Measurement method and measuring jig

In a measurement method, a terminal is brought into contact with an electrode in an electrostatic chuck in contact with a substrate that is grounded. Further, the terminal, the electrostatic chuck and the substrate are fixed, and a current value and a voltage value are measured using an ammeter and a voltmeter, respectively, that are connected to the terminal. In addition, whether or not the terminal and the electrode are electrically connected is determined from a slope of the current value and/or a peak current value based on the measured current value and the voltage value.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Japanese Patent Application No. 2018-248274, filed on Dec. 28, 2018, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a measurement method and a measuring jig.

BACKGROUND

Conventionally, a method for measuring an electrostatic capacitance of an electrostatic chuck has been suggested. For example, Japanese Patent Application Publication No. H07-211768 discloses a method in which a detection device for detecting parameters indicating an attraction state is installed at an electric circuit formed by an electrode plate and an object to be held by an electrostatic attraction device, and the attraction state is checked by comparing data detected by the detection device and pre-stored data using a comparison circuit.

Further, for example, Japanese Patent Application Publication No. 2001-308164 discloses an apparatus including an electrostatic capacitance monitoring circuit for monitoring an electrostatic capacitance between a wafer and an electrode or between a plurality of electrodes in a chuck. In this apparatus, a measured electrostatic capacitance is used for continuous closed-loop control of a chuck operation and a voltage applied to the chuck is controlled depending on the measured electrostatic capacitance.

The present disclosure provides a new technique for measuring an electrostatic capacitance of an electrostatic chuck.

SUMMARY

In accordance with an aspect of the present disclosure, there is provided a measurement method including: bringing a terminal into contact with an electrode in an electrostatic chuck in contact with a substrate that is grounded; fixing the terminal, the electrostatic chuck, and the substrate; measuring a current value and a voltage value using an ammeter and a voltmeter, respectively, that are connected to the terminal, respectively; and determining whether or not the terminal and the electrode are electrically connected from a slope of the current value and/or a peak current value based on the measured current value and the voltage value.

DETAILED DESCRIPTION

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Like reference numerals will be given to like parts throughout the drawings, and redundant description thereof will be omitted.

First, a configuration of a substrate processing apparatus100of the present embodiment will be described with reference toFIG. 1.FIG. 1is a schematic cross-sectional view showing an example of the substrate processing apparatus according to the embodiment.

The substrate processing apparatus100of the present embodiment is a capacitively-coupled parallel-plate substrate processing apparatus, and has a substantially cylindrical chamber C. The chamber C has an alumite-treated (anodically oxidized) surface. The inside of the chamber C serves as a processing chamber in which plasma processing such as etching or the like is performed using plasma. A mounting table2is disposed at a bottom portion of the chamber C.

The mounting table2includes an electrostatic chuck22and a base23. The base23is made of, e.g., aluminum (Al), titanium (Ti), silicon carbide (SiC), or the like. The electrostatic chuck22is disposed on the base23and attracts and holds the wafer W. The electrostatic chuck22has a structure in which an electrode21is embedded in a dielectric layer. The electrode21is connected to a power supply14. When a DC voltage (hereinafter, also referred to as “DC voltage” or “HV voltage”) is applied from the power supply14to the electrode21, the wafer W is attracted to and held by the electrostatic chuck22by a Coulomb force.

A stepped portion is formed at an outer periphery of the electrostatic chuck22and serves as an edge ring mounting surface on which an edge ring8is mounted. The edge ring8having an annular shape is mounted on the edge ring mounting surface to surround the periphery of the wafer W. The edge ring8is also referred to as a focus ring. The edge ring8is made of, e.g., silicon, and converges plasma toward the surface of the wafer W to improve the efficiency of the plasma processing. The electrode24is disposed in the electrostatic chuck22below the edge ring mounting surface and is connected to a power supply17. When a DC voltage is applied from the power supply17to the electrode24, a thickness of a sheath above the edge ring8is controlled. Accordingly, it is possible to suppress tilting that occurs at an edge portion of the wafer W and control an etching rate.

The substrate processing apparatus100includes a first high frequency power supply3and a second high frequency power supply4. The first high frequency power supply3generates a first high frequency power (HF) having a frequency suitable for plasma generation. The frequency of the first high frequency power is within a range of, e.g., 27 MHz to 100 MHz. The first high frequency power supply3is connected to the base23through a matching unit3a. The matching unit3ahas a circuit for matching an output impedance of the first high frequency power supply3with an impedance of a load side (the base23side). The first high frequency power supply3may be connected to an upper electrode1through the matching unit3a.

