltage at the point A is reduced to 150 V or less. Therefore, a “1” level is output.
When the voltage exceeds 300 V, a "0" level is output. Therefore, at time to when the arc discharge occurs, the Schmitt trigger circuit 23 outputs the "1" level to the INT of the CPU 22, as shown in FIG.

The output of the Schmitt trigger circuit 23 is "1"
At this level, the logic of the AND circuit 24 is established because the gate control signal a is at the "1" level. For this reason,
Regardless of the output level of the control signal b, the output signal c of the OR circuit 25 becomes “1” level (FIG. 2D).

Since the "1" level of the output signal c of the OR circuit 25 is input to the gate of the FET Q2,
TQ2 turns on. When the FET Q2 is turned on, the pulse transformer 26 is excited. As a result, the pulse voltage from the secondary coil 26 ₂ of the pulse transformer 26 is base of the transistor Q1 - are output to the scan, the transistor Q1 is turned on. As a result, the reverse voltage pulse p1 is output from the pulse transformer 12 (reverse voltage applying means).

Here, since both the pulse transformers 26 and 12 can transmit only a predetermined voltage-time product (ET product), the gate drive of the FET Q2 is stopped before reaching the voltage-time product, and the operation shifts to the reset operation. There is a need. That is, since the voltage at the point A is equal to or less than the determination level of the Schmitt trigger circuit 23, it is necessary to perform the pulse operation using the CPU 22.

First, the CPU 22 resets the counter 22c in synchronization with the rise of the "1" signal from the Schmitt trigger circuit 23, and at the same time, performs an interrupt process. In this interrupt processing, the CPU 22 sets the signal b to "1" and then sets the gate control signal a to "0" (time t2). Since the gate of the AND circuit 24 is closed by setting the gate control signal a to "0", the voltage at the point A and the gate drive of the FET Q2 become irrelevant.

When the set time T has elapsed from the time t0 at which the counter 22c started the time counting process, the signal b is set to "0".
(Time t3). Thus, the signal b is "0"
Falls, the two input signals of the OR circuit 25 both become "0", so that the FET Q2 is turned off.

[0049] With such FETQ2 is turned OFF, the current flowing through the primary coil 26 ₁ of the pulse transformer 26, flywheel - Rudaio - de D4, resistor r7, through the coil 26 ₁ flows back to the capacitor C2, secondary Coil 2
6 The _second reverse voltage is generated. As a result, the transistor Q
The gate voltage of 1 is reversed and transistor Q1 is turned off.

[0050] When the transistor Q1 is turned off, current flowing through the primary coil 12 ₁ of the pulse transformer 12 is flywheel - Rudaio - de D1 and the resistor r1 and primary coil 12
Cycle ₁

Then, since the voltage on the primary side of the pulse transformer 12 is reversed, the voltage on the secondary side is also reversed, and the voltage at the point A becomes the sputtering voltage (300 V or more). At this time, due to the straight capacity and inductance of the circuit, FIG.
As shown in (A), the voltage at point A oscillates for about 2 μs.

As shown in FIG. 2F, after the signal b of the CPU 22 falls to the "0" level, the gate control signal a
Time to rise to the "1" level by the counter 22c
By setting the setting time to 5 μs, for example, the malfunction is prevented.

When the set time is counted by the counter 22c, the gate control signal a rises to "1" level as shown in FIG. 2 (E). Thus, from time t3 when the output of the OR circuit 25 falls, 5
Since the gate control signal a is set to the "0" level during the period of .mu.s (reverse voltage application control means), the threshold value is determined by the oscillation g of the voltage at the point A generated after the output of the OR circuit 25 falls. Even if the signal h exceeding Vth is generated, it is not erroneously determined that arc discharge has occurred.

That is, even if the output of the Schmitt trigger circuit 23 changes to the "1" level due to the vibration g,
Since the gate control signal a is at the "0" level, the FE
TQ2 is not turned on.

A problem in operating this circuit is that only a predetermined voltage-time product can be operated as a transformer because a transformer is used. The point is that the next pulse voltage cannot be applied unless a reverse voltage is applied to the transformer before the voltage-time product is reached to reset the magnetization state of the iron core.

