JP2007186724A - Sputtering method and sputtering apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively detect arc discharge generated through a part subjected to capacitive coupling when film deposition is performed by sputtering using an AC power source. <P>SOLUTION: Voltage is applied to a pair of targets 41a, 41b provided in a vacuum chamber 11 via an AC power source E at prescribed frequency in such a manner that polarity is alternately changed, each target is alternately changed to an anode electrode and a cathode electrode, glow discharge is generated between the anode electrode and the cathode electrode to form a plasma atmosphere, and each target is subjected to sputtering. At that time, the voltage between each target and a ground level is respectively detected, and, when the detected voltage exceeds a prescribed value, the output from the AC power source is cut off. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sputtering method and a sputtering apparatus capable of forming a film on the surface of a processing substrate using an AC power source.

  In the sputtering method, ions in a plasma atmosphere are accelerated and bombarded toward a target formed in a predetermined shape according to the composition of a thin film to be formed on the surface of the processing substrate, and target atoms are scattered, thereby processing the substrate surface. A thin film is formed. In this case, a plasma atmosphere may be formed by applying a voltage to the target, which is a cathode electrode, via a DC power supply or an AC power supply to cause glow discharge between the cathode electrode and the anode electrode. When an AC power supply is used, a more stable discharge can be obtained by applying the opposite phase voltage to cancel the charge accumulated on the target surface.

  As a sputtering apparatus using an AC power source, a pair of targets are arranged in a vacuum chamber, and a voltage is applied to the pair of targets by alternately changing the polarity at a predetermined frequency via the AC power source. There is known a technique in which an anode electrode and a cathode electrode are alternately switched, a glow discharge is generated between the anode electrode and the cathode electrode to form a plasma atmosphere, and each target is sputtered (for example, Patent Document 1).

During such glow discharge, it is known that arc discharge occurs for some reason, and if this arc discharge occurs locally at the cathode electrode, problems such as generation of particles and splash are induced, which is good. Film formation is impossible. Therefore, in the past, focusing on the fact that the voltage and current between the targets change greatly when arc discharge occurs, for example, the effective value or average value of the output voltage from the AC power source to the pair of targets is obtained. It has been considered to convert the output voltage to DC and detect the occurrence of arc discharge based on this DC voltage.
International Publication No. WO2003 / 14410 (see, for example, claim 1)

  By the way, in the above sputtering apparatus, each target is alternately switched to an anode electrode and a cathode electrode to form a plasma atmosphere, so although the output part from the AC power source to each target is not grounded, this output part is It is capacitively coupled to ground level components provided in the vacuum chamber, such as a vacuum chamber and a protective plate. For this reason, arc discharge may occur through the capacitively coupled portion.

  When an arc discharge occurs through a capacitively coupled portion, an output voltage waveform between a pair of targets generates only a momentary voltage drop of several hundred nS to μS or less, and this voltage drop amount (voltage drop level) is The amount of voltage drop when arc discharge occurs between targets is extremely small. For this reason, the arc discharge detection method described above cannot effectively detect the arc discharge generated through the capacitively coupled portion. As a result, problems such as generation of particles and splash are induced, and good film formation cannot be performed. There was a case.

  Therefore, in view of the above points, an object of the present invention is to provide a sputtering method and a sputtering apparatus that can effectively detect an arc discharge generated through a capacitively coupled portion when forming a film by sputtering using an AC power source. It is in.

  In order to solve the above-described problem, the sputtering method according to claim 1 applies a voltage to a pair of targets provided in a vacuum chamber by alternately changing the polarity at a predetermined frequency via an AC power source. In which sputtering is performed by alternately switching between the anode electrode and the cathode electrode, generating a glow discharge between the anode electrode and the cathode electrode to form a plasma atmosphere, and sputtering each target. Are detected, and when the detected voltage exceeds a predetermined value, the output from the AC power supply is cut off.

