Method for polishing substrate mounting table and substrate mounting table

Abstract

To prevent generation of steps due to processing mismatches caused by the processing tool tilting due to the effect of cutting load during processing of a substrate placement table, thereby suppressing generation of etching spots.SOLUTION: A polishing method for a substrate placement table having a substrate and a sprayed film provided on the substrate includes the steps of forming a bank sprayed film on a peripheral portion of a sprayed film, impregnating the bank sprayed film with an impregnation agent, planarizing the impregnated bank sprayed film by grinding, and masking the planarized bank sprayed film, and roughening a central portion of the sprayed film excluding the peripheral portion.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a method for polishing a substrate stage and a substrate stage. [Background technology]

[0002] Patent Document 1 discloses a substrate mounting table having a roughened portion on a substrate mounting surface formed of an insulating film and a smooth portion provided around the roughened portion, and a method for manufacturing the same. This substrate mounting table can effectively suppress the occurrence of etching spots without damaging the substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-119326 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology according to the present disclosure suppresses the occurrence of steps due to processing mismatches that occur when a processing tool tilts due to the influence of a cutting load during processing of a substrate table, thereby suppressing the occurrence of etching spots. [Means for solving the problem]

[0005] One aspect of the present disclosure is a method for polishing a substrate support having a base material and a sprayed film provided on the base material, the method comprising the steps of forming a bank sprayed film on a peripheral portion of the sprayed film, impregnating the bank sprayed film with an impregnation agent, planarizing the impregnated bank sprayed film by grinding, and masking the planarized bank sprayed film, and roughening a central portion of the sprayed film excluding the peripheral portion. [Effects of the Invention]

[0006] According to the present disclosure, it is possible to suppress the occurrence of steps due to processing mismatches that occur when a processing tool tilts due to the influence of cutting load during processing of a substrate placing table, and to suppress the occurrence of etching spots. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 10 is an explanatory diagram regarding processing mismatch. [Figure 2] 1 is a longitudinal sectional view showing an outline of the configuration of a plasma processing apparatus according to an embodiment of the present invention. [Figure 3] 1 is a cross-sectional view showing an outline of the configuration of a plasma processing apparatus according to an embodiment of the present invention. [Figure 4] 5A to 5C are explanatory views of a method for polishing a mounting table according to the present embodiment. [Figure 5] 10A and 10B are explanatory views of a method for polishing a mounting table according to a first alternative embodiment. [Figure 6] 10A and 10B are explanatory views of a method for polishing a mounting table according to a second alternative embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] In the manufacturing process of plasma panel displays (FPDs), plasma etching is performed on a substrate, which is the workpiece. In plasma etching, a substrate is placed on a substrate support table, which functions as the lower electrode, in a processing chamber containing, for example, a pair of parallel plate electrodes (upper and lower electrodes). High-frequency power is applied to at least one of the electrodes to form a high-frequency electric field between the electrodes. This high-frequency electric field generates plasma of a processing gas, which then etches a material film on the substrate. Repeated plasma etching may result in the generation of etching products, which may adhere to and accumulate on the surface of the substrate support table. In this case, the presence of deposits on the surface of the substrate support table creates areas where deposits are present between the back surface of the substrate and the surface of the substrate support table, resulting in differences in thermal conductivity and electrical conductivity compared to areas without deposits. This results in areas with high and low etching rates within the substrate, resulting in unevenness known as etching spots.

[0009] In recent years, the production of flexible panels has increased in FPD manufacturing equipment, and customer requirements regarding display unevenness of panels have become stricter. Therefore, it is necessary to process and polish the surface of the sprayed film (insulating film) sprayed on the surface of the substrate mounting table (lower electrode) to a more suitable shape (for example, flat at the macro level and rough at the micro level). Patent Document 1 discloses a configuration in which an insulating film formed on the surface of a substrate mounting table is smoothed, and then only the inner part of the insulating film is subjected to a blasting treatment to form a roughened portion, leaving the surrounding area smooth.

[0010] In the prior art, machining using a processing tool is known as a method for processing a thermally sprayed film on the surface of a substrate support. In machining, the processing tool tilts due to the cutting load during processing, resulting in the formation of steps on the surface, a problem known as processing mismatch. FIG. 1 is an explanatory diagram of processing mismatch. As shown in FIG. 1(a), when cutting with a processing tool 200, the processing tool tilts due to the cutting resistance, resulting in the formation of minute steps 203 on the surface of the substrate support 202. Furthermore, as shown in FIG. 1(b), if etching products 204 adhere to the surface of the substrate support 202 while the steps 203 are formed, the steps cause differences in heat transfer depending on the position on the substrate, which can lead to temperature differences (temperature unevenness) and etching spots.