The second high frequency power supply4generates a second high frequency power (LF). The second high frequency power has a frequency lower than that of the first high frequency power. In the case of using both of the first high frequency power and the second high frequency power, the second high frequency power is used as a bias high frequency power for attracting ions into the wafer W. The frequency of the second high frequency power is within a range of, e.g., 400 kHz to 13.56 MHz. The second high frequency power supply4is connected to the base23through a matching unit4a. The matching unit4ahas a circuit for matching an output impedance of the second high frequency power supply4with the impedance of the load side (the base23side).

The plasma may be generated using only one high frequency power, i.e., the second high frequency power without using the first high frequency power. In this case, the frequency of the second high frequency power may be higher than 13.56 MHz, e.g., 40 MHz. The substrate processing apparatus100may not include the first high frequency power supply3and the matching unit3a. The mounting table2serves as a lower electrode disposed to be opposite to the upper electrode1.

A switch11is connected to the base23. When the switch11is turned on, the base23is grounded. When the switch11is turned off, the base23and the wafer W are in a floating state.

The upper electrode1is attached to block an opening formed at a ceiling portion of the chamber C through a shield ring (not shown) that coves an outer peripheral portion thereof. The upper electrode1is grounded. The upper electrode1may be made of silicon.

The upper electrode1has a gas inlet port1afor introducing a gas and a diffusion space1bfor diffusing the gas. A gas supply unit5supplies a gas to the diffusion space1bthrough the gas inlet port1a. The gas is diffused in the diffusion space1band introduced into the chamber C from a plurality of gas injection holes1c.

A gas exhaust unit16exhausts the gas in the chamber C from a gas exhaust port formed at the bottom surface of the chamber C. Accordingly, a pressure in the chamber C can be maintained at a predetermined vacuum level. A gate valve G is disposed on a sidewall of the chamber C. The gate valve G is opened so that the wafer W can be loaded into or unloaded from the chamber C.

Next, an operation of the substrate processing apparatus100will be briefly described. When the gate valve G is opened, the wafer W held by a transfer arm (not shown) is loaded into the chamber C and mounted on the mounting table2, and the gate valve G is closed. When a DC voltage is applied from the power supply14to the electrode21, the wafer W is electrostatically attracted to and held on the electrostatic chuck22. When the processing gas is supplied from the gas supply unit5into the chamber C and the first high frequency power and the second high frequency power are respectively applied from the first high frequency power supply3and the second high frequency power supply4to the mounting table2, plasma is generated above the wafer W in the chamber C and plasma processing is performed on the wafer W. Particularly, when the second high frequency power is applied from the second high frequency power supply4to the mounting table2, ions in the plasma are attracted to the wafer W.

After the plasma processing, a DC voltage having the same magnitude but opposite polarity as that of the voltage applied from the power supply14to the electrode21before the plasma processing is applied to neutralize charges on the wafer W. Accordingly, the wafer W is separated from the electrostatic chuck22and transferred to the transfer arm while being held by pins. When the gate valve G is opened, the wafer W held on the transfer arm is unloaded from the chamber C through the gate valve G. Then, the gate valve G is closed.

The respective components of the substrate processing apparatus100are connected to and controlled by a controller200. The respective components may include the gas exhaust unit16, the matching units3aand4a, the first high frequency power supply3, the second high frequency power supply4, the switch11, the power supplies14and17, the gas supply unit5, and the like.

The controller200is a computer including a CPU205and a memory such as a ROM210, a RAM215, or the like. The CPU205reads out and executes a processing recipe and a control program of the substrate processing apparatus100which are stored in the memory. The CPU205controls the plasma processing such as etching or the like.

Further, the controller200turns on and off the switch11at a predetermined measurement timing and stores a voltage value measured by a voltmeter13and a current value measured by an ammeter12connected to the electrode21in a signal storing device15. The ammeter12is connected in series to the power supply14, and the voltmeter13is connected in parallel to the power supply14. The current value and the voltage value stored in the signal storing device15are transmitted to the controller200. Accordingly, the controller200calculates a spark discharge start voltage value (hereinafter referred to as “discharge start voltage value”) based on the measured current value and the measured voltage value. Then, the controller200calculates an electrostatic capacitance C of the electrostatic chuck22as will be described later.

A program for executing these operations or a recipe indicating processing conditions may be stored in a hard disk or a semiconductor memory. Further, the recipe may be set to a predetermined position while being stored in a portable computer-readable storage medium such as a CD-ROM, a DVD, or the like, and read out from the storage medium.