  According to the present invention, when a voltage is applied to a pair of targets via an AC 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 atmosphere. Then, ions in the plasma atmosphere are accelerated and bombarded toward the target serving as the cathode electrode, and the target atoms are scattered to form a thin film on the surface of the processing substrate.

  When an arc discharge occurs through the capacitively coupled portion during sputtering, a voltage drop occurs between the target (cathode electrode) where the arc discharge occurred and the ground level, and the target becomes the ground level. The output from the AC power supply to the other target where no discharge has occurred shifts to the positive voltage side. In this case, since the voltage is detected between each target and the ground level, the arc discharge generated through the capacitively coupled portion can be effectively detected from the voltage shifted to the positive voltage side. As a result, the output to each target is cut off, the energy at the time of arc discharge occurrence is reduced, and the generation of particles and splashes can be effectively prevented.

  If the predetermined value of the voltage is set to 100 V or more, even if noise of several tens to hundreds of V is actually generated when the film is formed by sputtering, the arc is not affected by this noise. The occurrence of discharge can be detected.

  When the output voltage waveform to the pair of targets is detected and it is determined that the voltage drop time of the output voltage waveform is shorter than that during normal glow discharge, the output from the AC power supply is cut off. If so, the occurrence of arc discharge can be detected directly from the length of the voltage drop time of the output voltage waveform to the target, and arc discharge generated between a pair of targets can be detected quickly, and as a result, it is generated through the capacitively coupled part. Combined with the effective detection of the arc discharge, a good film formation by sputtering is possible.

  The sputtering apparatus according to claim 4 includes a pair of targets provided in the vacuum chamber, and an alternating current power source that alternately applies a voltage at a predetermined frequency and applies a voltage between the pair of targets. First arc detecting means for detecting that the voltage between the target and the ground level has exceeded a predetermined value, and blocking means for cutting off the output from the AC power supply by the output from the first arc detecting circuit. It is provided.

  In this case, the first arc detecting means is constituted by a voltage dividing circuit configured by connecting resistors in series between each target and the ground level, and a positive voltage and a detection level from the voltage dividing circuit are respectively input. And an arc detection circuit having a comparator.

  Further, there is provided a second arc detecting means for detecting a voltage drop in which the voltage drop time of the output voltage waveform to the target is shorter than that in the normal glow discharge, and an output from the second arc detection circuit is provided. You may enable it to interrupt | block the output from AC power supply by the said interruption | blocking means.

  As described above, the sputtering method and the sputtering apparatus of the present invention have an effect that the arc discharge generated through the capacitively coupled portion can be detected effectively.

  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 in-line type, and has a vacuum chamber 11 that can be maintained at a predetermined degree of vacuum via a vacuum exhaust means (not shown) such as a rotary pump or a turbo molecular pump. A substrate transfer means is provided in the upper part of the vacuum chamber 11. This substrate transport means has a known structure, for example, has a carrier 2 on which the process substrate S is mounted, and intermittently drives the drive means to sequentially transport the process substrates S to a position facing a target to be described later. it can.

A gas introducing means 3 is provided in the vacuum chamber 11. The gas introduction means 3 communicates with a gas source 33 through a gas pipe 32 provided with a mass flow controller 31, and O ₂ , H ₂ O, H ₂ , used for sputtering gas such as Ar, or reactive sputtering. A reactive gas such as N ₂ can be introduced into the vacuum chamber 11 at a constant flow rate. A cathode electrode C is disposed below the vacuum chamber 11.

  The cathode electrode C has a pair of targets 41a and 41b disposed to face the processing substrate S. Each target 41a, 41b is manufactured by a known method according to the composition of a thin film to be formed on the processing substrate S, such as Al, Ti, Mo, or ITO, and is formed in a substantially rectangular parallelepiped (rectangular in a top view). Yes. Each target 41a, 41b is joined to a backing plate 42 for cooling the target 41a, 41b during sputtering through a bonding material such as indium or tin, and is attached to the frame of the cathode electrode C through an insulating material (not shown). In the vacuum chamber 11, it is arranged in a floating state.