[0011] Therefore, the technology disclosed herein realizes a substrate mounting table that can suppress the occurrence of processing mismatches that occur during machining using a processing tool when polishing the surface of the substrate mounting table, and effectively prevent the occurrence of etching spots.

[0012] The configuration of a plasma processing apparatus including a substrate mounting table according to this embodiment will be described below with reference to the drawings. Note that in this specification, elements having substantially the same functional configuration are designated by the same reference numerals, and redundant description will be omitted.

[0013] <Plasma processing equipment> 2 and 3 are a longitudinal sectional view and a transverse sectional view, respectively, showing the outline of the configuration of the plasma processing apparatus according to this embodiment.

[0014] 2 performs substrate processing, i.e., plasma processing, using plasma of a processing gas on a rectangular glass substrate G (hereinafter referred to as "substrate G") as a substrate. The plasma processing performed by the plasma processing apparatus 1 includes, for example, film formation processing for FPDs, etching processing, ashing processing, etc. Through these processings, electronic devices such as light-emitting elements and driving circuits for the light-emitting elements are formed on the substrate G.

[0015] The plasma processing apparatus 1 includes a container body 10 having a rectangular cylindrical shape with a bottom. The container body 10 is made of a conductive material, such as aluminum, and is electrically grounded. Because plasma processing often uses corrosive gases, the inner wall surface of the container body 10 is subjected to a corrosion-resistant coating treatment, such as anodizing, to improve corrosion resistance. An opening is formed on the top surface of the container body 10. This opening is airtightly sealed by a rectangular metal window 20 insulated from the container body 10. Specifically, the opening is airtightly sealed by the metal window 20 and a metal frame 14, which will be described later. The space surrounded by the container body 10 and the metal window 20 is a processing space S1 in which a substrate G to be processed in plasma processing is located during plasma processing, and the space above the metal window 20 is an antenna chamber S2 in which a high-frequency antenna (plasma antenna) 90, which will be described later, is disposed. A sidewall of the container body 10 on the negative side in the X direction (the left side in FIG. 2) is provided with a loading / unloading port 11 for loading / unloading the substrate G into / out of the processing space S1 and a gate valve 12 for opening / closing the loading / unloading port 11.

[0016] A substrate mounting table (hereinafter also referred to simply as a mounting table) 30 on which a substrate G is placed is provided on the bottom wall 10a of the container body 10 so as to face the metal window 20. The mounting table 30 is formed, for example, in a rectangular shape when viewed from above. The mounting table 30 has a table body 31, the upper surface of which serves as the mounting surface for the substrate G. A base material 36 made of a conductive material, for example, aluminum or an aluminum alloy, is provided below the table body 31. The base material 36 is placed on an insulating member 32 made of an insulating material, and the table body 31 is installed on the bottom wall 10a of the container body 10 via the base material 36 and the insulating member 32.

[0017] A power supply member 44 is connected to the underside of the base 36. A high-frequency power supply 41, which serves as a bias power supply, is connected to the power supply member 44 via a matching box 40. The high-frequency power supply 41 supplies high-frequency power for bias, for example, high-frequency power having a frequency of 3.2 MHz, to the stage body 31. This generates an RF bias, which can attract ions in the plasma generated in the processing space S1 to the substrate G. In this way, the stage 30 forms a bias electrode that generates the RF bias.

[0018] 2, a step is formed by the base body 31, the outer periphery of the base material 36, and the upper part of the insulating member 32, and a rectangular focus ring 37 is formed on the step. The focus ring 37 is made of ceramics such as alumina. When the substrate G is placed on the upper surface of the base body 31, the edge of the upper surface of the focus ring 36 facing the mounting table is covered by the outer periphery of the substrate G.

[0019] The base material 36 is provided with a temperature control medium flow path 47a that snakes around to cover the entire surface. Both ends of the temperature control medium flow path 47a are connected to a feed pipe 47b, through which the temperature control medium is supplied to the temperature control medium flow path 47a, and a return pipe 47c, through which the temperature control medium that has been heated by flowing through the temperature control medium flow path 47a is discharged. As shown in FIG. 2, the feed pipe 47b and the return pipe 47c are connected to a feed flow path 51 and a return flow path 52, respectively, which are connected to a chiller 50. The chiller 50 includes a main body that controls the temperature and discharge flow rate of the temperature control medium, and a pump that pumps the temperature control medium (neither is shown). A refrigerant is used as the temperature control medium, and examples of such refrigerants include Galden (registered trademark) and Fluorinert (registered trademark). The illustrated temperature control method involves circulating a temperature control medium through the substrate 36. However, the substrate 36 may incorporate a heater or the like, and temperature control may be performed using the heater, or temperature control may be performed using both a temperature control medium and a heater. Furthermore, instead of using a heater, temperature control may be performed by circulating a high-temperature temperature control medium. The heater, which is a resistive element, is made of tungsten, molybdenum, or a compound of one of these metals with alumina, titanium, or the like. In addition, while the illustrated example shows the temperature control medium flow path 47a formed in the substrate 36, the base body 31 may also have a temperature control medium flow path, for example.