FIG. 2shows an example of a processing cycle for processing the wafer W in the substrate processing apparatus100. When this processing is started, first, the gate valve G is opened and the wafer W is loaded (step S1). Next, a predetermined gas from the gas supply unit5fills the chamber C to control the pressure in the chamber C (step S2). The gas for filling the chamber C is preferably an inert gas such as argon gas or the like, but may be nitrogen gas or the like.

Next, the switch11is turned off; and the base23and the wafer W are set to a floating state; and a DC voltage is applied from the power supply14to the electrode21(step S3). During the process of step S3, the current value and the voltage value are measured and stored in the signal storing device15. Next, the wafer W is separated from the electrostatic chuck22(step S4), and the wafer W is unloaded through the gate valve G (step S5).

At this timing, the processing of one wafer W is completed, and one processing cycle is completed. Before a processing cycle of a next wafer W2is resumed, waferless dry cleaning (WLDC) is performed and the charges on the electrostatic chuck22are neutralized (step S6). The WLDC is merely an example of a process of neutralizing charges on the electrostatic chuck22, and the charge neutralization is not limited thereto. In addition, cleaning such as surface treatment or the like of the electrostatic chuck22may be performed before the charge neutralization.

Then, the next wafer W is loaded (step S1), and the processes subsequent to step S1are repeated.

The current value and the voltage value are not necessarily measured whenever one wafer is processed, and may be measured whenever several wafers are processed, or after the cleaning of the chamber C, or after the replacement of the parts in the chamber C.

Next, an example of a sequence of measuring the current value and the voltage value will be described with reference toFIGS. 3 and 4.FIG. 3shows a discharge start voltage measurement sequence according to the embodiment.FIGS. 4A to 4Cexplain a discharge start voltage measurement method according to the embodiment. The measurement sequence is controlled by the controller200.

When the measurement sequence is started, the switch11is controlled to be off, and the base23and the wafer W are in a floating state. In this state, the measurement sequence is started at phase “1” inFIG. 3; a gas is supplied (ON) from the gas supply unit5at phase “2”; and the pressure in the chamber C is controlled by the supplied gas at phase “3”.

FIG. 4Ashows a state in which the gas is supplied into the chamber C and the pressure in the chamber C is controlled to a predetermined pressure. At this time, no DC voltage (HV voltage) is applied from the power supply14to the electrode21.

Next, the application of a DC voltage from the power supply14to the electrode21is started at phase “4” inFIG. 3, and the applied DC voltage is increased from 0 [V] to +V [V]. When the phase “4” is started, the ammeter12and the voltmeter13start the measurement, and the current value measured by the ammeter12and the voltage value measured by the voltmeter13are stored in the signal storing device15.

Next, at phase “5”, the DC voltage applied from the power supply14to the electrode21is lowered from +V [V] to −V [V]. During the phase “5”, the measurements of the ammeter12and the voltmeter13are continued, and the measured current value and the measured voltage value are stored in the signal storing device15.

Next, at phase “6”, the DC voltage applied from the power supply14to the electrode21is increased from −V [V] to 0 [V]. During the phase “6”, the measurements of the ammeter12and the voltmeter13are continued, and the measured current value and the measured voltage value are stored in the signal storing device15.

Accordingly, a positive DC voltage is applied to the electrode21during the phases “4” to “6” as shown inFIG. 4B, and spark discharge occurs between the upper electrode1and the chuck22as shown inFIG. 4C. The DC voltage applied to the electrode21during the phases “4” to “6” is not necessarily a positive voltage, and may be a negative voltage.

Next, the gas supply is stopped (OFF) at phase “7” inFIG. 3, and the measurement sequence is completed at phase “8”.

In the above-described measurement sequence, the DC voltage is applied by increasing and decreasing the voltage. However, the present disclosure is not limited thereto. For example, the DC voltage may be applied by only increasing or only decreasing the voltage.

As described above, in the measurement method of the present embodiment, plasma is not generated and the pressure in the chamber C is controlled by supplying a gas. At this time, the gas exhaust operation of the gas exhaust unit16is not performed. When the application of the DC voltage is on and the DC voltage is increased and decreased to a certain voltage value, positive charges are accumulated on the electrode21of the electrostatic chuck22. Accordingly, positive charges are accumulated on the surface of the wafer W.

