Plasma processing apparatus and plasma processing method

Abstract

To provide a plasma processing apparatus and a plasma processing method that can control the circumferential distribution of plasma.SOLUTION: The plasma processing apparatus has a processing container that provides a processing space, an emission part configured to emit electromagnetic waves into the processing space, and a waveguide configured to supply electromagnetic waves to the emission part. The waveguide includes an upstream waveguide that forms part of the waveguide and a downstream waveguide that forms part of the waveguide and is connected to the upstream waveguide via an elastic member. The gap length between the upstream waveguide and the downstream waveguide is configured to be adjustable by the pressing force between the upstream waveguide and the downstream waveguide.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a plasma processing apparatus and a plasma processing method. [Background technology]

[0002] The plasma processing apparatus disclosed in Patent Document 1 includes a processing vessel, a stage, an upper electrode, an introduction portion, and a waveguide portion. The stage is provided in the processing vessel. The upper electrode is provided above the stage through a space in the processing vessel. The introduction portion is a high-frequency introduction portion. The high-frequency wave is a VHF wave or a UHF wave. The introduction portion is provided at a lateral end of the space and extends in a circumferential direction around a central axis of the processing vessel. The waveguide portion is configured to supply a high-frequency wave to the introduction portion. The waveguide portion includes a resonator that provides a waveguide. The waveguide of the resonator extends in a circumferential direction around the central axis, extends in the direction in which the central axis extends, and is connected to the introduction portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-92031 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a plasma processing apparatus and a plasma processing method capable of controlling the circumferential distribution of plasma. [Means for solving the problem]

[0005] According to an aspect of the present disclosure, a plasma processing apparatus includes a processing vessel providing a processing space, an emitter configured to emit an electromagnetic wave into the processing space, and a waveguide configured to supply the electromagnetic wave to the emitter. The waveguide includes an upstream waveguide forming a part of the waveguide, and a downstream waveguide forming a part of the waveguide and connected to the upstream waveguide via an elastic member, and a gap length between the upstream waveguide and the downstream waveguide is adjustable by a pressing force between the upstream waveguide and the downstream waveguide. Effect of the Invention

[0006] According to the present disclosure, the circumferential distribution of plasma can be controlled. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic perspective view showing an example of a plasma processing apparatus according to a first embodiment of the present disclosure. [Diagram 2] FIG. 2 is a cross-sectional view showing an example of the AA cross section of FIG. [Diagram 3] FIG. 3 is a cross-sectional view showing an example of the cross section taken along line BB of FIG. [Figure 4] FIG. 4 is a cross-sectional view showing an example of the CC cross section of FIG. [Diagram 5] FIG. 5 is an enlarged cross-sectional view showing an example of the vicinity of the connection surface between the upstream waveguide and the downstream waveguide. [Figure 6] FIG. 6 is a flowchart showing an example of the plasma processing in the first embodiment. [Figure 7] FIG. 7 is a schematic cross-sectional view showing an example of a plasma processing apparatus according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of a plasma processing apparatus and a plasma processing method will be described in detail with reference to the accompanying drawings. Note that the disclosed technology is not limited to the following preferred embodiments.

[0009] In the above-mentioned plasma processing apparatus, when an introduction part for introducing high frequency waves, such as VHF (Very High Frequency) waves or UHF (Ultra High Frequency) waves, extends in the circumferential direction at the lateral end of the space in the processing vessel, the waveguide of the resonator is fixed to the upper electrode. The upper electrode is provided above the stage, that is, at the top of the processing vessel. The waveguide of the resonator and the upper electrode are fixed, for example, by screws without a gap. For this reason, in order to adjust the circumferential distribution of plasma, it is required to adjust the gap between the waveguide and the upper electrode by adjusting the screws according to the state of film formation. However, if the screws for fixing the waveguide are manually adjusted, the result of the adjustment is not known until the film is actually formed. Therefore, it is expected that the circumferential distribution of plasma can be controlled by adjusting the gap between the waveguide and the upper electrode or between the divided waveguides even during plasma processing.

[0010] (First embodiment) [Configuration of plasma processing device 1] Fig. 1 is a schematic perspective view showing an example of a plasma processing apparatus according to the first embodiment of the present disclosure. The plasma processing apparatus 1 shown in Fig. 1 includes a control unit 5, a chamber 10, a substrate support unit 12, an upper electrode 14, a discharge unit 16, and a waveguide unit 18.

[0011] The chamber 10 provides a processing space 10s therein. The processing space 10s includes a plasma generation space. The chamber 10 is an example of a processing vessel. In the plasma processing apparatus 1, the substrate W is processed in the processing space 10s. The chamber 10 is made of a metal such as aluminum and is grounded. The chamber 10 has a sidewall 10a and is open at its upper end. The chamber 10 and the sidewall 10a may have a substantially cylindrical shape. The processing space 10s is provided inside the sidewall 10a. The central axis of each of the chamber 10, the sidewall 10a, and the processing space 10s is the axis AX. The chamber 10 may have a corrosion-resistant film on its surface. The corrosion-resistant film may be a ceramic film containing an yttrium oxide film, an yttrium oxide fluoride film, an yttrium fluoride film, an yttrium oxide, or an yttrium fluoride film.

[0012] The bottom of the chamber 10 provides an exhaust port 10e. An exhaust system is connected to the exhaust port 10e. The exhaust system may include a vacuum pump, such as a dry pump and / or a turbomolecular pump, and an automatic pressure control valve.

[0013] The substrate support 12 is provided in the processing space 10s. The substrate support 12 is configured to support the substrate W placed on its upper surface in an approximately horizontal manner. The substrate support 12 has an approximately disk shape. The central axis of the substrate support 12 is an axis AX.

[0014] The upper electrode 14 is provided above the substrate support 12 with a processing space 10s interposed therebetween. The upper electrode 14 is made of a conductor such as a metal (e.g., aluminum) and has a substantially disk shape. The central axis of the upper electrode 14 is an axis AX.

[0015] The emission part 16 is provided to emit electromagnetic waves from there to the processing space 10s. In the plasma processing apparatus 1, the electromagnetic waves emitted from the emission part 16 to the processing space 10s excite the gas in the processing space 10s to generate plasma. The electromagnetic waves emitted from the emission part 16 to the processing space 10s may be high frequency waves such as VHF waves or UHF waves. The emission part 16 is formed of a dielectric material such as quartz, aluminum nitride, or aluminum oxide. The emission part 16 is provided at the lateral end of the processing space 10s and extends in the circumferential direction around the axis line AX. The emission part 16 may have a ring shape. In addition, a plurality of electric field probes 60 (described later) for detecting the electric field intensity are provided on the side surface 16a on the outer circumferential side of the emission part 16. Note that airtightness is maintained between the emission part 16 and the side wall 10a, between the emission part 16 and the shower plate 22 (described later), and between the emission part 16 and the upper electrode 14 by O-rings 70 to 72, respectively.

[0016] The waveguide 18 is configured to supply electromagnetic waves to the emitter 16. The electromagnetic waves are generated by a radio frequency power supply 24, which will be described later. The electromagnetic waves propagate through the waveguide 18 to the emitter 16, and are introduced from the emitter 16 into the processing space 10s. The waveguide 18 includes a resonator 20. Details of the resonator 20 will be described later. The waveguide 18 is an example of a waveguide, and may include a waveguide in the upper electrode 14.

[0017] In one embodiment, the plasma processing apparatus 1 may further include a shower plate 22. The shower plate 22 may be made of a metal such as aluminum. The discharge unit 16 extends to surround the shower plate 22. The discharge unit 16 and the shower plate 22 are arranged to close an opening at the upper end of the chamber 10. The shower plate 22 provides a plurality of gas holes 22h. The plurality of gas holes 22h extend in the thickness direction (vertical direction) of the shower plate 22 and penetrate the shower plate 22.

[0018] The shower plate 22 is provided below the upper electrode 14. The shower plate 22 and the upper electrode 14 define a gas diffusion space 14d therebetween. The central axis of the gas diffusion space 14d may be the axis AX. A plurality of gas holes 22h of the shower plate 22 are connected to the gas diffusion space 14d. The upper electrode 14 also provides an inlet 14h. The inlet 14h may extend on the axis AX as shown in the gas supply pipe 27, for example. The inlet 14h is connected to the gas diffusion space 14d. A gas supply unit 26 is connected to the gas diffusion space 14d. The gas output from the gas supply unit 26 is supplied to the processing space 10s via the gas supply pipe 27, the inlet 14h, the gas diffusion space 14d, and the plurality of gas holes 22h. The outer periphery of the gas diffusion space 14d between the shower plate 22 and the upper electrode 14 is kept airtight by an O-ring 73. In addition, the plasma processing apparatus 1 may be configured so that plasma generated in a plasma generation chamber (remote plasma chamber) not shown in the figure is supplied to the processing space 10s via the gas supply pipe 27, the inlet 14h, the gas diffusion space 14d, and multiple gas holes 22h.

[0019] The plasma processing apparatus 1 may further include a high-frequency power source 24. The high-frequency power source 24 is electrically coupled to the waveguide of the resonator 20 and configured to generate high-frequency power whose frequency is variable. The electromagnetic wave introduced into the chamber 10 is generated based on the high-frequency power generated by the high-frequency power source 24. The high-frequency power source 24 may be directly connected to the waveguide of the resonator 20 using a coaxial line 28. That is, the high-frequency power source 24 may be coupled to the waveguide of the resonator 20 without going through a matching device for impedance matching.

[0020] Hereinafter, FIG. 2 to FIG. 5 will be referred to together with FIG. 1. FIG. 2 is a cross-sectional view showing an example of the AA cross section of FIG. 1. The resonator 20 provides a waveguide 20w. The waveguide 20w may provide a cavity surrounded by a wall (hereinafter, referred to as a "conductor wall") formed from a conductor such as metal. The conductor wall of the waveguide 20w may be formed from an aluminum alloy, copper, nickel, stainless steel, or the like, and may be coated with a low resistance material such as silver, gold, or rhodium. In addition, among the conductor walls, the outer circumferential side of the resonator 20 may be configured to have a plurality of columnar members 211 arranged on a circumference as shown in FIG. 2. The interval between the plurality of columnar members 211 is determined based on the wavelength of the electromagnetic wave supplied from the high frequency power supply 24. In other words, if the interval between the plurality of columnar members 211 is sufficiently narrower than the wavelength of the electromagnetic wave, it can be treated in the same way as the case of a wall. Note that the outer circumferential side may be configured with a wall member instead of a plurality of columnar members.

[0021] The resonator 20 includes a first short-circuit portion 201 and a plurality of second short-circuit portions 202. The first short-circuit portion 201 constitutes one end of the waveguide 20w of the resonator 20. In one embodiment, the first short-circuit portion 201 may extend along the circumferential direction around the axis line AX. The plurality of second short-circuit portions 202 constitute the other end of the waveguide 20w of the resonator 20.

[0022] In the resonator 20, the upper conductor wall 203 and the lower conductor wall 210 are connected by a plurality of columnar members 211 on the outer periphery side, and are connected by a wall member 212 on the inner periphery side. The wall member 212 is an example of a conductor on the central axis side of the chamber 10 in the resonator 20. Note that instead of the wall member 212, the inner periphery side may be configured by a columnar member similarly to the outer periphery side. In addition, disk-shaped plate members 204 to 206 are disposed between the upper conductor wall 203 and the lower conductor wall 210. The plate member 205 is connected to the wall member 212. On the other hand, the plate member 205 is not connected to the columnar member 211, and the portion between the end of the plate member 205 on the outer periphery side and the columnar member 211 forms a part of the waveguide 20w. In addition, the plate members 204 and 206 are connected to a plurality of columnar members 211. On the other hand, the plate members 204 and 206 are not connected to the wall member 212, and the portions between their inner peripheral ends and the wall member 212 form part of the waveguide 20w. That is, in the plate members 204 to 206, circular plates connected to a plurality of columnar members 211 and circular plates connected to the wall member 212 are alternately arranged so that the waveguide 20w is intertwined. That is, the waveguide 20w may have a layered structure including an upper portion 20a, a lower portion 20b, and a middle portion 20c.

[0023] As shown in FIG. 2, the lower conductor wall 210 has a plurality of slots 20g near the inner periphery of a plurality of columnar members 211 formed on the circumference of the outer periphery. The plurality of slots 20g penetrate the lower conductor wall 210 along its thickness direction (vertical direction) and extend long in the circumferential direction. The plurality of slots 20g are spaced apart from each other and arranged along the circumferential direction around the axis line AX. The plurality of slots 20g may be arranged at equal intervals. Between each of the plurality of slots 20g are second short-circuit portions 202. The second short-circuit portions 202 are arranged alternately with the plurality of slots 20g along the circumferential direction around the axis line AX. The plurality of slots 20g are electromagnetically coupled to the emission portion 16 via the plurality of slots 142 and the annular waveguide 143. The plurality of second short-circuit portions 202 connect the inner portion and the outer portion of the lower conductor wall 210 to each other.

[0024] A distance d in the circumferential direction between any two second short-circuit portions 202 adjacent to each other in the circumferential direction among the multiple second short-circuit portions 202 may satisfy the following formula (1).

[0025] 0.05λg <d<0.2λg ···(1)

[0026] Here, λg is the wavelength of the electromagnetic wave in the waveguide 20w. When formula (1) is satisfied, the resonator 20 can supply a part of the electromagnetic wave propagating through the waveguide 20w to the emission section 16, and can have a suitably large reflection coefficient of the electromagnetic wave at the other end of the resonator 20.

[0027] The resonator length L of the resonator 20 between the first short-circuit portion 201 and the multiple second short-circuit portions 202 (the distance connecting the first short-circuit portion 201 and the multiple second short-circuit portions 202 along the waveguide 20w) may satisfy the following formula (2).

[0028] (n-0.2)λg / 2 <L<nλg / 2 ···(2)

[0029] As described above, λg is the wavelength of the electromagnetic wave in the waveguide 20w. Also, n is an integer equal to or greater than 1. The reactance in the multiple slots 20g is inductive. Therefore, the resonator length L can be set to a value slightly smaller than nλg / 2 so as to satisfy formula (2).

[0030] In the plasma processing apparatus 1, electromagnetic waves resonate between the first short circuit portion 201 and the plurality of second short circuit portions 202. The electromagnetic waves resonated in the resonator 20 are supplied to the plurality of slots 142 formed in the connection portion 140 of the upper electrode 14 through the plurality of slots 20g.

[0031] In one embodiment, the plasma processing apparatus 1 may further include a connector 40 for introducing an electromagnetic wave into the waveguide 20w. The connector 40 is a part of the coaxial line 28. The high frequency power supply 24 is coupled to the upper portion 20a via the coaxial line 28 and the connector 40. The connector 40 may be coupled to the upper portion 20a at a position radially spaced apart from the axis AX. The connector 40 may be, for example, a coaxial connector. Note that the length (height) of the upper portion 20a in the direction in which the axis AX extends may be longer than the length in the vertical direction of other portions (the lower portion 20b, the middle portion 20c) of the waveguide 20w.

[0032] Fig. 3 is a cross-sectional view showing an example of the cross section BB of Fig. 1. The multiple slots 142 of the upper electrode 14 are formed to correspond to the multiple slots 20g of the lower conductor wall 210 of the resonator 20, respectively. The multiple slots 142 are also formed to penetrate the annular connection part 140 on the outer periphery of the upper electrode 14 in the direction in which the axis line AX extends. An upper surface 144 of the connection part 140 faces a lower surface 220 of the lower conductor wall 210.

[0033] 4 is a cross-sectional view showing an example of the CC cross section of FIG. 1. As shown in FIG. 4, an annular waveguide 143 is formed below the multiple slots 142. The annular waveguide 143 is an example of an annular space. That is, the waveguide 143 is connected to each of the multiple slots 142, and is formed to penetrate the connection portion 140 together with the multiple slots 142 in the direction in which the axis line AX extends. The lower portion of the waveguide 143 contacts the upper surface of the emission portion 16 as shown in FIG. 1. That is, the electromagnetic waves propagating through the multiple slots 142 and the waveguide 143 are supplied to the emission portion 16.

[0034] In the following description, the section from the connector 40 of the resonator 20 to the connection surface (the connection surface between the upper surface 144 and the lower surface 220) between the multiple slots 20g and the multiple slots 142 may be referred to as an upstream waveguide UW, and the section from the connection surface to the emission section 16 may be referred to as a downstream waveguide DW. In other words, the waveguide section 18 includes the upstream waveguide UW and the downstream waveguide DW. For example, in the above-mentioned resonator 20, the connection portion with the downstream waveguide DW (the lower surface 220 of the lower conductor wall 210) may be referred to as having multiple slots 20g provided in the circumferential direction of the chamber 10.

[0035] 5 is an enlarged cross-sectional view showing an example of the vicinity of the connection surface between the upstream waveguide and the downstream waveguide. As shown in FIG. 5, the upstream waveguide UW and the downstream waveguide DW are connected at the connection surface between the upper surface 144 and the lower surface 220.

[0036] Grooves 213 and 214 are formed in an annular shape on the lower surface 220. The groove 213 is formed on the inner periphery side of the multiple slots 20g, and the groove 214 is formed on the outer periphery side of the multiple slots 20g. Elastic members 215 and 216 are fitted into the grooves 213 and 214, respectively. The elastic members 215 and 216 are, for example, obliquely wound coil springs. When the gap G between the upper surface 144 and the lower surface 220 is adjusted by the control of the actuator 50 and the rod 51 to form a gap, the gap formed between the upstream waveguide UW and the downstream waveguide DW is electromagnetically shielded by the elastic members 215 and 216. Note that FIG. 5 shows a case where the upper surface 144 and the lower surface 220 are in contact with each other, and the gap length of the gap G when a gap is formed is shown between the two-dot chain lines.

[0037] 2 and 3, four actuators 50 and four rods 51 are provided in the circumferential direction of the chamber 10, for example, at 0 o'clock, 3 o'clock, 6 o'clock, and 9 o'clock in a plan view of the chamber 10. The actuators 50 and the rods 51 are preferably arranged at equal intervals in the circumferential direction of the chamber 10. Each actuator 50 is controlled by the control unit 5. The number of actuators 50 and rods 51 is not limited to four, and for example, two or more actuators 50 and rods 51 may be provided in the circumferential direction of the chamber 10. The number of actuators 50 and rods 51 is more preferably in the range of three to six.

[0038] The rod 51 is inserted into a through hole 222 penetrating from the upper surface 221 to the lower surface 220 of the lower conductor wall 210 and a hole 141 formed in the upper surface 144 of the connection part 140. The actuator 50 can adjust the gap length of the gap G by moving the rod 51 in the direction in which the axis AX extends. That is, the actuator 50 adjusts the pressing force at the connection surface between the upstream waveguide UW and the downstream waveguide DW. That is, the gap length of the gap G between the upstream waveguide UW and the downstream waveguide DW is configured to be adjustable by the pressing force between the upstream waveguide UW and the downstream waveguide DW. The gap length of the gap G can be adjusted, for example, in a range of about 0 mm (contact state) to 1 mm, and the shorter the gap length of the gap G, the stronger the electric field detected by the electric field probe 60 at the corresponding location. That is, the control part 5 can control the gap length of the gap G by controlling each actuator 50, thereby controlling the circumferential distribution of the plasma. It is more preferable that the gap length of the gap G is adjustable within a range of 0 mm to 0.6 mm, with a reference value of 0.3 mm, for example. The actuator 50 and the rod 51 may be configured to be capable of adjusting the gap length of the gap G using a screw and a ball screw. Since it is only necessary to press the lower conductive wall 210 toward the upper electrode 14, it is not essential to provide the through-hole 222 in the lower conductive wall 210. In this case, the actuator 50 may be fixed to a frame (not shown) or the like.

[0039] The electric field probe 60 is an example of an electric field sensor, and is, for example, a coaxial probe. For example, as shown in Figs. 1 to 5, a plurality of electric field probes 60 are provided on an extension line of a line connecting the actuator 50 and the rod 51 with the axis AX (the center of the chamber 10) in a plan view of the chamber 10. For example, four electric field probes 60 are provided in the circumferential direction, for example, at 0 o'clock, 3 o'clock, 6 o'clock, and 9 o'clock directions in a plan view of the chamber 10. When a plurality of electric field probes 60 are provided, the positions (heights) in the direction in which the axis AX of the chamber 10 extends are set to be the same. The number of electric field probes 60 is not limited as long as it is one or more.

[0040] The outer peripheral end of the electric field probe 60 has a coaxial connector shape and has an internal conductor 61 and an external conductor 62. The internal conductor 61 is extended to the vicinity of the side surface 16a of the emission section 16, and the internal conductor 61 and the side surface 16a are spaced apart by a small distance. This makes it possible to minimize the effect of the electric field probe 60 on the plasma distribution. The internal conductor 61 may be in contact with the side surface 16a, or may be extended into the dielectric inside the emission section 16. The external conductor 62 is electrically connected to the side wall 10a of the chamber 10. Information on the electric field detected by the electric field probe 60 (e.g., electric field intensity) is input to the control section 5.

[0041] The control unit 5 processes computer-executable instructions that cause the plasma processing apparatus 1 to execute various processes such as film formation and etching. The control unit 5 may be configured to control each element of the plasma processing apparatus 1 to execute various processes. In one embodiment, a part or all of the control unit 5 may be included in the plasma processing apparatus 1. The control unit 5 may include a processing unit, a storage unit, and a communication interface. The control unit 5 is realized, for example, by a computer. The processing unit may be configured to perform various control operations by reading a program from the storage unit and executing the read program. This program may be stored in the storage unit in advance, or may be acquired via a medium when necessary. The acquired program is stored in the storage unit, and is read from the storage unit by the processing unit and executed. The storage unit stores, for example, a process sequence of the plasma processing apparatus 1 and a process recipe that is a control parameter. The medium may be various computer-readable storage media, or may be a communication line connected to the communication interface. The processing unit may be a CPU (Central Processing Unit). The storage unit may include a random access memory (RAM), a read only memory (ROM), a hard disk drive (HDD), a solid state drive (SSD), or a combination of these. The communication interface may communicate with the plasma processing apparatus 1 via a communication line such as a local area network (LAN).

[0042] The control unit 5 can perform a predetermined control according to the selected process recipe. For example, the control unit 5 controls each unit of the plasma processing apparatus 1 to perform a plasma processing method described later. In a detailed example, the control unit 5 executes a process of carrying the substrate W into the chamber 10 and preparing it. The control unit 5 executes a process of supplying a processing gas into the chamber 10 to generate plasma, and performing plasma processing on the substrate W using the generated plasma. Here, the plasma processing may be, for example, a film formation process, an etching process, or other processes. In addition, when plasma processing is performed on the substrate W to be processed in the processing space 10s in the chamber 10, the control unit 5 controls each actuator 50 to adjust the gap length of the gap G so that, for example, the electric field strengths of the multiple electric field probes 60 are equal. That is, the control unit 5 controls each actuator 50 so as to uniform the circumferential distribution of the plasma. In addition, the control unit 5 may control the multiple actuators 50 so as to change the gap length of the gap G along the circumferential direction of the chamber 10.

[0043] [Plasma treatment method] Next, a plasma processing method according to the first embodiment will be described below. Fig. 6 is a flow chart showing an example of the plasma processing method according to the first embodiment.

[0044] The control unit 5 opens the loading / unloading port (not shown) by controlling a gate valve (not shown). When the loading / unloading port is open, the substrate W is loaded into the processing space 10s of the chamber 10 through the loading / unloading port and placed on the substrate support unit 12. That is, the control unit 5 controls the plasma processing device 1 to load the substrate W into the chamber 10 (step S1). The control unit 5 may be a control device for the entire substrate processing system (not shown) including the plasma processing device 1 and a transfer device of a transfer chamber (not shown) adjacent to the chamber 10. The control unit 5 closes the loading / unloading port by controlling the gate valve. Step S1 is an example of a process of loading the substrate W into the chamber 10 and preparing it.

[0045] The control unit 5 reduces the pressure in the chamber 10 to a predetermined pressure by controlling an exhaust device (not shown) connected to the exhaust port 10e. The control unit 5 controls the gas supply unit 26 to supply the plasma generating gas to the chamber 10 from the multiple gas holes 22h. The control unit 5 controls the high-frequency power supply 24 to ignite plasma with a predetermined power. The control unit 5 executes a plasma processing step for performing plasma processing on the substrate W using the plasma of the plasma generating gas for a predetermined time (step S2).

[0046] When plasma processing is performed on the substrate W in the plasma processing step, the control unit 5 controls each actuator 50 to adjust the gap length of the gap G so that the electric field strengths of the multiple electric field probes 60 are equal. That is, the control unit 5 feedback-controls the gap length based on the detected electric field. The control unit 5 may also continuously control each actuator 50 to adjust the gap length of the gap G so as to rotate the plasma strength distribution (electric field strength distribution) in the circumferential direction along the circumferential direction of the chamber 10.

[0047] When the plasma processing step is completed, the control unit 5 stops the electromagnetic waves to stop the generation of plasma. The control unit 5 also controls the gate valve to open the loading / unloading port. The control unit 5 controls the plasma processing device 1 to lift the substrate W by making the substrate support pins (not shown) protrude from the upper surface of the substrate support unit 12. When the loading / unloading port is open, the substrate W is unloaded from the chamber 10 by an arm of the transfer chamber (not shown) through the loading / unloading port. That is, the control unit 5 controls the plasma processing device 1 to unload the substrate W from the chamber 10 (step S3). In this way, the control unit 5 can control the circumferential distribution of plasma by adjusting the gap length of the gap G even during plasma processing.

[0048] Second embodiment In the above first embodiment, the electromagnetic wave is supplied using the resonator 20, but the plasma processing apparatus may be configured to supply the electromagnetic wave from the central upper portion of the upper electrode 14, and an embodiment in this case will be described as the second embodiment.

[0049] Fig. 7 is a schematic cross-sectional view showing an example of a plasma processing apparatus in the second embodiment. The plasma processing apparatus 300 shown in Fig. 7 includes a chamber 301 having an opening at the top, a lid 301L for sealing the top opening of the chamber 301, a substrate support (mounting table) 302 disposed in the chamber 301, and a plasma generation source located above the substrate support 302. The chamber 301 is an example of a processing vessel. The substrate support 302 is also called a lower electrode or a stage.

[0050] The plasma generation source has an upper electrode 305 arranged opposite to the substrate support 302, and an emitter 307 having an electromagnetic wave emission port. The emitter 307 corresponds to the emitter 16 of the first embodiment. A plasma generation space U is formed between the upper electrode 305 and the substrate support 302 in the chamber 301. The emitter 307 is made of a dielectric material such as alumina (Al2O3). The electromagnetic wave is emitted from the emitter 307 to the plasma generation space U. The emitter 307 is an introduction part for the electromagnetic wave, and a step having an annular upper surface is formed on the inner wall surface of the chamber 301. The emitter 307 engages with the step, is disposed on the upper surface, and is supported by the upper surface. The emitter 307 is fitted along the entire circumference of the chamber 301. That is, the electromagnetic wave is emitted downward over the entire circumference from the emitter 307 arranged in the circumferential direction of the chamber 301.

[0051] The substrate W is placed on the substrate support 302. The substrate W is not particularly limited as long as it is subjected to plasma processing, and examples of the substrate W include a semiconductor substrate, an insulating substrate such as glass or alumina, and a metal substrate.

[0052] The gas inside the chamber 301 can be exhausted to the outside by the exhaust device 320 through the gas exhaust port 319. A process gas is supplied to the inside of the chamber 301 from a gas supply source 318 through a supply pipe 317. Specifically, the upper electrode 305 has a shower structure having a gas diffusion chamber 316 in its internal space, and the supply pipe 317 penetrates the lid 301L, crosses the waveguide 309, and is connected to the inside of the gas diffusion chamber 316. The upper electrode 305 in this example has a metallic shower plate structure, and has a gas diffusion chamber 316 into which a process gas is introduced, and a plurality of gas holes 314 that communicate the gas diffusion chamber 316 with the space inside the chamber 301. The upper electrode 305 is composed of an upper metal member 305A having a recess on the lower surface and a lower metal member 305B having a plurality of gas holes 314, and the gas diffusion chamber 316 is formed at the position of the recess between these metal members. The process gas introduced into the gas diffusion chamber 316 is supplied into the chamber 301 through a plurality of gas holes 314 provided in a lower region of the upper electrode 305. The upper electrode 305 is an example of an electrode to which an electromagnetic wave for generating plasma is applied.

[0053] A waveguide 309 is formed between the upper electrode 305 and the lower surface of the lid 301L and the inner surface of the chamber 301 along the outer periphery of the upper electrode 305. The chamber 301 has an upper annular member 301A and a chamber body 301B. The annular member 301A and the chamber body 301B are connected via an elastic member 340. That is, the annular member 301A can be said to be a member obtained by dividing the upper part of the side wall of the chamber 301. The elastic member 340 is, for example, a diagonally wound coil spring. The upper part of the annular member 301A is in contact with the lower surface of the lid 301L. A flange 330 is formed on the lower part of the annular member 301A. In addition, a flange 331 is formed on the upper part of the opposing chamber body 301B. The flanges 330 and 331 are provided with, for example, a plurality of actuators 350 and rods 351, and the gap length between the flanges 330 and 331 can be adjusted. The gap between flange 330 and flange 331 is the gap between the lower surface of annular member 301A and the upper surface of chamber body 301B, and corresponds to gap G in the first embodiment. That is, in plasma processing apparatus 300 of the second embodiment, the waveguide length from waveguide 309 to emission section 307 is adjustable. Also, the gap generated between flange 330 and flange 331 is electromagnetically shielded by elastic member 340. Actuator 350 and rod 351 correspond to actuator 50 and rod 51 in the first embodiment and have similar functions, so description thereof will be omitted.

[0054] Electric field probes 360 are provided on the upper part of the side wall of the chamber body 301B on the outer circumferential side corresponding to each actuator 350 in the circumferential direction of the chamber 301 in a plan view, and can detect the electric field of the emission section 307. Information on the electric field detected by the electric field probe 360 ​​(for example, electric field intensity) is output to the control section 400. The electric field probe 360 ​​corresponds to the electric field probe 60 of the first embodiment, and has the same function.

[0055] In the plasma processing apparatus 300, electromagnetic power is supplied from a power source 311 to the upper part of the upper electrode 305 via a first matching box 310 and a power transmission line 308. The supplied electromagnetic wave travels radially in the horizontal direction through a waveguide 309. When this electromagnetic wave hits the inner surface of the chamber 301 (annular member 301A), it travels downward, passes through the inside of the emission part 307, and is emitted into the plasma generation space U from the inner tip surface of the lower protrusion and the multipactor discharge part 315. The electromagnetic wave travels horizontally toward the central axis of the chamber 301. The electromagnetic wave may be an electromagnetic wave in the VHF band or UHF band (microwave band). In the second embodiment, the portion of the waveguide 309 from the center of the upper electrode 305 to the position of the connection surface between the lower surface of the annular member 301A and the upper surface of the chamber body 301B is an example of an upstream waveguide UW, and the portion from the connection surface to the upper surface of the emission section 307 is an example of a downstream waveguide DW.

[0056] When a process gas is introduced into the chamber 301 and the inside of the chamber 301 is depressurized by the exhaust device 320 to a pressure at which plasma can be generated, an electromagnetic wave is introduced into the chamber 301, and plasma is generated in a plasma generation space U below the upper electrode 305. The plasma generation space U is located directly below the upper electrode 305. One end of the power source 311 is connected to the first matching device 310, and the other end is connected to the ground. The power transmission line 308 may be any one capable of transmitting electromagnetic waves such as VHF bands, and a coaxial cable may be used as an electromagnetic wave transmission component in addition to a waveguide. In this example, the substrate support part 302 is electrically connected to the ground, but it is also possible to apply high frequency waves, electromagnetic waves, etc.

[0057] The central axis extending in the vertical direction in the chamber 301 is the Z axis, the axis perpendicular to the Z axis is the X axis, and the axis perpendicular to both the Z axis and the X axis is the Y axis. In this case, the XY plane constitutes a horizontal plane. The central axis of the release section 307 coincides with the central axis (Z axis) of the chamber 301 in the vertical direction.

[0058] The control unit 400 processes computer-executable instructions that cause the plasma processing apparatus 300 to execute various processes such as film formation and etching. The control unit 400 may be configured to control each element of the plasma processing apparatus 300 to execute various processes. In one embodiment, a part or all of the control unit 400 may be included in the plasma processing apparatus 300. The control unit 400 may include a processing unit, a storage unit, and a communication interface. The control unit 400 is realized, for example, by a computer. The processing unit may be configured to perform various control operations by reading a program from the storage unit and executing the read program. This program may be stored in the storage unit in advance, or may be acquired via a medium when necessary. The acquired program is stored in the storage unit and is read from the storage unit by the processing unit and executed. The medium may be various storage media readable by a computer, or may be a communication line connected to the communication interface. The processing unit may be a CPU. The storage unit may include a RAM, a ROM, a HDD, an SSD, or a combination thereof. The communication interface may communicate with the plasma processing apparatus 300 via a communication line such as a LAN.

[0059] In this manner, also in the plasma processing apparatus 300 of the second embodiment, the circumferential distribution of plasma can be controlled by adjusting the gap length between the flanges 330 and 331 during plasma processing using the control unit 400.

[0060] According to each embodiment described above, the plasma processing apparatus (plasma processing apparatus 1, 300) has a processing vessel (chamber 10, 301) that provides a processing space (processing space 10s, plasma generation space U), an emitter (emitter 16, 307) configured to emit an electromagnetic wave into the processing space, and a waveguide (waveguide 18, waveguide 309) configured to supply an electromagnetic wave to the emitter. The waveguide includes an upstream waveguide UW that forms a part of the waveguide, and a downstream waveguide DW that forms a part of the waveguide and is connected to the upstream waveguide UW via an elastic member (elastic member 215, 216, 340), and the gap length between the upstream waveguide UW and the downstream waveguide DW is configured to be adjustable by the pressing force between the upstream waveguide UW and the downstream waveguide DW. As a result, the circumferential distribution of plasma can be controlled.

[0061] According to each embodiment, the elastic member is a coil spring, so that the connection surface between the upstream waveguide UW and the downstream waveguide DW can be shielded.

[0062] Moreover, according to each embodiment, the plasma processing apparatus further includes a plurality of actuators (actuators 50, 350) for adjusting the pressing force at the connection surface between the upstream waveguide UW and the downstream waveguide DW. As a result, the waveguide length can be adjusted, and the circumferential distribution of plasma can be controlled.

[0063] According to each embodiment, the plasma processing apparatus further includes an electric field sensor (electric field probe 60, 360) for detecting an electric field at the emission section. The gap length is adjusted based on the detected electric field. As a result, the circumferential distribution of the plasma can be controlled based on the detected electric field.

[0064] Moreover, according to each embodiment, the plasma processing apparatus further includes a control unit (control unit 5, 400). The control unit is configured to control the plasma processing apparatus to control the actuators so as to change the gap length along the circumferential direction of the processing vessel when plasma processing is performed on the substrate W to be processed in the processing space. As a result, the circumferential distribution of plasma can be controlled to rotate, and the in-plane uniformity can be further improved in one or more of the film formation process and the etching process.

[0065] According to the first embodiment, the upstream waveguide UW includes a resonator 20 capable of resonating with an electromagnetic wave. In the resonator 20, a circular plate (plate member 205) connected to a conductor (wall member 212) on the central axis side of the processing vessel and a circular plate (plate members 204, 206) connected to a conductor (columnar member 211) on the outer wall side of the processing vessel are alternately arranged, and a plurality of slots 20g are formed in the connecting portion (lower surface 220 of the lower conductor wall 210) with the downstream waveguide DW in the circumferential direction of the processing vessel. As a result, an electromagnetic wave can be supplied to the emission portion 16.

[0066] According to the first embodiment, the downstream waveguide DW includes an annular space (waveguide 143). The slots 20g are connected to the annular space. As a result, the electromagnetic wave can be supplied to the emission portion 16.

[0067] Moreover, according to the first embodiment, the elastic members 215, 216 are provided on the inner and outer circumferential sides of the multiple slots 20g. As a result, even if the gap G is adjusted to leave a gap, the gap formed between the upstream waveguide UW and the downstream waveguide DW is electromagnetically shielded by the elastic members 215, 216.

[0068] According to each embodiment, the plasma processing apparatus further includes a shower plate (shower plate 22, lower metal member 305B) for supplying processing gas to the processing space. The emission section is formed of an annular dielectric material and is provided so as to surround the shower plate. As a result, electromagnetic waves can be supplied from the outer periphery of the chamber 10, 301 toward the center.

[0069] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The above-described embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended claims.

[0070] In the above-described embodiments, the plasma processing apparatus 1,300 is described as supplying electromagnetic waves to the emission part 16,307 provided on the side wall of the chamber 10,301, but is not limited thereto. For example, in the case of a plasma processing apparatus in which electromagnetic waves are supplied from a high-frequency power source to an upper electrode using a waveguide, the waveguide may be divided into an upstream waveguide UW and a downstream waveguide DW, and an elastic member may be provided between the upstream waveguide UW and the downstream waveguide DW, and an actuator and a rod may be provided.

