Substrate processing method and substrate processing apparatus

Abstract

The present invention provides a substrate processing method and a substrate processing apparatus, which are technologies for suppressing the adhesion of fine particles to a substrate. The substrate processing method includes the following steps: changing the pressure of the gas supplied from the gas supply unit between the substrate and the adsorption unit from a first pressure to a second pressure lower than the first pressure; changing the applied voltage applied to the adsorption unit from a first voltage to a second voltage lower than the first voltage; changing the temperature of the adsorption unit from a first temperature to a second temperature; electrostatically adsorbing the substrate by the adsorption unit for a first period of time while setting the pressure of the gas supplied from the gas supply unit to the second pressure and setting the applied voltage applied to the adsorption unit to the second voltage; changing the pressure of the gas supplied from the gas supply unit from the second pressure to a third pressure lower than the first pressure and higher than the second pressure; and changing the applied voltage applied to the adsorption unit from the second voltage to a third voltage higher than the second voltage.

Description

Technical Field

[0001] The present disclosure relates to a substrate processing method and a substrate processing apparatus. Background Art

[0002] Patent Document 1 discloses the following technique: the relative adsorption force is decreased by flowing backside gas between the adsorption surface of an electrostatic chuck and a wafer, so that the wafer makes a sliding movement relative to the adsorption surface, thereby reducing the generation of fine particles.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2000-21964 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] The present disclosure provides a technique capable of suppressing the adhesion of fine particles to a substrate.

[0008] Solutions for Solving the Problems

[0009] A substrate processing method according to one aspect of the present disclosure is a method of changing the temperature of a substrate by using a substrate processing apparatus. The substrate processing apparatus includes a processing container, a stage, an adsorption unit, and a gas supply unit. The stage is disposed in the processing container. The adsorption unit is provided on the stage, the temperature of which can be changed, and electrostatically adsorbs the substrate according to an applied voltage. The gas supply unit supplies a heat transfer gas between the substrate disposed on the adsorption unit and the adsorption unit. The temperature change method includes the following steps: changing the pressure of the gas supplied from the gas supply unit between the substrate and the adsorption unit from a first pressure to a second pressure lower than the first pressure; changing the applied voltage applied to the adsorption unit from a first voltage to a second voltage lower than the first voltage; changing the temperature of the adsorption unit from a first temperature to a second temperature; electrostatically adsorbing the substrate by the adsorption unit to hold the substrate for a first time in a state where the pressure of the gas supplied from the gas supply unit is the second pressure and the applied voltage applied to the adsorption unit is the second voltage; changing the pressure of the gas supplied from the gas supply unit from the second pressure to a third pressure lower than the first pressure and higher than the second pressure; and changing the applied voltage applied to the adsorption unit from the second voltage to a third voltage higher than the second voltage.

[0010] Effects of the Invention

[0011] According to the present disclosure, the adhesion of fine particles to the substrate can be suppressed. Brief Description of the Drawings

[0012] Figure 1 It is a schematic cross-sectional view showing an example of the structure of a substrate processing apparatus according to an embodiment.

[0013] Figure 2 It is a timing chart showing an example of a conventional substrate processing method.

[0014] Figure 3 It is a diagram for explaining the cause of particle generation.

[0015] Figure 4 It is a timing chart showing an example of a substrate processing method according to the present embodiment.

[0016] Figure 5 It is a diagram showing the damage length generated on a wafer according to the applied voltage applied to an electrostatic chuck.

[0017] Figure 6 It is a diagram showing the determination result based on the leakage amount of a heat transfer gas.

[0018] Figure 7 summarizes Figure 5 and Figure 6 The diagram of the determination result.

[0019] Figure 8 It is a diagram showing the temperature change of a wafer.

[0020] Figure 9 summarizes Figure 5 , Figure 6 and Figure 8 The diagram of the determination result.

[0021] Figure 10 It is a line graph showing the average value of particles attached to the edge region of a wafer.

[0022] Explanation of Reference Numerals

[0023] 1: Processing container; 2: Mounting table; 6: Electrostatic chuck; 6a: Electrode; 6b: Insulator; 6c: Heater; 8: Wafer; 17: Wiring; 18: Heater power supply; 25: Heat transfer gas supply unit; 26: Gas supply line; 26a: Gas supply line; 26b: Valve; 26c: Valve; 90: Control unit; 91: Process controller; 92: User interface; 93: Storage unit; 100: Substrate processing apparatus. Detailed implementation mode

[0024] Hereinafter, embodiments of the substrate processing method and the substrate processing apparatus disclosed in the present application will be described in detail with reference to the drawings. In addition, the disclosed substrate processing method and substrate processing apparatus are not limited by this embodiment.

[0025] In addition, in a substrate processing apparatus that performs substrate processing on a substrate, an electrostatic chuck (ESC: Electrostatic chuck) for electrostatically adsorbing the substrate is provided on a stage to stably hold the substrate. Further, the substrate processing apparatus controls the temperature of the substrate adsorbed on the stage to a temperature suitable for substrate processing by changing the temperature of the stage. However, in the substrate processing apparatus, when the temperature of the substrate and the stage is changed in a state where the substrate is adsorbed, fine particles are generated due to friction at the contact portion between the substrate and the electrostatic chuck because of the different thermal expansion coefficients of the substrate and the electrostatic chuck.

[0026] Therefore, in the technique of Patent Document 1, a gas is caused to flow between the adsorption surface of the electrostatic chuck and the wafer to reduce the relative adsorption force, so that the wafer slides relative to the adsorption surface.

[0027] However, the gas flowing between the adsorption surface of the electrostatic chuck and the substrate sometimes leaks from the outer periphery of the substrate, and fine particles are raised from the outer periphery of the substrate due to the leaked gas and the fine particles adhere to the substrate. In the technique of Patent Document 1, since a gas is caused to flow between the adsorption surface of the electrostatic chuck and the substrate to reduce the adsorption force, the amount of gas leaking from the outer periphery of the substrate increases, and fine particles are easily raised from the outer periphery of the substrate. Therefore, suppressing the adhesion of fine particles to the substrate has been desired.

[0028] [Embodiment]

[0029] [Device Structure]

[0030] An example of a substrate processing apparatus that implements the substrate processing method according to the embodiment will be described. In the present embodiment, plasma processing such as plasma etching will be taken as an example to describe the substrate processing. Further, a plasma processing apparatus will be taken as an example for description. Figure 1 FIG. is a schematic cross-sectional view showing an example of the structure of a substrate processing apparatus 100 according to the embodiment. The substrate processing apparatus 100 is hermetically configured and has a processing container 1 that is electrically grounded. The processing container 1 is formed in a cylindrical shape and is made of, for example, aluminum or the like. A processing space for generating plasma is formed inside the processing container 1. A stage 2 for horizontally supporting a semiconductor wafer (hereinafter simply referred to as "wafer") 8 as a substrate is provided in the processing container 1.

