JP2002352998A - Discharge detecting method and apparatus in treatment apparatus utilizing discharge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for detecting discharge, by which discharge can be surely detected without the need for adding an special circuit or an element for detecting discharge in a treatment apparatus utilizing discharge, detection of discharge can be achieved even when high-frequency power is low, and respective discharges can be separately surely detected, even when a plurality of discharges are caused to occur simultaneously in a treatment chamber. SOLUTION: The apparatus is applied to an apparatus for producing plasma by discharge, based on high-frequency power within a chamber 12 to conduct formation of a film or a processing treatment for a substrate 11 and constructed by a matching circuit 20 provided between a high-frequency power source 18 and a cathode device 14 in the chamber, detection means 25a, 25b for detecting capacitance values of variable capacitors 21, 22 included in the matching circuit and a control unit 30 that compares ranges of changes of the capacitor values or the like with capacitance values or the like, when matching is made as well as discharging, thereby determining that discharge has occurred.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for detecting a discharge in a processing apparatus using a discharge, and more particularly, to an apparatus for performing a film forming process or a processing process using a glow discharge to generate the glow discharge phenomenon. The present invention relates to a method and an apparatus capable of reliably detecting an appropriate matching condition on a high frequency power supply side even during low voltage discharge.

[0002]

2. Description of the Related Art In a process of manufacturing semiconductor devices such as LSIs, displays such as liquid crystal displays, and hard disks, a vacuum apparatus which performs various processes and processes using a plasma generated by a discharge phenomenon, particularly a glow discharge, is used. Have been. Examples of such an apparatus include a sputtering apparatus, a plasma CVD apparatus, and a reactive ion etching apparatus. As described above, in an apparatus that performs a film forming process or the like in a vacuum chamber, in order to increase productivity or deposit a high-quality film, a substrate is sequentially placed in a plurality of vacuum chambers arranged along a transport path. An automatic apparatus capable of performing a so-called continuous process or a continuous process for carrying a film formation process by transporting the film to a substrate is used. Therefore, in a vacuum apparatus that performs processing or processing using these plasmas, it is necessary to be able to detect that plasma is generated by discharge under set conditions and that the plasma is stably maintained.

[0003] The plasma used in the above apparatus is:
An inert gas, a reactive gas, or a mixed gas thereof is introduced into a chamber that is evacuated and decompressed, and a DC voltage, a high-frequency voltage, a microwave, or the like is applied between the electrodes provided in the chamber, thereby accelerating. It is generated by utilizing the collision ionization phenomenon of electrons and gas molecules. In the plasma, there are ions, electrons, atoms or molecules in the excited state, neutral active species generated by dissociation of molecules, etc., and light is emitted when the excited atoms or molecules return to the ground state, so-called atomic-specific plasma Luminescence is observed.

Conventionally, various methods have been proposed for detecting plasma, that is, detecting discharge. Among these methods, typical and basic methods will be described with reference to the accompanying drawings.

FIG. 5 shows a method for detecting light (discharge light) generated by the light emission phenomenon of plasma. The RF power output from the RF power source 102 is supplied to the chamber 101 where the processing or processing is performed via the automatic matching unit 103. 104 is a high-frequency electrode. The high-frequency electrode 104 is usually provided with a target. As a result, a discharge 105 is generated in the chamber 101, and plasma is generated. Needless to say, in order to induce a discharge in the chamber 101 to generate plasma, it is assumed that not only the supplied power condition but also the pressure condition and the source gas condition are satisfied. In the discharge 105 at the time of plasma generation, discharge light 106 is generated. On the other hand, a light receiving element (phototransistor or the like) 107 for detecting the discharge light 106 is provided at an appropriate position on the wall of the chamber 101 so that the discharge light 106 is detected. Further CP
A control unit 108 made of U is provided. Control unit 10
Reference numeral 8 has a function of controlling the output of the RF power supply 102 based on the discharge light detection signal output from the light receiving element 107 so that desired discharge light is generated in the chamber 101. That is, the control unit 108 turns on the operation state of the RF power supply 102 to output RF power, and determines whether the emission level of the discharge light 106 generated in the chamber 101 is higher than a set value. The continuation control is performed, and when it is low, the control of the discharge stop is performed. In the latter case, it means that a state where no discharge occurs is confirmed at the initial stage of starting the discharge.