The circuit for resetting is a circuit of r1 and D1 in the pulse transformer 12, and a circuit of D4 and r7 in the pulse transformer 26. The higher the reverse voltage applied, the shorter the reset time.
6, it is possible to select the resistor r7 to be a large value which is equal to or less than the gate withstand voltage of the transistor Q1 and set it shorter than the on-time of the transistor Q2. If r1 is increased, the withstand voltage of the transistor Q1 will be exceeded. If only the withstand voltage of the transistor is used, a countermeasure is taken by connecting a plurality of transistors in series. However, since the voltage applied to the sputter source 14 instantaneously increases, a control circuit for applying a reverse voltage for interrupting the arc discharge is conventionally used. Reset time was secured. This reset time was a rest period of 30 μs or more.

When sputtering was actually performed using a conventional circuit, it was found that the arc discharge was normally sufficiently suppressed, but sometimes it could not be suppressed. It is: If the time from the occurrence of the arc discharge to the reverse voltage pulse is long, the arc discharge grows, and the arc discharge occurs immediately after the reverse voltage pulse ends.
It becomes a continuous arc discharge.

2. Therefore, if the pause time until the next pulse is issued after the end of the reverse voltage pulse is shortened, the effect appears from about 15 μs. If the time is set to 5 μs or less, the reverse voltage pulse is applied as long as the reverse arc discharge does not occur. Immediately
It was found that discharge did not occur.

3. In this case, the transformer 26 can operate without magnetic saturation by optimizing the resistance r7, but the transformer 12 is considered to be useless as it is. The reset time cannot be obtained only in the case of continuous arc discharge.
It has been found that the transformer 12 can be used without magnetically saturating the transformer 12 by eliminating the occurrence of continuous arc discharge exceeding the number of pulses and by designing the voltage-time product of the transformer 12 to be four pulses or more.

From an electrical circuit point of view, it is the correct theory to secure a pause time for resetting the voltage-time product of the transformer as in the prior art. The effect of the reverse voltage pulse changes depending on the occurrence of the arc discharge at the timing, and the reverse voltage pulse will not be effective after increasing the arc discharge. The occurrence of arc discharge is suppressed, and as a result, the reset time is secured.

There are two types of continuous arc discharge. One is when the arc discharge develops and the effect of the reverse voltage pulse is lost. The other is when the reverse voltage pulse is applied. If the reverse arc discharge occurs in the arc discharge generated by the voltage, the arc discharge in the forward direction will almost always occur after the end of the reverse voltage pulse. That is, since the cause of the continuous arc discharge when the pause period is shortened is the reverse arc discharge, the continuous arc discharge is prevented by preventing the reverse arc discharge. It is possible to

The method for preventing the reverse arc discharge is as follows. Reduce reverse voltage. a) Change the turns ratio of the transformer. b) Supply current in parallel to the sputtering source. 1. Limit the voltage with a resistance value or zener diode. C) Limit the current flowing when a reverse voltage is applied. C) The forward current is a diode, and the resistance of the reverse arc discharge is appropriately selected.

Specifically, in the forward direction, a low impedance is connected so that the current of the sputtering discharge flows, and an impedance higher than this impedance and connected in parallel to prevent the reverse arc current is connected.

D) It is conceivable to use a current limiting circuit with a bipolar transistor, IGBT, MOSFET or the like as the impedance. In this case, the impedance of the reverse arc discharge was about 1Ω, and the impedance which did not produce the arc discharge in the reverse direction was 200Ω. . In addition, this 100Ω
Are the resistors used in the second embodiment described later.

Next, a second embodiment of the present invention will be described with reference to FIG. In this second embodiment,
The same portions as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. In the second embodiment, the point A and the output cable 1 in the first embodiment of FIG.
3 between the end of _one of the lines 13 ₁
Is connected to a diode D10 having a cathode connected to the DC power supply 11 side, and a resistor r10 is connected in parallel so as to bypass the diode D10. It is similar to the circuit of FIG. The resistance r1
0 is, for example, about 100 [Ω] as described above.