[0031] The mounting stage 2 includes a base (pedestal) 2a and an electrostatic chuck (ESC) 6. The base 2a is made of a conductive metal, such as aluminum, and has the function of a lower electrode. The electrostatic chuck 6 has the function of electrostatically adsorbing the wafer 8. The mounting stage 2 is supported by a support stage 4. The support stage 4 is supported by a support member 3 made of a dielectric such as quartz, for example. In addition, an edge ring 5 such as a focus ring formed of single crystal silicon is provided on the outer periphery above the mounting stage 2. And, inside the processing container 1, a cylindrical inner wall member 3a made of a dielectric such as ceramics is provided so as to surround the periphery of the mounting stage 2 and the support stage 4.

[0032] The base 2a is connected to a first high-frequency power supply 10a via a first matcher 11a. In addition, the base 2a is connected to a second high-frequency power supply 10b via a second matcher 11b. The first high-frequency power supply 10a is a power supply that generates high-frequency power for generating plasma. When performing plasma processing, the first high-frequency power supply 10a supplies high-frequency power of a specified frequency in the range of 27 to 100 MHz, and in one example, high-frequency power of 40 MHz, to the base 2a of the mounting stage 2. The second high-frequency power supply 10b is a power supply that generates high-frequency power for attracting ions (for biasing). When performing plasma processing, the second high-frequency power supply 10b supplies high-frequency power of a specified frequency in the range of 400 kHz to 13.56 MHz, which is lower than that of the first high-frequency power supply 10a, and in one example, high-frequency power of 3 MHz, to the base 2a of the mounting stage 2. In this way, the mounting stage 2 is configured to be able to apply two high-frequency powers of different frequencies from the first high-frequency power supply 10a and the second high-frequency power supply 10b. On the other hand, above the mounting stage 2, a shower head 16 having the function of an upper electrode is provided so as to face the mounting stage 2 in parallel. The shower head 16 and the mounting stage 2 function as a pair of electrodes (upper electrode and lower electrode).

[0033] In addition, the base 2a is electrically grounded via a wiring 13. A switch 13a such as a relay switch is provided on the wiring 13. The base 2a is configured to be electrically switchable between a grounded state and a floating state by turning on / off the switch 13a.

[0034] The electrostatic chuck 6 is formed in a disk shape with a flat upper surface. The upper surface of the electrostatic chuck 6 is provided as a mounting surface 6e for mounting the wafer 8. The electrostatic chuck 6 is constituted by sandwiching electrodes 6a between insulators 6b. The electrodes 6a are connected to a DC power supply 12. The electrostatic chuck 6 adsorbs the wafer 8 by using the Coulomb force generated by applying a DC voltage from the DC power supply 12 to the electrodes 6a.

[0035] In the electrostatic chuck 6, a heater 6c is provided below the electrode 6a within the insulator 6b. The heater 6c is connected to a heater power supply 18 via a wiring 17. The heater power supply 18 supplies adjusted power to the heater 6c based on the control of a control unit 90 described later. Thereby, the heat emitted by the heater 6c is controlled to adjust the temperature of the wafer 8 disposed on the electrostatic chuck 6.

[0036] A flow path 20 is formed inside the base 2a. One end of the flow path 20 is connected to a refrigerant inlet pipe 21a. The other end of the flow path 20 is connected to a refrigerant outlet pipe 21b. The refrigerant inlet pipe 21a and the refrigerant outlet pipe 21b are connected to a cooling device (not shown). The flow path 20 is located below the wafer 8 and functions to absorb the heat of the wafer 8. The substrate processing apparatus 100 is configured such that by circulating a refrigerant such as cooling water, an organic solvent such as a heat transfer fluid (GALDEN), etc. from the cooling device through the refrigerant inlet pipe 21a and the refrigerant outlet pipe 21b into the flow path 20, the stage 2 can be controlled to a specified temperature.

[0037] In addition, the substrate processing apparatus 100 further includes a heat transfer gas supply unit 25 and a gas supply line 26. One end of the gas supply line 26 is connected to a through hole formed in the electrostatic chuck 6, and the other end is connected to the heat transfer gas supply unit 25. Further, the gas supply line 26 branches out a gas supply line 26a midway. The branched gas supply line 26a is connected to an exhaust device 83. The exhaust device 83 has a vacuum pump, and by operating the vacuum pump, exhaust can be performed. An openable and closable valve 26b is provided on the gas supply line 26a. Further, on the gas supply line 26, an openable and closable valve 26c is provided at a position closer to one end side than the branch point where the gas supply line 26a branches out. The opening and closing of the valves 26b and 26c are controlled by the control unit 90 described later.

[0038] The heat transfer gas supply unit 25 is connected to a gas supply source that supplies the heat transfer gas. The heat transfer gas supply unit 25 is provided with a mass flow controller and an on-off valve, and supplies a specified flow rate of the heat transfer gas to the gas supply line 26 under the control of a control unit 90 described later. As the heat transfer gas, for example, He (helium) gas and Ar (argon) gas are listed. When the valve 26b is in the closed state and the valve 26c is in the open state, the heat transfer gas supplied from the heat transfer gas supply unit 25 is supplied via the gas supply line 26 between the wafer 8 placed on the mounting table 2 and the electrostatic chuck 6. On the other hand, when the valve 26b is in the open state and the valve 26c is in the closed state, the heat transfer gas supplied from the heat transfer gas supply unit 25 is exhausted to the exhaust device 83 via the gas supply line 26a. When supplying the heat transfer gas between the wafer 8 and the electrostatic chuck 6 from the heat transfer gas supply unit 25, the valve 26b is in the closed state and the valve 26c is in the open state.

[0039] The shower head 16 is provided on the top wall portion of the processing container 1. The shower head 16 includes a main body portion 16a and an upper top plate 16b that forms an electrode plate. The shower head 16 is supported on the upper portion of the processing container 1 via an insulating member 95. The main body portion 16a is made of a conductive material, such as aluminum whose surface has been anodized, and is configured to be able to support the upper top plate 16b in a detachable manner at the lower portion.

[0040] A gas diffusion chamber 16c is provided inside the main body portion 16a. In addition, a large number of gas flow holes 16d are formed in the lower portion of the gas diffusion chamber 16c in the main body portion 16a. In the upper top plate 16b, gas introduction holes 16e are provided so as to penetrate the upper top plate 16b in the thickness direction and coincide with the gas flow holes 16d. With such a structure, the processing gas supplied to the gas diffusion chamber 16c is dispersed and supplied in a shower shape into the processing container 1 via the gas flow holes 16d and the gas introduction holes 16e.

