TWI392755B - Sputtering method and sputtering device - Google Patents

Description

Sputtering method and sputtering device

The present invention relates to a sputtering method and a sputtering apparatus which can form a film on a surface of a substrate to be processed.

In the sputtering method, the ions in the plasma environment are made to correspond to the composition of the film to be formed on the surface of the substrate to be accelerated, and the target atoms are accelerated to scatter, and the target atoms are scattered to form a film on the surface of the substrate. . In this case, a target is applied to the cathode electrode via a direct current power source or an alternating current power source, whereby a glow discharge is generated between the cathode electrode and the anode electrode or the ground electrode to form a plasma environment.

In such a glow discharge, arc discharge occurs for some reason, and if the arc discharge occurs locally in the cathode electrode, problems such as particles or splashes are induced, and film formation cannot be performed satisfactorily.

In response to this, for example, there is a sputtering method using a DC power source, which detects a voltage between a cathode electrode and a ground electrode, and if the amount of the voltage drop exceeds a predetermined value, an arc discharge is detected, and an arc discharge is detected. The power supply is interrupted from the DC power supply within a certain period of time after the occurrence (Patent Document 1)

[Patent Document 1] Japanese Laid-Open Patent Publication No. Hei 11-200036 (for example, refer to claim 1).

However, by sputtering using an alternating current power source, that is, alternately changing the polarity at a predetermined frequency via an alternating current power source, voltages are applied to a pair of targets floating in each other in a vacuum reaction chamber, and each target is alternately switched to an anode electrode. When the cathode electrode is sputtered, the polarity of the voltage applied to each target changes constantly, and the voltage drop occurs in succession. Therefore, it is difficult to apply the detected arc detection based on the voltage drop between the cathode electrode and the anode electrode. law.

In this case, in the past, the actual value or average value of the output voltage from the AC power source to the target was obtained, and the output voltage was DC-formed, and the arc voltage was detected based on the DC voltage, but it was added to change the AC voltage. Since the time of the DC voltage is generated, the occurrence of the arc discharge is delayed, and there is a problem that the occurrence of particles or splash cannot be effectively prevented.

Therefore, in view of the above problems, an object of the present invention is to provide a method for rapidly detecting the occurrence of arc discharge when forming a film by sputtering using an alternating current power source, thereby blocking the output to the target and reducing the arc discharge. A sputtering method and a sputtering apparatus that can effectively prevent the occurrence of particles or splashes, etc., at the time of occurrence of energy.

In order to solve the above problem, the sputtering method according to claim 1 is characterized in that a voltage is alternately changed at a predetermined frequency via an alternating current power source, and a voltage is applied to a pair of targets provided in the vacuum reaction chamber, and each target is alternately switched to an anode electrode. The cathode electrode is a sputtering method in which a glow discharge is generated between the anode electrode and the cathode electrode to form a plasma environment to sputter each target, and the output voltage waveform of the pair of targets is detected. When the voltage drop time of the output voltage waveform is shorter than that of the normal glow discharge, the output from the above AC power source is blocked.

According to the present invention, when a voltage is applied to a pair of targets via an alternating current power source, each target is alternately switched between an anode electrode and a cathode electrode, and a glow discharge is generated between the anode electrode and the cathode electrode to form a plasma environment, and in a plasma environment. The ions will accelerate toward the target of the cathode electrode, causing the target atoms to scatter and form a thin film on the surface of the treated substrate.

When an arc discharge occurs during sputtering, the impedance of the plasma is rapidly reduced. First, the voltage between the targets becomes small, and a large current flows. In this case, since the occurrence of the arc discharge is directly detected by the length of the voltage drop of the output voltage waveform of the target, the change in the current value between the targets or the effective value or average of the output voltage to the target is obtained. In contrast to the case where the arc discharge is detected, the arc discharge can be quickly detected and the output to the target can be blocked. As a result, the energy at the time of occurrence of the arc discharge can be reduced to effectively prevent the occurrence of particles or splashes.

In this case, the output current waveform between the pair of targets is detected, and if the absolute value of the output current waveform exceeds a predetermined value, the glow discharge is generated, and the absolute value of the current waveform is output to create a current gate. a signal, and the voltage pulse signal is generated by the absolute value of the output voltage waveform. If the voltage pulse signal is turned off in the open state of the current gate signal, the voltage drop time of the output voltage waveform can be determined to be longer than the normal glow. Shorter time when discharging.

Thereby, since the occurrence of the voltage drop is detected when the current flows between the targets, for example, erroneous detection of the arc discharge can be reduced.

In order to detect the occurrence of arc discharge with higher accuracy, it is preferable to control the phase of the output current waveform and the output voltage waveform of the conventional target in the above sputtering.

In this case, it is preferable that the predetermined value is changed in accordance with the input power from the AC power source to the pair of targets.

Further, the voltage pulse signal is generated from the absolute value of the output voltage waveform, and the pulse width of the voltage pulse signal is detected. When the pulse width ratio is smaller than the predetermined value, the voltage drop time of the output voltage waveform can be determined to be longer than the normal glow. Shorter time when discharging.

