Plasma processing apparatus and plasma processing method

Abstract

This invention initiates plasma processing after confirming that the substrate is adhered to the electrostatic chuck. The plasma processing apparatus includes an electrostatic chuck, a first switch, a second switch, and a control unit. The electrostatic chuck adheres the substrate to be plasma processed by applying a voltage to its internal electrodes. The first switch is located in the wiring between the power supply and the electrodes. The second switch is located in the wiring between the detector and the electrodes. The control unit controls the first and second switches to the closed state, causing the power supply to output a first voltage. When the detector detects the first voltage, it determines that the first and second switches are in the closed state. Furthermore, after determining that the first and second switches are in the closed state, the control unit starts processing the substrate using plasma by controlling the first and second switches to the open state and controlling the electrodes to a floating state.

Description

[Technical Field]

[0001] The various forms and embodiments of the present invention relate to a plasma treatment apparatus and a plasma treatment method. [Previous Technology]

[0002] For example, Patent Document 1 below discloses a plasma processing apparatus in which a switch is provided between an electrode disposed on an electrostatic chuck that adsorbs and holds a substrate as the object of processing, and a DC power supply that applies a DC voltage to the electrode. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-46997 [Summary of the Invention]

[0004] [The problem the invention aims to solve]

[0005] This invention provides a plasma processing apparatus and method that can begin plasma processing after confirming that the substrate has been adsorbed onto an electrostatic chuck. [Technical Means for Solving the Problem]

[0006] One embodiment of the present invention is a plasma processing apparatus, comprising an electrostatic chuck, a first switch, a second switch, and a control unit. The electrostatic chuck is disposed within a chamber and has electrodes inside, adsorbing a substrate to be processed using plasma by applying a voltage to the electrodes. The first switch is disposed in the wiring between a power supply supplying voltage to the electrodes and the electrodes. The second switch is disposed in the wiring between a detector for detecting the voltage of the electrodes and the electrodes. The control unit controls the first and second switches to a closed state, controlling the power supply to output a predetermined first voltage from the power supply. When the detector detects the first voltage, a first determination process is performed to determine that the first and second switches are in a closed state. Furthermore, after determining that the first and second switches are in a closed state, the control unit starts processing the substrate using plasma by controlling the first and second switches to an open state and controlling the electrodes to a floating state. [Effects of the Invention]

[0007] According to various forms and embodiments of the present invention, plasma processing can begin after confirming that the substrate is adsorbed onto the electrostatic chuck.

Implementation Method

[0009] Hereinafter, embodiments of the disclosed plasma treatment apparatus and plasma treatment method will be described in detail based on the drawings. However, the disclosed plasma treatment apparatus and plasma treatment method are not limited to the following embodiments.

[0010] Furthermore, when a malfunction occurs, such as a switch on the wiring between the electrode located within the electrostatic chuck and the power supply that applies voltage to the electrode remaining in the open state, the required voltage cannot be applied to the electrode. When the required voltage is not applied to the electrode, the electrode will not generate the required electrostatic force, and the substrate will not be attracted to the electrostatic chuck. Therefore, when substrate processing has been performed using plasma, the substrate may sometimes move relative to the electrostatic chuck, resulting in a decrease in the processing accuracy of the substrate.

[0011] Therefore, the present invention provides a technique that allows plasma processing to begin after confirming that the substrate is adsorbed onto an electrostatic chuck.

[0012] [Configuration of Plasma Processing System 100] Hereinafter, an example of the configuration of the plasma processing system 100 will be described. FIG1 is a diagram showing an example of a plasma processing system 100 according to one embodiment of the present invention. The plasma processing system 100 includes a capacitively coupled plasma processing apparatus 1 and a control unit 2. The plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply 30, and an exhaust system 40. Furthermore, the plasma processing apparatus 1 includes a substrate support unit 11 and a gas introduction unit. The gas introduction unit is configured to introduce at least one type of processing gas into the plasma processing chamber 10. The gas introduction unit includes a cluster nozzle 13. The substrate support unit 11 is disposed within the plasma processing chamber 10. The cluster nozzle 13 is disposed above the substrate support unit 11. In one embodiment, the cluster nozzle 13 constitutes at least a portion of the ceiling of the plasma processing chamber 10.

[0013] The plasma processing chamber 10 has a plasma processing space 10s defined by the cluster nozzle 13, the sidewall 10a of the plasma processing chamber 10, and the substrate support portion 11. The plasma processing chamber 10 has at least one gas supply port for supplying at least one type of processing gas to the plasma processing space 10s, and at least one gas outlet for discharging gas from the plasma processing space 10s. The sidewall 10a is grounded. The cluster nozzle 13 and the substrate support portion 11 are electrically insulated from the housing of the plasma processing chamber 10.