FIG. 6 shows a method of detecting a self-bias voltage (Vdc) caused by a difference in mobility between ions and electrons in plasma. In FIG. 6, elements substantially the same as the elements described in FIG. 5 are denoted by the same reference numerals. Chamber 1
RF power is supplied from the RF power supply 102 to the high-frequency electrode 104 via the automatic matching unit 103. Chamber 10
1, a light receiving element for detecting discharge light is not specially provided. In this example, the internal configuration of the automatic matching unit 103 is clearly shown. The automatic matching unit 103 includes the variable capacitor 20
1, 202 and a coil 203, and a resistor 20
A Vdc detection unit 206 including 4,205 is provided. The self-bias voltage (DC voltage) detected by the Vdc detection unit 206 is fed back to the control unit 108.
The control unit 108 determines whether or not Vdc (DC component) is smaller than a set value. When Vdc (direct current component) is smaller, the controller 108 controls the continuation of the discharge.

FIG. 7 shows a device for applying a high-frequency voltage to discharge and detecting a reflected wave, which is a value of a matching result obtained by an automatic matching device provided for matching a load and a power supply. In FIG. 7, substantially the same elements as those described in the above example are denoted by the same reference numerals, and the above description is referred to, and the description will be omitted. In this device, the RF power source 102
The reflected wave monitor value that can be extracted by the control unit 108
Feedback. The control unit 108 determines whether or not the reflected wave monitor value is smaller than the set value. If the value is smaller, the discharge is continued, and if larger, the discharge is stopped.
Other configurations are the same as the above-described example.

As a document which discloses an invention relating to a configuration for detecting a discharge as described above, for example, Japanese Patent Application Laid-Open No. 52-31
No. 985 (“Detection device of glow discharge occurrence and display of matching state”), JP-A-59-41475 (“Discharge state monitoring device in discharge processing device”),
326490 ("discharge detector"),
No. 326214 ("Method for setting matching conditions for glow discharge emission spectroscopy and glow discharge emission spectroscopy").

[0009] Of the above documents, in particular, JP-A-7-3264
The discharge detector disclosed in Japanese Patent Publication No. 90 is an antenna for collecting a high-frequency signal from a high-frequency power supply line in a matching device.
Is provided, a harmonic is detected from a high-frequency signal collected by the antenna, the harmonic is rectified, and a voltage is measured from the rectified DC signal. This detection method utilizes the fact that the input waveform of the harmonic power at the time of discharge is distorted by the harmonic. If the voltage finally measured is higher than a predetermined value, it indicates that the discharge has started and continues, and if it is lower than the predetermined value, it means that the discharge has not started. ing.

[0010]

According to the method for detecting the discharge light shown in FIG. 5, a photoelectric element is required as the light receiving element 107. Further, in the case of a weak discharge based on low power of, for example, about 10 W, Has a problem that it may not be detected due to insufficient light intensity. In a sputtering apparatus, a plurality of targets may be discharged simultaneously in one chamber in order to form a complicated film structure. In such a case, there is a problem that it is not possible to perform the detection that distinguishes the discharge light originating from each of the plurality of targets.

According to the method for detecting self-bias shown in FIG. 6, a Vdc detection circuit is required. However, when a plurality of targets are to be discharged at the same time, since the Vdc detection circuit is provided individually for each of the targets, the discharge of each of the plurality of targets can be individually detected. In this self-bias detection method, when no discharge occurs, Vdc is not detected because ions and electrons are not ionized, and when the discharge occurs, the above-described ionization occurs and Vdc is detected. A discharge state can be detected for the target. However, even with this self-bias detection method, it is difficult to detect Vdc in the case of low power as in the case of light detection. Furthermore, in the case of a conductor target or a low-resistance insulator target, Vdc can be detected. However, in the case of a high-resistance insulator such as SiO ₂ , the target serves as a blocking capacitor, and the DC is floating. Vdc cannot be detected due to the state.