[0041] A gas introduction port 16g for introducing the processing gas into the gas diffusion chamber 16c is formed in the main body portion 16a. The gas introduction port 16g is connected to one end of a gas supply pipe 15a. The other end of the gas supply pipe 15a is connected to a processing gas supply source 15 that supplies the processing gas. On the gas supply pipe 15a, a mass flow controller (MFC) 15b and an on-off valve 15c are provided in sequence from the upstream side. The processing gas for plasma etching is supplied from the processing gas supply source 15 via the gas supply pipe 15a. The processing gas is dispersed and supplied in a shower shape into the processing container 1 from the gas diffusion chamber 16c via the gas flow holes 16d and the gas introduction holes 16e.

[0042] A cylindrical ground conductor 1a is provided so as to extend from the side wall of the processing container 1 to a position above the height position of the shower head 16. The cylindrical ground conductor 1a has a top wall at the upper part.

[0043] An exhaust port 81 is formed at the bottom of the processing container 1. The exhaust port 81 is connected to an exhaust device 83 via an exhaust pipe 82. The exhaust device 83 reduces the pressure inside the processing container 1 to a specified vacuum degree by operating a vacuum pump. On the other hand, a loading / unloading port 84 for the wafer 8 is provided on the side wall inside the processing container 1, and a gate valve 85 for opening and closing the loading / unloading port 84 is provided at the loading / unloading port 84.

[0044] Inside the side part of the processing container 1, a deposit shield 86 is provided along the inner wall surface. The deposit shield 86 is used to prevent etching by-products (deposits) from adhering to the processing container 1. A conductive member (GND block) 89 connected in a manner capable of controlling the potential with respect to ground is provided at a height position substantially the same as that of the wafer 8 on the deposit shield 86, thereby preventing abnormal discharge. In addition, a deposit shield 87 extending along the inner wall member 3a is provided at the lower end of the deposit shield 86. The deposit shields 86 and 87 are provided to be detachable.

[0045] The operation of the substrate processing apparatus 100 having the above structure is uniformly controlled by a control unit 90. The control unit 90 is provided with a process controller 91 having a CPU and controlling each part of the substrate processing apparatus 100, a user interface 92, and a storage unit 93.

[0046] The user interface 92 includes a keyboard for an operation manager to input commands for managing the substrate processing apparatus 100, a display for visually displaying the working condition of the plasma processing apparatus 100, and the like.

[0047] In the storage unit 103, processes are stored, and the processes store control programs (software), processing condition data, etc. for implementing various processes executed by the substrate processing apparatus 100 through the control of the process controller 91. Moreover, as needed, an arbitrary process is retrieved from the storage unit 93 based on an instruction from the user interface 92 and the process controller 91 is made to execute the process, thereby performing a desired process using the substrate processing apparatus 100 under the control of the process controller 91.

[0048] [Substrate Processing Method]

[0049] Next, a substrate processing method in which the substrate processing apparatus 100 processes the wafer 8 will be described. The substrate processing apparatus 100 can control the temperature of the wafer 8 disposed on the electrostatic chuck 6 by controlling the heat generation of the heater 6c. During substrate processing, the substrate processing apparatus 100 controls the heat generation of the heater 6c, thereby controlling the temperature of the wafer 8. The substrate processing apparatus 100 sometimes performs a plurality of processes during substrate processing. For example, when the substrate processing apparatus 100 etches the wafer 8 on which a multilayer film is formed, the substrate processing apparatus 100 performs a plurality of plasma processes, which are a plurality of processes with processing conditions such as the temperature of the wafer 8 changed. When the substrate processing apparatus 100 performs a plurality of processes, the temperature of the wafer 8 is controlled to a temperature suitable for each process in each process. In this case, the substrate processing apparatus 100 changes the temperature of the wafer 8 between the respective processes.

[0050] Figure 2 is a timing chart showing an example of a conventional substrate processing method. In Figure 2 is shown a case where the process B is performed on the wafer 8 after the process A. The process A and the process B are, for example, plasma processes for etching a multilayer film formed on the wafer 8. The temperature suitable for the process A of the wafer 8 is set to 80°C. The temperature suitable for the process B of the wafer 8 is set to 30°C. In Figure 2 is shown the applied voltage HV (ESC HV) applied to the electrostatic chuck 6 and the pressure BP (Torr) of the heat transfer gas supplied as the backside gas from the heat transfer gas supply unit 25 between the wafer 8 and the electrostatic chuck 6. Further, in Figure 2 is shown the temperature of the electrostatic chuck 6 (ESC Temp) and the high-frequency power RF supplied from the first high-frequency power supply 10a and the second high-frequency power supply 10b to the base 2a of the stage 2. The temperature of the wafer 8 (Wafer Temp) is also shown by a dotted line for the temperature of the electrostatic chuck 6 (ESC Temp). Further, in Figure 2 is shown the electrical state of the base 2a of the stage 2 based on the on / off of the switch 13a (Relay).

[0051] As Figure 2 shown, in the first process (process A) performed previously, the applied voltage HV applied to the electrostatic chuck (ESC) 6 is set to 2500 V. Further, in the first process, the valve 26b is set to the closed state and the valve 26c is set to the open state to supply the heat transfer gas from the heat transfer gas supply unit 25 between the wafer 8 and the electrostatic chuck 6 at 30 Torr. Further, in the first process, the high-frequency power RF corresponding to the first process is supplied from the first high-frequency power supply 10a and the second high-frequency power supply 10b to the base 2a of the stage 2, and the switch 13a is turned off to make the base 2a of the stage 2 in a floating state.

[0052] In Figure 2In the conventional substrate processing method shown, when changing the temperature of the wafer 8, the high-frequency power RF supplied from the first high-frequency power supply 10a and the second high-frequency power supply 10b is cut off and changed to 0 W, and the temperatures of the electrostatic chuck 6 and the wafer 8 are changed from 80°C to 30°C. Regarding the applied voltage HV (V), the pressure BP (Torr) of the heat transfer gas, and the electrical state of the susceptor 2a, the state in the first process is maintained when changing the temperature of the wafer 8.

[0053] However, when the substrate processing apparatus 100 changes the temperatures of the electrostatic chuck 6 and the wafer 8 while the wafer 8 is electrostatically adsorbed to the electrostatic chuck 6, particles (PA) may be generated.