  In this case, the targets 41a and 41b are juxtaposed so that the unused sputtering surface 411 is located on the same plane parallel to the processing substrate S, and between the opposing side surfaces 412 of the targets 41a and 41b. Does not have any components such as an anode or a shield. The external dimensions of the targets 41a and 41b are set to be larger than the external dimensions of the processing substrate S when the targets 41a and 41b are arranged side by side.

  Further, the cathode electrode C is equipped with a magnet assembly 5 positioned behind each of the targets 41a and 41b. The magnet assembly 5 includes a support plate 51 provided in parallel with the targets 41a and 41b. The support plate 51 is made of a rectangular flat plate formed so as to extend to both sides of the targets 41a and 41b along the longitudinal direction of the targets 41a and 41b. The support plate 51 amplifies the magnet's adsorption force. Made of magnetic material. On the support plate 51, a bar-shaped central magnet 52 along the longitudinal direction of the targets 41a and 41b and a peripheral magnet 53 provided along the outer periphery of the support plate 51 are provided. In this case, the volume when converted to the same magnetization of the central magnet 52 is, for example, equal to the sum of the volumes when converted to the same magnetization of the peripheral magnet 52 (peripheral magnet: center magnet: peripheral magnet = 1: 2: 1). It is designed to be.

  Thereby, balanced closed-loop tunnel-shaped magnetic fluxes are formed in front of the targets 41a and 41b, respectively, and the ions ionized in front of the targets 41a and 41b and the secondary electrons generated by sputtering are captured. The plasma density can be increased by increasing the electron density in front of each of 41a and 41b. The pair of targets 41a and 41b is connected to an output cable K that is an output unit from the AC power source E, and the pair of targets 41a and 41b are alternately changed in polarity at a predetermined frequency (1 to 400 KHz). Voltage can be applied.

  As shown in FIG. 2, the AC power source E includes an electric power supply unit 6 that can supply electric power, and an oscillation unit 7 that alternately changes polarity at a predetermined frequency and outputs a voltage to each target 41 a and 41 b. Composed. In this case, the waveform of the output voltage is a substantially sine wave, but is not limited thereto, and may be a substantially square wave, for example.

  The power supply unit 6 includes a first CPU circuit 61 that controls its operation, an input unit 62 to which commercial AC power (three-phase AC 200 V or 400 V) is input, and rectifies the input AC power to generate DC power. 6 diodes 63 for converting to DC, and plays a role of outputting DC power to the oscillation unit 7 via the DC power lines 64a and 64b.

  The power supply unit 6 is connected to a switching transistor 65 provided between the DC power lines 64a and 64b and a first CPU circuit 61 so as to be communicable, and controls the on / off of the switching transistor 65. A driver circuit 66a and a first PMW control circuit 66b are provided. In this case, a detection circuit 67a and an AD conversion circuit 67b are provided which have a current detection sensor and a voltage detection transformer and detect the current and voltage between the DC power lines 64a and 64b, and are provided via the detection circuit 67a and the AD conversion circuit 67b. Are input to the CPU circuit 61.

  On the other hand, the oscillating unit 7 includes four second CPU circuits 71 communicably connected to the first CPU circuit 61 and four oscillation switch circuits 72 provided between the DC power lines 64a and 64b. The second to fourth switching transistors 72a, 72b, 72c, 72d are connected to the second CPU circuit 71 in a communicable manner, and control the on / off of the switching transistors 72a, 72b, 72c, 72d. A driver circuit 73a and a second PMW control circuit 73b are provided.

  Then, by the second driver circuit 73a and the second PMW control circuit 73b, for example, on and off timings of the first and second switching transistors 72a and 72b and the third and fourth switching transistors 72c and 72d. When the operations of the switching transistors 72a, 72b, 72c, 72d are controlled so as to be inverted, sinusoidal AC power can be output via the AC power lines 74a, 74b from the oscillation switch circuit 72. In this case, a detection circuit 75a and an AD conversion circuit 75b for detecting an oscillation voltage and an oscillation current are provided, and are input to the second CPU circuit 71 via the detection circuit 75a and the AD conversion circuit 75b.