In the case of discharge generated by RF power (high-frequency power) supplied from an RF power source (high-frequency power source) 102, for example, in a high-frequency plasma generator using 13.56 MHz, it is necessary to maximize input power. It is necessary to perform electrical matching between the load side impedance and the power supply side impedance (normally 50Ω) between the load side (target) and the power supply side.

The general load-side impedance can be simply expressed as a cathode capacitance (C) for insulating a cathode from an electrode, an electrical loss (loss resistance: R) in a power introduction path, and power input. It consists of a plasma impedance (Z1) based on the generated plasma. Therefore, the load-side impedance when not discharging and when discharging changes by Z1. That is, RF
When a high-frequency voltage is applied from the power supply 102, mismatching occurs due to the plasma impedance Z1 when the target is conductive and due to the plasma impedance Z1 and the impedance change due to the target when the target is insulating. Then, the RF power supplied to the chamber 101 returns as a reflected wave without flowing to the equivalent circuit on the load side. The above automatic matching device is RF
The internal variable element is automatically adjusted to change each capacitance so as to reduce the reflected wave accompanying the input of power. Thereby, the impedances on the power supply side and the load side are matched.

Therefore, as described above, the adjustment is performed by inserting the automatic matching unit 103 for automatically performing the matching between the RF power source 102 and the target of the chamber 101.

In the method shown in FIG. 7, a traveling wave of RF power supplied from an RF power source 102 is configured by using an automatic matching unit 103 originally provided in an apparatus for processing or processing using plasma. The discharge is detected by monitoring the magnitude of the reflected wave. This method can easily detect the discharge without increasing the size of the apparatus, but may not discharge even when the matching is achieved, that is, even when the reflected wave is sufficiently small.
However, there is a problem in that heat generation and failure of No. 2 are caused, and the yield of products is deteriorated due to a defect in plasma processing.

In order to solve the above problem, the invention described in the above-mentioned Japanese Patent Application Laid-Open No. 7-326490 is proposed. According to the discharge detector according to the present invention, as described above,
Since the high-frequency waveform output from the RF power supply is different between the time of discharging and the time of non-discharging, this is solved by using this. On the other hand, according to the discharge detector proposed in the publication, it is necessary to provide an antenna at a distance along a high-frequency power supply line in order to detect a high-frequency waveform.
Further, even with this discharge detector, when a plurality of targets provided in the same chamber are simultaneously discharged, it has been difficult to individually detect the discharge by each target due to the interference of the discharges.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problem, and it is not necessary to add a special circuit or element for detecting a discharge in the detection of the discharge in a processing apparatus using the discharge. Discharge can be reliably detected, and discharge can be detected even when the high-frequency power supplied to the processing apparatus is low.Each discharge can be performed simultaneously when multiple discharges are generated in the processing chamber. An object of the present invention is to provide a method and an apparatus for detecting a discharge which can be individually and reliably detected.

[0018]

A discharge detecting method and a discharge detecting apparatus according to the present invention are configured as follows to achieve the above object.

A discharge detection method according to the present invention (corresponding to claim 1) is a method applied to an apparatus for generating a plasma by a discharge based on a high-frequency power and performing film formation and processing with the plasma. The impedance value of the variable impedance circuit element included in the matching circuit provided between the device and the cathode device is obtained, matched, and compared with the impedance value at the time of discharge, and the impedance value is included in a predetermined range. This is a method in which it is sometimes determined that a discharge has occurred. In the above method, preferably, the impedance value is calculated based on the operation amount of the drive motor that changes the impedance value of the variable impedance circuit element (corresponding to claim 2).
In the above method, preferably, the variable impedance circuit element is a variable capacitor, and the impedance value is a capacitance value (corresponding to claim 3). In the above method, preferably, the variable impedance circuit element is a variable coil, and the impedance value is an inductance value (corresponding to claim 4).

A discharge detecting apparatus according to the present invention (corresponding to claim 5) is an apparatus for generating plasma by discharge based on high-frequency power in a chamber and performing film formation and processing on a substrate with the plasma. A matching circuit provided between the high-frequency power supply and the cathode device of the chamber, detecting means for detecting an impedance value of a variable impedance circuit element included in the matching circuit, And an arithmetic processing means for determining that discharge has occurred when the value falls within a predetermined range as compared with the impedance value. In the above discharge detection device, preferably, the arithmetic processing means calculates the impedance value based on the operation amount of the drive motor that changes the impedance value of the variable impedance circuit element (corresponding to claim 6). In the above discharge detection device, preferably, the variable impedance circuit element is a variable capacitor, and the impedance value is a capacitance value (corresponding to claim 7). In the above discharge detection device, preferably, the variable impedance circuit element is a variable coil, and the impedance value is an inductance value (corresponding to claim 8).

[0021]

When the high frequency power is supplied from the high frequency power supply to the cathode device of the processing chamber, the high frequency power is supplied under the pressure condition and gas condition.
A glow discharge is induced in the processing chamber and a plasma is generated. Usually, an automatic matching circuit is provided between the high-frequency power supply and the cathode device, and when high-frequency power is supplied, the impedance (capacitance or the like) of an impedance circuit element (a variable capacitor or the like) included in the matching circuit reduces reflected waves to zero. Automatically adjusted, matched, and induced to discharge under the following conditions: However, strictly matching does not necessarily mean that a discharge has occurred in the processing chamber. The matching range is determined according to the processing conditions in the processing chamber, and a predetermined range that satisfies the discharge is further limited on the matching range, and whether the discharge is generated based on the limited matching / discharge range is determined. Or to detect. Within a predetermined range, the target of detection is the impedance value of the variable impedance circuit element included in the matching circuit. The operation amount of the drive motor that operates the variable impedance circuit element is extracted, and the impedance value of the variable impedance circuit element is obtained based on a predetermined relationship. Next, the impedance is compared with the impedance (at the time of matching) actually obtained in a certain specific process in advance, and based on whether or not the impedance is within the range satisfying the above-mentioned matching and discharging conditions. To detect the presence or absence of discharge. Based on a predetermined range that satisfies the matching condition and the discharging condition, the presence or absence of discharge is detected according to the impedance value of the variable impedance circuit element obtained from the automatic matching circuit. Even if the supplied high frequency power is low power, it is possible to reliably detect the presence or absence of discharge.

[0022]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

The structures, shapes, sizes and arrangements described in the embodiments are merely schematically shown to the extent that the present invention can be understood and implemented. Is merely an example. Therefore, the present invention is not limited to the embodiments described below, and can be modified in various forms without departing from the scope of the technical idea described in the claims.

FIG. 1 shows an example in which the discharge detection device according to the present invention is applied to a sputtering device. The sputtering apparatus is an example, and any apparatus can be used as long as it performs processing or processing using electric discharge. The sputtering apparatus 10 generates a plasma by inducing glow discharge to generate a plasma, and performs a film forming or processing process on the substrate 11 with the plasma; a substrate holder 13 for holding the substrate 11 on both surfaces; 13 are provided with two cathode (cathode) devices 14 arranged on both sides.
The chamber 12 has at least an evacuation mechanism and a vacuum pump (not shown) for creating a required vacuum state by depressurizing the inside.
And a gas supply mechanism (not shown) for introducing a process gas for generating plasma. The chamber 12 is formed of a conductive member, and has a structure and strength enough to withstand a high vacuum inside.
The substrate holder 13 transports the substrate 11 while holding the substrate 11 while being supported by a transport mechanism (not shown). Substrate holder 13
Is not limited to two. The substrate holder 13 holds the substrate such that the processing surface of the substrate 11 is parallel to the facing surface of the cathode device 14. Each of the two cathode devices 14 has an electrode (cathode) 15 and a target 16. The target 16 is formed of the same material as the film to be formed on the substrate 11. A target 16 is attached to the inner surface of the electrode 15, and the inner surface of the target 16 faces the internal space of the chamber 12. Target 16
Is substantially parallel to the processing surface of the substrate 11 conveyed by the substrate holder 13. Target 1
6, a target cover 17 is further provided around the periphery along the side.

Each of the two cathode devices 14 is individually connected to a corresponding high frequency power supply (RF power supply) 1 for glow discharge.
8 is connected. An automatic matching circuit 20 is provided between the electrode 15 on the rear side of the cathode device 14 and the high-frequency power supply 18 for electrical matching between the two.

The automatic matching circuit 20 includes two variable capacitors 21 and 22 and a coil 23 as main circuit elements. The value of the capacitance of the variable capacitor 21 is VC1, the value of the capacitance of the variable capacitor 22 is VC2, and the value of the inductance of the coil 23 is L. The connection structure between the variable capacitors 21 and 22 and the coil 23 is conventionally known. The circuit configuration of the automatic matching circuit 20 is not limited to the illustrated one.

In the automatic matching circuit 20, the variable capacitors 21 and 22 can be individually changed in capacitance value by a drive motor 24 which is preferably a stepping motor (pulse motor). Further, the value of the capacitance of the variable capacitors 21 and 22 can be read based on the function of monitoring each variable capacitor. The monitoring function of each of the variable capacitors 21 and 22 is realized by detecting the rotation operation position (operation amount) of the corresponding drive motors 24a and 24b. Encoders 25a and 25b are provided as means for detecting the amount of rotation of the drive motors 24a and 24b, respectively.

Further, in the automatic matching circuit 20, each of the driving motors 24a and 24b has a motor driving unit 33.
a and 33b are provided. Motor drive units 33a, 3
3b gives a drive signal for operating a corresponding drive motor and receives an operation amount of the drive motor as an output signal from each encoder. Automatic matching circuit 2
In 0, a matching device control unit 35 is provided for each of the two motor driving units 33a and 33b to receive commands from a higher-level control device.

A control device 30 is provided for the automatic matching circuit 20 having the above configuration. The control device 30 includes a CPU for performing arithmetic processing, a memory for storing various control programs and data, and various functional units are realized by executing the various programs by the CPU. In the block of the control device 30, the illustration of the CPU and the memory is omitted, and only the functional units are shown. The control device 30 includes an arithmetic processing unit 31, two power supply adjustment units 32 that adjust the outputs of the two high-frequency power supplies 18, and two automatic matching circuits 2.
The operation position input / output unit 34a, which exchanges a command signal and a signal relating to the operation position with each matching unit control unit 35 within 0,
34b are provided. Inside the control device 30, 2
Automatic matching circuit 2 corresponding to each of the two cathode devices 14
A corresponding circuit portion is provided for each 0. The arithmetic processing unit 31 receives a required signal (data) from each automatic matching circuit 20 and performs discharge detection and operation control of the high-frequency power supply 18 based on the discharge detection as described later. The arithmetic processing unit 31 of the control device 30 also controls automatic matching of the automatic matching circuit 20.

In the above configuration, high-frequency power is supplied from the high-frequency power supply 18 between the substrate 11 and the target of the cathode device 14 in the chamber 12 of the sputtering apparatus 10 so that other predetermined conditions such as matching are satisfied. Under these conditions, a glow discharge is generated to generate plasma. In the glow discharge, a required pressure condition is satisfied by exhaustion, a process gas (a rare gas such as argon, a reactive gas such as oxygen, or a mixed gas thereof) is introduced, and necessary power is supplied from a high frequency power supply 18. , Induced. Confirmation of the discharge is performed by the confirmation means. In order to maintain the discharge, the variable capacitors 21 and
The capacitance value of 22 is adjusted according to the process conditions.

Next, the principle (method or basic configuration) of discharge detection will be described in more detail with reference to FIGS. 2 and 3 based on the configuration of FIG. 1 described above. 2 and 3, the same reference numerals are given to substantially the same elements as those described with reference to FIG. FIG. 2 shows a high-frequency power supply system for one cathode device 14 in the chamber 12, a control device 30 for issuing a command to the high-frequency power supply 18, and a state feedback system from the automatic matching circuit 20 to the control device 30. 4 is a flowchart showing the control content of the high-frequency power supply 18 executed by the arithmetic processing unit 31 of the control device 30 according to the feedback content.

In an automatic matching circuit 20 provided between the high-frequency power supply 18 and the cathode device 14 as a load for performing electrical matching between the two, it is determined whether or not a glow discharge has occurred in the chamber 12. For this purpose, it is necessary to detect the state of the matching or to detect the impedance of the components in the matching circuit. In the configuration of the present embodiment, the presence or absence of the discharge in the chamber 12 is detected by detecting the impedance of the constituent element. In the automatic matching circuit 20, as described above, the two variable capacitors 2
1, 22 and the coil 23 are connected. The capacitance (capacity) of the variable capacitors 21 and 22 is determined by the drive motor (24) obtained by the encoders (25a and 25b).
a, 24b: stepping motor). That is, when the drive motor is a stepping motor, it is generally known that there is a proportional relationship or another correspondence between the rotational operation amount of the motor and the capacitance (capacity). By obtaining data on the operating position, the capacitance of the variable capacitor can be known relatively (indirectly).

In FIG. 2, the value of the capacitance (capacity) from the variable capacitors 21 and 22 is
The operating positions of the encoders a and 24b (output values of the encoders 25a and 25b) are extracted and input to the control device 30. The control device 30, which has input the signal (data) relating to the operating position of the drive motors 24a, 24b, uses the variable capacitor 21,
The value of the capacitance 22 is calculated, and a command 36 relating to the operation is issued to the high frequency power supply 18 based on the value.

As a specific configuration of the control device 30, the arithmetic processing unit 31, the power supply adjusting unit 32 for adjusting the output of the high frequency power supply 18, and the encoders 25a, 2 explained in FIG.
The operation position input / output units 34a and 34b which take in the signal relating to the operation position from 5b are related.

Here, the matching condition when the matching state is established in the automatic matching circuit 20 will be described. When the power source side impedance (Zi) is expressed as Zi = Ri + jXi and the load side impedance (Zo) is expressed as Zo = Ro + jXo, the matching conditions are Ri = Ro and Xi = -Xo. Since the calculation of the plasma impedance is performed in the complex notation and is complicated, the Smith chart is often used for the analysis. FIG. 4 shows the change in the discharge state for easy understanding. By using the Smith chart, it is possible to easily know the degree of deviation from the matching state when the constants of the components in the matching circuit are changed. When the above equation of the matching condition is satisfied, the change range of the rotational operation amount of the drive motors 24a and 24b of the variable capacitors 21 and 22, that is, the value of the capacitance of the variable capacitors 21 and 22 (VC
1, VC2). That is, as shown in FIG. 4, in the Smith chart 41, the capacitance VC1 of the variable capacitor 21 intersects with a plurality of circumferential lines 43 intersecting with the line 42 representing the real part by changing the amount of rotation of the drive motor 24a. Direction (state change trajectory 44), and the drive motor 2
4b by changing the amount of rotation of the variable capacitor 2b.
The capacitance VC2 of No. 2 changes in the latitude direction (the direction along the circumferential line 43) (state change locus 45).

The variable capacitor 21 of the automatic matching circuit 20,
By changing the value of each capacitance 22, a specific change range can be expressed on the Smith chart 41.
That is, when the normal matching is achieved in the automatic matching circuit 20, that is, when the reflected wave related to the high-frequency power supply 18 becomes 0, the locus of VC1 and VC2 is surrounded by a thick line shown in FIG. It moves within the range 46 which was set. However, even within the range 46, there is a state where no discharge is actually generated, and the range where the discharge is actually performed and the matching is achieved is an extremely narrow range. An example of an extremely narrow range that satisfies the matching condition and the discharge generation condition is shown as 47 in FIG. Range 4
The position and width of 7 change according to the process conditions and the processing chamber. By drawing on the Smith chart 41 in this manner, it becomes visually easy to understand. However, drive motor 2
Since the positions of the drive motors 24a and 24b and the capacitances of the variable capacitors 21 and 22 are in a proportional relationship or another corresponding relationship, if the operating positions of the drive motors 24a and 24b are known,
The capacitance of the capacitor can be known.