[0054] As a result of investigating the generation of these particles, the following generation causes were found. Figure 3 This is a diagram for explaining the cause of particle generation. In Figure 3 the structure near the outer periphery of the susceptor 2 is schematically shown. The wafer 8 is disposed on the electrostatic chuck 6. The wafer 8 and the electrostatic chuck 6 expand or contract according to temperature changes. However, when changing the temperatures of the wafer 8 and the susceptor 2 while the wafer 8 is adsorbed to the electrostatic chuck 6, due to the different thermal expansion coefficients of the wafer 8 and the electrostatic chuck 6, the contact portion between the wafer 8 and the electrostatic chuck 6 is damaged by friction, thereby generating particles PA. In the conventional substrate processing method, a heat transfer gas is supplied between the adsorption surface of the electrostatic chuck 6 and the wafer 8 to reduce the adsorption force, so the heat transfer gas leaks from the outer periphery of the wafer 8. The generated particles PA are lifted from the outer periphery of the wafer 8 into the processing chamber 1 due to the heat transfer gas leaking from the outer periphery of the wafer 8. As a result, the particles PA are adsorbed on the surface of the wafer 8.

[0055] Therefore, when changing the temperature of the wafer 8, the substrate processing apparatus 100 according to the present embodiment implements the substrate processing method according to the present embodiment described below. Figure 4 This is a timing chart showing an example of the substrate processing method according to the present embodiment. In Figure 4 it is shown, in the same manner as Figure 2 the case where after process A, process B is performed on the wafer 8 as plasma processing. The temperature of the wafer 8 suitable for process A is set to 80°C. The temperature of the wafer 8 suitable for process B is set to 30°C. In Figure 4 it is shown the applied voltage HV (ESC HV) applied to the electrostatic chuck 6 and the pressure BP (Torr) of the heat transfer gas supplied as a backside gas from the heat transfer gas supply unit 25 between the wafer 8 and the electrostatic chuck 6. In addition, in Figure 4The temperature of the electrostatic chuck 6 (ESC Temp) and the high-frequency power RF supplied from the first high-frequency power supply 10a and the second high-frequency power supply 10b to the base 2a of the stage 2 are shown. The temperature of the wafer 8 (Wafer Temp) is also shown by a dashed line for the temperature of the electrostatic chuck 6 (ESC Temp). In addition, in Figure 4 the electrical state of the base 2a of the stage 2 based on the on / off of the switch 13a (Relay) is shown.

[0056] As Figure 4 shown, in the first process (Process A), the applied voltage HV is set to 2500V. In addition, in the first process, the valve 26b is set to the closed state and the valve 26c is set to the open state to supply the heat transfer gas at 30 Torr from the heat transfer gas supply unit 25 between the wafer 8 and the electrostatic chuck 6. In addition, in the first process, the high-frequency power RF corresponding to the first process is supplied from the first high-frequency power supply 10a and the second high-frequency power supply 10b to the base 2a of the stage 2, and the switch 13a is turned off to make the base 2a of the stage 2 in a floating state.

[0057] In Figure 4 the substrate processing method according to the present embodiment shown, when changing the temperature of the wafer 8, the pressure of the heat transfer gas supplied from the heat transfer gas supply unit 25 between the wafer 8 and the electrostatic chuck 6 is changed from the first pressure to a second pressure lower than the first pressure. For example, the control unit 90 controls the heat transfer gas supply unit 25 to change the pressure BP of the heat transfer gas supplied from the heat transfer gas supply unit 25 to 0 Torr. Thereby, it is possible to suppress the generation of fine particles from the outer periphery of the wafer 8. In addition, the control unit 90 may control the valves 26b and 26c to the closed state to exhaust the heat transfer gas from the heat transfer gas supply unit 25 via the gas supply line 26a, thereby virtually changing the pressure of the heat transfer gas between the wafer 8 and the electrostatic chuck 6 to 0 Torr.

[0058] Next, in the substrate processing method according to the present embodiment, the applied voltage HV applied to the electrostatic chuck 6 is changed from the first voltage to a second voltage lower than the first voltage.

[0059] Here, in Figure 2 the conventional substrate processing method of the wafer 8 shown, when changing the temperature of the wafer 8, it is not necessary to generate plasma, so the high-frequency power RF is cut off and changed to 0W.

[0060] However, when changing the applied voltage HV, it is preferable to supply high-frequency power to the stage 2 to avoid a sharp change in the potential of the wafer 8. In addition, it is preferable to ground the stage 2 to suppress the potential change of the stage 2 and reduce the discharge risk.

[0061] Therefore, in the substrate processing method according to the present embodiment, when changing the applied voltage HV, it is decreased relative to the plasma processing and high-frequency power is supplied to the stage 2. Further, in the substrate processing according to the present embodiment, during the period of changing the temperature of the wafer 8, the stage 2 is grounded. For example, the control unit 90 controls the first high-frequency power supply 10a and the second high-frequency power supply 10b to supply at least one of the high-frequency power HF for generating plasma and the high-frequency power LF for bias. In Figure 4 the example, the power is decreased compared to the high-frequency power RF in the first process (process A), and 100 W of high-frequency power HF for generating plasma or 100 W of high-frequency power LF for bias is supplied. Further, the control unit 90 turns on the switch 13a to ground the base 2a of the stage 2. In Figure 4 , after delaying the operation waiting time ta1 of the switch 13a from the time when the high-frequency power RF is decreased, the base 2a of the stage 2 becomes the ground potential (GND). The control unit 90 controls the DC power supply 12 to change the applied voltage HV from 2500 V to 1000 V after the standby time ta2 has elapsed since the change in which the high-frequency power RF is decreased. Thereby, a rapid change in the potential of the wafer 8 when changing the applied voltage HV can be suppressed. Further, by grounding the stage 2, a change in the potential of the stage 2 can be suppressed to reduce the risk of discharge.

[0062] Next, in the substrate processing method according to the present embodiment, the temperature of the stage 2 is changed from the first temperature to the second temperature. Further, in the substrate processing method according to the present embodiment, when changing the temperature of the stage 2 from the first temperature to the second temperature, the high-frequency power supplied to the stage 2 is cut off. For example, the control unit 90 controls the heater power supply 18 to decrease the calorific value of the heater 6c, and changes the temperature of the stage 2 from 80°C to 30°C. Further, the control unit 90 controls the first high-frequency power supply 10a and the second high-frequency power supply 10b to cut off the high-frequency power HF for generating plasma and the high-frequency power LF for bias, thereby setting the high-frequency power RF to 0 W.

[0063] Next, in the substrate processing method according to the present embodiment, in a state where the pressure of the heat transfer gas supplied from the heat transfer gas supply unit 25 is set to a second pressure and the applied voltage HV applied to the electrostatic chuck 6 is set to a second voltage, the wafer 8 is electrostatically adsorbed by the electrostatic chuck 6 to hold the wafer 8 for a first period of time. For example, the control unit 90 maintains the state where the pressure BP of the heat transfer gas supplied from the heat transfer gas supply unit 25 is set to 0 Torr and the applied voltage HV applied to the electrostatic chuck 6 is set to 1000 V for a time ta3. As a result, the temperature of the mounting stage 2 decreases. The temperature of the wafer 8 electrostatically adsorbed to the electrostatic chuck 6 decreases as the temperature of the mounting stage 2 decreases. The time ta3 is set to the time until the temperature of the wafer 8 decreases to a temperature close to the temperature of the mounting stage 2, and is determined in advance by experiments or the like.