As described above, the diode D10 and the resistor r10
When a magnetron discharge is generated in the vacuum chamber 15 and sputtering is performed, the current generated by the magnetron discharge flows in the forward direction of the diode D10 (that is, the anode). (From the cathode to the cathode), the effect of the resistor r10 does not occur.

However, as described in the first embodiment, when a reverse voltage pulse is applied so that the sputtering source 14 has a positive potential, a reverse arc is applied from the vacuum chamber 15 toward the sputtering source 14. The resistor r10 is provided on the assumption that a discharge occurs.

The occurrence of reverse arc discharge is suppressed by the resistor r10. The voltage of the DC power supply 11 is set to, for example, 80
When the voltage is set to 0 V, the voltage of the sputtering source 14 when the reverse voltage pulse is applied is 0.1 E (80 V). If the resistance is 80 Ω and 100Ω, only a current of 0.8 A flows.
The occurrence of spark discharge can be suppressed. This is clear from the general load characteristics of arc discharge.

Next, a third embodiment of the present invention will be described.
This will be described with reference to FIG. In the third embodiment,
In the circuit of FIG. 3, a resistor r11 and a diode D10 are connected between the anode of the diode D10 and the collector of the transistor Q1.
The circuit is the same as the circuit in FIG. 3 except that only a circuit in which 11 are connected in series is connected.

As described above, the resistance r11 and the diode D
By providing 11, the reverse voltage applied to the sputter source 14 when a reverse voltage pulse is applied can be reduced, so that the occurrence of reverse arc discharge can be suppressed.

In the description of the first to third embodiments, the gate control signal a is set to the "1" level 5 μs after the fall of the reverse voltage pulse, but within 1 to 10 μs. Is also good. Also, this time is optimally 2-5 μm.
s.

When chemical conversion sputtering is performed using the circuit used in the above embodiment, arc discharge occurs at a substantially constant period and is completely cut off. However, since the arc discharge generation cycle changes depending on the consumption of the target and the process conditions, the sputtering power changes, which is inconvenient in terms of process reproducibility.

In this case, if a reverse voltage pulse is applied in a cycle shorter than the arc discharge generation cycle irrespective of the detection of the arc discharge, the cutoff time with respect to the sputtering time becomes a constant ratio, and the process is stabilized. In the above-described embodiment, the pulse transformer 12 is used as the reverse voltage generating means. However, an automatic transformer may be used.

[0074]

According to the first aspect of the present invention, the interval between the application of the reverse voltage pulse is 1 to 10 μm when the arc discharge is detected.
Since it is performed at time intervals of s or less, the probability of occurrence of continuous arc discharge can be extremely reduced.

According to the second and third aspects of the present invention, when a reverse voltage pulse is applied, when the reverse arc discharge occurs, the reverse impedance is set to be larger than the forward impedance so as to suppress the arc discharge current. In addition, since the reverse impedance is provided in parallel, the occurrence of the arc discharge in the reverse direction can be suppressed, so that the probability of occurrence of the continuous arc discharge can be extremely reduced.

According to the fourth aspect of the present invention, when a reverse voltage pulse is applied, the current flowing through the vacuum chamber (sputter source) and the current flowing through the diode D11 are changed to a resistance value r11.
Substrate damage due to substrate arc discharge.
Can be prevented.

According to the fifth and sixth aspects of the present invention, since the winding ratio of the transformer is set to 1: 1.1 to 1: 1.3, it is 0.1 to 0.3 times the DC power supply. Can be output from the transformer.

According to the seventh aspect of the present invention, the magnetic saturation of the transformer for generating the reverse voltage pulse can be eliminated by designing the voltage-time product of the transformer for generating the reverse voltage pulse to be four pulses or more. Since it is possible, control failure can be prevented.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a power supply device for a sputtering apparatus according to a first embodiment of the present invention.

FIG. 2 is a timing chart for explaining the operation of the present invention.

FIG. 3 is a circuit diagram showing a power supply device for a sputtering apparatus according to a second embodiment of the present invention.