Thereby, the occurrence of arc discharge is detected only by the voltage between the targets, so that it is not necessary to consider the phase shift between the output voltage waveform and the output current waveform, and it is possible to detect even if the output voltage waveform and the phase of the output current waveform are not coincident at the start. An arc discharge occurs.

In this case, the predetermined value can be directly determined by the absolute value of the output voltage waveform, or the pulse width at the time of arc discharge is not measured in advance, and the predetermined value can be relatively determined.

Further, a differential waveform proportional to the voltage drop of the output voltage waveform is detected, and when the differential waveform exceeds a predetermined value, the voltage drop time of the output voltage waveform can be determined to be shorter than the normal glow discharge time.

Thereby, the arc discharge detecting circuit can be realized by a simple circuit configuration, and the arc discharge is detected only by the voltage between the targets, so that it is not necessary to consider the phase shift of the output voltage waveform and the output current waveform, even when starting, etc. When the output voltage waveform does not coincide with the phase of the output current waveform, arc discharge can be detected.

In this case, in order to detect the occurrence of the arc discharge with higher accuracy, it is preferable to remove the noise of the output voltage waveform via the filter circuit before detecting the differential waveform.

Further, it is preferable that the output voltage waveform is substantially a sine wave.

Further, the output current waveform between the pair of targets is detected, and the output voltage waveform is adjusted so as to substantially match the phase and amplitude of the output current waveform, and then the difference waveform of the waveforms is detected. When the differential waveform becomes larger than the predetermined value, it can be judged that the voltage drop time of the output voltage waveform is shorter than that of the normal glow discharge.

Therefore, the waveform used in the arc detection is synthesized by the difference between the appropriately adjusted current waveform and the voltage waveform. When the arc discharge occurs, the output of the differential waveform forms a larger output waveform, and thus is less susceptible to The effect of noise can reduce false detections.

In this case, in order to detect the occurrence of the arc discharge with higher accuracy, it is preferable to remove the noise of the output voltage waveform and the output current waveform through the filter circuit before detecting the differential waveform.

Further, it is preferable that the output voltage waveform and the output current waveform are substantially sinusoidal.

Moreover, in order to solve the above-described problems, the sputtering apparatus according to claim 13 is characterized in that the arc detecting means includes a target that is disposed in one of the vacuum reaction chambers and alternately changes polarity at a predetermined frequency. An alternating current power source for applying a voltage between the pair of targets detects a voltage drop of a voltage drop time to the output voltage waveform of the target is shorter than a normal glow discharge; and a blocking means is performed from the arc detection The output of the output circuit blocks the output from the AC power source.

In this case, the AC power supply may be provided with a phase adjustment means for substantially matching the phase of the output voltage waveform and the output current waveform of the pair of targets.

Further, the arc detecting means includes: a first absolute value detecting circuit and a second absolute value detecting circuit that detect an output current waveform and an absolute value of an output voltage waveform between the pair of targets; a gate signal generating circuit and a voltage pulse signal generating circuit for respectively inputting a comparator for inputting an absolute value and a detected level from the first absolute value detecting circuit and the second absolute value detecting circuit; and detecting the voltage drop a circuit for inputting a current gate signal and a voltage pulse signal from the current gate signal generating circuit and the voltage pulse signal generating circuit; wherein the voltage gate signal is turned off when the current gate signal is turned on , a voltage drop that is shorter than the normal glow discharge is detected.

Further, the arc detecting means of another form is an absolute value detecting circuit that detects an absolute value of an output voltage waveform between the pair of targets, and a voltage pulse generating circuit that sets an input from the absolute value. a comparator for detecting an absolute value of the circuit and a detection level; and a voltage drop detection circuit for inputting a voltage pulse signal from the voltage pulse generation circuit; configured to detect a voltage input to the voltage drop detection circuit The pulse width of the pulse signal, when the pulse width is smaller than the predetermined value, detects a voltage drop that is shorter than the normal glow discharge.

Further, the arc detecting means of another aspect is a differential circuit that detects a differential waveform proportional to a voltage drop of an output voltage waveform between the pair of targets, and an absolute value detecting circuit that detects An absolute value of a voltage waveform from the differentiating circuit; and a voltage differential waveform circuit having a comparator that inputs an absolute value and a detected level from the absolute value detecting circuit; and when the absolute value of the differential waveform exceeds When the value is increased, a voltage drop is detected shorter than the normal glow discharge.

Further, the arc detecting means of the other aspect is characterized in that the first and second gain adjusting circuits adjust the amplitude of the output voltage waveform and the output current waveform between the pair of targets to be substantially identical; a dynamic amplifier that detects a differential waveform of an output voltage waveform and an output current waveform from each gain adjustment circuit; an absolute value detection circuit that detects an absolute value of a differential waveform from the differential amplifier; and a differential waveform a detection circuit having a comparator for inputting a differential waveform and a detection level from an absolute value detection circuit; wherein when the absolute value of the differential waveform exceeds a predetermined value, the detection is larger than normal The glow of the glow is reduced in a shorter time.