[0020] The base body 31 includes a lower sprayed film 33 made of a dielectric material, e.g., a ceramic such as alumina, and an upper sprayed film 34 disposed on the lower sprayed film 33. The upper sprayed film 34 is formed by a thermal spraying method in which a ceramic such as alumina or a metal-ceramic composite is thermally sprayed. The upper surface of the upper sprayed film 34 serves as a substrate mounting surface 35 on which a substrate G is mounted. The substrate mounting surface 35 includes a roughened portion 35a having a rough surface with a surface roughness Ra of 1 μm to 6 μm, for example, and a smooth portion 35b surrounding the roughened portion 35a and having a surface roughness Ra of less than 2 μm. That is, the substrate mounting surface 35 is composed of the roughened portion 35a as a central portion (hereinafter also referred to as the central portion) and the smooth portion 35b as a peripheral portion (hereinafter also referred to as the peripheral portion).

[0021] The roughened portion 35a has minute projections and recesses, and the projections contact the substrate G at multiple points, thereby supporting the substrate G without scratching the backside of the substrate. Furthermore, even if etching products adhere to the roughened portion 35a, the etching products can be trapped in the recesses on the surface. When the substrate G is placed on the mounting table 30, the backside of the peripheral edge of the substrate G adheres closely to the surface of the smooth portion 35b, allowing the substrate G to be stably placed on the mounting table 30. This configuration makes it possible to form an enclosed space between the substrate G and the roughened portion 35a of the upper-layer sprayed film 34. In particular, when a heat transfer gas is supplied to the backside of the substrate G to control the temperature, the heat transfer gas can be confined to the backside of the substrate G, thereby improving heat transfer efficiency.

[0022] Surface roughness Ra refers to the arithmetic mean roughness as specified in JIS B0601-1994, and is calculated by determining a reference length from the roughness curve in the direction of the mean line, adding up the absolute values ​​of the deviations from the mean line to the roughness curve measured within this reference length, and expressing the average value in micrometers (μm).

[0023] The table main body 31 is also provided with an electrode layer 31a that constitutes an electrostatic chuck that attracts and holds the substrate G. A DC power supply 46 is connected to the electrode layer 31a via a power supply line 45. A Coulomb force is generated by applying a DC voltage from the DC power supply 46 to the electrode layer 31a, and the substrate G is held in a state where it is placed on the table main body 31 by this Coulomb force.

[0024] Further, exhaust ports 13 are formed in the bottom wall 10a of the container body 10. A plurality of exhaust ports 13 are provided on each side of the mounting table 30, which has a rectangular shape in a plan view, along the side. As shown in FIG. 2, an exhaust unit 60 having a vacuum pump or the like is connected to the exhaust ports 13. The processing space S1 is depressurized by the exhaust unit 60. The exhaust unit 60 may be provided for each of the plurality of exhaust ports 13, or may be provided in common to the plurality of exhaust ports 13.

[0025] A metal frame 14, which is a rectangular frame made of a metal material such as aluminum, is provided on the upper surface of the side wall of the vessel body 10. A seal member 15 for keeping the processing space S1 airtight is provided between the vessel body 10 and the metal frame 14. The vessel body 10, the metal frame 14, and the metal window 20 together form a processing vessel in which a mounting table 30 is provided.

[0026] The metal window 20 is divided into a plurality of partial windows 21, which are arranged inside the metal frame 14, and form the metal window 20 having a rectangular shape as a whole.

[0027] Each partial window 21 functions as a shower head that supplies processing gas to the processing space S1. For example, each partial window 21 is formed with a number of gas discharge holes 21a that discharge processing gas downward and a diffusion chamber 21b that diffuses the processing gas, and the gas discharge holes 21a and the diffusion chamber 21b are in communication with each other.

[0028] The diffusion chamber 21b of each partial window 21 is connected to a process gas supply unit 71 via a gas supply pipe 70. The process gas supply unit 71 includes a flow rate adjustment valve (not shown), an on-off valve (not shown), and the like, and supplies process gases required for film formation, etching, ashing, and the like to the diffusion chamber 21b. For convenience of illustration, FIG. 2 shows a state in which the process gas supply unit 71 is connected to one partial window 21, but in reality, the process gas supply unit 71 is connected to the diffusion chamber 21b of each partial window 21.