Then, the DC voltage is increased to a voltage value at which spark discharge occurs. Negative charges are attracted to the wafer W by the spark discharge that occurs between the upper electrode1and the electrode21. Accordingly, a current flows between the electrode21and the upper electrode1. A current value and a voltage value at that time are measured by the ammeter12and the voltmeter13, respectively.

Examples of the measured current value and the measured voltage value will be described. Here, examples of the current value and the voltage value that are measured when the DC voltage is increased at the phase “4” inFIG. 3will be described with reference toFIG. 5.FIG. 5shows examples of the measured voltage value and the measured current value according to the embodiment.

The horizontal axis inFIG. 5represents a measurement time in the case of setting a start time of the phase “4” inFIG. 3to 0. The left side of the vertical axis represents a voltage value measured at the phase “4”, and the right side of the vertical axis represents a current value measured at the phase “4”. A line A inFIG. 5indicates voltage values (ESC Vol) measured by the voltmeter13at the phase “4”. Lines B0, B1, B2, and B3inFIG. 5indicate current values (ESC Cur) measured by the ammeter12at the phase “4.”

The results shown inFIG. 5shows that the spark discharge was started when the voltage value was V0, and current values i(t0) to i(t1) were measured from a discharge start time t0to a discharge end time t1as indicated by the line B1. Then, as indicated by the lines B2and B3, the measured current values were considerably decreased as in the case of the line B1.

From the above-described measurement results, it is clear that the electrical conduction between the electrostatic chuck22in a floating state and the grounded upper electrode1were instantaneously made due to the gas discharge (spark discharge) in the chamber C, and the discharge occurred between the upper electrode1and the electrode21. In other words, in the present disclosure, the gas discharge is generated by generating a voltage difference between the electrostatic chuck22and the upper electrode1disposed to be opposite to the electrostatic chuck22by applying a positive or a negative DC voltage to the electrode21.

The discharge start voltage value V0and the current values i(t0) to i(t1) measured from the discharge start time t0at which the discharge start voltage value V0was measured to the discharge end time t1are substituted into the following equation (1). Accordingly, a charge amount q of the electrostatic chuck22during the spark discharge can be calculated.
q=∫t0t1i(t)dt(1)
Equation (1)

The, the electrostatic capacitance C of the electrostatic chuck22can be calculated from the following equation (2).
C=q/V0Equation (2)

Although the controller200in the present embodiment acquires the current value and the voltage value stored in the signal storing device15and calculates the electrostatic capacitance C based on the discharge start voltage value V0and the current values i(t0) to i(t1), the present disclosure is not limited thereto. For example, it is possible to substitute the current values i measured from the start to the end of the first discharge indicated by the line B1, the second discharge indicated by the line B2, and the third discharge indicated by the line B3inFIG. 5into the equation (1) to calculate respective charge amounts q and calculate an average of the three charge amounts q. The electrostatic capacitance C of the electrostatic chuck22can be calculated by substituting the average of the charge amounts q into the equation (2). By using the average of the charge amounts q, it is possible to suppress deterioration in the accuracy of the calculation result of the electrostatic capacitance C of the electrostatic chuck22due to variance in the measured current value and the measured voltage value.

Next, an attractive force determination process using the calculated electrostatic capacitance C of the electrostatic chuck22will be described with reference toFIG. 6.FIG. 6is a flowchart showing the attractive force determination process using the electrostatic capacitance according to the embodiment.

The attractive force determination process is controlled by the controller200. Here, it is assumed that the current values and the voltage values are measured by the ammeter12and the voltmeter13, respectively, while the DC voltage is applied from the power supply14to the electrode21by being increased and decreased and stored in the signal storing device15.

When this process is started, the discharge start voltage value V0and the current values i(t0) to i(t1) that are the spark discharge currents flowing from the discharge start time t0at which the discharge start voltage value V0 is measured to the discharge end time t1are measured from the stored current values and the stored voltage values (step S10).

Next, the electrostatic capacitance C of the electrostatic chuck22is calculated using the discharge start voltage value V0and the spark discharge current values i(t0) to i(t1), and the equations (1) and (2) (step S12).

Next, it is determined whether or not the electrostatic capacitance C is greater than a predetermined threshold Th of the electrostatic capacitance (step S14). When it is determined that the electrostatic capacitance C is greater than the threshold Th, it is determined that the electrostatic chuck22has a sufficient attractive force, and this processing is terminated.

On the other hand, when it is determined that the electrostatic capacitance C is smaller than or equal to the threshold Th, it is determined that the electrostatic chuck does not have a sufficient attractive force, and the maintenance operation is performed by opening the lid of the chamber C (step S16). Then, this processing is terminated.