As described above, in the sputtering method and the sputtering apparatus of the present invention, when a film is formed by sputtering using an alternating current power source, the arc discharge can be quickly detected, the output to the target can be interrupted, and the arc discharge can be reduced. The energy at the time is effective to prevent the occurrence of particles or splashes.

Referring to Fig. 1, reference numeral 1 denotes a magnetron sputtering apparatus (hereinafter referred to as "sputtering apparatus") of the present invention. The sputtering apparatus 1 is of an inline type and has a vacuum reaction chamber 11 held at a predetermined degree of vacuum via a vacuum exhausting means (not shown) such as a rotary pump or a turbo molecular pump. A substrate transporting means is provided on the upper portion of the vacuum reaction chamber 11. This substrate transfer means has a conventional structure. For example, the carrier 2 having the processing substrate S is mounted, and the driving means is intermittently driven to sequentially transport the processed substrate S to a position facing the target to be described later.

The gas introduction means 3 is provided in the vacuum reaction chamber 11. The gas introduction means 3 is connected to the gas source 33 via the gas pipe 32 in which the mass flow controller 31 is provided, a sputtering gas such as Ar, or O ₂ , H ₂ O, H ₂ , N ₂ or the like used for reactive sputtering. The reaction gas can be introduced into the vacuum reaction chamber 11 at a constant flow rate. A cathode electrode C is disposed on the lower side of the vacuum reaction chamber 11.

The cathode electrode 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 conventional method in accordance with a composition of a film which is formed on the substrate S by Al, Ti, Mo, ITO or the like, and is formed into a substantially rectangular parallelepiped (a rectangular shape in the upper direction). Each of the targets 41a and 41b is a back plate 42 that bonds the cooling targets 41a and 41b via a bonding material such as indium or tin during sputtering, and is attached to the frame of the cathode electrode C via an insulating material (not shown) in the vacuum reaction chamber. 11 is configured to be in a floating state.

In this case, the targets 41a and 41b are disposed such that the sputtering surface 411 when not in use can be positioned on the same plane parallel to the processing substrate S, and the opposing side surfaces 412 of the respective targets 41a and 41b are not provided with any A component such as an anode or a shield. The outer dimensions of the respective targets 41a and 41b are set to be larger than the outer dimensions of the processing substrate S when the respective targets 41a and 41b are disposed in parallel.

Further, the cathode electrode C is provided with the magnet assembly 5 at the rear of each of the targets 41a and 41b. The magnet assembly 5 has a support plate 51 provided in parallel with each of the targets 41a and 41b. The support plate 51 is formed to have a smaller lateral width than each of the targets 41a and 41b, and is formed of a rectangular flat plate that extends to the both sides of the targets 41a and 41b so as to extend the magnetic force of the magnet. Material system. The support plate 51 is provided with a rod-shaped central magnet 52 along the longitudinal direction of the targets 41a and 41b, and a peripheral magnet 53 provided along the outer circumference of the support plate 51. In this case, the volume of the same magnetization converted into the central magnet 52 is equal to the sum of the volumes converted to the same magnetization of the peripheral magnet 53 (peripheral magnet: center magnet: peripheral magnet = 1:2:1).

Thereby, a balanced closed-circuit tunnel-shaped magnetic flux is formed in front of each of the targets 41a and 41b, and electrons ionized in front of the targets 41a and 41b and secondary electrons generated by sputtering are captured. The electron density in front of each of the targets 41a, 41b is increased to increase the plasma density. Further, an output cable K from the AC power supply E can be connected to each of the pair of targets 41a and 41b, and the polarity can be alternately changed at a predetermined frequency (1 to 400 KHz) to apply a voltage to the pair of targets 41a and 41b.

As shown in FIG. 2, the AC power supply E is composed of a power supply unit 6 that can supply electric power, and an oscillating unit 7 that alternately changes polarity at a predetermined frequency and outputs a voltage to each of the targets 41a and 41b. In this case, although the waveform of the output voltage is a substantially sinusoidal wave, it is not limited thereto, and may be, for example, a substantially square wave.

The power supply unit 6 includes a first CPU circuit 61 that controls its operation, an input unit 62 that inputs commercial AC power (three-phase AC 200V or 400V), and six AC powers that are rectified and converted into DC power. The diode 63 can perform a task of outputting DC power to the oscillation unit 7 via the DC power lines 64a and 64b.

Further, the power supply unit 6 is provided with a switching transistor 65 provided between the DC power lines 64a and 64b, and a first driver circuit that is communicably connected to the first CPU circuit 61 and controls the opening and closing of the switching transistor 65. 66a and the first PMW control circuit 66b. In this case, the current detecting sensor and the voltage detecting transformer are provided with the detecting circuit 67a and the AD converting circuit 67b that detect the current and voltage between the DC power lines 64a and 64b, and can be converted by the detecting circuit 67a and the AD. The circuit 67b is input to the CPU circuit 61.