[0014] The substrate support portion 11 includes a body portion 111 and a ring assembly 112. The body portion 111 has a central region for supporting the substrate W, namely the substrate support surface 111a, and an annular region for supporting the ring assembly 112, namely the ring support surface 111b. The substrate W is sometimes also referred to as a wafer. The ring support surface 111b of the body portion 111 surrounds the substrate support surface 111a of the body portion 111 when viewed from above. The substrate W is disposed on the substrate support surface 111a of the body portion 111, and the ring assembly 112 is disposed on the ring support surface 111b of the body portion 111 in such a way that it surrounds the substrate W on the substrate support surface 111a of the body portion 111.

[0015] In one embodiment, the main body 111 includes an electrostatic chuck 1110 and a base 1111. The base 1111 includes a conductive member. The conductive member of the base 1111 functions as a lower electrode. The electrostatic chuck 1110 is disposed on the base 1111. The upper surface of the electrostatic chuck 1110 is a substrate support surface 111a. An electrode 1110a is provided on the electrostatic chuck 1110. A variable DC power supply 115 is connected to the electrode 1110a via a wiring 113. A first switch 114 is provided on the wiring 113. The electrode 1110a generates an electrostatic force on the substrate support surface 111a by the DC voltage applied from the variable DC power supply 115 when the first switch 114 is in the closed state. Thereby, the electrostatic chuck 1110 adsorbs the substrate W disposed on the substrate support surface 111a. When the substrate W is attached to the electrostatic chuck 1110, the variable DC power supply 115 applies a first voltage of a predetermined magnitude (hereinafter sometimes referred to as H voltage) to the electrode 1110a.

[0016] Furthermore, in this embodiment, after the substrate W is adsorbed onto the electrostatic chuck 1110, the first switch 114 is turned on, thereby making the electrode 1110a float. In the floating state, the charge accumulated on the electrode 1110a before it became floating is maintained. Subsequently, after the electrode 1110a becomes floating, plasma treatment of the substrate W is performed using plasma. By performing plasma treatment while the electrode 1110a is floating, excessive charging of the substrate W during plasma treatment can be suppressed. Furthermore, by performing plasma treatment while the electrode 1110a is floating, excessive adsorption force between the substrate W and the electrostatic chuck 1110 during plasma treatment can be suppressed.

[0017] Furthermore, a detector 118 is connected to electrode 1110a via wiring 116. A second switch 117 is provided on wiring 116. When the second switch 117 is in the closed state, the detector 118 detects the voltage of electrode 1110a via wiring 116. For example, after destatic discharge of electrode 1110a is performed after plasma treatment of substrate W, the detector 118 detects the voltage of electrode 1110a. When the voltage of electrode 1110a detected by detector 118 is a second voltage (hereinafter sometimes referred to as L voltage) that is lower than the first voltage, the control unit 2 determines that destatic discharge has been completed and begins to remove substrate W after plasma treatment.

[0018] Here, if the second switch 117 is not provided, and the electrode 1110a and the detector 118 are always connected via the wiring 116, the charge accumulated in the floating electrode 1110a will leak through the wiring 116 and the detector 118. If the charge accumulated in the electrode 1110a leaks through the wiring 116 and the detector 118, the charge accumulated in the electrode 1110a will decrease, and therefore the adsorption force between the substrate W and the electrostatic chuck 1110 will decrease during plasma processing. As a result, it is difficult to maintain the position of the substrate W relative to the electrostatic chuck 1110 at a predetermined position.

[0019] Therefore, in this embodiment, a second switch 117 is provided in the wiring 116, and the second switch 117 is controlled to be closed only when it is necessary to detect the voltage of the electrode 1110a. Especially in plasma processing, the second switch 117 is controlled to be open. In this way, in plasma processing, the reduction of charge accumulated in the floating state of the electrode 1110a can be suppressed, and the reduction of the adsorption force between the substrate W and the electrostatic chuck 1110 can be suppressed. In this way, the position of the substrate W relative to the electrostatic chuck 1110 can be maintained at a predetermined position.

[0020] However, when the first switch 114 malfunctions in the open state, even if the control unit 2 tries to control the first switch 114 to the closed state, the first switch 114 will not become closed. Hereinafter, a switch state that remains open even though it is controlled to be closed will be referred to as an open malfunction. When the first switch 114 is in an open malfunction, the substrate W will not adhere to the electrostatic chuck 1110 if no voltage is applied to the electrode 1110a. In order for the substrate W to adhere to the electrostatic chuck 1110, it is necessary to confirm that the first switch 114 is not in an open malfunction. When the first switch 114 is in an open malfunction, countermeasures such as stopping plasma processing must be performed. Therefore, in this embodiment, it is necessary to confirm that the first switch 114 is not in an open malfunction before starting plasma processing.