Therefore, in the present embodiment, the VC at the time of discharging is set in advance.
1 and VC2 are determined, and the variable capacitors 21 and
Since the operating positions of the drive motors 24a and 24b of the 22 can be detected based on the above-described monitor function, the change state of VC1 and VC2 at the time of discharge can be known by this function. Then, the condition of the range of VC1 and VC2 specified by the range 47 in which the generation of discharge is more surely guaranteed in the range 46 in which the matching is achieved, that is, a ≦ V
When the conditions of C1 ≦ b and c ≦ VC2 ≦ d are satisfied, occurrence / non-generation of discharge in the chamber 12 can be reliably detected. a ≦ VC1 ≦ b, c ≦ VC2
Satisfying ≦ d is a condition for confirming that a discharge has occurred. Note that a, b, c, and d are set values determined by the relationship with the range 47, and are set values related to the operating position of the drive motor.

In the control shown in FIG. 3 performed by the control device 30, when the supply of the high-frequency power from the high-frequency power supply 18 is on (step S11), the variable capacitors 21 and 22 are determined in the determination step S12. VC1 and VC2 representing the respective capacitances of the above are a ≦ VC1 ≦
It is determined whether the condition of b and c ≦ VC2 ≦ d is satisfied. If the determination in step S12 is YES, the discharge is continued (step S13), and if the determination is NO, the discharge is stopped (step S14).

Returning to FIG. 1, the discharge detection in the chamber 12 will be described with reference to FIG. The acquisition of the capacitance (capacity) from the variable capacitors 21 and 22 shown in FIG. 2 is performed as shown in FIG.
encoders 25a, 25 attached to each of
It is calculated based on a predetermined calculation formula from data b, which is the operation position (operation amount) of the drive motor.

In the actual process, in order to perform the process, a process gas is introduced into the chamber 12 in a required vacuum state, and high-frequency power is supplied from the high-frequency power supply 18 to the cathode device 14 of the chamber 12. At this time, regarding the capacitance values VC1 and VC2 of the variable capacitors 21 and 22 that can be given to the arithmetic processing unit 31 of the control device 30 by the above-described feedback route, the arithmetic processing unit 31 performs the above-described predetermined processing as described in the determination step S12. It is determined whether or not it is within the range 47. If VC1 and VC2 are within the predetermined range, it is considered that the discharge is surely generated in the chamber 12, so that the discharge is continued for a time necessary for performing the processing on the substrate 11 (the above-described step S1).
3). If it is out of the predetermined range, the output of the high-frequency power from the high-frequency power supply 18 is immediately stopped.

Therefore, according to the configuration of the above-described embodiment, the occurrence of discharge can be detected accurately, so that the high-frequency power supply 18 may generate heat or a failure, or may fail to perform normal plasma processing. For example, it is possible to prevent the formation of a substrate having a thickness smaller than a desired film thickness, thereby preventing a reduction in product yield.

Particularly, even when a low power is supplied from the high frequency power supply 18 to the chamber 12, the change amount of the plasma impedance can be reliably detected.
Very effective for low power discharge.

Further, in the configuration of the above-described embodiment, even when two or more cathode devices 14 are provided in the chamber 12, it is possible to individually and reliably detect the discharge of each of the cathode devices 14.

Further, in the above embodiment, the substrate holder 1
3, the cathode device 14 is arranged on both sides. However, the present invention can be applied to a case where a single cathode device is provided as a sputtering method from one side of the substrate holder. Further, the method and apparatus for detecting discharge according to the present invention,
Needless to say, the present invention can be applied to an apparatus for processing a thin film on a substrate other than the film formation. Further, in the present embodiment, an example in which the substrate and the target, that is, the electrodes are substantially parallel has been described. However, the present invention is similarly applied to a case where the relationship between the two is not parallel, that is, when the electrodes are inclined. Can be applied.

Further, in the above embodiment, the capacitance of the variable capacitor is obtained from the output value of the encoder, but a potentiometer can be used instead of the encoder. The matching circuit is preferably an automatic matching circuit, but is not limited to this.