[0071] The present disclosure can also be configured as follows. (1) a processing vessel providing a processing space; an emission unit configured to emit electromagnetic waves into the processing space; a waveguide configured to provide the electromagnetic wave to the emitter; having the waveguide includes an upstream waveguide that forms a part of the waveguide, and a downstream waveguide that forms a part of the waveguide and is connected to the upstream waveguide via an elastic member; A gap length between the upstream waveguide and the downstream waveguide is configured to be adjustable by a pressing force between the upstream waveguide and the downstream waveguide. Plasma processing equipment. (2) The elastic member is a coil spring. The plasma processing apparatus according to (1) above. (3) Further, the optical waveguide has a plurality of actuators for adjusting a pressing force at a connection surface between the upstream waveguide and the downstream waveguide. The plasma processing apparatus according to (1) or (2). (4) The emission portion further includes an electric field sensor for detecting an electric field, The gap length is adjusted based on the detected electric field. The plasma processing apparatus according to (3) above. (5) Further, the control unit is provided. the control unit is configured to control the plasma processing apparatus to control the actuators so as to change the gap length along a circumferential direction of the processing vessel when plasma processing is performed on a substrate to be processed in the processing space. The plasma processing apparatus according to (4) above. (6) the upstream waveguide includes a resonator capable of resonating with the electromagnetic wave, the resonator is arranged such that a circular plate connected to a conductor on a central axis side of the processing vessel and a circular plate connected to a conductor on an outer wall side of the processing vessel are alternately arranged, and a plurality of slots are formed in a connection portion with the downstream waveguide in a circumferential direction of the processing vessel. The plasma processing apparatus according to any one of (1) to (5) above. (7) the downstream waveguide includes an annular space; The plurality of slots are connected to the annular space. The plasma processing apparatus according to (6) above. (8) The elastic members are provided on inner and outer circumferential sides of the plurality of slots. The plasma processing apparatus according to (6) or (7) above. (9) a shower plate for supplying a processing gas to the processing space; The emission section is formed of an annular dielectric material and is provided so as to surround the shower plate. The plasma processing apparatus according to any one of (1) to (8) above. (10) A plasma processing method in a plasma processing apparatus, comprising: The plasma processing apparatus includes: a processing vessel providing a processing space; an emission unit configured to emit electromagnetic waves into the processing space; a waveguide configured to supply the electromagnetic wave to the emission portion, the waveguide including an upstream waveguide forming a part of the waveguide, and a downstream waveguide forming a part of the waveguide and connected to the upstream waveguide via an elastic member; a plurality of actuators for adjusting a pressing force at a connection surface between the upstream waveguide and the downstream waveguide in order to adjust a gap length between the upstream waveguide and the downstream waveguide; having controlling the plurality of actuators so as to change the gap length along a circumferential direction of the processing vessel when plasma processing is performed on a substrate to be processed in the processing space; Plasma treatment method. [Explanation of symbols]

[0072] 1,300 Plasma processing equipment 5,400 Control section 10,301 Chambers 10s Processing space 12 Substrate support 14 Upper electrode 16,307 Discharge section 18 Waveguide 20 resonator 20g Slot 22 Shower Plate 24 High frequency power supply 50,350 Actuator 60,360 Electric Field Probe 143 Waveguide 204~206 Plate members 210 Lower Conductor Wall 212 Wall components 215, 216, 340 Elastic members 220 Bottom 305B Lower metal member G Gap DW downstream waveguide U Plasma generation space UW upstream waveguide W substrate

Claims

1. a processing vessel providing a processing space; an emission unit configured to emit electromagnetic waves into the processing space; a waveguide configured to provide the electromagnetic wave to the emitter; having the waveguide includes an upstream waveguide that forms a part of the waveguide, and a downstream waveguide that forms a part of the waveguide and is connected to the upstream waveguide via an elastic member; A gap length between the upstream waveguide and the downstream waveguide is configured to be adjustable by a pressing force between the upstream waveguide and the downstream waveguide. Plasma processing equipment.

2. The elastic member is a coil spring. The plasma processing apparatus according to claim 1 .

3. Further, the optical waveguide has a plurality of actuators for adjusting a pressing force at a connection surface between the upstream waveguide and the downstream waveguide.

3. The plasma processing apparatus according to claim 1 or 2.

4. The emission portion further includes an electric field sensor for detecting an electric field, The gap length is adjusted based on the detected electric field. The plasma processing apparatus according to claim 3 .

5. Further, the control unit is provided. the control unit is configured to control the plasma processing apparatus to control the actuators so as to change the gap length along a circumferential direction of the processing vessel when plasma processing is performed on a substrate to be processed in the processing space. The plasma processing apparatus according to claim 4 .

6. the upstream waveguide includes a resonator capable of resonating with the electromagnetic wave, the resonator is arranged such that a circular plate connected to a conductor on a central axis side of the processing vessel and a circular plate connected to a conductor on an outer wall side of the processing vessel are alternately arranged, and a plurality of slots are formed in a connection portion with the downstream waveguide in a circumferential direction of the processing vessel.

3. The plasma processing apparatus according to claim 1 or 2.

7. the downstream waveguide includes an annular space; The plurality of slots are connected to the annular space. The plasma processing apparatus according to claim 6 .

8. The elastic members are provided on inner and outer circumferential sides of the plurality of slots. The plasma processing apparatus according to claim 6 .

9. a shower plate for supplying a processing gas to the processing space; The emission section is formed of an annular dielectric material and is provided so as to surround the shower plate.

3. The plasma processing apparatus according to claim 1 or 2.

10. A plasma processing method in a plasma processing apparatus, comprising: The plasma processing apparatus includes: a processing vessel providing a processing space; an emission unit configured to emit electromagnetic waves into the processing space; a waveguide configured to supply the electromagnetic wave to the emission portion, the waveguide including an upstream waveguide forming a part of the waveguide, and a downstream waveguide forming a part of the waveguide and connected to the upstream waveguide via an elastic member; a plurality of actuators for adjusting a pressing force at a connection surface between the upstream waveguide and the downstream waveguide in order to adjust a gap length between the upstream waveguide and the downstream waveguide; having controlling the plurality of actuators so as to change the gap length along a circumferential direction of the processing vessel when plasma processing is performed on a substrate to be processed in the processing space; Plasma treatment method.

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