FIG. 4 is a circuit diagram showing a power supply device for a sputtering apparatus according to a third embodiment of the present invention.

[Explanation of symbols]

 11: DC power supply, 12: Pulse transformer, 13: Output cable, 14: Sputter source, 15: Vacuum chamber, 16: Substrate, 21: DC power supply for control circuit, 22: CPU for control, 23: Schmitt trigger circuit , 24 ... AND circuit, 25 ... OR circuit, 26 ... Transformer.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI H01L 21/285 H01L 21/285 S (72) Inventor Takashi Fujii 6-25-22 Sagamigaoka, Zama City, Kanagawa Prefecture Sagami Co., Ltd. Inside the factory (56) References JP-A-9-279337 (JP, A) JP-A-9-71863 (JP, A) JP-A-7-233472 (JP, A) JP-A-8-41636 (JP, A) JP-A-5-31418 (JP, A) JP-A-9-137271 (JP, A) JP-A-2-1944831 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C23C 14/34 C23C 14/38 C23C 14/54 H01L 21/203 H01L 21/285

Claims (7)

(57) [Claims] In a sputtering apparatus for introducing an inert gas into a grounded vacuum chamber and applying a negative voltage to a sputter source disposed in the vacuum chamber to perform sputtering, a DC voltage is applied to the sputter source. A direct current power supply for applying the voltage; a reverse voltage generating means for applying a reverse voltage to the sputter source in order to stop the generation of an arc discharge generated during the sputtering; and a reverse voltage generating means for generating the reverse voltage. Switch means for applying the reverse voltage to the sputter source; arc discharge detection means for detecting the occurrence of arc discharge in the vacuum chamber; and arc discharge detection means for detecting the arc discharge. When the occurrence is detected, the switch means is turned on for a set time, and a reverse voltage applying means for applying a reverse voltage generated from the reverse voltage generating means to the sputtering source, When the occurrence of the arc discharge is detected by the arc discharge detection means, the reverse voltage generated by the reverse voltage generation means is applied to the sputtering source for a set time, and after the application is completed, When the occurrence of an arc discharge is detected again by the arc discharge detecting means, a reverse voltage application control for applying the reverse voltage generated by the reverse voltage generating means to the sputtering source within 1 to 10 μS. And a power supply device for a sputtering apparatus. 2. A forward impedance connected between the reverse voltage generating means and the sputtering source in a direction in which a current of a sputtering discharge flows, and a reverse impedance larger than the forward impedance and connected in parallel. 2. A power supply device for a sputtering apparatus according to claim 1, further comprising a reverse arc discharge prevention circuit comprising a reverse impedance for preventing occurrence of arc discharge. 3. The power supply device for a sputtering device according to claim 2, wherein in the reverse arc discharge prevention circuit, the forward impedance is a diode and the reverse impedance is a resistance. 4. A connection between the sputter source side of the reverse arc discharge prevention circuit and the positive electrode side of the DC power supply so that current flows from the anode side of the diode toward the positive electrode side of the DC power supply. 3. A power supply device for a sputtering apparatus according to claim 2, wherein a second diode is provided, and a resistor is connected in series with said second diode. 5. The reverse voltage generating means is a pulse transformer having the primary side connected to the DC power supply and the secondary side connected to the sputter source. The primary and secondary windings of the pulse transformer are connected. The power supply for a sputtering apparatus according to any one of claims 1 to 4, wherein the ratio is 1: 1.1 to 1: 1.3. 6. The reverse voltage generating means is an autotransformer having the primary side connected to the DC power supply and the secondary side connected to the sputter source, and the primary and secondary windings of the autotransformer. The power supply for a sputtering apparatus according to any one of claims 1 to 4, wherein the ratio is 1: 1.1 to 1: 1.3. 7. The reverse arc discharge prevention circuit according to claim 7,
The occurrence of continuous arc discharge of two or more pulses in the vacuum chamber is eliminated, and the voltage / time product of the transformer as the reverse voltage generating means is set to four pulses or more, so that the transformer is not magnetically saturated. The power supply device for a sputtering apparatus according to any one of claims 2 to 6, wherein: