Plasma processing system and plasma processing method

Abstract

To provide a technique that can improve the accuracy of plasma processing and can improve the efficiency of cleaning processing.SOLUTION: A plasma processing system includes: a plasma processing chamber that can execute plasma processing; a substrate support part that supports a substrate inside the plasma processing chamber, and supports a ring arranged around the substrate; and a control unit. The control unit controls (A) a step of causing the substrate support part to hold the substrate, and before the plasma processing, moving the ring relative to the substrate support part to be brought into contact with the substrate, (B) after the step of (A), executing the plasma processing on the substrate, and (C) after the step of (B), moving the ring relative to the substrate support part to be separated from the substrate.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a plasma processing system and a plasma processing method.

Background Art

[0002] Patent Document 1 discloses a plasma processing system that performs plasma processing such as etching in a state where a substrate and a ring (edge ring) are placed on a substrate support in a plasma processing chamber. In this type of plasma processing system, deposits generated by plasma processing adhere to an electrostatic chuck or the like through the gap between the substrate and the ring. Therefore, the plasma processing apparatus periodically performs a cleaning process for removing deposits adhering to each component in the plasma processing chamber.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure provides a technology capable of improving the accuracy of plasma processing and enhancing the efficiency of cleaning processing.

Means for Solving the Problems

[0005] According to one aspect of the present disclosure, there is provided a plasma processing system including a plasma processing chamber capable of performing plasma processing, a substrate support unit that supports a substrate inside the plasma processing chamber and supports a ring disposed around the substrate, and a control unit. The control unit controls: (A) a step of holding the substrate by the substrate support unit and moving the ring relative to the substrate support unit to contact the substrate before the plasma processing; (B) a step of performing the plasma processing on the substrate after the step (A); and (C) a step of moving the ring relative to the substrate support unit to separate the ring from the substrate after the step (B).

Advantages of the Invention

[0006] According to one aspect, it is possible to improve the accuracy of plasma processing and enhance the efficiency of cleaning processing.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0008] Hereinafter, embodiments for carrying out the present disclosure will be described with reference to the drawings. In each drawing, the same reference numerals are assigned to the same components, and redundant descriptions may be omitted.

[0009] First, a configuration example of the plasma processing system according to the embodiment will be described with reference to FIG. 1. FIG. 1 is an explanatory diagram schematically showing the plasma processing system.

[0010] The plasma processing system includes a capacitively coupled plasma processing apparatus 1 which is a substrate processing apparatus, and a control unit 2. The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply 30, and an exhaust system 40. Further, 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 processing gas into the plasma processing chamber 10. The gas introduction unit includes a shower head 13. The substrate support unit 11 is disposed within the plasma processing chamber 10. The shower head 13 is disposed above the substrate support unit 11. In one embodiment, the shower head 13 constitutes at least a part of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the shower head 13, the side wall 10a of the plasma processing chamber 10, and the substrate support unit 11. The plasma processing chamber 10 has at least one gas supply port for supplying at least one processing gas to the plasma processing space 10s, and at least one gas discharge port for discharging gas from the plasma processing space. The side wall 10a is grounded. The shower head 13 and the substrate support unit 11 are electrically insulated from the plasma processing chamber 10 housing.

[0011] The substrate support portion 11 includes a main body portion 111 and a ring R. The main body portion 111 has a central region (substrate support surface) 111a for supporting a substrate (wafer) W and an annular region (ring support surface) 111b for supporting the ring R. The annular region 111b of the main body portion 111 surrounds the central region 111a of the main body portion 111 in a plan view. The substrate W is disposed on the central region 111a of the main body portion 111, and the ring R is disposed on the annular region 111b of the main body portion 111 so as to surround the substrate W on the central region 111a of the main body portion 111. The ring R includes one or more annular members. At least one of the one or more annular members is an edge ring or a focus ring. In one embodiment, the main body portion 111 is configured by assembling a base 14, an electrostatic chuck 15, a protection member 17, etc. The base 14 includes a conductive member. The conductive member of the base 14 functions as a lower electrode. The electrostatic chuck 15 is disposed on the base 14. The electrostatic chuck 15 has the central region 111a and the annular region 111b on its upper surface. Also, although not shown, the substrate support portion 11 may include a temperature module configured to adjust at least one of the electrostatic chuck 15, the ring R, and the substrate to a target temperature. For example, the temperature module may be provided inside the base 14 and may be configured to include a heater, a heat transfer medium, a flow path, or a combination thereof. A heat transfer fluid such as brine or gas flows through the flow path.

[0012] The shower head 13 is configured to introduce at least one process gas from the gas supply portion 20 into the plasma processing space 10s. The shower head 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and a plurality of gas introduction ports 13c. The process gas supplied to the gas supply port 13a passes through the gas diffusion chamber 13b and is introduced into the plasma processing space 10s from the plurality of gas introduction ports 13c. Also, the shower head 13 includes a conductive member. The conductive member of the shower head 13 functions as an upper electrode. Note that the gas introduction portion may include one or more side gas injectors (SGI) attached to one or more openings formed in the side wall 10a in addition to the shower head 13.

