Plasma processing device, method for manufacturing electrode plate, and method for regenerating electrode plate

Abstract

This plasma processing device is provided with an electrode plate that is disposed so as to face a substrate mounting table across a processing space. The electrode plate is provided with a first plate that comprises silicon and has a refrigerant flow path formed therein, and a second plate that comprises silicon and is provided with a buffer chamber for supplying a processing gas to the processing space. The electrode plate is integrally formed by joining the first plate and the second plate.

Description

Plasma processing apparatus, electrode plate manufacturing method, and electrode plate regeneration method

[0001] The present disclosure relates to a plasma processing apparatus, a method for manufacturing an electrode plate, and a method for regenerating an electrode plate.

[0002] For example, Patent Document 1 discloses a ceiling electrode plate that is suspended from an electrode support having a temperature adjustment mechanism, that is in contact with the electrode support via a cooling plate, and that has a heat transfer sheet formed on the surface that contacts the cooling plate.

[0003] Japanese Patent Application Laid-Open No. 2012-216607

[0004] The present disclosure provides a technique for preventing damage to electrode plates due to heat.

[0005] According to one aspect of the present disclosure, there is provided a plasma processing apparatus comprising an electrode plate arranged opposite a substrate mounting table across a processing space, the electrode plate comprising a first plate made of silicon and having a coolant flow path formed therein, and a second plate made of silicon and having a buffer chamber for supplying processing gas to the processing space, the electrode plate being integrally formed by bonding the first plate and the second plate.

[0006] The present disclosure provides a technique for preventing damage to electrode plates due to heat.

[0007] FIG. 1 is a diagram illustrating the configuration of a plasma processing system including a plasma processing apparatus according to this embodiment. FIG. 2 is a cross-sectional view illustrating a shower head in the plasma processing apparatus according to this embodiment. FIG. 3 is a flow diagram illustrating a method for manufacturing a shower head in the plasma processing apparatus according to this embodiment. FIG. 4 is a cross-sectional view (part 1) illustrating a first plate forming step in the method for manufacturing a shower head in the plasma processing apparatus according to this embodiment. FIG. 5 is a cross-sectional view (part 2) illustrating a first plate forming step in the method for manufacturing a shower head in the plasma processing apparatus according to this embodiment. FIG. 6 is a cross-sectional view (part 1) illustrating a second plate forming step in the method for manufacturing a shower head in the plasma processing apparatus according to this embodiment. FIG. 7 is a cross-sectional view (part 2) illustrating a second plate forming step in the method for manufacturing a shower head in the plasma processing apparatus according to this embodiment. FIG. 8 is a cross-sectional view illustrating a bonding step in the method for manufacturing a shower head in the plasma processing apparatus according to this embodiment. FIG. 9 is a cross-sectional view illustrating a worn shower head in the plasma processing apparatus according to this embodiment. FIG. 10 is a flow diagram illustrating a method for regenerating a shower head in the plasma processing apparatus according to this embodiment. FIG. 11 is a cross-sectional view (part 1) illustrating a method for regenerating a shower head in the plasma processing apparatus according to this embodiment. 12 and 13 are cross-sectional views (part 2 and part 3) illustrating the method for regenerating the shower head in the plasma processing apparatus according to the present embodiment.

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In this specification and the drawings, substantially identical components are designated by the same reference numerals, and redundant description will be omitted. To facilitate understanding, the scale of each part in the drawings may differ from the actual scale. Directions such as parallel, right-angled, orthogonal, horizontal, vertical, up / down, left / right, and the like are permitted to a degree that does not impair the effects of the embodiments. The shape of corners is not limited to right angles and may be rounded. Parallel, right-angled, orthogonal, horizontal, and vertical may include approximately parallel, approximately right-angled, approximately orthogonal, approximately horizontal, and approximately vertical.

[0009] <Plasma Processing System> An example of the configuration of a plasma processing system will be described below. Fig. 1 is a diagram illustrating the configuration of a plasma processing system including a plasma processing apparatus 1, which is an example of a plasma processing apparatus according to this embodiment.

[0010] The plasma processing system includes a capacitively coupled plasma processing apparatus 1 and a controller 2. The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply 20, a power supply 30, an exhaust system 40, and a heat transfer fluid supply 50. The plasma processing apparatus 1 also includes a substrate support 11 and a gas inlet. The gas inlet is configured to introduce at least one process gas into the plasma processing chamber 10. The gas inlet includes a showerhead 13. The substrate support 11 is disposed within the plasma processing chamber 10. The showerhead 13 is disposed above the substrate support 11. In one embodiment, the showerhead 13 forms at least a portion of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the showerhead 13, a sidewall 10a of the plasma processing chamber 10, and the substrate support 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 exhaust port for exhausting gas from the plasma processing space. The sidewall 10a is grounded. The plasma processing chamber 10 also has an upper wall 10b that covers the showerhead 13 from above. The showerhead 13 and the substrate support 11 are electrically insulated from the plasma processing chamber 10 housing.

[0011] The substrate support 11 includes a main body 111 and a ring assembly 112. The main body 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 assembly 112. The annular region 111b of the main body 111 surrounds the central region 111a of the main body 111 in a plan view. The substrate W is disposed on the central region 111a of the main body 111, and the ring assembly 112 is disposed on the annular region 111b of the main body 111 so as to surround the substrate W on the central region 111a of the main body 111. In one embodiment, the main body 111 includes a base and an electrostatic chuck. The base includes a conductive member. The conductive member of the base functions as a lower electrode. The electrostatic chuck is disposed on the base. The upper surface of the electrostatic chuck has the substrate support surface 111a. The ring assembly 112 includes one or more annular members. At least one of the one or more annular members is an edge ring. Although not shown, the substrate support 11 may also include a temperature control module configured to adjust at least one of the electrostatic chuck, the ring assembly 112, and the substrate to a target temperature. The temperature control module may 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. The substrate support 11 may also include a heat transfer gas supply unit configured to supply a heat transfer gas between the back surface of the substrate W and the substrate support surface 111 a.

[0012] The showerhead 13 is configured to introduce at least one process gas from the gas supply unit 20 into the plasma processing space 10s. The showerhead 13 is positioned opposite the substrate support 11 (substrate support table) across the plasma processing space 10s. The showerhead 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, multiple gas inlets 13c, a heat transfer fluid inlet 13d, a fluid flow path 13e, and a heat transfer fluid outlet 13f. 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 multiple gas inlets 13c. The showerhead 13 also includes a conductive member. The showerhead 13 is made of silicon. The conductive member of the showerhead 13 functions as an upper electrode. The heat transfer fluid RF supplied from the heat transfer fluid supply unit 50 flows from the heat transfer fluid inlet 13d into the fluid flow path 13e in the showerhead 13. The heat transfer fluid RF cools the shower head 13 while flowing through the fluid flow path 13e. The heat transfer fluid RF that has flowed through the fluid flow path 13e is discharged from the heat transfer fluid outlet 13f to the heat transfer fluid supply unit 50. The fluid flow path 13e is formed, for example, in a spiral shape from the heat transfer fluid inlet 13d to the heat transfer fluid outlet 13f inside the shower head 13. The fluid flow path 13e is an example of a refrigerant flow path. The heat transfer fluid RF is, for example, brine. In addition to the shower head 13, the gas introduction unit may include one or more side gas injectors (SGIs) attached to one or more openings formed in the side wall 10a.

[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 a corresponding gas source 21 to the showerhead 13 via a corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Additionally, the gas supply unit 20 may include one or more flow modulation devices to modulate or pulse the flow rate of the 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. This causes plasma to be formed from at least one process gas supplied to the plasma processing space 10s. Therefore, the RF power supply 31 can function as at least a part of a plasma generating unit configured to generate plasma from one or more process gases in the plasma processing chamber 10. Furthermore, supplying a bias RF signal to the conductive member of the substrate support 11 generates a bias potential on the substrate W, thereby attracting ion components in the formed plasma to the substrate W.

[0015] In one embodiment, the RF power supply 31 includes a first RF generator 31a and a second RF generator 31b. The first RF generator 31a is coupled to the conductive members of the substrate support 11 and / or the conductive members of the showerhead 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 generator 31a may be configured to generate multiple source RF signals having different frequencies. The generated one or more source RF signals are supplied to the conductive members of the substrate support 11 and / or the conductive members of the showerhead 13. The second RF generator 31b is coupled to the conductive members of the substrate support 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 generator 31b may be configured to generate multiple bias RF signals having different frequencies, and the generated bias RF signals or signals may be supplied to the conductive members of the substrate support 11. Also, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0016] The power supply 30 may also include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generator 32a and a second DC generator 32b. In one embodiment, the first DC generator 32a is connected to a conductive member of the substrate support 11 and 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 another electrode, such as an electrode in an electrostatic chuck. In one embodiment, the second DC generator 32b is connected to a conductive member of the showerhead 13 and configured to generate a second DC signal. The generated second DC signal is applied to the conductive member of the showerhead 13. In various embodiments, at least one of the first and second DC signals may be pulsed. The first and second DC generating units 32a and 32b may be provided in addition to the RF power supply 31, or the first DC generating unit 32a may be provided instead of the second RF generating unit 31b.

[0017] The exhaust system 40 may be connected to, for example, a gas exhaust port 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 regulated by the pressure regulating valve. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0018] The heat transfer fluid supply unit 50 supplies cooled heat transfer fluid RF to the shower head 13. The heat transfer fluid supply unit 50 also recovers the heat transfer fluid RF heated in the shower head 13. The heat transfer fluid supply unit 50 then cools the recovered heat transfer fluid RF.

[0019] The controller 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to perform the various processes described in this disclosure. The controller 2 may be configured to control each element of the plasma processing apparatus 1 to perform the various processes described herein. In one embodiment, part or all of the controller 2 may be included in the plasma processing apparatus 1. The controller 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 may be configured to perform various control operations based on programs stored in the storage unit 2a2. The storage unit 2a2 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 thereof. The communication interface 2a3 may communicate with the plasma processing apparatus 1 via a communication line such as a LAN (Local Area Network).

[0020] A plasma processing apparatus according to this embodiment will be described. The plasma processing apparatus according to this embodiment includes an electrode plate disposed opposite a substrate mounting table across a processing space. The electrode plate in the plasma processing apparatus according to this embodiment includes a first plate made of silicon and having a coolant flow path formed therein, and a second plate made of silicon and having a buffer chamber for supplying a processing gas to the processing space. The electrode plate in the plasma processing apparatus according to this embodiment is integrally formed by bonding the first plate and the second plate.

[0021] The electrode plate in the plasma processing apparatus according to this embodiment will be described in detail with reference to Fig. 2. Fig. 2 is a diagram illustrating the shower head 13, which is an example of the electrode plate in the plasma processing apparatus 1, which is an example of the plasma processing apparatus according to this embodiment. Specifically, Fig. 2 shows a cross-sectional view of the vicinity of the shower head 13 in the plasma processing apparatus 1.

[0022] The plasma processing apparatus 1 includes a shower head 13 as an example of an electrode plate. The shower head 13 is integrally formed by joining a first plate 13A and a second plate 13B.

[0023] The first plate 13A is made of silicon and has a fluid flow path 13e through which the heat transfer fluid RF flows. In other words, the first plate 13A has the fluid flow path 13e through which the heat transfer fluid RF flows.

[0024] The second plate 13B is made of silicon and includes a gas diffusion chamber 13b, which is an example of a buffer chamber that supplies the process gas PG to the plasma processing space 10s. In other words, the second plate 13B is provided with a buffer chamber (gas diffusion chamber 13b) that supplies the process gas PG to the processing space (plasma processing space 10s).

[0025] The first plate 13A and the second plate 13B are bonded by activating the bonding surfaces and applying pressure at a low temperature (for example, room temperature). Specifically, a silicon oxide layer is formed on the surface of the first plate 13A, and is bonded to the silicon on the surface of the second plate 13B.

[0026] The side wall 10a and the top wall 10b of the plasma processing apparatus 1 are arranged so that stress is not applied to the shower head 13 due to the pressure difference even when the outside of the plasma processing chamber 10 is at atmospheric pressure ATM and the plasma processing space 10s is in a vacuum state.

[0027] A method for manufacturing the shower head 13 in the plasma processing apparatus 1, which is an example of the plasma processing apparatus according to this embodiment, will be described. By describing the method for manufacturing the shower head 13, a method for manufacturing the electrode plate in the plasma processing apparatus according to this embodiment will be described. Figure 3 is a flow diagram illustrating the method for manufacturing the shower head 13 in the plasma processing apparatus 1, which is an example of the plasma processing apparatus according to this embodiment.

[0028] The method for manufacturing the shower head 13 includes a first plate forming step (step S10) for forming the first plate 13A, and a second plate forming step (step S20) for forming the second plate 13B. The method for manufacturing the shower head 13 also includes a bonding step (step S30) for bonding the first plate 13A and the second plate 13B together.

[0029] (Step S10) First, the first plate 13A is formed (first plate forming step). The first plate forming step includes an oxide film forming step (step S11) and a processing step (step S12).

[0030] [Step S11] First, in an oxide film formation step, a silicon oxide film is formed on a silicon substrate made of silicon. Figure 4 is a cross-sectional view illustrating a first plate formation step in a method for manufacturing a shower head 13 in a plasma processing apparatus 1, which is an example of a plasma processing apparatus according to this embodiment. Specifically, Figure 4 is a diagram illustrating a process for forming a silicon oxide film on a silicon substrate.

[0031] In the oxide film forming step (step S11), a silicon oxide film 13Asa is formed on the surface 13AsS of the silicon substrate 13As made of silicon. The silicon oxide film 13Asa is formed by, for example, thermal oxidation.

[0032] [Step S12] Next, in a processing step, the silicon substrate on which the silicon oxide film has been formed is processed to form fluid and gas flow paths. Figure 5 is a cross-sectional view illustrating a first plate forming step in a method for manufacturing a shower head 13 in a plasma processing apparatus 1, which is an example of a plasma processing apparatus according to this embodiment. Figure 5 is a diagram illustrating a step of forming fluid and gas flow paths by processing a silicon substrate on which a silicon oxide film has been formed.

[0033] In the processing step (step S12), grooves 13Ag are processed to form fluid flow paths 13e in the shower head 13. Also in the processing step (step S12), through holes 13Ar are processed in the shower head 13, connecting to either the heat transfer fluid inlet 13d or the heat transfer fluid outlet 13f. Furthermore, in the processing step (step S12), through holes 13Ah are processed in the shower head 13, passing through the first plate 13A and connecting to the gas supply port 13a. The through holes 13Ah form part of the gas flow paths that allow the process gas to flow into the gas diffusion chamber, which is a buffer chamber.

[0034] The processing performed in the processing step (step S12) may be, for example, etching or cutting.

[0035] When the processes up to step S12 are performed, the first plate 13A is formed. The surface of the silicon oxide film 13Aa remaining after processing becomes a bonding surface 13AS that is bonded to the second plate 13B.

[0036] (Step S20) Next, the second plate 13B is formed (second plate forming step). The second plate forming step includes a shape forming step (step S21) and a hydrogen ion implanted layer forming step (step S22).

[0037] [Step S21] First, in a shape forming step, a gas diffusion chamber, which is an example of a buffer chamber, and a plurality of gas inlets are formed. Figure 6 is a cross-sectional view illustrating a second plate forming step in a method for manufacturing a shower head 13 in a plasma processing apparatus 1, which is an example of a plasma processing apparatus according to this embodiment. Specifically, Figure 6 is a view illustrating a process for forming the shape of the second plate 13B.

[0038] In the shape forming process (step S21), a silicon substrate 13Bs is formed, which includes a gas diffusion chamber 13Bb that serves as the gas diffusion chamber 13b, a plurality of gas inlets 13Bc that serve as the gas inlets 13c, and through-holes 13Bh that connect to the gas supply ports 13a. The through-holes 13Bh form part of a gas flow path that allows the process gas to flow into the gas diffusion chamber that serves as a buffer chamber. The silicon substrate 13Bs may be formed, for example, by laminating silicon, by bonding multiple members together with brazing material, or by thermocompression bonding.

[0039] [Step S22] Next, in the hydrogen ion implantation layer formation step, a hydrogen ion implantation layer is formed on the silicon substrate whose shape has been formed in the shape formation step (step S21). Figure 7 is a cross-sectional view illustrating the second plate formation step in the method for manufacturing the shower head 13 in the plasma processing apparatus 1, which is an example of the plasma processing apparatus according to this embodiment. Figure 7 is a diagram illustrating the process of forming a hydrogen ion implantation layer on the silicon substrate whose shape has been formed.

[0040] In the hydrogen ion implantation layer formation process (step S22), hydrogen is implanted from the surface 13BS. Then, the hydrogen ion implantation layer 13Bi is formed at a depth of several nanometers from the surface 13BS. By forming the hydrogen ion implantation layer 13Bi, the second plate 13B is formed. Although hydrogen is used as an example here, helium or the like can be used instead of hydrogen. For example, by using helium instead of hydrogen, a helium implantation layer may be formed instead of the hydrogen ion implantation layer 13Bi.

[0041] When the process is completed up to step S22, the second plate 13B is formed. The surface 13BS becomes a joining surface that joins with the second plate 13B.

[0042] (Step S30) Next, the first plate 13A and the second plate 13B are bonded together (bonding step). The bonding surfaces of the first plate 13A and the second plate 13B are activated, and the plates are bonded together by applying pressure at low temperature (room temperature). Figure 8 is a cross-sectional view illustrating the bonding step in the method for manufacturing the shower head 13 in the plasma processing apparatus 1, which is an example of the plasma processing apparatus according to this embodiment. Specifically, Figure 8 is a diagram illustrating the process of bonding the first plate 13A and the second plate 13B.

[0043] Specifically, a joining surface 13AS (first joining surface) of the first plate 13A and a surface 13BS (second joining surface) which is a joining surface of the second plate 13B are joined together.

[0044] When the processes up to step S30 are performed, the shower head 13 is formed.

[0045] Next, a method for regenerating the shower head 13 in the plasma processing apparatus 1, which is an example of the plasma processing apparatus according to this embodiment, will be described. By describing the method for regenerating the shower head 13, a method for regenerating the electrode plate in the plasma processing apparatus according to this embodiment will be described.

[0046] FIG. 9 is a cross-sectional view illustrating a worn shower head 13z in a plasma processing apparatus 1, which is an example of a plasma processing apparatus according to this embodiment.

[0047] In the showerhead 13, the side of the second plate 13B where the gas inlet 13Bc is formed is worn away by the plasma. Showerhead 13z indicates a showerhead 13z worn away by the plasma. In the showerhead 13z, the first plate 13A is not exposed to the plasma and therefore undergoes little change in shape. On the other hand, the second plate 13B, particularly the side where the gas inlet 13Bc is formed, is worn away because it is exposed to the plasma. For example, as shown by the dotted line frame 13Br in FIG. 9 , the second plate 13B is worn away by the plasma. As shown by the dotted line frame 13Br, a portion of the second plate 13B is worn away, resulting in a thinner second plate 13B, as shown by the second plate 13Bz.

[0048] Therefore, in the plasma processing apparatus according to this embodiment, the worn second plate 13Bz is replaced, whereas the first plate 13A is reused.

[0049] A method for regenerating the shower head 13 in the plasma processing apparatus 1, which is an example of the plasma processing apparatus according to this embodiment, will be described. By describing the method for regenerating the shower head 13, a method for regenerating the electrode plate in the plasma processing apparatus according to this embodiment will be described. Figure 10 is a flow diagram illustrating the method for regenerating the shower head 13 in the plasma processing apparatus 1, which is an example of the plasma processing apparatus according to this embodiment.

[0050] The method for regenerating the shower head 13 includes a peeling step (step S110) of peeling off the first plate 13A of the shower head 13, and a polishing step (step S120) of polishing the first plate 13A. The method for regenerating the shower head 13 also includes a bonding step (step S130) of bonding the polished first plate 13A to a new second plate 13B.

[0051] (Step S110) First, the first plate 13A is peeled off from the second plate 13B of the shower head 13. Fig. 11 is a cross-sectional view illustrating a method for regenerating the shower head 13 in the plasma processing apparatus 1, which is an example of the plasma processing apparatus according to this embodiment. Specifically, Fig. 11 is a view showing a process of peeling off the first plate 13A1 from the second plate 13B1 of the worn shower head 13z.

[0052] 11 , the first plate 13A1 and the second plate 13B1 are separated at the hydrogen ion-implanted layer 13Bi in the second plate 13B. In other words, the first plate 13A1 is peeled off from the second plate 13B1 along a cutting plane CL that is a plane including the hydrogen ion-implanted layer 13Bi. For example, the shower head 13z is heated to a temperature of about 400° C., whereby the hydrogen ion-implanted layer 13Bi is peeled off.

[0053] The first plate 13A1 and the second plate 13B1 are separated at the hydrogen ion implantation layer 13Bi. Because the first plate 13A1 and the second plate 13B1 are separated at the hydrogen ion implantation layer 13Bi, the first plate 13A1 includes the hydrogen ion implantation layer 13Ai, which is a part of the hydrogen ion implantation layer 13Bi in the second plate 13B. The first plate 13A1 also includes the silicon layer 13Aj, which is a silicon layer extending from the hydrogen ion implantation layer 13Ai to the bonding surface in the second plate 13B. In other words, the first plate 13A1 is peeled off with the hydrogen ion implantation layer 13Ai and the silicon layer 13Aj, which are silicon layers, remaining on the surface of the silicon oxide film 13Aa of the first plate 13A1.

[0054] The second plate 13B1 may be melted and reused as a material.

[0055] (Step S120) Next, the hydrogen ion implanted layer 13Ai and the silicon layer 13Aj adhering to the first plate 13A1 are removed by polishing. Furthermore, by polishing the first plate 13A1, the bonding surface of the first plate 13A1 is planarized. Figure 12 is a cross-sectional view illustrating a method for regenerating the shower head 13 in the plasma processing apparatus 1, which is an example of the plasma processing apparatus according to this embodiment. Specifically, Figure 12 illustrates a process of polishing the surface of the first plate 13A1 to form the bonding surface 13A2S.

[0056] For example, the surface of the first plate 13A1 is polished by CMP (Chemical Mechanical Polishing) to remove the attached hydrogen ion implanted layer 13Ai and silicon layer 13Aj, and then the bonding surface 13A2S of the first plate 13A2 from which the attached hydrogen ion implanted layer 13Ai and silicon layer 13Aj have been removed is polished and planarized.

[0057] 12, the hydrogen ion implanted layer 13Ai and the silicon layer 13Aj are removed by polishing with an abrasive (slurry) while rotating the polishing pad PAD. The abrasive (slurry) is preferably selected so as to selectively remove the silicon layer relative to the silicon oxide film layer. This allows the surface of the silicon oxide film 13Aa of the first plate 13A2 to be restored as the bonding surface 13A2S.

[0058] When removing the hydrogen ion implanted layer 13Ai and the silicon layer 13Aj attached to the first plate 13A1, wet etching or dry etching may be used.

[0059] (Step S130) Next, the polished and refurbished first plate 13A2 is bonded to a newly prepared second plate 13B2 to form a new shower head. Figure 13 is a cross-sectional view illustrating a method for refurbishment of the shower head 13 in the plasma processing apparatus 1, which is an example of the plasma processing apparatus according to this embodiment. Specifically, Figure 13 is a diagram showing a refurbished shower head 13R formed by bonding the refurbished first plate 13A2 to a newly prepared second plate 13B2.

[0060] For a specific joining method, please refer to step S30 and a detailed description thereof will be omitted here.

[0061] <Summary> The plasma processing apparatus according to this embodiment can prevent damage to the electrode plate due to heat. The plasma processing apparatus according to this embodiment is manufactured using a single material without any contact interface, which can prevent damage due to differences in materials.

[0062] For example, if an electrode plate is formed from a cooling plate made of metal and a top plate made of silicon, the difference in linear expansion between the metal and silicon may cause thermal stress on the top plate, resulting in damage. Furthermore, if an electrode plate is formed from a cooling plate made of metal and a top plate made of silicon, the contact thermal resistance between the cooling plate and the top plate increases because replacement is required. High contact thermal resistance increases the temperature difference between components. If the temperature difference between components increases, the electrode plate may be damaged due to the difference in thermal expansion.

[0063] In particular, in a plasma processing apparatus, when the power of a high-frequency signal becomes high, on the order of several tens of kilowatts, the upper part of the electrode plate is cooled by the cooling plate and shrinks, while the surface exposed to the plasma expands due to the heat from the plasma. Therefore, in a plasma processing apparatus, when the power becomes high, the electrode plate may deform into a downward convex shape and be damaged.

[0064] Furthermore, if the top plate expands laterally due to the heat of the plasma, it may be damaged by the clamping portion.

[0065] The electrode plate in the plasma processing apparatus according to this embodiment is integrally formed from a single material, silicon, thereby eliminating thermal resistance at the interface and reducing the temperature difference between the upper and lower portions. Furthermore, the electrode plate in the plasma processing apparatus according to this embodiment is integrally formed from a single material, silicon, eliminating the need for a clamping structure. By eliminating the need for a clamping structure, the electrode plate in the plasma processing apparatus according to this embodiment can be prevented from being damaged by the clamping.

[0066] For example, the results of a simulation evaluation of a case where a heat transfer fluid whose temperature is adjusted to 120° C. is used and a heat input of 1500 watts from the plasma will be described.

[0067] In the electrode plate of the plasma processing apparatus according to this embodiment, the temperature at the plasma processing surface was 126.4° C., i.e., the temperature difference was 6.4° C. In addition, in the electrode plate of the plasma processing apparatus according to this embodiment, the maximum displacement was 0.01 mm.

[0068] On the other hand, when a silicon top plate and a metal cooling plate were used, the surface temperature of the silicon top plate was 147.5°C, i.e., the temperature difference was 27.5°C. Also, when a silicon top plate and a metal cooling plate were used, the maximum displacement of the silicon top plate was 0.365 mm.

[0069] The electrode plate in the plasma processing apparatus according to this embodiment can bring the surface temperature of the electrode plate closer to the temperature of the heat transfer fluid. In other words, the electrode plate in the plasma processing apparatus according to this embodiment can reduce the temperature difference between the upper and lower parts. Furthermore, the electrode plate in the plasma processing apparatus according to this embodiment can reduce deformation of the electrode plate.