  The AC power lines 74a and 74b are connected to an output transformer 76 having a known structure via a resonance LC circuit in series or parallel or a combination thereof, and an output cable K from the output transformer 76 is connected to a pair of targets 41a and 41b. Are connected to each. In this case, a detection circuit 77a and an AD conversion circuit 77b are provided, which have a current detection sensor and a voltage detection transformer, and detect an output voltage and an output current to the pair of targets 41a and 41b. To be input to the second CPU circuit 71 via. This makes it possible to apply a constant voltage to the pair of targets 41a and 41b while changing the polarity alternately at a constant frequency via the AC power source E during sputtering.

  The output from the detection circuit 77a is connected to a detection circuit 78a that detects the output phase and frequency of the output voltage and output current, and through an output phase frequency control circuit 78b that is communicably connected to the detection circuit 78a. Thus, the phase and frequency of the output voltage and output current are input to the second CPU circuit 71. Thus, the on / off of each switching transistor 72a, 72b, 72c, 73d of the oscillation switch circuit 72 is controlled by the second driver circuit 73a by the control signal from the second CPU circuit 71, and the output voltage and output current are controlled. The output phase frequency control circuit 78b, the second CPU circuit 71, and the second driver circuit 73a constitute a phase adjusting means.

  Then, the processing substrate S is transferred to a position facing the pair of targets 41 a and 41 b by the substrate transfer means, and a 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 generate a plasma atmosphere. Form. As a result, ions in the plasma atmosphere are accelerated and bombarded toward one of the targets 41a and 41b that have become cathode electrodes, and target atoms are scattered to form a thin film on the surface of the processing substrate S.

  In this case, the magnet assembly 5 is provided with driving means such as a motor (not shown), and is reciprocated between the two positions along the horizontal direction of the targets 41a and 41b in parallel and at a constant speed by the driving means. In addition, the erosion area is obtained uniformly over the entire surface of the targets 41a and 41b.

  Incidentally, it is known that arc discharge occurs for some reason during the glow discharge. In this case, when the plasma atmosphere is formed by alternately switching the targets 41a and 41b to the anode electrode and the cathode electrode, the output cable K from the AC power source E to the targets 41a and 41b is not grounded. The cable K is capacitively coupled to a ground level component provided in the vacuum chamber 11 such as the illustrated vacuum chamber 11 or a not-shown deposition plate. For this reason, the above-described arc discharge may occur not only between the pair of targets 41a and 41b but also through a capacitively coupled portion. When arc discharge occurs locally, problems such as generation of particles and splash are induced. To form a thin film satisfactorily, the occurrence of arc discharge is detected quickly and the output from the AC power source E is immediately It is necessary to shut off.

  In the present embodiment, the oscillating unit 7 is provided with the first arc detecting means 8 that can detect the arc discharge generated through the capacitively coupled portion. When the first arc detection means 8 detects the occurrence of arc discharge, an arc output signal is output to the second CPU circuit 71 connected so as to be communicable, and the first CPU which can communicate with the second CPU circuit 71 is provided. The operation of the switching transistor 65 is controlled by the first driver circuit 66a by the control signal from the CPU circuit 71, and the output to the pair of targets 41a and 41b is immediately cut off.

  In this case, each switching transistor of the oscillation switch circuit 72 is controlled by the second driver circuit 73a with the control signal from the second CPU circuit 71 so that the potential between the AC power lines 74a and 74b becomes the same, for example. You may control the operation | movement of 72a, 72b, 72c, 72d, and interrupt | block the output to a pair of target 41a, 41b immediately.

  As shown in FIGS. 3 (a) and 3 (b), the first arc detection means 8 includes two resistors R1, between each output cable K to the pair of targets 41a and 41b and the ground level. Two arcs having two voltage dividing circuits 81a and 81b configured by connecting R2 in series, and a comparator 821 to which a positive voltage and a detection level from both voltage dividing circuits 81a and 81b are respectively input. It comprises detection circuits 82a and 82b.

  Next, arc discharge detection by the first arc detection means 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 72 a, 72 b, 72 c, 72 d is controlled by a control signal from the second CPU circuit 71, and an alternating voltage is applied to the pair of targets 41. At this time, the voltage waveform to the pair of targets 41a and 41b is, for example, a waveform close to a sine wave when the differential voltage is measured with an oscilloscope, but the pair of targets 41a and 41b serving as the anode and cathode electrodes are mutually connected. The plasma discharged between them is capacitively coupled with the internal components such as the vacuum chamber 11 and the deposition plate at the ground level, and when the output voltage waveform from the ground level to each of the targets 41a and 41b is measured, In order to show diode characteristics, the waveform is such that there is no positive portion of a negative voltage sine wave (see FIG. 3B).

  When an arc discharge is generated through a portion that is capacitively coupled for some reason, a voltage drop occurs between one of the targets 41a and 41b where the arc discharge has occurred and the ground level. On the other hand, the other targets 41a and 41b in which no arc is generated shifts as a positive voltage waveform from the negative voltage waveform that is below the ground level.

  Therefore, the voltage from each of the voltage dividing circuits 82a and 82b and a preset detection level are respectively input to the comparator 821, and when the voltage exceeds the detection level, arc discharge occurs through the capacitively coupled portion. (See FIG. 3B).

  In this case, even when arc discharge does not occur, noise of about several tens to hundreds of V is generated. Therefore, the detection level (voltage threshold) at the time of actual detection is set to 100 V or more although it varies depending on the process voltage. If this is the case, arc discharge can be detected without causing malfunction due to noise or the like.

  When the first arc detection means 8 detects the occurrence of arc discharge, the occurrence of arc discharge is output to the second CPU circuit 71, and for example, the second driver circuit 73a oscillates with a control signal from the second CPU circuit 71. The operation of each switching transistor 72a, 72b, 72c, 72d of the switch circuit 72 is controlled, and the output to the pair of targets 41a, 41b is cut off. Thereby, the arc discharge generated through the capacitively coupled portion can be detected effectively.

  After detecting the occurrence of arc discharge by any one of the arc detection circuits 82a and 82b and shutting off the output to the pair of targets 41a and 41b, the output from the AC power source E is restored after at least several μS has elapsed, and arc countermeasures are taken. It may be operated. In this case, the time until the output is restored may be changed according to the film forming process.

  Further, in the present embodiment, the voltage drop time of the output voltage waveform to the pair of targets 41a and 41b is sent to the oscillation unit 7 so that arc discharge generated between the pair of targets 41a and 41b can be detected quickly. The second arc detection means 9 for detecting a voltage drop that is shorter than that during normal glow discharge is provided. When the second arc detection means 9 detects the occurrence of arc discharge, it outputs a voltage drop arc output signal to the second CPU circuit 71 connected so as to be communicable and communicates with the second CPU circuit 71 as described above. The operation of the switching transistor 65 is controlled by the first driver circuit 66a by a control signal from the first CPU circuit 71, or the second driver circuit 73a by the control signal from the second CPU circuit 71. For example, the operation of each switching transistor 72a, 72b, 72c, 72d of the oscillation switch circuit 72 is controlled so that the potential between the AC power lines 74a, 74b is the same, and output to the pair of targets 41a, 41b. Shut off immediately.