On the other hand, the oscillation unit 7 is provided with a second CPU circuit 71 that is communicably connected to the first CPU circuit 61 and a first one that constitutes four of the oscillation switch circuits 72 provided between the DC power lines 64a and 64b. The fourth switch transistors 72a, 72b, 72c, and 72d are connected to the second CPU circuit 71 in a communicative manner, and the second driver circuit 73a and the second PMW control for controlling the opening and closing of the switch transistors 72a, 72b, 72c, and 72d are controlled. Circuit 73b.

Then, by the second driver circuit 73a and the second PMW control circuit 73b, for example, the timings of turning on and off the first and fourth switching transistors 72a and 72d and the second and third switching transistors 72b and 72c can be performed. By controlling the operation of each of the switch transistors 72a, 72b, 72c, and 72d by the inversion, the AC power of the sine wave can be output via the AC power lines 74a and 74b from the oscillation switch circuit 72. In this case, the detection circuit 75a and the AD conversion circuit 75b that detect the oscillation voltage and the oscillation current are provided, and can be input to the second CPU circuit 71 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 conventional configuration via a series or parallel or combined resonant LC circuit, and the output cables K from the output transformer 76 are respectively connected to a pair of targets 41a. 41b. In this case, the current detecting sensor and the voltage detecting transformer are provided, and the detecting circuit 77a and the AD converting circuit 77b that detect the output voltage and the output current of the pair of targets 41a and 41b are provided, and can be detected. The circuit 77a and the AD conversion circuit 77b are input to the second CPU circuit 71. Thereby, in the sputtering, a constant voltage can be applied to the pair of targets 41a and 41b by alternately changing the polarity at a constant frequency via the AC power source E.

Further, the output from the detecting circuit 77a is connected to the detecting circuit 78a that detects the output phase and frequency of the output voltage and the output current, and is communicably connected to the output phase frequency control circuit 78b of the detecting circuit 78a. The phase and frequency of the output voltage and the output current are input to the second CPU circuit 71. Thereby, by using the control signal from the second CPU circuit 71, the second driver circuit 73a controls the switching transistors 72a, 72b, 72c, and 73d of the oscillation switching circuit 72 to be turned on and off, and can be controlled to output voltage and output. The phases of the currents are substantially identical to each other, and the output phase frequency control circuit 78b, the second CPU circuit 71, and the second driver circuit 73a constitute phase adjustment means.

Then, the processing substrate S is transported to a position facing the pair of targets 41a and 41b by the substrate transfer means, and the predetermined 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 between the anode electrode and the cathode electrode, and a glow discharge is generated between the anode electrode and the cathode electrode to form a plasma environment. Thereby, ions in the plasma environment are accelerated toward one of the targets 41a and 41b of the cathode electrode, and the target atoms are scattered to form a thin film on the surface of the substrate S.

In this case, the magnet assembly 5 is provided with a driving means such as a motor (not shown), and the driving means can be reciprocated in parallel and at a constant speed in two positions along the horizontal direction of the targets 41a and 41b. The field of erosion can be achieved uniformly in the targets 41a, 41b.

However, in the above-described glow discharge, arc discharge occurs for some reason, and if the arc discharge occurs locally in the pair of targets 41a and 41b, problems such as particles or splash are induced, so that a thin film is formed in order to form a thin film. It is necessary to quickly detect the occurrence of arc discharge and immediately interrupt the output from the AC power source E.

In the present embodiment, the arc detecting means 8 is provided in the oscillating portion 7, and the voltage drop time of the output voltage waveform of the pair of targets 41a, 41b is detected to be shorter than the normal glow discharge time. lower. When the arc detecting means 8 detects the occurrence of the arc discharge, the voltage drop arc output signal is output to the second CPU circuit 71 that is communicably connected, and the control is performed by the first CPU circuit 61 that is freely communicable from the second CPU circuit 71. The signal is controlled by the first driver circuit 66a to control the operation of the switching transistor 65, and the output to the pair of targets 41a and 41b is immediately blocked.

In this case, the control signal from the second CPU circuit 71 can be used, and the second driver circuit 73a can control the switching transistors of the oscillation switching circuit 72 in the same manner as the potential between the AC power lines 74a and 74b. The operations of 72a, 72b, 72c, and 72d immediately interrupt the output of the pair of targets 41a and 41b.