[0013] The gas supply unit 20 may 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 process gas from the corresponding gas source 21 to the showerhead 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. Further, the gas supply unit 20 may include one or more flow modulation devices that modulate or pulse the flow rate of at least one process gas.

[0014] The power supply 30 includes an RF 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 (RF power), such as a source RF signal and a bias RF signal, to the conductive member of the substrate support 11 and / or the conductive member of the showerhead 13. Thereby, plasma is formed from at least one process gas supplied to the plasma processing space 10s. Accordingly, 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 process gases in the plasma processing chamber 10. Also, by supplying a bias RF signal to the conductive member of the substrate support 11, a bias potential is generated on the substrate W, and the ion component in the formed plasma can be drawn into the substrate W.

[0015] In one embodiment, the RF power supply 31 includes a first RF generation unit 31a and a second RF generation unit 31b. The first RF generation unit 31a is coupled to the conductive member (base 14) of the substrate support unit 11 and / or the conductive member of the shower head 13 via at least one impedance matching circuit, and is configured to generate a source RF signal (source RF power) for plasma generation. 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 generation unit 31a may be configured to generate a plurality of source RF signals having different frequencies. The generated one or more source RF signals are supplied to the conductive member of the substrate support unit 11 and / or the conductive member of the shower head 13. The second RF generation unit 31b is coupled to the conductive member of the substrate support unit 11 via at least one impedance matching circuit, and is configured to generate a bias RF signal (bias RF power). In one embodiment, the bias RF signal has a frequency lower than that of 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 be configured to generate a plurality of bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to the conductive member of the substrate support unit 11. Also, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0016] In addition, the power supply 30 may include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generation unit 32a and a second DC generation unit 32b. In one embodiment, the first DC generation unit 32a is connected to a conductive member of the substrate support 11 and is configured to generate a first DC signal. The generated first bias DC signal is applied to the conductive member of the substrate support 11. In one embodiment, the first DC signal may be applied to other electrodes such as the electrodes in the electrostatic chuck. In one embodiment, the second DC generation unit 32b is connected to a conductive member of the shower head 13 and is configured to generate a second DC signal. The generated second DC signal is applied to the conductive member of the shower head 13. In various embodiments, at least one of the first and second DC signals may be pulsed. Note that the first and second DC generation units 32a and 32b may be provided in addition to the RF power supply 31, or the first DC generation unit 32a may be provided in place of the second RF generation unit 31b.

[0017] The exhaust system 40 may be connected to, for example, a gas outlet 10e provided 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 in the plasma processing space 10s is adjusted by the pressure regulating valve. The vacuum pump may include a turbo molecular pump, a dry pump, or a combination thereof.

[0018] The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to execute various processes described in the present disclosure. The control unit 2 can be configured to control each element of the plasma processing apparatus 1 so as to execute 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 (CPU: Central Processing Unit) 2a1, a storage unit 2a2, and a communication interface 2a3. The processing unit 2a1 can be configured to perform various control operations based on a program stored in the storage unit 2a2. The storage unit 2a2 may include a RAM (Random Access Memory), a ROM (Read Only Memory), an HDD (Hard Disk Drive), an SSD (Solid State Drive), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing apparatus 1 via a communication line such as a LAN (Local Area Network).

[0019] As configured above, in the plasma processing system, as described above, deposits are generated in the plasma processing chamber 10 during plasma processing such as etching processing. In particular, when the substrate W and the ring R are separated, the deposits move so as to enter the electrostatic chuck 15 having a low temperature from the gap between the substrate W and the ring R, and adhere to the stepped outer peripheral surface 111c (shoulder portion: see FIG. 2) of the electrostatic chuck 15. In the plasma processing system, when plasma processing is performed multiple times, a cleaning process for removing deposits in the plasma processing chamber 10 is performed. However, since it is difficult to remove the deposits adhering to the stepped outer peripheral surface 111c, this becomes a factor that lengthens the execution period of the cleaning process.

[0020] Therefore, the plasma processing system according to the embodiment is configured to move the ring R supported by the substrate support portion 11, and suppresses the adhesion of deposits to the electrostatic chuck 15 by contacting the substrate W during plasma processing. Further, the plasma processing apparatus 1 suppresses rubbing with the ring R when the substrate W is taken out by separating the ring R from the substrate W after plasma processing. Hereinafter, the configuration of the ring R and the substrate support portion 11 will be described in detail with reference to FIG. 2.

[0021] FIG. 2 is a side cross-sectional view showing an enlarged outer peripheral portion of the ring R and the substrate support portion 11. The lower surface Ru of the ring R and the ring support surface 111b of the substrate support portion 11 are in surface contact with each other, and the ring R is slidable relative to the ring support surface 111b. Specifically, the ring R moves on the ring support surface 111b between a contact position P1 that contacts the substrate W close to the stepped outer peripheral surface 111c and a retracted position P2 that is separated from the substrate W close to the protective member 17 side. The ring R is configured as an assembly (assembly) composed of a plurality of arc-shaped parts R1 to R3 divided along the circumferential direction in order to realize the movement between the contact position P1 and the retracted position P2 (see also FIGS. 3(B) and 3(C)).

[0022] The ring R (each of the arc-shaped parts R1 to R3) has a lower surface Ru inclined with respect to the horizontal plane. Similarly, the ring support surface 111b is also formed as a surface inclined downward in the vertical direction from the contact position P1 toward the retracted position P2. The lower surface Ru of the ring R and the ring support surface 111b are inclined at the same angle obliquely downward toward the outer side in the radial direction of the substrate support portion 11. The inclination angle θ of the lower surface Ru of the ring R and the ring support surface 111b with respect to the horizontal plane is not particularly limited, but is preferably set in the range of, for example, 10° to 45°. When the inclination angle θ is smaller than 10°, the ring R may be difficult to move to the retracted position P2. When the inclination angle θ is larger than 45°, the ring R may be difficult to move to the contact position P1.

[0023] The upper surface of the ring R is parallel to (extends along a horizontal plane) the upper surface of the substrate W held by the substrate support portion 11 in a state where the lower surface Ru is supported by the ring support surface 111b. The upper surface of this ring R includes an outer annular surface Rout disposed radially outward and an inner annular surface Rin located inside the outer annular surface Rout. The inner annular surface Rin is lower than the outer annular surface Rout, and the upper surface of the ring R exhibits a stepped structure having an annular stepped inner peripheral surface RS between the outer annular surface Rout and the inner annular surface Rin. In other words, the ring R has a thinner thickness at the portion of the inner annular surface Rin compared to the thickness at the portion of the outer annular surface Rout.

[0024] The stepped inner peripheral surface RS of the ring R is inclined with respect to the vertical direction. Also, the stepped inner peripheral surface RS that circulates annularly in a plan view has an inner diameter slightly larger than the outer diameter of the substrate W. At the position where the ring R has moved to the contact position P1 (the contact state between the substrate W and the inner annular surface Rin), a slight gap is formed between the outer edge of the substrate W and the stepped inner peripheral surface RS. In this way, while contacting the lower surface of the substrate W, the separation between the outer edge of the substrate W and the stepped inner peripheral surface RS can suppress rubbing between the outer edge of the substrate W and the ring R.

[0025] The inner annular surface Rin makes surface contact with the lower surface of the substrate W supported by the substrate support surface 111a when the ring R moves to the contact position P1. On the other hand, the outer annular surface Rout is disposed at substantially the same height as the upper surface of the substrate W held by the substrate support portion 11 at the position where the ring R has moved to the contact position P1.

[0026] The above ring R (each arc-shaped part R1 to R3) is preferably formed of a conductive material such as silicon (Si) or silicon carbide (SiC), or an insulating material such as quartz. The ring R formed of such a material has hardness and a coefficient of thermal expansion that can sufficiently suppress thermal expansion with respect to the substrate support portion 11 and heat input from the plasma.

[0027] On one hand, the ring support surface 111b of the substrate support portion 11 has an annular shape that encircles the outside of the circular substrate support surface 111a in a plan view (also refer to Fig. 3(A)). As described above, this ring support surface 111b is formed in a tapered shape where the radially inner side (the contact position P1 side) is high while the radially outer side (the retracted position P2 side) is low. The inclination of the ring support surface 111b and the inclination of the lower surface Ru of the ring R enable the movement of the ring R between the contact position P1 and the retracted position P2 while maintaining the horizontal postures of the outer annular surface Rout and the inner annular surface Rin.

[0028] Also, the width in the normal direction of the ring support surface 111b (the distance between the stepped outer peripheral surface 111c and the inner peripheral surface of the protection member 17) is set wider than the width in the normal direction of the ring R (the distance between the inner peripheral surface and the outer peripheral surface of the ring R). For example, it is preferable that the width of the ring support surface 111b is set in the range of about 1.1 times to 1.8 times the width of the ring R. Thereby, the movement distance of the ring R can be shortened, and the energy required for the movement of the ring R can be suppressed.

[0029] And the substrate support portion 11 has a moving mechanism 16 for moving the ring R in order to move the ring R. The moving mechanism 16 according to the embodiment realizes the movement of the ring R by installing a plurality of electrodes at different positions within the electrostatic chuck 15 separately from the electrode 15a that adsorbs the substrate W on the substrate support surface 111a and changing the driving electrode.

[0030] Specifically, the moving mechanism 16 has a fixing electrode 16a that adsorbs the ring R at the contact position P1, a contact position side electrode 16b that moves the ring R to the contact position P1 side, and a retracted position side electrode 16c that moves the ring R to the retracted position P2 side. In Fig. 2, the fixing electrode 16a is used as a counter electrode, and each of the contact position side electrode 16b and the retracted position side electrode 16c is used as a single electrode, but the configuration of the electrodes is not particularly limited.

[0031] The fixing electrode 16a is provided near the stepped outer peripheral surface 111c on the ring support surface 111b. The fixing electrode 16a is installed along the inclination angle θ of the ring support surface 111b and can face a wide range of the lower surface Ru of the ring R. After the ring R is brought into contact with the substrate W, this fixing electrode 16a is driven to continuously adsorb the ring R during plasma processing. Thereby, the plasma processing apparatus 1 can maintain good contact between the substrate W and the ring R during plasma processing.

[0032] The contact position side electrode 16b is provided in proximity to the stepped outer peripheral surface 111c and is arranged along the stepped outer peripheral surface 111c (in the vertical direction). By applying an attractive force to the ring R as it is driven, this contact position side electrode 16b moves the ring R located at the retracted position P2 to the contact position P1. The plasma processing apparatus 1 stops driving the contact position side electrode 16b at the timing when the ring R comes into contact with the substrate W, while starting to drive the fixing electrode 16a to start fixing the ring R.

[0033] On the other hand, the retracted position side electrode 16c is provided near the protective member 17 on the ring support surface 111b. By applying an attractive force to the ring R as it is driven, the retracted position side electrode 16c moves the ring R located at the contact position P1 to the retracted position P2. As described above, since the ring support surface 111b is inclined downward in the vertical direction, the ring R is likely to move to the retracted position P2 due to its own weight. For this reason, the moving mechanism 16 may be configured without the retracted position side electrode 16c. Further, the protective member 17 functions as a stopper that restricts the movement of the ring R when the ring R moves to the retracted position P2.

[0034] FIG. 3(A) is a plan view showing the substrate support portion 11 without the ring R. FIG. 3(B) is a plan view showing the state in which the ring R is disposed at the contact position P1. FIG. 3(C) is a plan view showing the state in which the ring R is disposed at the retracted position P2. FIG. 3(D) is a cross-sectional view taken along line III-D of FIG. 3(B) showing the rings R located at the contact position P1 and the retracted position P2. As shown in FIGS. 3(A) and 3(B), the ring R placed on the ring support surface 111b of the substrate support portion 11 is pre-divided into a plurality (three in FIG. 3(B)) of arc-shaped parts R1 to R3 along the circumferential direction. The three arc-shaped parts R1 to R3 are formed in a continuous annular shape exactly at the contact position P1 and are separated from each other at the retracted position P2. Note that the number of arc-shaped parts of the ring R is not limited to three, and may be two or four or more.

[0035] Further, the substrate support portion 11 has a plurality of gas holes 18 for discharging heat transfer gas to the ring R corresponding to each of the arc-shaped parts R1 to R3, and also has a plurality of seal portions 19 facing the outer peripheral portions of the lower surfaces of each of the arc-shaped parts R1 to R3. Each seal portion 19 is formed in a shape substantially matching the planar shape of each of the arc-shaped parts R1 to R3 and surrounds a plurality (two in FIG. 3(A)) of gas holes 18 inside.

[0036] Each gas hole 18 extends inside the substrate support portion 11 and is connected to a heat transfer gas supply portion (not shown) provided outside the plasma processing chamber 10 (see FIG. 1). The heat transfer gas supply portion supplies a heat transfer gas such as helium (He) gas, for example, and discharges the heat transfer gas from each gas hole 18 to the ring R to adjust the temperature of the ring R. Although not shown, a plurality of gas holes 18 are also formed in the substrate support surface 111a, and the heat transfer gas is discharged to the substrate W placed on the substrate support surface 111a to adjust the temperature of the substrate W.

[0037] The sealing portion 19 moves to the contact position P1 and seals the outer peripheral portions of the lower surfaces of the arc-shaped parts R1 to R3 adsorbed by the fixing electrode 16a. For example, the sealing portion 19 is formed as a smooth surface that is flush with the ring support surface 111b and has a larger coefficient of friction than other surfaces and can adhere closely to the ring R. With this sealing portion 19, the plasma processing apparatus 1 can fill the heat transfer gas inside the lower surfaces of the arc-shaped parts R1 to R3 and inside the sealing portion 19, and adjust the temperature of the ring R to a uniform temperature along the circumferential direction.

[0038] As shown in FIGS. 3(B) and 3(C), each of the arc-shaped parts R1 to R3 of the ring R is continuous in the circumferential direction at the contact position P1, while at the retracted position P2, they move to positions separated from each other along the circumferential direction. Each of the arc-shaped parts R1 to R3 simultaneously slides to the stepped outer peripheral surface 111c side by driving the contact position side electrode 16b, and thus moves to the contact position P1 almost simultaneously and comes into contact with each other to form a single annular ring R.

[0039] Also, as shown in FIG. 3(D), each of the arc-shaped parts R1 to R3 has an interface Rc that is inclined with respect to the vertical direction. As a result, at the contact position P1, the interfaces Rc of the arc-shaped parts R1 to R3 overlap obliquely, and it becomes possible to reliably cover the ring support surface 111b with the arc-shaped parts R1 to R3. That is, the interfaces Rc of the arc-shaped parts R1 to R3 can prevent the exposure of the ring support surface 111b in plan view and suppress the adhesion of deposits and damage to the ring support surface 111b during plasma processing.

[0040] The plasma processing apparatus 1 according to the embodiment is basically configured as described above, and its operation (plasma processing method) will be described below with reference to FIGS. 4 to 6. FIG. 4 is a flowchart showing the plasma processing method according to the embodiment. FIG. 5(A) is a cross-sectional view showing the first operation of the ring R. FIG. 5(B) is a cross-sectional view showing the second operation of the ring R. FIG. 5(C) is a cross-sectional view showing the third operation of the ring R. FIG. 6(A) is a cross-sectional view showing the first effect of the ring R in the etching process. FIG. 6(B) is a cross-sectional view showing the second effect of the ring R in the etching process. FIG. 6(C) is a cross-sectional view showing the etching process of the ring R according to the reference example.

[0041] The plasma processing system performs the processing flow of steps S101 to S107 shown in FIG. 4 under the control of the control unit 2. In the plasma processing method, in addition to the processing flow shown in FIG. 4, processes such as adjusting the temperature, pressure, and gas purge in the plasma processing chamber 10 are executed at appropriate timings.

[0042] In the plasma processing method, first, with the ring R disposed at the retracted position P2 on the ring support surface 111b, the substrate W is placed on the substrate support surface 111a (step S101).

[0043] At this time, the control unit 2 stops driving the electrode 16c on the retracted position side to make the ring R in a non-adsorbed state. Even in this state, since the outside of the ring R is supported by the protection member 17, it is prevented from falling off the inclined ring support surface 111b. Note that, with the ring R positioned at the retracted position P2, the plasma processing system may drive the electrode 16c on the retracted position side to adsorb the ring R. After placing the substrate W on the substrate support surface 111a, the plasma processing system drives the electrode 15a on the substrate support surface 111a to adsorb the substrate W to the substrate support surface 111a.

[0044] Next, the plasma processing system moves the ring at the retracted position P2 to the contact position P1 in contact with the substrate W (step S102). Specifically, as shown in FIG. 5(A), the control unit 2 drives the contact position side electrode 16b to generate an attractive force on the stepped outer peripheral surface 111c. In FIGS. 5(A) to 5(C), the driven electrodes are shown in black.

[0045] Thereby, the ring R moves from the retracted position P2 toward the contact position P1, and the inner annular surface Rin contacts the lower surface of the substrate W at the contact position P1. In this state, the inner peripheral surface of the ring R does not contact the stepped outer peripheral surface 111c of the substrate support portion 11, creating a slight gap. Thereby, the plasma processing system can reliably bring the ring R into contact with the lower surface of the substrate W.

[0046] Then, at the timing when the ring R moves to the contact position P1 and contacts the substrate W, the plasma processing system drives the fixing electrode 16a to fix the ring R to the ring support surface 111b (step S103 in FIG. 4). That is, as shown in FIG. 5(B), the control unit 2 generates an attractive force by the fixing electrode 16a to adsorb the ring R, thereby maintaining the arrangement at the contact position P1. As a result, the contact state between the substrate W and the ring R is maintained. The driving timing of the fixing electrode 16a should be held in advance by conducting experiments or the like so that it is the time from the start of driving of the contact position side electrode 16b until the ring R contacts the lower surface of the substrate W while the ring R does not bend the substrate W. Then, the control unit 2 stops driving the contact position side electrode 16b after starting the driving of the fixing electrode 16a, thereby stopping the inward movement of the ring R.

[0047] With the ring R in contact with the substrate W and fixed at the contact position P1, the plasma processing system performs an etching process on the substrate W (step S104). In the etching process, the plasma processing system supplies an appropriate processing gas to the plasma processing space 10s of the plasma processing chamber 10 by the gas supply unit 20, and exhausts the gas in the plasma processing chamber 10 by the exhaust system 40. Further, the plasma processing system supplies a source RF signal and a bias RF signal from the power supply 30 to the substrate support unit 11 or the shower head 13.

[0048] For example, when a bias RF signal is supplied to the substrate support unit 11, as shown in FIG. 6(A), a sheath electric field SE is formed above the substrate W and above the ring R. At this time, since the inner annular surface Rin of the ring R is in contact with the lower surface of the substrate W, the height positions of the upper surface of the substrate W and the outer annular surface Rout of the ring R are substantially the same. Therefore, the sheath electric field SE formed above the substrate W and the ring R is formed at a substantially constant height.

[0049] The plasma processing system can directly draw active species such as ions and radicals in the plasma generated in the plasma processing space 10s toward the substrate W. In particular, even at the outer peripheral portion of the substrate W, the sheath electric field SE of the substrate W and the sheath electric field SE of the ring R are stably continuous. Therefore, the plasma processing system can suppress the oblique drawing of the active species in the plasma at the outer peripheral portion of the substrate W, and can reduce inconveniences such as obliquely etching the film of the substrate W.

[0050] Further, the ring R moved to the contact position P1 contacts the entire outer peripheral portion of the lower surface of the substrate W, so that the temperature of the entire ring R and the temperature of the substrate W can be adjusted to be substantially the same. In particular, the substrate support unit 11 can uniformly adjust the temperature of the ring R by the plurality of gas holes 18 and the seal portion 19, and can avoid local temperature changes in the substrate W and the ring R. Thereby, the plasma processing system promotes the uniformization of the in-plane temperature distribution of the substrate W, and can execute the etching process with higher accuracy.

[0051] Further, as shown in FIG. 6(B), in the etching process, deposition (depo) occurs in the plasma processing space 10s. This depo adheres to the upper surface of the ring R or the like. Since the ring R and the substrate W are in contact, the plasma processing system can prevent the depo from adhering to the electrostatic chuck 15 of the substrate support portion 11. Hereinafter, in order to explain this effect, the movement of the depo in the plasma processing system according to the reference example shown in FIG. 6(C) will be described first.

[0052] The plasma processing system according to the reference example is configured not to move with respect to the ring R' placed on the ring support surface 111b'. This ring R' is arranged at a position separated from the substrate W in order to suppress the occurrence of rubbing due to local contact with the substrate W and the change in the temperature distribution. That is, in the state where the substrate W and the ring R' are placed, a gap is formed between the substrate W and the ring R'. As a result, the stepped outer peripheral surface 111c' of the electrostatic chuck 15' of the substrate support portion 11' is exposed in this gap.

[0053] For example, in the etching process, the temperature of the electrostatic chuck 15' is adjusted to be low. In this case, the depo generated by the etching process moves through the gap by going around from the outer edge of the substrate W to the lower surface of the substrate W, and adheres to the stepped outer peripheral surface 111c' of the electrostatic chuck 15'. Although the plasma processing system periodically performs a cleaning process for removing the depo, the depo adhering to the stepped outer peripheral surface 111c' is difficult to remove, which becomes a factor for increasing the cleaning period.

[0054] On the other hand, as shown in FIG. 6(B), in the plasma processing system according to the embodiment, the lower surface of the substrate W and the inner annular surface Rin of the ring R are in contact, and there is no gap through which the depo can move. Therefore, the plasma processing system can significantly reduce the adhesion of the depo to the stepped outer peripheral surface 111c of the electrostatic chuck 15. Therefore, the plasma processing system can shorten the implementation period of the cleaning process for removing the depo, and can improve the working efficiency of the entire operation of the plasma processing.

[0055] Returning to FIG. 4, during the execution of the etching process, the control unit 2 monitors whether to end the etching process (step S105). For example, the control unit 2 compares the target period preset in the recipe of the etching process or the like with the actual execution period of the etching process. If the execution period has not reached the target period, the control unit 2 determines to continue the etching process (step S105: NO) and repeats step S104. On the other hand, when the execution period reaches the target period, the control unit 2 determines to end the etching process (step S105: YES) and proceeds to step S106.

[0056] In step S106, the plasma processing system moves the ring R located at the contact position P1 to the retracted position P2. Specifically, as shown in FIG. 5(C), the control unit 2 stops driving the fixing electrode 16a while driving the retracted position side electrode 16c to generate an attractive force toward the protective member 17 side of the ring support surface 111b. As a result, the ring R moves from the contact position P1 toward the retracted position P2 due to the self-weight of the ring R and the attractive force of the retracted position side electrode 16c.

[0057] The ring R contacts the inner peripheral surface of the protective member 17 at the retracted position P2 and its movement is restricted. Then, after the ring R has moved to the retracted position P2, the plasma processing system stops driving the retracted position side electrode 16c and places the ring R in a standby state.

[0058] With the ring R disposed at the retracted position P2, the plasma processing system removes the substrate W from the plasma processing chamber 10 by lifting the substrate W from the substrate support surface 111a by a lifter mechanism (not shown) and delivering it to the transfer device (step S107). At this time, since the ring R is separated from the substrate W, rubbing between the substrate W and the ring R can be prevented and the substrate W can be removed.

[0059] As described above, by configuring the plasma processing system to move the ring R between the contact position P1 and the retracted position P2, it is possible to improve the accuracy of plasma processing and to enhance the efficiency of the cleaning process. That is, when the ring R and the substrate W are in contact during plasma processing, the sheath electric field SE can be stably formed and the temperature of the entire outer peripheral portion of the substrate W can be uniformly adjusted. Further, by suppressing the deposition generated during plasma processing from adhering to the stepped outer peripheral surface 111c of the electrostatic chuck 15, it is possible to shorten the time required for the cleaning process.

[0060] In addition, the plasma processing system can easily perform the positioning of the ring R by moving the ring R by the moving mechanism 16 having a plurality of electrodes. Further, since the ring support surface 111b is inclined, it is possible to press the inner annular surface Rin of the ring R against the lower side of the substrate W and to facilitate the movement of the ring R to the retracted position.

[0061] Note that the plasma processing system and the plasma processing method of the present disclosure are not limited to the above-described embodiments and can take various modifications. For example, the moving mechanism 16 that moves the ring R may adopt a configuration that mechanically moves the ring R or a configuration that applies a negative pressure to the ring R to move it, without using a plurality of electrodes. Further, in the plasma processing method, after the plasma processing is completed, the substrate W may be carried out before (or during) moving the ring R from the contact position P1 to the retracted position P2. Thereby, the plasma processing method can improve the processing efficiency.

[0062] FIG. 7(A) is a first cross-sectional view showing the substrate support portion 11A and the ring R according to the modification. FIG. 7(B) is a second cross-sectional view showing the substrate support portion 11A and the ring R according to the modification. As shown in FIGS. 7(A) and 7(B), the substrate support portion 11A may be configured to move the ring R up and down, bring the ring R into contact with the substrate W at the upper contact position P1, and separate the ring R from the substrate W at the lower retracted position P2.

[0063] In this case, the moving mechanism 16A provided in the substrate support portion 11A includes a movable body 161 that supports the ring R and a lifting mechanism 162 that raises and lowers the movable body 161. The ring R is placed on the ring support surface 111b on the upper surface of the movable body 161. The movable body 161 preferably has an electrode that attracts and fixes the ring R and a temperature adjustment module or the like that can adjust the temperature of the ring R inside. Since the ring R moves up and down by the movable body 161, it does not need to adopt a configuration in which it is divided into a plurality along the circumferential direction.

[0064] The lifting mechanism 162 has a drive source such as a motor or a cylinder (both not shown) and a drive transmission portion that transmits the driving force of the drive source to the movable body 161. The lifting mechanism 162 is connected to the control unit 2 and moves the ring R between the contact position P1 and the retracted position P2 by lifting and lowering the movable body 161 under the control of the control unit 2.

[0065] Thus, even with the moving mechanism 16A according to the modification, it is possible to switch between a state where the ring R is in contact with the substrate W and a state where the ring R is separated from the substrate W. Therefore, the plasma processing system according to the modification can also obtain the same effects as the configuration in which the ring R is moved along the ring support surface 111b described above.

[0066] The embodiments disclosed above include, for example, the following aspects. [Appendix 1] A plasma processing chamber capable of performing plasma processing, A substrate support portion that supports a substrate inside the plasma processing chamber and supports a ring disposed around the substrate, A plasma processing system including a control unit, The control unit, (A) A step of holding the substrate by the substrate support portion and moving the ring relative to the substrate support portion to bring the ring into contact with the substrate before the plasma processing, (B) A step of performing the plasma processing on the substrate after the step of (A), After step (B), controlling a step of moving the ring relative to the substrate support and separating it from the substrate. Plasma processing system. [Appendix 2] The substrate support has a moving mechanism for moving the ring between a contact position where the ring contacts the substrate in step (A) and a retracted position where the ring separates from the substrate in step (C). The plasma processing system according to Appendix 1. [Appendix 3] The substrate support has a ring support surface for supporting the ring. The contact position is set inside the ring support surface, while the retracted position is set outside the ring support surface. The plasma processing system according to Appendix 2. [Appendix 4] The ring support surface is inclined downward in the vertical direction from the contact position toward the retracted position. The plasma processing system according to Appendix 3. [Appendix 5] The ring is parallel to the upper surface of the substrate held by the substrate support with its lower surface supported by the ring support surface. The plasma processing system according to Appendix 4. [Appendix 6] The upper surface of the ring includes an inner annular surface that contacts the substrate at the contact position and an outer annular surface that is arranged at the same height as the upper surface of the substrate held by the substrate support outside the inner annular surface. The plasma processing system according to Appendix 5. [Appendix 7] The moving mechanism is configured by installing a plurality of electrodes for sucking the ring on the substrate support. The plasma processing system according to any one of Appendices 2 to 6. [Appendix 8] The moving mechanism has a fixing electrode for fixing the ring at the contact position and a contact position side electrode for moving the ring toward the contact position. The plasma processing system described in Supplementary Note 7. [Supplementary Note 9] The moving mechanism has a retracted position side electrode that moves the ring toward the retracted position. The plasma processing system described in Supplementary Note 7. [Supplementary Note 10] The ring is divided into a plurality of arc-shaped parts along the circumferential direction. The plurality of arc-shaped parts are formed in an annular shape that is continuously connected in series at the contact position and are separated from each other at the retracted position. The plasma processing system according to any one of Supplementary Notes 2 to 9. [Supplementary Note 11] At the contact position, the opposing boundary surfaces of the arc-shaped parts are inclined with respect to each other. The plasma processing system described in Supplementary Note 10. [Supplementary Note 12] The substrate support portion has a seal portion that seals the outer peripheral portion of the lower surface of the ring that has moved to the contact position, and a gas hole that discharges heat transfer gas to the ring inside the seal portion. The plasma processing system according to any one of Supplementary Notes 2 to 11. [Supplementary Note 13] The moving mechanism includes a movable body that supports the ring, and a lifting mechanism that raises and lowers the movable body between the contact position and the retracted position. The plasma processing system described in Supplementary Note 2. [Supplementary Note 14] A plasma processing chamber capable of performing plasma processing, A plasma processing method for a plasma processing system including a substrate support portion that supports a substrate inside the plasma processing chamber and supports a ring disposed around the substrate, the method comprising: (A) a step of holding the substrate by the substrate support portion and moving the ring relative to the substrate support portion to bring the ring into contact with the substrate before the plasma processing; (B) a step of performing the plasma processing on the substrate after the step (A); (C) After the step of (B), moving the ring relative to the substrate support and separating it from the substrate. Plasma processing method.

[0067] The plasma processing system and the plasma processing method according to the presently disclosed embodiments are illustrative in all respects and not restrictive. The embodiments can be modified and improved in various forms without departing from the scope and gist of the appended claims. The matters described in the above-described multiple embodiments can also adopt other configurations and can be combined within a non-contradictory range.

[0068] The substrate processing apparatus of the present disclosure is applicable to any type of apparatus such as an Atomic Layer Deposition (ALD) apparatus, a Capacitively Coupled Plasma (CCP), an Inductively Coupled Plasma (ICP), a Radial Line Slot Antenna (RLSA), an Electron Cyclotron Resonance Plasma (ECR), and a Helicon Wave Plasma (HWP).

Description of reference numerals

[0069] 2 Control unit 10 Plasma processing chamber 11 Substrate support R Ring W Substrate

Claims

1. A plasma processing system including: a plasma processing chamber capable of performing plasma processing; a substrate support unit that supports a substrate inside the plasma processing chamber and supports a ring disposed around the substrate; and a control unit, wherein the control unit controls: (A) a step of holding the substrate by the substrate support unit and moving the ring relative to the substrate support unit to bring the ring into contact with the substrate before the plasma processing; (B) a step of performing the plasma processing on the substrate after the step (A); and (C) a step of moving the ring relative to the substrate support unit to separate the ring from the substrate after the step (B). A plasma processing system.

2. The substrate support unit has a moving mechanism that moves the ring between a contact position where the ring contacts the substrate in the step (A) and a retracted position where the ring separates from the substrate in the step (C). The plasma processing system according to claim 1.

3. The substrate support unit has a ring support surface that supports the ring, wherein the contact position is set inside the ring support surface, and the retracted position is set outside the ring support surface. The plasma processing system according to claim 2.

4. The ring support surface is inclined downward in the vertical direction from the contact position toward the retracted position. The plasma processing system according to claim 3.

5. The ring is in a state where its lower surface is supported by the ring support surface, and its upper surface is parallel to the upper surface of the substrate held by the substrate support unit. The plasma processing system according to claim 4.

6. The upper surface of the ring includes an inner annular surface that contacts the substrate at the contact position and an outer annular surface that is disposed at the same height as the upper surface of the substrate held by the substrate support unit outside the inner annular surface. The plasma processing system according to claim 5.

7. The moving mechanism is configured by installing a plurality of electrodes for sucking the ring on the substrate support unit. The plasma processing system according to any one of claims 2 to 6.

8. The moving mechanism has a fixing electrode that fixes the ring at the contact position and a contact position side electrode that moves the ring toward the contact position. The plasma processing system according to claim 7.

9. The moving mechanism has a retracted position side electrode that moves the ring toward the retracted position. The plasma processing system according to claim 7.

10. The ring is divided into a plurality of arc-shaped parts along the circumferential direction. The plurality of arc-shaped parts are formed in a continuous annular shape at the contact position and are separated from each other at the retracted position. The plasma processing system according to any one of claims 2 to 6.

11. At the contact position, the opposing boundary surfaces of the arc-shaped parts are inclined with respect to each other. The plasma processing system according to claim 10.

12. The substrate support portion has a seal portion that seals the outer peripheral portion of the lower surface of the ring that has moved to the contact position, and a gas hole that discharges a heat transfer gas to the ring inside the seal portion. The plasma processing system according to any one of claims 2 to 6.

13. The moving mechanism includes a movable body that supports the ring, and a lifting mechanism that raises and lowers the movable body between the contact position and the retracted position. The plasma processing system according to claim 2.

14. A plasma processing chamber capable of performing plasma processing, A plasma processing method for a plasma processing system including a substrate support portion that supports a substrate inside the plasma processing chamber and supports a ring disposed around the substrate, the method comprising: (A) a step of holding the substrate by the substrate support portion and moving the ring relative to the substrate support portion to bring the ring into contact with the substrate before the plasma processing; (B) a step of performing the plasma processing on the substrate after the step (A); (C) a step of moving the ring relative to the substrate support portion to separate the ring from the substrate after the step (B). Plasma processing method.

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