  As shown in FIGS. 4A to 4E, the second arc detection means 9 includes an output voltage from the detection circuit 77a, a current sensor amplifier 91 and a voltage transformer amplifier 92 that amplify the output current, and a current. It has a first absolute value detection circuit 93a and a second absolute value detection circuit 93b for detecting the absolute values of the output current waveform and the output voltage waveform amplified by the sensor amplifier 91 and the voltage transformer amplifier 92. The second arc detection means 9 is a comparator to which the absolute values from the first and second absolute value detection circuits 93a and 93b and the preset current gate detection level and voltage pulse detection level are input. A current gate generation circuit 94a and a voltage pulse generation circuit 94b having 941 respectively, and a voltage drop detection circuit 95 to which the current gate signal and the voltage pulse signal from the current gate generation circuit 94a and the voltage pulse generation circuit 94b are respectively input. . In this case, the preset current gate detection level and voltage pulse detection level (predetermined values) are changed according to the output from the power supply unit 6 to the pair of targets 41a and 41b, for example, and the arc is more accurately You may enable it to detect.

  Next, detection of occurrence of arc discharge in the second arc detection circuit 9 will be described. Similarly to the above, first, the switching transistor 65 is controlled by the control signal from the first CPU circuit 61 of the power supply unit 6, and DC power is supplied to the oscillation unit 7 through the DC power lines 64 a and 64 b. Next, the operation of the first to fourth switching transistors 72 a, 72 b, 72 c, 72 d is controlled by a control signal from the second CPU circuit 71, and an alternating voltage is applied to the pair of targets 41. In this case, the current drop detection circuit 95 is reset by inputting a reset signal (see FIG. 4C).

  Next, the absolute value of the current waveform from the first absolute value detection circuit 93a and the current gate detection level are input to the comparator 941 of the current gate generation circuit 94a via the detection circuit 77a, and the absolute value is detected by the current gate detection. If it exceeds the level, it is considered that glow discharge has occurred in the vacuum chamber 11, and a normal discharge signal is input to the current drop detection circuit 95 (see FIG. 4C). 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 substantially coincide with each other.

  Next, the absolute values from the first and second absolute value detection circuits 93a and 93b, the current gate detection level and the preset voltage pulse detection level are input to each comparator 941, and current gate generation is performed based on the input values. A current gate signal and a voltage pulse signal are input from the circuit 94a and the voltage pulse generation circuit 94b to the voltage drop detection circuit 95, and a high-speed clock signal is input to the voltage drop detection circuit 95 to start detection of occurrence of arc discharge. 4 (c)).

  Here, when arc discharge occurs between the pair of targets 41a and 41b, first, the output voltage to the pair of targets 41a and 41b drops, and then the output current increases rapidly. In this case, the current gate signal remains “1” (ON state), but only the voltage pulse signal becomes “0” (OFF state) (see FIG. 4B). That is, in detecting the occurrence of arc discharge, the voltage drop detection circuit 95 determines whether the current gate signal is “0”. When the current gate signal is “0”, the current gate signal is turned off. Next, when the current gate signal becomes “1”, a voltage pulse drop waiting state is entered. In this case, it is determined whether the voltage pulse signal is “1”. If the voltage pulse signal is “1”, normal glow discharge is performed. Is determined to have occurred. If the voltage pulse signal becomes “0” when the current gate signal becomes “0”, the current gate signal returns to the off state.

  On the other hand, when the voltage pulse signal becomes “0” in the voltage pulse drop waiting state where the current gate signal is “1”, it is determined that a voltage drop has occurred and arc discharge has occurred (FIG. 4 ( d)). In this case, since the voltage drop can be detected with a delay of one clock or two clocks of the high-speed clock signal, the occurrence of arc discharge can be detected quickly (see FIG. 4E).

  When the occurrence of arc discharge is detected by the second arc detection means 9, the occurrence of arc discharge is output to the second CPU circuit 71 as described above. For example, the second driver circuit 73a is controlled by a control signal from the second CPU circuit 71. Thus, the operation of each switching transistor 72a, 72b, 72c, 72d of the oscillation switch circuit 72 is controlled, and the output to the pair of targets 41a, 41b is cut off.