As shown in FIGS. 3(a) to 3(e), the arc detecting means 8 includes a current sense amplifier 81 and a voltage transformer coupling amplifier 82 for amplifying an output voltage from the detecting circuit 77a, an output current, and detection. The first absolute value detecting circuit 83a and the second absolute value detecting circuit 83b which are the absolute values of the output current waveform and the output voltage waveform amplified by the current sense amplifier 81 and the voltage transformer coupling amplifier 82 are provided. Further, the arc detecting means 8 is provided with each of the absolute values input from the first and second absolute value detecting circuits 83a and 83b and a preset current gate detecting level and a voltage pulse detecting level. The current gate generating circuit 84a of the comparator 841, the voltage pulse generating circuit 84b, and the voltage drop detecting circuit 85 for inputting the current gate signal and the voltage pulse signal from the current gate generating circuit 84a and the voltage pulse generating circuit 84b, respectively. In this case, the current gate detection level and the voltage pulse detection level (determined value) set in advance are changed, for example, in accordance with the output from the power supply unit 6 of the pair of targets 41a and 41b. High precision arc detection.

Next, the detection of occurrence of arc discharge in the arc detecting circuit 8 will be described. First, the switching transistor 65 is controlled by a control signal from the first CPU circuit 61 of the power supply unit 6, and DC power is supplied to the oscillation unit 7 via the DC power lines 64a and 64b. Next, the operation of the first to fourth switching transistors 72a, 72b, 72c, and 72d is controlled by the control signal from the second CPU circuit 71, and an alternating voltage is applied to the pair of targets 41. At this time, the current drop detection circuit 85 inputs a reset signal and resets it (see FIG. 3(c)).

Next, the absolute value of the current waveform from the first absolute value detecting circuit 83a and the current gate detecting level are input to the comparator 841 of the current gate generating circuit 84a via the detecting circuit 77a, and when the absolute value exceeds When the current gate detection level is normal, it is regarded as glow discharge in the vacuum reaction chamber 11, and a normal discharge signal is input to the current drop detection circuit 85 (refer to Fig. 3(c)). In this case, it is preferable to input a normal discharge signal after the phases of the output voltage waveform and the output current waveform are substantially identical to each other.

Next, the absolute values from the first and second absolute value detecting circuits 83a and 83b, the current gate detecting level, and the preset voltage pulse detecting level are input to the respective comparators 841, and The current gate generating circuit 84a and the voltage pulse generating circuit 84b input the current gate signal and the voltage pulse signal to the voltage drop detecting circuit 85, and input the high speed clock signal to the voltage drop detecting circuit 85 to start the arc discharge. The occurrence of detection (refer to Figure 3 (c)).

Here, when arcing occurs between the pair of targets 41a and 41b, first, the output voltage to the pair of targets 41a and 41b is lowered, and then the output current is rapidly increased. In this case, the current gate signal is maintained at "1" (on state), and only the voltage pulse signal forms "0" (off state) (refer to FIG. 3(b)). That is, in the detection of arc discharge occurrence, the voltage drop detection circuit 85 determines whether the current gate signal is "0", and when the current gate signal is "0", the current gate signal is turned off. . Next, if the current gate signal forms "1", a voltage pulse lowering wait state is formed. In this case, it is judged whether the voltage pulse signal is "1", and if the voltage pulse signal is "1", it is judged that normal glow discharge occurs. Then, when the current gate signal forms "0", if the voltage pulse signal is "0", the current gate signal is turned off.

On the other hand, when the voltage pulse signal of the current gate signal is "1" is lowered, the voltage drop is generated when the voltage pulse signal is "0" (see FIG. 3(d)). In this case, since the voltage drop is detected by the delay of the one-time pulse or the two-cycle pulse amount of the high-speed clock signal, the occurrence of the arc discharge can be quickly detected (see FIG. 3(e)).

When the arc detecting means 8 detects the occurrence of the arc discharge, the arc discharge is generated and output to the second CPU circuit 71. For example, the control signal from the second CPU circuit 71 is used, and the second driver circuit 73a controls the oscillation. The operation of each of the switching transistors 72a, 72b, 72c, and 72d of the switch circuit 72 blocks the output of the pair of targets 41a and 41b.

Thereby, the arc discharge is directly detected by the length of the voltage drop of the output voltage waveform of the pair of targets 41a and 41b, and the change in the current value between the targets 41a and 41b is obtained or the targets 41a and 41b are obtained. When the actual value or the average value of the output voltage is detected to detect the arc discharge, the occurrence of the arc discharge can be quickly detected, and the output from the AC power source E can be blocked. As a result, the energy at the time of occurrence of the arc discharge can be reduced to effectively prevent the occurrence of particles or splashes, and the occurrence of a voltage drop is detected when the output current flows. Therefore, for example, erroneous detection of the arc discharge can be reduced.

4(a) to 4(e), the reference numeral 80 is an arc detecting means of another embodiment. The arc detecting means 80 is a person who detects the arc discharge only by the output voltage, and has a voltage transformer coupling amplifier 810 that amplifies the output voltage from the detecting circuit 77a, and detects amplification by the voltage transformer coupling amplifier 810. The absolute value of the absolute value of the output voltage waveform is detected by the circuit 820. Further, the arc detecting means 80 has a voltage pulse generating circuit 830 for inputting a comparator 830a for inputting an absolute value from the absolute value detecting circuit 820 and a voltage pulse detecting level, and an input from the voltage pulse generating circuit 830. The voltage of the voltage pulse signal is lowered by the detection circuit 840 and the pulse width detection gate generator 841.