[0064] Next, in the substrate processing method according to the present embodiment, the pressure of the heat transfer gas supplied from the heat transfer gas supply unit 25 is changed from the second pressure to a third pressure that is lower than the first pressure and higher than the second pressure. For example, the control unit 90 controls the heat transfer gas supply unit 25 to change the pressure BP of the heat transfer gas supplied from the heat transfer gas supply unit 25 to 10 Torr. By increasing the pressure BP of the heat transfer gas supplied from the heat transfer gas supply unit 25 in this way, heat is transferred by the heat transfer gas, and the temperature of the wafer 8 electrostatically adsorbed to the electrostatic chuck 6 rapidly changes to the temperature of the mounting stage 2.

[0065] Next, in the substrate processing method according to the present embodiment, the applied voltage HV applied to the electrostatic chuck 6 is changed from the second voltage to a third voltage that is higher than the second voltage.

[0066] Here, as described above, when changing the applied voltage HV, it is preferable to supply high-frequency power to the mounting stage 2 to avoid a sharp change in the potential of the wafer 8.

[0067] Therefore, in the substrate processing method according to the present embodiment, high-frequency power is supplied to the mounting stage 2 when changing the applied voltage HV. For example, the control unit 90 controls the first high-frequency power supply 10a and the second high-frequency power supply 10b to supply the high-frequency power HF for generating plasma and the bias high-frequency power LF for the second process (process B) to be performed next. The control unit 90 controls the DC power supply 12 to change the applied voltage HV from 1000 V to 2500 V after a standby time ta4 from the change to increase the high-frequency power RF. In addition, the control unit 90 opens the switch 13a to make the base 2a of the mounting stage 2 in a floating state, so as to suppress the potential change of the mounting stage 2 and reduce the discharge risk. In Figure 4 In, after a waiting time ta5 for delaying the operation of the switch 13a from the rise of the high-frequency power RF, the base 2a of the mounting stage 2 becomes in a floating state.

[0068] Through the substrate processing method according to this embodiment, the substrate processing apparatus 100 can suppress the adhesion of particles to the wafer 8 by changing the temperature of the wafer 8.

[0069] In the substrate processing method according to this embodiment, after changing to the third voltage, the pressure of the gas supplied from the heat transfer gas supply unit 25 is changed from the third pressure to a fourth pressure higher than the third pressure. For example, the control unit 90 controls the heat transfer gas supply unit 25 to change the pressure BP of the heat transfer gas supplied from the heat transfer gas supply unit 25 to 30 Torr in the second process (Process B).

[0070] Through the substrate processing method according to this embodiment, the substrate processing apparatus 100 performs the processing of the second process (Process B) on the wafer 8 whose temperature changes by 30°C.

[0071] In the substrate processing method according to this embodiment, when changing the temperature of the wafer 8 between the first process (Process A) and the second process (Process B), it is possible to suppress the adhesion of particles to the wafer 8 and change the temperature of the wafer 8.

[0072] [Appropriate ranges of the pressure BP of the heat transfer gas and the applied voltage HV]

[0073] Next, an example of appropriate ranges of the pressure BP of the heat transfer gas and the applied voltage HV applied to the electrostatic chuck 6 when changing the temperature of the wafer 8 will be described.

[0074] As Figure 3 shown, the surface of the wafer 8 is damaged due to friction at the contact portion between the wafer 8 and the electrostatic chuck 6, generating particles. Therefore, for example, when the applied voltage HV is decreased to decrease the adsorption force between the wafer 8 and the electrostatic chuck 6, surface damage to the wafer 8 and the electrostatic chuck 6 can be suppressed, and thus generation of particles can be suppressed.

[0075] Figure 5 is a graph showing the damage length generated in the wafer 8 according to the voltage HV applied to the electrostatic chuck 6. In Figure 5Shows the damage lengths generated in the wafer 8 for the temperature difference Δt between the wafer 8 and the electrostatic chuck 6 in each case where the applied voltage HV is set to 1000V, 1500V, 2000V, and 2500V. When the applied voltage HV is 2000V, damage is generated in the wafer 8 when the temperature difference Δt is large. The damage generated in the wafer 8 when the applied voltage HV is 2500V is longer than the damage generated in the wafer 8 when the applied voltage HV is 2000V. On the other hand, almost no damage is generated when the applied voltage HV is 1000V and 1500V. Therefore, in order to suppress the generation of damage, the applied voltage HV is preferably set to 1500V or less, and more preferably set to 1000V or less.

[0076] In addition, the substrate processing apparatus 100 suppresses the leakage of the heat transfer gas supplied between the wafer 8 and the electrostatic chuck 6 by adsorbing the wafer 8 to the electrostatic chuck 6. When the applied voltage HV applied to the electrostatic chuck 6 is decreased in the substrate processing apparatus 100, the electrostatic adsorption force of the electrostatic chuck 6 on the wafer 8 decreases, and the leakage of the heat transfer gas increases.

[0077] Figure 6 Is a graph showing the determination result based on the leakage amount of the heat transfer gas. In Figure 6 It shows the leakage amount of the heat transfer gas when the pressure BP of the heat transfer gas supplied from the heat transfer gas supply unit 25 is set to 0 to 30 Torr and the applied voltage HV is set to 500 to 2500V in numbers.

[0078] In order to suppress the leakage of the heat transfer gas less, it is necessary to increase the pressure BP of the heat transfer gas supplied from the heat transfer gas supply unit 25, and the higher this pressure BP is, the higher the applied voltage HV needs to be. In the substrate processing apparatus 100, wafer deviation and wafer detachment are likely to occur, so it is preferable that the leakage of the heat transfer gas is small. For example, it is not preferable that the leakage amount of the heat transfer gas exceeds 1.0, it is preferably 1.0 or less, and more preferably less than 0.5. In Figure 6 、 7 And 9, the "×" is marked for the non-preferred results, the "△" is marked for the preferred results, and the "○" is marked for the more preferred results. In Figure 6 It marks the part where the leakage amount of the heat transfer gas is less than 0.5 with "○", the part where the leakage amount is 0.5 to 1.0 with "△", and the part where the leakage amount exceeds 1.0 with "×". For example, when the pressure BP of the heat transfer gas supplied from the heat transfer gas supply unit 25 is 30 Torr, it is preferable to set the applied voltage HV to 1500V or more.

[0079] In this way, in order to suppress the generation of damage, it is preferable to reduce the applied voltage HV. However, in order to suppress the leakage amount of the heat transfer gas, it is necessary not to make the applied voltage HV too low so that the wafer 8 is adsorbed to the electrostatic chuck 6.

[0080] Figure 7 summarizes Figure 5 and Figure 6 is a graph showing the determination results. In Figure 7 it reflects the range of the applied voltage HV that can suppress the generation of damage obtained according to the results of Figure 5 In Figure 7 a part where the applied voltage HV is 1500 V is marked with "△", a part where it is 1000 V or less is marked with "○". A part where the applied voltage HV is greater than 2500 V is marked with "×". In Figure 7 it also reflects the range that can suppress the leakage of the heat transfer gas shown in Figure 6 In Figure 7 a part where the pressure BP of the heat transfer gas is 10 Torr or more when the applied voltage HV is 500 V and a part where the pressure BP of the heat transfer gas is 20 Torr or more when the applied voltage HV is 1000 V are changed to "×".

[0081] In addition, in the substrate processing method according to the present embodiment shown in Figure 4 during the period T1 when the temperature of the electrostatic chuck 6 changes, the applied voltage HV is decreased to decrease the adsorption force between the wafer 8 and the electrostatic chuck 6, and the pressure BP of the heat transfer gas is decreased. Moreover, in the substrate processing method according to the present embodiment, the pressure BP of the heat transfer gas during the period T2 rises to 10 Torr. Explain the temperature change of the wafer 8 during the period T1 and the period T2.

[0082] Figure 8 is a graph showing the temperature change of the wafer 8. In Figure 8 after the temperature of the wafer 8 is made about 90 °C during the period T3, the temperature of the wafer 8 is changed to 30 °C during the periods T4 and T5. The period T3 reproduces the temperature of the wafer 8 in the first process (process A) of Figure 4 The periods T4 and T5 reproduce the temperature of the wafer 8 during the periods T1 and T2 of Figure 4 During the period T3, the applied voltage HV is set to 2500 V, the pressure BP of the heat transfer gas is set to 30 Torr, and the temperature of the wafer 8 is heated to about 90 °C. On the right side of Figure 8 is an enlarged view of the dashed part of the period T5 after magnification.

[0083] Figure 8"1000V 10T" represents the temperature change of wafer 8 when the applied voltage HV is set to 1000V during period T4, the pressure BP of the heat transfer gas is set to 0 Torr, and the pressure BP of the heat transfer gas is changed to 10 Torr during period T5. "1500V 0T" represents the temperature change of wafer 8 when the applied voltage HV is set to 1500V during period T4, the pressure BP of the heat transfer gas is set to 0 Torr, and the pressure BP of the heat transfer gas is still maintained at 0 Torr during period T5. "1500V 10T" represents the temperature change of wafer 8 when the applied voltage HV is set to 1500V during period T4, the pressure BP of the heat transfer gas is set to 0 Torr, and the pressure BP of the heat transfer gas is changed to 10 Torr during period T5. "1500V 30T" represents the temperature change of wafer 8 when the applied voltage HV is set to 1500V during period T4, the pressure BP of the heat transfer gas is set to 0 Torr, and the pressure BP of the heat transfer gas is changed to 30 Torr during period T5. "2500V 30T" represents the temperature change of wafer 8 when the applied voltage HV is set to 2500V and the pressure BP of the heat transfer gas is set to 30 Torr during periods T4 and T5 in the same manner as in period T3.

[0084] "2500V 30T" can rapidly change the temperature of wafer 8 to 30 °C. However, for "2500V 30T", during periods T4 and T5, the voltage is applied to the electrostatic chuck 6 in the same manner as in period T3 to maintain the pressure BP of the heat transfer gas, so that fine particles are lifted from the outer periphery of wafer 8 into the processing chamber 1.

[0085] Regarding "1500V 0T", "1500V 10T", and "1500V 30T", the temperature of wafer 8 drops in the same way during period T4. Regarding "1500V 10T" and "1500V 30T", during period T5, the temperature of wafer 8 is rapidly changed to around 30 °C by supplying the heat transfer gas. On the other hand, for "1500V 0T", the pressure BP of the heat transfer gas is also set to 0 Torr during period T5, resulting in a decrease in heat transfer performance, a decrease in the followability of the temperature of wafer 8, and a time-consuming decrease in the temperature of wafer 8.

[0086] Regarding "1000V 10T", during period T4, the degree of temperature change is lower than that of "1500V 10T" etc., but the temperature of wafer 8 drops. During period T5, the temperature of wafer 8 is rapidly changed to around 30 °C by supplying the heat transfer gas. Therefore, from the perspective of temperature change, it is preferable to set the pressure BP of the heat transfer gas to 10 Torr or more.

[0087] Figure 9 summarizes Figure 5 、Figure 6 and Figure 8 graph of the determination result Figure 9 For Figure 7 shows the result of the range that can rapidly change the temperature of the Figure 8 wafer 8 shown. In Figure 9 , the temperature of the wafer 8 cannot be rapidly changed, so the part where the pressure BP of the heat transfer gas in Figure 7 is 5 Torr or less is changed to "×".

[0088] According to Figure 9 the result shown, in the substrate processing method according to the present embodiment, during Figure 4 period T1, the applied voltage HV is set to 1000V to 1500V, and the pressure BP of the heat transfer gas is set to 10 Torr or less, preferably 0 Torr. During period T2, the pressure BP of the heat transfer gas is preferably set to 10 Torr. In addition, during period T1, it is more preferable to set the applied voltage HV to 1000V and the pressure BP of the heat transfer gas to 0 Torr. During period T2, it is more preferable to set the pressure BP of the heat transfer gas to 10 Torr.

[0089] [Change in the number of particles]

[0090] Next, the experimental results obtained by counting the particles actually attached to the wafer 8 will be described. In the experiment, the applied voltage HV and the pressure BP of the heat transfer gas during periods T1 and T2 of the substrate processing method according to the present embodiment are changed, and the temperature of the wafer 8 is changed, and the particles attached to the wafer 8 are counted. Regarding the size of the wafer 8, the radius is 150 mm. In the experiment, the number of particles attached to the edge region of the wafer 8 is counted. The edge region of the wafer 8 is the region of the wafer 8 outside the radius of 120 mm. Figure 10 is a graph showing the average value of the particles attached to the edge region of the wafer 8. "2500V 30T" indicates the case where the applied voltage HV is set to 2500V and the pressure BP of the heat transfer gas is set to 30 Torr during periods T1 and T2. That is, for "2500V 30T", in the same manner as the Figure 2 conventional substrate processing method shown, without changing the applied voltage HV and the pressure BP of the heat transfer gas, the temperature of the electrostatic chuck 6 and the wafer 8 is changed from 80°C to 30°C. "1500V 20T" indicates the case where the applied voltage HV is set to 1500V and the pressure BP of the heat transfer gas is set to 0 Torr during period T1 and the pressure BP of the heat transfer gas is changed to 20 Torr during period T2. "1000V 10T" indicates the case where the applied voltage HV is set to 1000V and the pressure BP of the heat transfer gas is set to 0 Torr during period T1 and the pressure BP of the heat transfer gas is changed to 10 Torr during period T2. InFigure 10 In [description], regarding "2500V 30T", "1500V 20T", and "1000V 10T", the average number of particles attached to the edge regions of two wafers 8 is represented by a line graph respectively. Compared with "2500V 30T", the average number of particles of "1500V 20T" and "1000V 10T" is less. That is, "1500V 20T" and "1000V 10T" compared with Figure 2 the conventional substrate processing method shown can suppress the attachment of particles to the wafer 8. In addition, compared with "1500V 20T", the average number of particles of "1000V 10T" is less. That is, "1000V 10T" can most effectively suppress the attachment of particles to the wafer 8.

[0091] [Effect]

[0092] As described above, the substrate processing method according to the present embodiment is a substrate processing method in which the substrate processing apparatus 100 processes the wafer 8 (substrate). The substrate processing apparatus 100 includes a processing container 1, a mounting stage 2, an electrostatic chuck 6 (adsorbing portion), and a heat transfer gas supply unit 25 (gas supply unit). The mounting stage 2 is disposed inside the processing container 1. The electrostatic chuck 6 is provided on the mounting stage 2, the temperature can be changed, and the wafer 8 is electrostatically adsorbed according to the applied voltage. The heat transfer gas supply unit 25 supplies a gas for heat transfer between the wafer 8 disposed on the electrostatic chuck 6 and the electrostatic chuck 6. The substrate processing method includes the following steps: changing the pressure of the gas supplied from the heat transfer gas supply unit 25 between the wafer 8 and the electrostatic chuck 6 from a first pressure to a second pressure lower than the first pressure; changing the applied voltage applied to the electrostatic chuck 6 from a first voltage to a second voltage lower than the first voltage; changing the temperature of the electrostatic chuck 6 from a first temperature to a second temperature; electrostatically adsorbing the wafer 8 by the electrostatic chuck 6 to hold the wafer 8 for a first period of time in a state where the pressure of the gas supplied from the heat transfer gas supply unit 25 is the second pressure and the applied voltage applied to the electrostatic chuck 6 is the second voltage; changing the pressure of the gas supplied from the heat transfer gas supply unit 25 from the second pressure to a third pressure lower than the first pressure and higher than the second pressure; and changing the applied voltage applied to the electrostatic chuck 6 from the second voltage to a third voltage higher than the second voltage. Thereby, the substrate processing method according to the present embodiment can suppress the attachment of particles to the wafer 8.

[0093] In addition, before the process of changing to the second pressure, the substrate processing method according to the present embodiment further includes a process of performing a first process on the wafer 8 at a first temperature. After the process of changing to the third voltage, the substrate processing method according to the present embodiment further includes a process of performing a second process on the wafer 8 at a second temperature. Thus, when the temperature of the wafer 8 is changed between the process of the first process and the process of the second process, the substrate processing method according to the present embodiment can suppress the attachment of fine particles to the wafer 8.

[0094] In addition, after changing to the third voltage, the substrate processing method according to the present embodiment further includes a process of changing the pressure of the gas supplied from the heat transfer gas supply unit 25 from the third pressure to a fourth pressure higher than the third pressure. Thus, the substrate processing method according to the present embodiment can improve the heat transfer performance and can improve the temperature followability of the wafer 8.

[0095] In addition, the substrate processing method according to the present embodiment is set such that the first pressure is equal to the fourth pressure. Thus, the substrate processing method according to the present embodiment can control the temperature of the wafer 8 by controlling the temperature of the electrostatic chuck 6.

[0096] In addition, the substrate processing method according to the present embodiment is set such that the first voltage is equal to the third voltage. Thus, the substrate processing method according to the present embodiment can stably hold the wafer 8 by the electrostatic chuck 6.

[0097] In addition, in the process of changing to the second pressure, the substrate processing method according to the present embodiment changes the pressure of the gas supplied between the wafer 8 and the electrostatic chuck 6 from the first pressure to a second pressure lower than the first pressure by exhausting the gas supplied from the heat transfer gas supply unit 25 to the exhaust system. Thus, the substrate processing method according to the present embodiment can change the pressure of the gas supplied between the wafer 8 and the electrostatic chuck 6 without changing the pressure of the gas supplied from the heat transfer gas supply unit 25. In addition, by changing the pressure of the gas to a second pressure lower than the first pressure, it is possible to suppress the generation of fine particles from the periphery of the wafer 8.

[0098] In addition, the substrate processing method according to the present embodiment sets the first temperature to be higher than the second temperature. Thus, even when a change for lowering the temperature of the wafer 8 is made, the substrate processing method according to the present embodiment can suppress the attachment of fine particles to the wafer 8.

[0099] In addition, in the process of changing the applied voltage applied to the electrostatic chuck 6, the substrate processing method according to the present embodiment supplies high-frequency power to the stage 2. Thus, the substrate processing method according to the present embodiment can suppress a sharp change in the potential of the wafer 8 when the applied voltage applied to the electrostatic chuck 6 is changed.

[0100] The above has described the embodiments, but it should be considered that the disclosed embodiments are illustrative in all respects and not restrictive. In fact, the above embodiments can be specifically implemented in various ways. Additionally, the above embodiments can be omitted, replaced, or changed in various ways without departing from the claims and their gist.

[0101] For example, in the above embodiment, the case where the temperature of the wafer 8 is decreased by the substrate processing method has been described as an example. However, it is not limited thereto. When the temperature of the wafer 8 is increased, similarly to the case where the temperature of the wafer 8 is decreased, the contact portion between the wafer 8 and the electrostatic chuck 6 is damaged by friction to generate particulates PA. Therefore, even when the substrate processing method according to the present embodiment is changed to increase the temperature of the wafer 8, the adhesion of particulates to the wafer 8 can be suppressed.

[0102] In addition, in the above embodiment, it has been described as an example that Figure 4 during the period T1, the control unit 90 causes the temperature of the wafer 8 to decrease to a temperature close to the temperature of the stage 2 by waiting for the elapsed time ta3. However, it is not limited thereto. The control unit 90 may also detect the actual temperature of the electrostatic chuck 6 for control. For example, a detection unit such as a temperature sensor for detecting the temperature of the electrostatic chuck 6 is provided for the electrostatic chuck 6. The control unit 90 electrostatically adsorbs the wafer 8 by the electrostatic chuck 6 and holds the wafer 8 until the difference between the temperature of the electrostatic chuck 6 detected by the temperature sensor and the second temperature becomes within a specified value. Moreover, when the difference between the temperature of the electrostatic chuck 6 and the second temperature becomes within a specified value, the control unit 90 may change the pressure of the gas supplied from the heat transfer gas supply unit 25 from the second pressure to a third pressure that is lower than the first pressure and higher than the second pressure.

[0103] In addition, in the above substrate processing method according to the present embodiment, the case where the power of the high-frequency power RF changes abruptly has been described as an example. However, it is not limited thereto. The control unit 90 may also slowly decrease the power of the high-frequency power RF during at least a part of the period of changing the high-frequency power RF. For example, the control unit 90 may slowly decrease the high-frequency power HF for generating plasma or the bias high-frequency power LF from 100 W to 0 W during the period T1.

[0104] In addition, in the above-described embodiment, the case where the substrate processing apparatus 100 is a capacitively coupled plasma processing apparatus has been described as an example. However, it is not limited thereto. The substrate processing method according to the present embodiment can employ any plasma processing apparatus. For example, the substrate processing apparatus 100 can also be any type of plasma processing apparatus, such as an inductively coupled plasma processing apparatus, a plasma processing apparatus that excites a gas by a surface wave such as a microwave, and the like.

[0105] In addition, in the above-described embodiment, the case where the susceptor 2a is connected to the first high-frequency power supply 10a and the second high-frequency power supply 10b has been described as an example, but the structure of the plasma source is not limited thereto. For example, the first high-frequency power supply 10a for generating plasma can also be connected to the shower head 16 having a function as an upper electrode. In addition, the second high-frequency power supply 10b for attracting ions (for biasing) may not be connected to the susceptor 2a.

[0106] In addition, the above-described substrate processing apparatus 100 is a plasma processing apparatus that performs etching as a plasma process, but a plasma processing apparatus that performs any plasma process can be employed. For example, the substrate processing apparatus 100 can be a single-wafer deposition apparatus that performs chemical vapor deposition (CVD), atomic layer deposition (ALD), physical vapor deposition (PVD), etc., or a plasma processing apparatus that performs plasma annealing, plasma implantation, etc.

[0107] In addition, in the above-described embodiment, the case where the substrate is a semiconductor wafer has been described as an example, but it is not limited thereto. The substrate can also be other substrates such as a glass substrate.

Claims

1. A substrate processing method, which is a substrate processing method for a substrate processing apparatus to process a substrate, The substrate processing apparatus includes: A processing chamber; A stage disposed within the processing chamber; An adsorption portion provided on the stage, whose temperature can be changed, and which electrostatically adsorbs the substrate according to an applied voltage; And A gas supply portion that supplies a heat transfer gas between the substrate disposed on the adsorption portion and the adsorption portion, The substrate processing method includes the following steps: Changing the pressure of the gas supplied from the gas supply portion between the substrate and the adsorption portion from a first pressure to a second pressure lower than the first pressure; Changing the applied voltage applied to the adsorption portion from a first voltage to a second voltage lower than the first voltage; Changing the temperature of the adsorption portion from a first temperature to a second temperature; While setting the pressure of the gas supplied from the gas supply portion to the second pressure and setting the applied voltage applied to the adsorption portion to the second voltage, electrostatically adsorbing the substrate by the adsorption portion to hold the substrate for a first period of time; Changing the pressure of the gas supplied from the gas supply portion from the second pressure to a third pressure lower than the first pressure and higher than the second pressure; And Changing the applied voltage applied to the adsorption portion from the second voltage to a third voltage higher than the second voltage.

2. The substrate processing method according to claim 1, wherein Before the step of changing to the second pressure, there is also a step of performing a first process on the substrate at the first temperature, After the step of changing to the third voltage, there is also a step of performing a second process on the substrate at the second temperature.

3. The substrate processing method according to claim 1 or 2, wherein After changing to the third voltage, there is also a step of changing the pressure of the gas supplied from the gas supply portion from the third pressure to a fourth pressure higher than the third pressure.

4. The substrate processing method according to claim 3, wherein The first pressure is equal to the fourth pressure.

5. The substrate processing method according to claim 1 or 2, wherein The first voltage is equal to the third voltage.

6. The substrate processing method according to claim 1 or 2, wherein In the step of changing to the second pressure, by exhausting the gas supplied from the gas supply portion to an exhaust system, the pressure of the gas supplied between the substrate and the adsorption portion is changed from the first pressure to a second pressure lower than the first pressure.

7. The substrate processing method according to claim 1 or 2, wherein When changing the temperature of the adsorption portion from the first temperature to the second temperature, the high-frequency power supplied to the stage is cut off.

8. The substrate processing method according to claim 1 or 2, wherein The first temperature is higher than the second temperature.

9. The substrate processing method according to claim 1 or 2, wherein The first temperature is lower than the second temperature.

10. The substrate processing method according to claim 1 or 2, characterized in that the substrate processing apparatus further has a detection unit that detects the temperature of the adsorption unit, in the process of holding, the substrate is electrostatically adsorbed by the adsorption unit to hold the substrate until the difference between the temperature of the adsorption unit detected by the detection unit and the second temperature becomes within a specified value, in the process of changing to the third pressure, when the difference between the temperature of the adsorption unit and the second temperature becomes within a specified value, the pressure of the gas supplied from the gas supply unit is changed from the second pressure to the third pressure that is lower than the first pressure and higher than the second pressure.

11. The substrate processing method according to claim 1 or 2, characterized in that in the process of changing the applied voltage applied to the adsorption unit, high-frequency power is supplied to the stage.

12. The substrate processing method according to claim 1 or 2, characterized in that during the period of changing the temperature of the substrate, the stage is in a grounded state.

13. A substrate processing apparatus, comprising: a processing container; a stage disposed in the processing container; an adsorption unit disposed on the stage, the temperature of which can be changed, and which electrostatically adsorbs a substrate according to an applied voltage; a gas supply unit that supplies a heat transfer gas between the substrate disposed on the adsorption unit and the adsorption unit; and a control unit that controls to change the pressure of the gas supplied from the gas supply unit between the substrate and the adsorption unit from a first pressure to a second pressure lower than the first pressure, change the applied voltage applied to the adsorption unit from a first voltage to a second voltage lower than the first voltage, change the temperature of the adsorption unit from a first temperature to a second temperature, electrostatically adsorb the substrate by the adsorption unit to hold the substrate for a first time in a state where the pressure of the gas supplied from the gas supply unit is the second pressure and the applied voltage applied to the adsorption unit is the second voltage, change the pressure of the gas supplied from the gas supply unit from the second pressure to a third pressure that is lower than the first pressure and higher than the second pressure, and change the applied voltage applied to the adsorption unit from the second voltage to a third voltage higher than the second voltage.

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