  Thus, by directly detecting the occurrence of arc discharge from the length of the voltage drop time of the output voltage waveform to the pair of targets 41a and 41b, the change in the current value between the targets 41a and 41b and the output to the targets 41a and 41b are detected. Compared with what detects an arc discharge by calculating | requiring the effective value and average value of a voltage, arc discharge generation | occurrence | production can be detected rapidly and the output from AC power supply E can be interrupted | blocked. As a result, it is possible to effectively prevent the occurrence of particles and splash by reducing the energy at the time of arc discharge, and to detect the occurrence of voltage drop when the output current is flowing. Detection can be reduced.

  The second arc detection means 9 is not limited to the above-described one. For example, a voltage pulse signal is created from the absolute value of the output voltage waveform, and the pulse width of the voltage pulse signal is detected. When the pulse width becomes smaller than a predetermined value, the voltage drop time of the output voltage waveform may be determined to be shorter than that during normal glow discharge.

  In addition, when a differential waveform proportional to the voltage drop of the output voltage waveform is detected and the differential waveform becomes larger than a predetermined value, the voltage drop time of the output voltage waveform is shorter than that during normal glow discharge. Furthermore, after detecting the output current waveform between the pair of targets 41a and 41b and adjusting the phase and amplitude of the output voltage waveform and the output current waveform to substantially coincide, When a differential waveform is detected and the differential waveform becomes larger than a predetermined value, it may be determined that the voltage drop time of the output voltage waveform is shorter than that during normal glow discharge.

The figure which shows typically the sputtering device of this invention. The figure explaining AC power supply. (A) is a figure which illustrates schematically the arc detection means which concerns on another form. (B) is a figure explaining the change of the output voltage to each target at the time of arc discharge generation | occurrence | production. (A) is a figure which illustrates an arc detection means roughly. (B) is a figure explaining the change at the time of arc discharge generation of the signal from a current waveform and a voltage waveform. FIG. 6C is a diagram for explaining signal input to the voltage drop detection circuit. (D) is a flowchart explaining arc discharge detection. (E) is a figure which expands and shows the change of the signal at the time of the arc discharge shown to (b).

Explanation of symbols

Sputtering apparatus 41a, 41b Target 6 Power supply unit 7 Oscillating unit 8 First arc detection means 9 Second arc detection means E AC power supply K Power cable

Claims (6)

A voltage is alternately applied to a pair of targets provided in the vacuum chamber at a predetermined frequency via an AC power source, and each target is alternately switched between an anode electrode and a cathode electrode. In this sputtering method, a glow discharge is generated to form a plasma atmosphere, and each target is sputtered. The voltage between each target and the ground level is detected, and the detected voltage exceeds a predetermined value. The sputtering method characterized by shutting off the output from the AC power source. The sputtering method according to claim 1, wherein the predetermined value is set to 100 V or more. An output voltage waveform to the pair of targets is detected, and when it is determined that the voltage drop time of the output voltage waveform is shorter than a normal glow discharge, the output from the AC power supply is cut off. The sputtering method according to claim 1 or 2. A pair of targets provided in the vacuum chamber and an alternating current power source for alternately applying a polarity at a predetermined frequency to apply a voltage between the pair of targets, and a voltage between each target and the ground level is predetermined. A sputtering apparatus comprising: a first arc detecting means for detecting that the value has been exceeded; and a blocking means for cutting off the output from the AC power supply by the output from the first arc detection circuit. A voltage dividing circuit configured by connecting resistors in series between each target and the ground level, and a comparator to which a positive voltage and a detection level from the voltage dividing circuit are respectively input. The sputtering apparatus according to claim 4, further comprising an arc detection circuit having There is provided second arc detection means for detecting a voltage drop in which the voltage drop time of the output voltage waveform to the target is shorter than that during normal glow discharge, and the interruption is performed by the output from the second arc detection circuit. 6. The sputtering apparatus according to claim 4, wherein the output from the AC power source can be cut off by means.

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