In the above embodiment, an example using a variable capacitor and its capacitance value has been described. However, a variable coil and its inductance value can be used instead of the variable capacitor. Of course, the impedance value can be used.

[0047]

As is apparent from the above description, according to the present invention, the change of the capacitance value of the variable capacitor and the like in the automatic matching circuit originally provided in the processing apparatus utilizing the discharge based on the high-frequency power. Since it is configured to detect the presence or absence of the discharge by comparing the range with the capacitance value at the time of discharging when the discharge is matched, a special circuit for detecting the discharge by detecting the discharge in the processing device or No additional elements are required, discharge can be detected reliably, and discharge can be detected even when the high-frequency power supplied to the processing equipment is low, and multiple discharges can occur simultaneously in the chamber In this case, each discharge can be detected individually and surely.

[Brief description of the drawings]

FIG. 1 is a configuration diagram schematically illustrating a main part configuration of a sputtering apparatus provided with a discharge detection device according to the present invention.

FIG. 2 is a block diagram illustrating the principle (basic configuration and method) of discharge detection of the discharge detection device according to the present invention.

FIG. 3 shows discharge detection and detection based on the discharge detection device according to the present invention.
It is a flowchart explaining control accompanying non-detection.

FIG. 4 is a Smith chart for explaining the principle of the discharge detection method according to the present invention.

FIG. 5 is a block diagram illustrating a first example of a conventional discharge detection method.

FIG. 6 is a block diagram illustrating a second example of a conventional discharge detection method.

FIG. 7 is a block diagram illustrating a third example of a conventional discharge detection method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Sputtering apparatus 11 Substrate 12 Chamber 13 Substrate holder 14 Cathode device 15 Electrode 16 Target 18 High frequency power supply 20 Automatic matching circuit 21, 22 Variable capacitor 23 Coil 24a, 24b Drive motor 25a, 25b Encoder

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) H05H 1/46 H05H 1/46 R (72) Inventor Noboru Hirata 5-8-1, Yotsuya, Fuchu-shi, Tokyo Inside Anelva Co., Ltd. (72) Inventor Kenji Okaya 5-8-1, Yotsuya, Fuchu-shi, Tokyo F-term (in reference) 4G075 AA24 AA30 AA65 BA05 BC02 BC04 BC06 BD14 CA15 CA47 EC25 EC30 4K029 CA05 EA06

Claims (8)

[Claims] 1. A method for detecting a discharge applied to an apparatus for generating a plasma by a discharge based on a high-frequency power and performing film formation and processing with the plasma, wherein the method is provided between a high-frequency power supply and a cathode device. The impedance value of the variable impedance circuit element included in the matching circuit is obtained, matching is achieved, and compared with the impedance value at the time of discharge, and when the impedance value is included in a predetermined range, discharge has occurred. A discharge detection method, wherein the determination is performed. 2. The discharge detection method according to claim 1, wherein the impedance value is calculated based on an operation amount of a drive motor that changes the impedance value of the variable impedance circuit element. 3. The discharge detection method according to claim 1, wherein the variable impedance circuit element is a variable capacitor, and the impedance value is a capacitance value. 4. The discharge detection method according to claim 1, wherein the variable impedance circuit element is a variable coil, and the impedance value is an inductance value. 5. An apparatus for generating plasma by discharge based on high-frequency power in a chamber and performing film formation and processing on a substrate using the plasma, wherein the apparatus is provided between a high-frequency power supply and a cathode device of the chamber. A matching circuit, detecting means for detecting an impedance value of a variable impedance circuit element included in the matching circuit, and the impedance value is matched and included in a predetermined range in comparison with the impedance value at the time of discharging. And an arithmetic processing means for determining that a discharge has occurred at the time. 6. The discharge detection device according to claim 5, wherein the arithmetic processing unit calculates the impedance value based on an operation amount of a drive motor that changes an impedance value of the variable impedance circuit element. 7. The discharge detection device according to claim 5, wherein the variable impedance circuit element is a variable capacitor, and the impedance value is a capacitance value. 8. The discharge detection device according to claim 5, wherein the variable impedance circuit element is a variable coil, and the impedance value is an inductance value.