[0070] Furthermore, according to the plasma processing apparatus of this embodiment, the electrode plate is made of a single material without any contact interface, so that the portions worn out by plasma exposure can be selectively separated and reattached, thereby reducing costs.

[0071] The plasma processing apparatus according to the present embodiment disclosed herein should be considered to be illustrative in all respects and not restrictive. The above-described embodiments can be modified and improved in various ways without departing from the spirit and scope of the appended claims. The features described in the above-described embodiments can be configured in other ways as long as they are not inconsistent, and can be combined as long as they are not inconsistent.

[0072] This application claims priority from basic patent application No. 2023-189188, filed with the Japan Patent Office on November 6, 2023, the entire contents of which are incorporated herein by reference.

[0073] REFERENCE SIGNS LIST 1 Plasma processing apparatus 10 Plasma processing chamber 10s Plasma processing space 11 Substrate support 13 Shower head 13b Gas diffusion chamber 13A, 13A1, 13A2 First plate 13Ai Hydrogen ion implanted layer 13As Silicon substrate 13Asa Silicon oxide film 13B, 13B1, 13B2, 13Bz Second plate 13Bb Gas diffusion chamber 13Bi Hydrogen ion implanted layer 13Bs Silicon substrate 13e Fluid flow path

Claims

1. A plasma processing apparatus comprising: an electrode plate arranged to face a substrate mounting table across a processing space, the electrode plate comprising: a first plate made of silicon and having a coolant flow path formed therein; and a second plate made of silicon and having a buffer chamber for supplying processing gas to the processing space, the electrode plate being integrally formed by bonding the first plate and the second plate.

2. The plasma processing apparatus according to claim 1, wherein the second plate has a hydrogen ion implanted layer on a bonding surface side bonding to the first plate.

3. The plasma processing apparatus according to claim 1, wherein the first plate has a silicon oxide layer on a bonding surface that bonds to the second plate.

4. The plasma processing apparatus according to claim 1, wherein the first plate has a gas flow path for causing the processing gas to flow into the buffer chamber.

5. The plasma processing apparatus according to claim 4, wherein the gas flow path is a through hole penetrating the first plate.

6. A method for manufacturing an electrode plate that is arranged to face a substrate mounting table across a processing space in a plasma processing apparatus, comprising: (a) a step of forming a first plate including a step of forming a silicon oxide film on a silicon substrate on a first bonding surface and a step of forming a coolant flow path on the first bonding surface; (b) a step of forming a second plate including a step of forming a buffer chamber that supplies processing gas to the processing space and a step of forming a hydrogen ion implantation layer from the side of the second bonding surface; and (c) a step of bonding the first plate and the second plate by bonding the first bonding surface and the second bonding surface.

7. A method for manufacturing an electrode plate that is arranged to face a substrate mounting table across a processing space in a plasma processing apparatus, comprising: (a) a step of forming a first plate including a step of forming a silicon oxide film on a silicon substrate on a first bonding surface and a step of forming a coolant flow path on the first bonding surface; (b) a step of forming a second plate including a step of forming a buffer chamber that supplies processing gas to the processing space and a step of forming a helium injection layer from the side of the second bonding surface; and (c) a step of bonding the first plate and the second plate by bonding the first bonding surface and the second bonding surface.

8. A method for manufacturing an electrode plate according to claim 6 or claim 7, wherein in step (c), the first joining surface and the second joining surface are joined while applying pressure at room temperature.

9. A method for regenerating an electrode plate which is integrally formed by bonding a first plate made of silicon and having a coolant flow path formed therein, and a second plate made of silicon and having a buffer chamber for supplying a processing gas to a processing space, the method comprising: (a) a step of separating the first plate from the second plate at a hydrogen ion implanted layer formed on the second plate; (b) a step of polishing the bonding surface of the first plate; and (c) a step of bonding the polished first plate to a new second plate.

10. The method for regenerating an electrode plate according to claim 9, wherein in step (b), the bonding surface is polished by CMP (Chemical Mechanical Polishing).

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