[0021] Furthermore, if the first switch 114 malfunctions while in the closed state, even if the control unit 2 attempts to control the first switch 114 to the open state, the first switch 114 will not become open. Hereinafter, a switch state that remains closed despite being controlled to the open state will be referred to as a closing fault. When the first switch 114 is in a closing fault state, the electrode 1110a cannot be in a floating state, and the following situation exists: the substrate W becomes overcharged during plasma processing, or excessive adsorption force is generated between the substrate W and the electrostatic chuck 1110. If excessive adsorption force is generated between the substrate W and the electrostatic chuck 1110, particles will be generated due to friction between the substrate W and the electrostatic chuck 1110. Also, if the substrate W is overcharged, particles easily adhere to the substrate W. Therefore, it is necessary to confirm that the first switch 114 is not in a closing fault state. Moreover, when the first switch 114 is in a closing fault state, countermeasures such as stopping the plasma processing must be performed. Therefore, in this embodiment, it is confirmed that the first switch 114 is not faulty.

[0022] The ring assembly 112 includes one or more annular members. At least one of the one or more annular members is an edge ring. Also, although not shown in the figure, the substrate support portion 11 may also include a temperature control module configured to adjust at least one of the electrostatic chuck 1110, the ring assembly 112, and the substrate W to a target temperature. The temperature control module may also include a heater, a heat transfer medium, a flow path, or a combination thereof. A heat transfer fluid such as brine or gas flows in the flow path. Furthermore, the substrate support portion 11 may also include a heat transfer gas supply portion configured to supply heat transfer gas between the substrate W and the substrate support surface 111a.

[0023] The cluster nozzle 13 is configured to introduce at least one type of processing gas from the gas supply unit 20 into the plasma processing space 10s. The cluster nozzle 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and a plurality of gas inlets 13c. The processing gas supplied to the gas supply port 13a is introduced into the plasma processing space 10s through the gas diffusion chamber 13b and the plurality of gas inlets 13c. Furthermore, the cluster nozzle 13 includes a conductive member. The conductive member of the cluster nozzle 13 functions as an upper electrode. In addition, besides the cluster nozzle 13, the gas inlet unit may also include one or more side gas injectors (SGIs), which are installed in one or more openings formed in the sidewall 10a.

[0024] The gas supply unit 20 may also include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is configured to supply at least one type of processing gas from the corresponding gas source 21 to the cluster nozzle 13 via the corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Furthermore, the gas supply unit 20 may also include one or more flow modulation devices for modulating or pulsedizing the flow rate of the at least one type of processing gas.

[0025] The power supply 30 includes an RF (Radio Frequency) power supply 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power supply 31 is configured to supply at least one RF signal, such as a source RF signal and a bias RF signal, to a conductive member of the substrate support portion 11, a conductive member of the cluster head 13, or both. This allows plasma to be formed from at least one type of processing gas supplied to the plasma processing space 10s. Therefore, the RF power supply 31 can function as at least a part of a plasma generation unit configured to generate plasma from one or more types of processing gases in the plasma processing chamber 10. Furthermore, by supplying a bias RF signal to the conductive member of the substrate support portion 11, a bias potential can be generated on the substrate W, feeding the ionic components of the formed plasma into the substrate W.

[0026] In one embodiment, the RF power supply 31 includes a first RF generating unit 31a and a second RF generating unit 31b. The first RF generating unit 31a is configured to couple with a conductive member of the substrate support 11, a conductive member of the cluster head 13, or both, via at least one impedance matching circuit to generate a source RF signal for plasma generation. The source RF signal may also be referred to as source RF power. In one embodiment, the source RF signal has a frequency in the range of 13 MHz to 150 MHz. In one embodiment, the first RF generating unit 31a may also be configured to generate a plurality of source RF signals with different frequencies. The generated one or more source RF signals are supplied to a conductive member of the substrate support 11, a conductive member of the cluster head 13, or both.

[0027] The second RF generation unit 31b is configured to couple with the conductive member of the substrate support unit 11 via at least one impedance matching circuit to generate a bias RF signal. The bias RF signal can also be referred to as bias RF power. In one embodiment, the bias RF signal has a frequency lower than the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 400 kHz to 13.56 MHz. In one embodiment, the second RF generation unit 31b may also be configured to generate a plurality of bias RF signals with different frequencies. One or more bias RF signals generated are supplied to the conductive member of the substrate support unit 11. Furthermore, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0028] Furthermore, the power supply 30 may also include a DC (Direct Current) power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generating unit 32a and a second DC generating unit 32b. In one embodiment, the first DC generating unit 32a is configured as a conductive member connected to the substrate support 11 to generate a first DC signal. The generated first DC signal is applied to the conductive member of the substrate support 11. In another embodiment, the first DC signal may also be applied to other electrodes, such as the electrode 1110a within the electrostatic chuck 1110. In one embodiment, the second DC generating unit 32b is configured as a conductive member connected to the cluster head 13 to generate a second DC signal. The generated second DC signal is applied to the conductive member of the cluster head 13. In various embodiments, at least one of the first and second DC signals may also be pulsed. Furthermore, a first DC generating unit 32a and a second DC generating unit 32b may be provided in addition to the RF power supply 31, or the first DC generating unit 32a may be provided to replace the second RF generating unit 31b.

[0029] The exhaust system 40 may be connected to, for example, a gas outlet 10e located at the bottom of the plasma processing chamber 10. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure within the plasma processing space 10s is adjusted by the pressure regulating valve. The vacuum pump may also include a turbomolecular pump, a dry pump, or a combination thereof.

[0030] The control unit 2 processes computer-executable commands that cause the plasma processing apparatus 1 to perform the various processes described herein. The control unit 2 may be configured to control various elements of the plasma processing apparatus 1 in a manner that executes the various processes described herein. In one embodiment, part or all of the control unit 2 may be included in the plasma processing apparatus 1. The control unit 2 may include, for example, a computer 2a. The computer 2a may include, for example, a processing unit 2a1, a memory unit 2a2, and a communication interface 2a3. The processing unit 2a1 may be configured to perform various control actions based on programs stored in the memory unit 2a2. The processing unit 2a1 may include a CPU (Central Processing Unit). The memory unit 2a2 may include RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or combinations thereof. The communication interface 2a3 communicates with the plasma processing device 1 via a communication line such as a LAN (Local Area Network).

[0031] [Plasma Processing Method] Figures 2 and 3 are flowcharts illustrating an example of a plasma processing method according to one embodiment of the present invention. The processes illustrated in Figures 2 and 3 are implemented by the control unit 2 controlling each part of the plasma processing apparatus 1. Hereinafter, the description will be conducted with reference to the timing diagram illustrated in Figure 4.

[0032] Furthermore, in the plasma processing method illustrated in Figures 2 and 3, in the initial state (period (a1) illustrated in Figure 4), the first switch 114 is controlled to be closed, the second switch 117 is controlled to be open, and the variable DC power supply 115 outputs an L voltage. Therefore, as shown in period (a1) illustrated in Figure 4, the voltage of the electrode 1110a in the electrostatic chuck 1110 is an L voltage, and the voltage detected by the detector 118 is also an L voltage. Furthermore, in the example of Figure 4, the closed state of each switch is recorded as "on", and the open state is recorded as "off".

[0033] First, the control unit 2 controls the conveying device (not shown) to start moving the substrate W into the plasma processing chamber 10 (S100).

[0034] Next, the control unit 2 controls the output voltage of the variable DC power supply 115 to an H voltage (S101). The processing of step S101 is an example of process a). Hereby, during the period (a2) illustrated in FIG4, the output voltage from the variable DC power supply 115 becomes an H voltage. Here, if the first switch 114 is in the closed state, during the period (a2) illustrated in FIG4, the voltage of the electrode 1110a in the electrostatic chuck 1110 becomes an H voltage, and the voltage detected by the detector 118 becomes an L voltage. On the other hand, if the first switch 114 is in the open state, during the period (a2) illustrated in FIG4, the voltage of the electrode 1110a remains at an L voltage, and the voltage detected by the detector 118 also remains at an L voltage.

[0035] Next, the control unit 2 determines whether the voltage detected by the detector 118 is an L voltage (S102). Even if the first switch 114 is controlled to the closed state and the second switch 117 is controlled to the open state, as shown in FIG5, when the first switch 114 and the second switch 117 are in the closed state, the voltage detected by the detector 118 is also an H voltage. In the example of FIG5, although the second switch 117 is controlled to the open state, the second switch 117 is still in the closed state, so the second switch 117 is in a closed fault state.

[0036] When the voltage detected by detector 118 is H voltage (S102: No), the second switch 117 is closed fault, so plasma processing is not started, and the plasma processing method illustrated in FIG2 and FIG3 ends.

[0037] On the other hand, when the voltage detected by detector 118 is L voltage (S102: Yes), control unit 2 controls the second switch 117 to the closed state (S103). Thus, during the period illustrated in FIG4 (a3), the second switch 117 is controlled to the closed state. The processing of step S103 is an example of process b). Furthermore, in step S102, even when the voltage detected by detector 118 is L voltage, as shown in FIG6, sometimes the first switch 114 is also in an open fault. Or, even when the voltage detected by detector 118 is L voltage, as shown in FIG7, sometimes the first switch 114 is also in an open fault, and the second switch 117 is also in a closed fault.

[0038] Next, the control unit 2 determines whether the voltage detected by the detector 118 is an H voltage (S104). If the voltage detected by the detector 118 is an L voltage (S104: No), at least one of the first switch 114 and the second switch 117 is in an open fault. Therefore, plasma processing is not started, and the plasma processing method illustrated in FIG2 and FIG3 ends.

[0039] On the other hand, when the voltage detected by detector 118 is voltage H (S104: Yes), during the period illustrated in FIG4 (a3), if controlled by control unit 2, the first switch 114 and the second switch 117 become closed. This confirms that the first switch 114 and the second switch 117 are at least not open. As long as the first switch 114 is not open, the voltage output from the variable DC power supply 115 is applied to the electrode 1110a via the first switch 114, and the substrate W is adsorbed onto the electrostatic chuck 1110. By confirming that the first switch 114 is at least not open, it can be confirmed that the substrate W is adsorbed onto the electrostatic chuck 1110. Therefore, plasma processing can begin after confirming that the substrate W is adsorbed onto the electrostatic chuck 1110. The processing in step S104 is an example of the first determination processing and process c).

[0040] Next, the control unit 2 controls the second switch 117 to the open state (S105). In step S105, the second switch 117 is controlled to the open state during the period (a4) illustrated in FIG4.

[0041] Next, the control unit 2 determines whether the voltage detected by the detector 118 is an L voltage (S106). If the voltage detected by the detector 118 is an H voltage (S106: No), the second switch 117 is in a closed fault state, so plasma processing does not start, and the plasma processing method illustrated in FIG2 and FIG3 ends. In this way, during plasma processing, the charge accumulated in the floating state electrode 1110a can be prevented from leaking through the wiring 116 and the detector 118, which would reduce the adsorption force between the substrate W and the electrostatic chuck 1110.

[0042] On the other hand, when the voltage detected by detector 118 is L voltage (S106: Yes), it is confirmed in step S104 that the first switch 114 is not open due to a fault, and therefore it is confirmed that the second switch 117 is not closed due to a fault. The processing in step S106 is an example of the second determination process.

[0043] Next, the control unit 2 controls the first switch 114 to the open state (S107). In step S107, the first switch 114 is controlled to the open state during the period (a5) illustrated in FIG4. Because the first switch 114 is in the open state, the electrode 1110a of the electrostatic chuck 1110 becomes a floating state. Furthermore, the processing in steps S101 to S107 is performed during the period of substrate W being transferred in before plasma processing.

[0044] Next, the control unit 2 performs plasma treatment on the substrate W (S108). In step S108, the plasma treatment is performed during the period (a6) illustrated in FIG4. Then, the plasma treatment ends during the period (a7) illustrated in FIG4. The process of step S108 is an example of process d).

[0045] Next, the control unit 2 controls the first switch 114 to the closed state (S109). In step S104, it is confirmed that the first switch 114 is not in an open fault, so in step S109, during the period (a8) illustrated in FIG4, the first switch 114 becomes the closed state.

[0046] Next, the control unit 2 controls the output voltage of the variable DC power supply 115 to an L voltage (S110). In step S110, during the period (a9) illustrated in FIG4, the output voltage of the variable DC power supply 115 is controlled to an L voltage. Thereby, the charge accumulated on the electrode 1110a flows through the variable DC power supply 115, and the electrode 1110a is destaticated. In this embodiment, after the electrode 1110a is destaticated, the voltage of the electrode 1110a and the output voltage of the variable DC power supply 115 both become L voltage.

[0047] Next, the control unit 2 controls the second switch 117 to the closed state (S111). In step S111, the second switch 117 is controlled to the closed state during the period (a10) illustrated in FIG4. In step S104, it is confirmed that the first switch 114 and the second switch 117 are not malfunctioning. Therefore, during the period (a10), by controlling the second switch 117 to the closed state, the detector 118 can detect the voltage of the electrode 1110a.

[0048] Furthermore, for a switch, switching at a lower applied voltage extends its lifespan. During the period (a9) to (a10) illustrated in Figure 4, the second switch 117 is switched from the open state to the closed state, but at this time, the voltage of the wiring 116 with the second switch 117 is set to L voltage. This extends the lifespan of the second switch 117.

[0049] Next, the control unit 2 determines whether the voltage detected by the detector 118 is an L voltage (S112 in FIG3). The processing in step S112 is an example of the third determination process. When the voltage detected by the detector 118 is an H voltage (S112: No), the electrostatic discharge of electrode 1110a cannot be sufficiently performed. If the electrostatic discharge of electrode 1110a cannot be sufficiently performed, when the processed substrate W is removed from the electrostatic chuck 1110 by means of a lifting pin (not shown), the substrate W may sometimes bounce or break. Therefore, the control unit 2 stops the removal of the plasma-processed substrate W and ends the plasma processing method illustrated in FIG2 and FIG3.

[0050] On the other hand, when the voltage detected by the detector 118 is L voltage (S112: Yes), the electrode 1110a is sufficiently destaticated, so the control unit 2 begins to remove the plasma-treated substrate W (S113). In step S113, the control unit 2 controls a drive unit (not shown) that drives the lifting pin to lift the substrate W by the lifting pin.

[0051] Next, the control unit 2 controls the first switch 114 and the second switch 117 to the open state (S114). In step S114, the first switch 114 and the second switch 117 are controlled to the open state during the period (a11) illustrated in FIG4.

[0052] Next, the control unit 2 controls the output voltage of the variable DC power supply 115 to H voltage (S115). In step S115, the output voltage of the variable DC power supply 115 is controlled to H voltage during the period illustrated in FIG4 (a12).

[0053] Next, the control unit 2 controls the second switch 117 to the closed state (S116). In step S116, the second switch 117 is controlled to the closed state during the period (a13) illustrated in FIG4. In step S104, it is confirmed that the second switch 117 is not faulty, so during the period (a13), by controlling the second switch 117 to the closed state, the detector 118 can detect the voltage of the electrode 1110a.

[0054] Next, the control unit 2 determines whether the voltage detected by the detector 118 is an L voltage (S117). If the voltage detected by the detector 118 is an H voltage (S117: No), the first switch 114 is in a closing fault, so the plasma processing of the next substrate W is stopped, and the plasma processing method illustrated in FIG2 and FIG3 is ended.

[0055] On the other hand, when the voltage detected by detector 118 is L voltage (S117: Yes), it is confirmed in step S104 that the second switch 117 is not open, and therefore it is confirmed that the first switch 114 is not closed. The processing of step S117 is an example of the fourth determination process.

[0056] Next, the control unit 2 controls the second switch 117 to the open state (S118). In step S118, the second switch 117 is controlled to the open state during the period (a14) illustrated in FIG4.

[0057] Next, the control unit 2 controls the output voltage of the variable DC power supply 115 to L voltage (S119). In step S119, the output voltage of the variable DC power supply 115 is controlled to L voltage during the period illustrated in FIG4 (a15).

[0058] Next, the control unit 2 controls the first switch 114 to the closed state (S120). In step S120, the first switch 114 is controlled to the closed state during the period (a16) illustrated in FIG4. The processing of steps S114 to S120 is performed during the period when the substrate W is removed after plasma treatment. Furthermore, in the example of FIG4, after the output voltage of the variable DC power supply 115 is switched from the H voltage to the L voltage from period (a14) to (a15), the first switch 114 is switched from the open state to the closed state from period (a15) to (a16). This extends the lifespan of the first switch 114.

[0059] Next, the control unit 2 determines whether to perform plasma treatment on the other substrate W (S121). If plasma treatment is performed on the other substrate W (S121: Yes), the control unit 2 executes the process shown in step S100 of FIG2 again. On the other hand, if plasma treatment is not performed on the other substrate W (S121: No), the control unit 2 ends the plasma treatment method illustrated in FIG2 and FIG3.

[0060] The first embodiment has been described above. As described above, the plasma processing apparatus 1 of this embodiment includes an electrostatic chuck 1110, a first switch 114, a second switch 117, and a control unit 2. The electrostatic chuck 1110 is disposed in the plasma processing chamber 10 and has an electrode 1110a inside. The substrate W to be processed by plasma is adsorbed by applying a voltage to the electrode 1110a. The first switch 114 is disposed in the wiring 113 between the variable DC power supply 115 that supplies voltage to the electrode 1110a and the electrode 1110a. The second switch 117 is disposed in the wiring 116 between the detector 118 that detects the voltage of the electrode 1110a and the electrode 1110a. Control unit 2 controls the first switch 114 and the second switch 117 to the closed state, and controls the variable DC power supply 115 to output a predetermined H voltage. When the detector 118 detects the H voltage, it performs a first determination process to determine that the first switch 114 and the second switch 117 are in the closed state. Furthermore, after determining that the first switch 114 and the second switch 117 are controlled to the closed state, control unit 2 starts plasma processing of the substrate W with the first switch 114 and the second switch 117 in the open state and the electrode 1110a in a floating state. This allows plasma processing to begin after confirming that the substrate W is adhered to the electrostatic chuck 1110. It also confirms that the first switch 114 and the second switch 117 are not malfunctioning.

[0061] Furthermore, in the above embodiment, the control unit 2 performs a second determination process. In the second determination process, the first switch 114 is controlled to be closed, and the second switch 117 is controlled to be open. The variable DC power supply 115 is controlled to output voltage H. When the detector 118 detects a voltage L that is lower than voltage H, it is determined that the second switch 117 is in the open state. In this way, it can be confirmed that the second switch 117 is not faulty.

[0062] Furthermore, in the above embodiment, the control unit 2 performs a third determination process. In the third determination process, after the plasma treatment of the substrate W is completed, the first switch 114 and the second switch 117 are controlled to be closed, and the variable DC power supply 115 is controlled to output voltage L. When the detector 118 detects voltage L, it is determined that the static electricity removal of electrode 1110a has been completed. After determining that the static electricity removal of electrode 1110a has been completed, the control unit 2 controls the drive unit of the lifting pin to lift the substrate W by means of the lifting pin. In this way, the substrate W after plasma treatment can be prevented from bouncing or breaking.

[0063] Furthermore, in the above embodiment, the control unit 2 performs the fourth determination process. In the fourth determination process, after controlling the variable DC power supply 115 to output L voltage by controlling the first switch 114 to the closed state, the first switch 114 is then controlled to the open state, and the second switch 117 is controlled to the closed state by controlling the variable DC power supply 115 to output H voltage by controlling the variable DC power supply 115. When the detector 118 detects L voltage, it is determined that the first switch 114 is in the open state. In this way, it can be confirmed that the first switch 114 is not faulty.

[0064] Furthermore, in the above embodiment, the control unit 2 performs the first determination process and the second determination process during the process of moving the substrate W before plasma processing into the plasma processing chamber 10. This increases the throughput when plasma processing multiple substrates W.

[0065] Furthermore, in the above embodiment, the control unit 2 performs the fourth determination process while removing the substrate W, which has finished plasma processing, from the plasma processing chamber 10. This increases the throughput when plasma processing multiple substrates W.

[0066] Furthermore, the plasma processing method of the above embodiment includes steps a), b), c), and d). In step a), the variable DC power supply 115 is controlled to output a predetermined voltage H, and the variable DC power supply 115 supplies voltage to the electrode 1110a disposed inside the electrostatic chuck 1110 of the substrate W to be processed by plasma. In step b), the first switch 114 of the wiring 113 between the electrode 1110a and the variable DC power supply 115 and the second switch 117 of the wiring 116 between the electrode 1110a and the detector 118 for detecting the voltage of the electrode 1110a are controlled to be in a closed state. In step c), when the detector 118 detects the voltage H, it is determined that the first switch 114 and the second switch 117 are in a closed state. In step d), after determining that the first switch 114 and the second switch 117 are in the closed state, plasma processing of the substrate W is started with the first switch 114 and the second switch 117 controlled to the open state and the electrode 1110a controlled to the floating state. This allows plasma processing to begin after confirming that the substrate W is adhered to the electrostatic chuck 1110. Furthermore, it can be confirmed that the first switch 114 and the second switch 117 are not malfunctioning.

[0067] [Others] Furthermore, the technology disclosed in this application is not limited to the above-described embodiments, and various variations can be implemented within the scope of its intent.

[0068] For example, in the above embodiment, during the period after the plasma treatment is completed (a13), the first switch 114 is controlled to the open state, the second switch 117 is controlled to the closed state, and the output voltage of the variable DC power supply 115 is controlled to the H voltage. Then, the closing failure of the first switch 114 is determined based on whether the L voltage is detected by the detector 118. However, the disclosed technology is not limited to this.

[0069] Figure 8 is a timing diagram showing another example of the control sequence. For example, as shown in Figure 8, during period (b1) after period (a3), the second switch 117 is kept closed, and the output voltage of the variable DC power supply 115 is controlled to L voltage. This removes static electricity from electrode 1110a. Then, during period (b2), the first switch 114 is controlled to open, and during period (b3), the output voltage of the variable DC power supply 115 is again controlled to H voltage. Furthermore, during period (b3), a failure to close the first switch 114 can be determined based on whether L voltage is detected by detector 118. Therefore, by determining a failure to close the first switch 114 before the start of plasma processing, electrode 1110a can be reliably controlled to a floating state during period (a5) before the start of plasma processing. This prevents the substrate W from bouncing or cracking after plasma processing.

[0070] Furthermore, during the period (b4) after determining whether the L voltage is detected by the detector 118, the second switch 117 is turned on again. Then, during the period (b5), the first switch 114 is turned off again, and the voltage output from the self-variable DC power supply 115 is applied to the electrode 1110a via the first switch 114. Also, after confirming the destatic discharge of the electrode 1110a during the period (a10), the second switch 117 is turned on again during the period (b6), returning to the initial state. The processing performed during periods (b1) to (b5) is preferably performed during the period when the substrate W before plasma processing is moved into the plasma processing chamber 10.

[0071] Furthermore, in the above embodiment, during period (a2), the output voltage of the variable DC power supply 115 is controlled from voltage L to voltage H, and during the subsequent period (a3), the second switch 117 is controlled from the open state to the closed state. However, the disclosed technology is not limited to this. For example, as shown in FIG9, the second switch 117 can also be controlled from the open state to the closed state during period (c2), and during the subsequent period (c3), the output voltage of the variable DC power supply 115 can be controlled from voltage L to voltage H. This can extend the lifespan of the second switch 117.

[0072] Furthermore, during the period (c5) illustrated in Figure 9, by controlling the output voltage of the variable DC power supply 115 from the H voltage to the L voltage, the output voltage of the variable DC power supply 115 can also be maintained at the L voltage during plasma processing.

[0073] Furthermore, in the example of Figure 9, during the period after plasma treatment (c8), the electrode 1110a is destaticated, and during the period (c9), the destatication is confirmed by the detector 118. Subsequently, after the destatication confirmation, the first switch 114 can also be controlled to be open while the second switch 117 is kept closed during the period (c10), and during the period (c11), the closure failure of the first switch 114 is determined.

[0074] Furthermore, in the above embodiment, a plasma processing system 100 using a capacitively coupled plasma (CCP) as an example of a plasma source has been described, but the plasma source is not limited to this. Examples of plasma sources other than capacitively coupled plasma include inductively coupled plasma (ICP), microwave-excited surface wave plasma (SWP), electron cyclotron resonance plasma (ECP), and helical wave excited plasma (HWP).

[0075] Furthermore, the embodiments disclosed herein should be considered illustrative rather than restrictive in all respects. In fact, the above embodiments can be implemented in various forms. Moreover, the above embodiments can also be omitted, substituted, and modified in various forms without departing from the scope and spirit of the appended patent applications. [Simplified Explanation of the Diagram]

[0008] Figure 1 is a diagram showing an example of a plasma treatment system according to one embodiment of the present invention. Figure 2 is a flowchart showing an example of a plasma treatment method according to one embodiment of the present invention. Figure 3 is a flowchart showing an example of a plasma treatment method according to one embodiment of the present invention. Figure 4 is a timing diagram showing an example of a control sequence. Figure 5 is a diagram showing an example of the state of the first switch and the second switch. Figure 6 is a diagram showing an example of the state of the first switch and the second switch. Figure 7 is a diagram showing an example of the state of the first switch and the second switch. Figure 8 is a timing diagram showing another example of a control sequence. Figure 9 is a timing diagram showing another example of a control sequence.

Claims

1. A plasma processing apparatus comprising: an electrostatic chuck disposed in a chamber having electrodes therein, for adsorbing a substrate to be processed by plasma by applying a voltage to the electrodes; a first switch disposed in a wiring between a power supply supplying voltage to the electrodes and the electrodes; a second switch disposed in a wiring between a detector for detecting the voltage of the electrodes and the electrodes; and a control unit; wherein the control unit performs a first determination process, the first determination process being: controlling the first switch and the second switch to a closed state, controlling the power supply to output a predetermined first voltage from the power supply, determining that the first switch and the second switch are closed when the detector detects the first voltage, controlling the first switch to an open state after determining that the first switch and the second switch are closed, controlling the first switch to an open state after the first switch is open, controlling the second switch to an open state after the first switch is open, and starting plasma processing of the substrate in a state where the electrodes are controlled to a floating state.

2. The plasma processing apparatus of claim 1, wherein the control unit performs a second determination process, the second determination process being: controlling the first switch to a closed state, controlling the second switch to an open state, controlling the power supply in such a way as to output the first voltage from the power supply, and determining that the second switch is in an open state when the detector detects a second voltage that is lower than the first voltage.

3. The plasma processing apparatus of claim 2, wherein the control unit performs a third determination process, the third determination process being: after the processing of the substrate using plasma has been completed, controlling the first switch and the second switch to be closed, controlling the power supply to output the second voltage from the power supply, determining that the destatic discharge of the electrodes has been completed when the detector detects the second voltage, and controlling the drive unit of the lifting pin to drive the lifting pin to lift the substrate by means of the lifting pin after determining that the destatic discharge of the electrodes has been completed.

4. The plasma processing apparatus of claim 3, wherein the control unit performs a fourth determination process, the fourth determination process being: after controlling the first switch to the closed state and controlling the power supply to output the second voltage from the power supply, controlling the first switch to the open state, controlling the second switch to the closed state and controlling the power supply to output the first voltage from the power supply, and determining that the first switch is in the open state when the detector detects the second voltage.

5. The plasma processing apparatus of claim 2, wherein the control unit performs the first determination process and the second determination process during the period when the substrate is moved into the chamber before being processed by plasma.

6. The plasma processing apparatus of claim 4, wherein the control unit performs the fourth determination process during the period when the substrate whose plasma processing has been completed is removed from the chamber.

7. The plasma processing apparatus of claim 4, wherein the control unit performs the fourth determination process during the period when the substrate is moved into the chamber before being processed by plasma.

8. A plasma treatment method, comprising the following steps: a) The power supply is controlled to output a predetermined first voltage from the power supply, and the power supply supplies voltage to the electrodes provided inside the electrostatic chuck of the substrate to be processed by plasma; b) The first switch of the wiring between the electrodes and the power supply, and the second switch of the wiring between the electrodes and the detector that detects the voltage of the electrodes are controlled to be closed; c) When the detector detects the first voltage, it is determined that the first switch and the second switch are closed; and d) After determining that the first switch and the second switch are closed, the first switch is controlled to be open, and after the first switch is controlled to be open, the second switch is controlled to be open, and the substrate is processed by plasma in a state where the electrodes are controlled to be in a floating state.

Images