Next, the detection of occurrence of arc discharge in the arc detecting circuit 80 will be described. First, the AC power source E is operated in the same manner as described above, and an AC voltage is applied to the pair of targets 41a and 41b. At this time, the reset signal is input to the voltage drop detection circuit 840 and reset (see FIG. 4(c)).

Next, the absolute value from the absolute value detecting circuit 820 and the preset voltage pulse detecting level are input to the comparator 830a, and the voltage pulse generating circuit 830 outputs the voltage pulse signal to the voltage drop detecting circuit 840, and will be normal. The discharge signal and the high-speed clock signal are input to the voltage drop detection circuit 840, and detection of occurrence of arc discharge is started (refer to FIG. 4(c)). Then, a voltage wide gate signal having a normal glow discharge state in the pulse width detecting gate generator 841 is generated by a voltage pulse signal input to the voltage drop detecting circuit 840, and the voltage gate signal is maintained. 1" (on state), when only the voltage pulse signal is "0" (off state), arc discharge is detected by the drop of the output voltage (see Fig. 4 (b)).

That is, in the detection of occurrence of arc discharge, the circuit 840 is detected under voltage drop, and when the voltage gate signal is "0", the voltage gate signal is turned off. Next, if the voltage gate signal forms "1", the voltage pulse signal is lowered to wait, and in this case, it is judged whether or not the voltage pulse signal is "1", and in this state, normal glow discharge is judged to occur. Moreover, when the voltage gate signal forms "0", if the voltage pulse signal is also "0", the voltage gate signal is turned off.

On the other hand, in the standby state of the voltage pulse signal drop, when the voltage pulse signal forms "0", a voltage drop occurs, and it is judged that an arc discharge is generated (refer to FIG. 4(d)). In this case, since the voltage drop is detected by the delay of the one-time pulse or the two-cycle pulse amount of the high-speed clock signal, the occurrence of the arc discharge can be quickly detected (refer to FIG. 4(e)).

Thereby, the arc discharge is detected only by the voltage between the pair of targets 41a and 41b. Therefore, it is not necessary to consider the phase shift of the voltage and the current, and the arc can be detected even when the phase of the voltage and the current do not coincide with each other at the time of starting. Discharge occurs.

Further, in the above embodiment, the voltage gate signal is directly generated by the absolute value. However, the present invention is not limited thereto. For example, the magnitude of the voltage width detected may be changed. In this case, the state in which the arc discharge is not detected is detected by another method, and then the voltage width of the non-arc discharge is relatively determined, and the voltage width at the time of the arc is detected to be small as a reference.

5(a) and 5(b), the component symbol 9 is an arc detecting means of another embodiment. The arc detecting means 9 is also a person who detects the arc discharge only by the output voltage, and has a voltage transformer coupling amplifier 91 that amplifies the output voltage from the detecting circuit 77a, and a conventional method that can remove the noise of the output voltage. The noise filter 92 and the differential circuit 93. The output from the differentiating circuit 93 is input to the absolute value detecting circuit 94, and is provided with a voltage pulse generating circuit which is provided with a comparator 95a for inputting the absolute value and the voltage differential waveform detecting level, respectively.

Next, the detection of occurrence of arc discharge in the arc detecting circuit 9 will be described. First, the AC power source E is operated in the same manner as described above, and an AC voltage is applied to the pair of targets 41a and 41b. Next, the absolute value from the absolute value detecting circuit 94 passing through the differentiating circuit 93 and the preset voltage differential waveform detecting level are input to the comparator 95a. In this case, when the absolute value is lower than the voltage differential waveform detection level, it is judged that the normal glow discharge occurs. On the other hand, when the absolute value exceeds the voltage differential waveform detection level, it is judged that arc discharge has occurred (refer to FIG. 5(b)).

Thereby, the arc discharge detecting circuit 9 can be realized with a simple circuit configuration, and since the occurrence of the arc discharge is detected only by the voltage between the targets 41a and 41b, the phase shift of the voltage and the current can be omitted, even if The occurrence of arc discharge can be detected even when the phase of the voltage and current are not the same at the time of starting.

6(a) and 6(b), the component symbol 90 is an arc detecting means of another embodiment. The arc detecting means 90 is a person who detects the occurrence of arc discharge by a difference waveform between the output voltage waveform and the output current waveform, and has a current sense amplifier 910 and a current transformer that amplify the output voltage and the output current from the detecting circuit 77a. The coupled amplifier 920 and the conventional noise filters 930a and 930b that can remove the noise of the output voltage waveform and the output current waveform, and the amplitudes of the output voltage waveform and the output current waveform through the noise filters 930a and 930b can The first and second gain adjustment circuits 940a and 940b are adjusted in a substantially uniform manner.