As described above, in accordance with the measurement method according to the embodiment, the state in the chamber can be determined based on the calculated electrostatic capacitance. For example, the attraction state between the electrostatic chuck22and the wafer W can be determined as an example of the state in the chamber. In addition, as will be described later, the attraction state between the electrostatic chuck22and the edge ring8can be determined as another example of the state in the chamber.

Therefore, when it is determined that the electrostatic capacitance C is smaller than or equal to the threshold Th, it is determined that the attraction state of the electrostatic chuck22is poor, and the maintenance operation is performed to improve the attraction state of the electrostatic chuck22. For example, when it is determined that the electrostatic capacitance C is smaller than or equal to the threshold Th, waferless dry cleaning (WLDC) and/or waferless treatment (WLT) may be performed as the maintenance operation. In addition, the replacement of the electrostatic chuck22or other parts may be performed as the maintenance operation.

Although the gas discharge between the upper electrode1and the electrostatic chuck22was mainly described in the above-described electrostatic capacitance measurement method, the gas discharge is not limited thereto since a grounded member other than the upper electrode1is disposed in the chamber C. In other words, the gas discharge in the present embodiment is not limited to the gas discharge between the upper electrode1and the electrostatic chuck22, and also includes the gas discharge between the electrostatic chuck22and a grounded member such as a sidewall of the chamber C, a deposition shield (not shown), a shutter (not shown), or the like.

In the present embodiment, the gas discharge is generated by applying a DC voltage from the power supply14to the electrode21. However, the gas discharge may be generated by applying a DC voltage from the power supply17to the electrode24disposed in the electrostatic chuck22below the edge ring8. In this case, the gas discharge may be generated by applying a DC voltage to the electrode24disposed in the electrostatic chuck22below the edge ring8in a state where the base23of the electrostatic chuck22and the edge ring8are in a floating state. Therefore, the electrostatic capacitance of the edge ring mounting surface of the electrostatic chuck22can be calculated. Accordingly, the attraction state between the edge ring8and the electrostatic chuck22can be determined. If it is determined that the attraction state is poor, the maintenance operation may be performed by opening the lid of the chamber C. As examples of the maintenance operation, the WLDC and/or the WLT may be performed, or the replacement of the electrostatic chuck22or other parts may be performed.

In the case of dividing the electrostatic chuck22into multiple zones and controlling each zone, the electrode21may be provided for each zone. In this case, the gas discharge may be generated by applying a DC voltage to each electrode. Therefore, the electrostatic capacitance of each zone of the electrostatic chuck22can be calculated. Accordingly, the attraction state of each zone of the electrostatic chuck22can be determined.

Next, a measuring jig300for measuring a discharge start voltage will be described with reference toFIG. 7.FIG. 7shows a measuring jig according to the embodiment.

The measuring jig300measures a contact state between a terminal T and the electrode21. The measuring jig includes the terminal T, fixing portions310and320, the ammeter12, the voltmeter13, and the controller200. First, a grounded wafer is brought into contact with the surface of the electrostatic chuck22. Then, the grounded wafer W, the electrostatic chuck22, and the base23are fixed to the fixing portion310. Accordingly, the grounded wafer W is disposed below the electrostatic chuck22, and the base23is disposed above the electrostatic chuck22. The grounded wafer W is an example of a substrate that is connected to the ground. The substrate is not limited thereto, and may be made of a silicon-containing material or a metal.

FIG. 7shows an example in which the electrostatic capacitance of the electrostatic chuck22is measured using the measuring jig300outside the substrate processing apparatus100. However, the electrostatic capacitance of the electrostatic chuck22may be measured inside the substrate processing apparatus100. In this case, the electrical conduction between the wafer W and the upper electrode1may be made by the gas discharge without directly connecting the wafer W to the ground.

The fixing portion320fixes the terminal T to the base23and brings the tip end thereof into contact with the electrode21. The fixing portion310fixes the terminal T, the electrostatic chuck22, and the wafer W. The ammeter12and the voltmeter13are connected to the terminal T. The ammeter12is connected in series to the power supply14and the voltmeter13is connected in parallel to the power supply14.

The controller200measures the values of a voltage and a current flowing through the terminal T using the voltmeter13and the ammeter12, respectively, and stores the measured current value and the measured voltage value in the signal storing device15. The controller200determines whether or not the terminal T and the electrode21are electrically connected from a slope of the current value and/or the peak current value based on the measured current value and voltage value, thereby determining whether or not contact failure of the terminal T has occurred.