Further, the arc detecting means 90 is a differential amplifier having a conventional structure in which an output voltage waveform and an output current waveform are input to the first and second gain adjusting circuits 940a and 940b, respectively, and are differentiated according to the difference. 950. An absolute value detecting circuit 960 that detects the absolute value of the differential waveform from the differential amplifier 950, and a differential waveform detecting circuit 970 that sets the comparator 970a that inputs the absolute value and the differential waveform detecting level, respectively.

Next, the detection of occurrence of arc discharge in the arc detecting circuit 90 will be described. First, the AC power source E is operated in the same manner as described above, and an AC voltage is applied to the pair of targets 41a and 41b. Next, using the control signal from the second CPU circuit 71, the second driver circuit 73a controls the switching transistors 72a, 72b, 72c, and 73d of the oscillation switching circuit 72 to be turned on and off, and is controlled to output voltage and output current. The phases will be roughly the same as each other.

Then, in accordance with the output voltage and the output current detected by the detection circuit 77a, the second CPU circuit 71 inputs the current gain adjustment signal and the voltage gain adjustment signal to the first and second gain adjustment circuits 940a and 940b, respectively. After the first and second gain adjustment circuits 940a and 940b adjust the output voltage waveform and the amplitude of the output current waveform to substantially match, the output voltage waveform and the output current waveform are input to the differential amplifier 950.

Next, the differential amplifier 950 inputs the absolute value of the differential waveform passing through the absolute value detecting circuit 960 and the preset differential waveform detecting level to the comparator 970a. In this case, when the absolute value of the differential waveform is lower than the differential waveform detection level, it is judged that a normal glow discharge occurs. On the other hand, when the absolute value exceeds the differential waveform detection level, it is judged that arc discharge has occurred (refer to FIG. 6(b)).

Thereby, the waveform used in the arc detection is synthesized by the difference between the appropriately adjusted current waveform and the voltage waveform. When the arc discharge occurs, the output of the differential waveform forms a larger output waveform (refer to FIG. 6). (b)), so it is not susceptible to noise, and the result is less false detection.

Further, in the above-described embodiment, the two targets 41a and 41b disposed in the vacuum reaction chamber 11 are described. However, the present invention is not limited thereto, and a plurality of (three or more) targets may be provided in parallel to enable at least It is also applicable to the arc detecting method of the present invention that two AC targets are alternately applied with an alternating voltage.

1. . . Sputtering device

41a, 41b. . . target

6. . . Power supply department

7. . . Oscillation section

8. . . Arc detection means

E. . . AC power

K. . . Power cable

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

Figure 2 is a diagram for explaining an AC power source.

Fig. 3(a) is a schematic view showing an arc detecting means, (b) is a view for explaining a change in arc discharge when a signal of a current waveform and a voltage waveform is generated, and (c) is for explaining a circuit for detecting a voltage drop. The input of the signal, (d) is a flowchart for explaining the detection of the arc discharge, and (e) is the change of the signal when the arc discharge shown in (b) is enlarged.

Fig. 4(a) is a view schematically showing an arc detecting means of another embodiment, (b) is a view for explaining a change in arcing of a signal from a voltage waveform, and (c) is for explaining a circuit for detecting a voltage drop. The input of the signal, (d) is a flowchart for explaining the detection of the arc discharge, and (e) is the change of the signal when the arc discharge shown in (b) is enlarged.

Fig. 5(a) is a schematic view showing another embodiment of the arc detecting means, and Fig. 5(b) is a view for explaining a change in the arc discharge when the voltage waveform is generated.

Fig. 6(a) is a view schematically showing another embodiment of the arc detecting means, and Fig. 6(b) is a view for explaining a change in the occurrence of arcing of the differential waveform.

8. . . Arc detection means

41a, 41b. . . target

71. . . Second CPU circuit

76. . . Output transformer

77a. . . Detection circuit

81. . . Current sense amplifier

82. . . Voltage transformer coupled amplifier

83a. . . First absolute value detection circuit

83b. . . 2nd absolute value detection circuit

84a. . . Current gate generating circuit

84b. . . Voltage pulse generating circuit

85. . . Voltage drop detection circuit

841. . . Comparators

K. . . Output cable

Claims (18)

A sputtering method is a method of applying a voltage to a pair of targets provided in a vacuum reaction chamber by alternately changing a polarity at a predetermined frequency via an alternating current power source, and alternately switching each target into an anode electrode and a cathode electrode to cause a glow discharge to be generated at the anode. A sputtering method for forming a plasma environment to sputter each target between the electrode and the cathode electrode, wherein the output voltage waveform of the pair of targets is detected, and when the voltage drop of the output voltage waveform is determined to be normal When the glow discharge is shorter, the output from the above AC power source is blocked. The sputtering method according to claim 1, wherein an output current waveform between the pair of targets is detected, and if an absolute value of the output current waveform exceeds a predetermined value, the glow discharge is regarded as being generated. The current value of the output current waveform is used to generate a current gate signal, and the voltage pulse signal is generated from the absolute value of the output voltage waveform. If the voltage pulse signal is turned off in the open state of the current gate signal, the output is determined. The voltage drop time of the voltage waveform is shorter than the normal glow discharge time. The sputtering method according to claim 1 or 2, wherein in the sputtering, the phase of the output current waveform and the output voltage waveform of the conventional target can be controlled to be substantially identical. The sputtering method according to claim 2, wherein the predetermined value is changed in accordance with an input power from an alternating current power source to a pair of targets. The sputtering method of claim 1, wherein the voltage pulse signal is generated from an absolute value of the output voltage waveform, and a pulse width of the voltage pulse signal is detected, and when the pulse width is smaller than a predetermined value, the above is determined. The voltage drop time of the output voltage waveform is shorter than the normal glow discharge time. The sputtering method according to claim 5, wherein the predetermined value is directly determined from an absolute value of an output voltage waveform, or the pulse width at which arc discharge is not generated is measured in advance to relatively determine the predetermined value. The sputtering method of claim 1, wherein a differential waveform proportional to a voltage drop of the output voltage waveform is detected, and when the differential waveform becomes larger than a predetermined value, determining a voltage drop of the output voltage waveform The time is shorter than the normal glow discharge. The sputtering method of claim 7, wherein the noise of the output voltage waveform is removed via the filter circuit before the differential waveform is detected. The sputtering method of claim 7 or 8, wherein the output voltage waveform is substantially sinusoidal. The sputtering method according to claim 1, wherein the output current waveform between the pair of targets is detected, and the output voltage waveform and the phase and amplitude of the output current waveform are substantially aligned. Detecting differential waveforms of the waveforms, when the differential waveform When the value exceeds the predetermined value, it is judged that the voltage drop time of the output voltage waveform is shorter than the normal glow discharge time. The sputtering method of claim 10, wherein the noise of the output voltage waveform and the output current waveform is removed by the filter circuit before the differential waveform is detected. The sputtering method of claim 10, wherein the output voltage waveform and the output current waveform are substantially sinusoidal. A sputtering apparatus characterized by: an arc detecting means comprising: a target disposed in one pair in a vacuum reaction chamber; and alternately changing a polarity at a predetermined frequency to apply a voltage between the pair of targets The AC power source detects a voltage drop of a voltage drop time to the output voltage waveform of the target that is shorter than a normal glow discharge time; and an interrupting means that interrupts the output from the arc detection circuit from the AC power source Output. The sputtering apparatus according to claim 13, wherein the AC power supply is provided with a phase adjustment means for substantially matching the phases of the output voltage waveform and the output current waveform of the pair of targets. The sputtering apparatus according to claim 13 or 14, wherein the arc detecting means is: a first absolute value detecting circuit and a second absolute value detecting circuit, wherein the pair of targets are detected The output current waveform and the absolute value of the output voltage waveform; the current gate signal generating circuit and the voltage pulse signal generating circuit, a comparator for inputting an absolute value and a detection level from the first absolute value detecting circuit and the second absolute value detecting circuit, and a voltage drop detecting circuit for inputting a current gate signal generating circuit And a current gate signal and a voltage pulse signal of the voltage pulse signal generating circuit; if the voltage gate signal is turned off in the open state of the current gate signal, it is detected to be shorter than a normal glow discharge The voltage of time drops. The sputtering apparatus of claim 13 or 14, wherein the arc detecting means is an absolute value detecting circuit that detects an absolute value of an output voltage waveform between the pair of targets; a pulse generating circuit for setting a comparator for inputting an absolute value and a detected level from the absolute value detecting circuit; and a voltage drop detecting circuit for inputting a voltage pulse signal from the voltage pulse generating circuit; The pulse width of the voltage pulse signal input to the voltage drop detection circuit is detected, and when the pulse width is smaller than the predetermined value, a voltage drop is detected shorter than the normal glow discharge. The sputtering apparatus of claim 13 or 14, wherein the arc detecting means is: a differential circuit that detects a differential proportional to a voltage drop of an output voltage waveform between the pair of targets Waveform; absolute value detection circuit that detects the voltage from the differential circuit An absolute value of the waveform; and a voltage differential waveform circuit having a comparator that inputs an absolute value and a detected level from the absolute value detecting circuit; and is configured to become larger when the absolute value of the differential waveform exceeds a predetermined value It detects a voltage drop that is shorter than the normal glow discharge. The sputtering apparatus according to claim 13 or 14, wherein the arc detecting means is: a first and second gain adjusting circuit that outputs an output voltage waveform and an output current between the pair of targets The amplitude of the waveform can be adjusted in a substantially uniform manner; the differential amplifier detects a differential waveform of the output voltage waveform and the output current waveform from each gain adjustment circuit; and an absolute value detection circuit detects the differential from the differential An absolute value of the differential waveform of the amplifier; and a differential waveform detecting circuit having a comparator for inputting a differential waveform from the absolute value detecting circuit and a detected level; wherein the absolute value of the differential waveform is When it is larger than the predetermined value, a voltage drop is detected shorter than the normal glow discharge.