FIGS. 8A and 8Bshow examples of the determination result for the contact state of the terminal T according to the embodiment. As shown inFIG. 8A, when a slope E1of a current value E while a voltage value F is controlled to be high is greater than or equal to a predetermined threshold, it is determined that the terminal T and the electrode21are in contact with each other as indicated by “OK” in the frame ofFIG. 7, or when a peak current value E2while the voltage value F is controlled to be high is greater than a predetermined value, it is determined that the terminal T and the electrode21are in contact with each other.

On the other hand, as shown inFIG. 8B, when a slope E3of the current value E while the voltage value F is controlled to be high is smaller than the predetermined threshold and when the peak current value is smaller than the predetermined value, it is determined that the terminal T and the electrode21are not in contact with each other as indicated by “NG” in the frame ofFIG. 7.

An RC filter19is connected between the terminal T and the ammeter12. The RC filter19cuts off a current in a predetermined frequency band. Since the electrostatic chuck22serves as a capacitor, it is possible to eliminate the influence of noise and a time constant of the electrostatic chuck and clearly display a current waveform of the terminal T by installing the RF filter19. However, the installation of the RC filter19is optional so that the RC filter19may not be provided.

The measuring jig300configured as described above is used to determine whether or not the terminal T is in contact with the electrode21before the application of the discharge start voltage value V0. When it is determined that the terminal T is in contact with the electrode21, the electrostatic capacitance of the electrostatic chuck22can be accurately calculated by measuring the discharge start voltage value V0.

<Terminal Contact Determination Process and Discharge Start Voltage Value Measurement Process>

Next, the process of determining the contact state of the terminal T and the process of measuring the discharge start voltage value V0will be described with reference toFIG. 9.FIG. 9is a flowchart of a terminal contact determination process and a discharge start voltage value measurement process according to the embodiment.

When this process is started, a wafer is brought into contact with the surface of the electrostatic chuck22in a state where the power supply14is turned off (step S20). Next, the tip end of the terminal T is brought into contact with the electrode21of the electrostatic chuck22, and the terminal T, the electrostatic chuck22, and the wafer W are fixed to the fixing portions310and320(step S22).

Next, the power supply14is turned on, and a predetermined DC voltage is applied to the electrode21by increasing and decreasing the voltage (step S24). Next, a voltage value V and a current value i flowing through the terminal T are measured by the voltmeter13and the ammeter12, respectively (step S26). Next, the power supply14is turned off (step S28).

Next, based on the measured current value i and the measured voltage value V, it is determined whether or not the terminal T and the electrode21are electrically connected from the slope of the current value i and/or the peak current value i (steps S30and S32).

If it is determined in step S32that the terminal T and the electrode21are not electrically connected, the process is terminated without measuring the discharge start voltage value V0. On the other hand, if it is determined in step S32that the terminal T and the electrode21are electrically connected, the switch11is turned off to set the base23to a floating state (step S33). Next, the charges on the wafer W are neutralized using plasma or the like, and the wafer W is lifted from the electrostatic chuck22and mounted on the surface of the electrostatic chuck22again (step S34). Then, a gas is supplied into the chamber C and the discharge start voltage value V0and the current values i(t0) to i(t1) during the gas discharge generation are measured (step S35).

Next, the charge amount q is calculated by substituting the measured discharge start voltage value V0and the measured current values i(t0) to i(t1) into the equation (1). Then, the electrostatic capacitance C of the electrostatic chuck22is calculated by substituting the calculated charge amount q and the discharge start voltage value V0into the equation (2) (step S36). Then, this processing is terminated.

As described above, the measuring jig and the discharge start voltage measurement method of the present embodiment can provide a new technique for measuring an electrostatic capacitance of an electrostatic chuck.

The measuring jig and the measurement method according to the embodiments of the present disclosure are illustrative in all respects and are not restrictive. The above-described embodiments can be embodied in various forms. Further, the above-described embodiments may be omitted, replaced, or changed in various forms without departing from the scope of the appended claims and the gist thereof.

The substrate processing apparatus of the present disclosure can be applied to any substrate processing apparatus using capacitively coupled plasma (CCP), inductively coupled plasma (ICP), a radial line slot antenna (RLSA), electron cyclotron resonance plasma (ECR), or helicon wave plasma (HWP).

The DC voltage applied to the electrode21from the power supply14may be a positive DC voltage or a negative DC voltage.