[0029] Furthermore, the partial window 21 is electrically insulated from the metal frame 14 by an insulating member 22, and adjacent partial windows 21 are also electrically insulated from each other by the insulating member 22. In order to protect the insulating member 22, an insulating member cover 23 is provided on the insulating member 22 to cover the surface of the insulating member 22 on the processing space S1 side.

[0030] Furthermore, a top plate portion 80 is disposed above the metal window 20. The top plate portion 80 is supported by a side wall portion 81 provided on the metal frame 14. The partial window 21 constituting the metal window 20 is suspended from the top panel portion 80 via a suspension member (not shown).

[0031] The space surrounded by the metal window 20, the side wall portion 81 and the top plate portion 80 constitutes an antenna chamber S2, and a high frequency antenna 90 is disposed inside the antenna chamber S2 so as to face the partial window 21.

[0032] The high-frequency antenna 90 is disposed at a distance from the partial window 21 via a spacer (not shown) made of, for example, an insulating material. A plurality of high-frequency antennas 90 are formed concentrically, for example in a spiral shape, so as to go around the circumferential direction of the rectangular metal window 20 along the surface corresponding to each partial window 21, thereby constituting a polycyclic antenna.

[0033] A high-frequency power supply 43 is connected to each high-frequency antenna 90 via a matching box 42. High-frequency power of, for example, 13.56 MHz is supplied to each high-frequency antenna 90 from the high-frequency power supply 43 via the matching box 42. As a result, during plasma processing, eddy currents are induced on the surface of each partial window 21, and these eddy currents form an induced electric field inside the processing space S1. The processing gas discharged from the gas discharge holes 21a is converted into plasma inside the processing space S1 by the induced electric field.

[0034] The plasma processing apparatus 1 is further provided with a control unit U. The control unit U is, for example, a computer equipped with a CPU, memory, etc., and has a program storage unit (not shown). The program storage unit stores a program for controlling the processing of the substrate G in the plasma processing apparatus 1. The above-mentioned program may be recorded on a computer-readable storage medium and installed into the control unit U from the storage medium. Part or all of the program may be realized by dedicated hardware (circuit board). The above-mentioned storage medium may be temporary or non-temporary.

[0035] <Substrate processing> Next, a description will be given of the substrate processing in the plasma processing apparatus 1. The following substrate processing is performed under the control of the control unit U. First, the gate valve 12 is opened, and the substrate G is loaded into the processing space S1 through the loading / unloading port 11 and placed on the mounting table 30. Thereafter, the gate valve 12 is closed.

[0036] Next, the processing gas is supplied into the processing space S1 from the processing gas supply unit 71 through the diffusion chambers 21b of each partial window 21. The processing space S1 is then evacuated by the exhaust unit 60, and the pressure inside the processing space S1 is adjusted to a desired level.

[0037] Next, high-frequency power is supplied from the high-frequency power supply 43 to the high-frequency antenna 90, which generates a uniform induction electric field in the processing space S1 through the metal window 20. As a result, the processing gas in the processing space S1 is converted into plasma by the induction electric field, generating high-density inductively coupled plasma. Then, ions in the plasma are attracted to the substrate G by the bias high-frequency power supplied from the high-frequency power supply 41 to the table body 31 of the mounting table 30, and plasma processing is performed on the substrate G.

[0038] After the plasma processing is completed, the power supply from the high frequency power sources 41 and 43 and the processing gas supply from the processing gas supply unit 71 are stopped, and the substrate G is unloaded in the reverse order to that of the loading. This completes the series of substrate processing steps.

[0039] <Method for polishing the substrate table> Next, a method for polishing the mounting table 30 will be described with reference to the drawings. FIG. 4 is an explanatory diagram of a method for polishing the mounting table (substrate mounting surface) according to this embodiment. First, as shown in FIG. 4(a), a structure A1 is prepared, which includes a lower-layer sprayed film 33, an electrode layer 31a, and an upper-layer sprayed film 34 formed on the upper surface of the lower-layer sprayed film 33 by thermal spraying. Then, to prevent the lower-layer sprayed film 33, the electrode layer 31a, and the upper-layer sprayed film 34 from being soaked in a grinding fluid in the next process, an impregnation process with an impregnation agent is performed. The impregnation agent may be a first impregnation agent with a low fill rate, such as fluororesin, silicone, or silicate, or a second impregnation agent with a high fill rate, such as acrylic, epoxy, or urethane.

[0040] 4(b), a grinding process as a planarization process is performed on the entire substrate mounting surface 35 using, for example, a grinding device (not shown) having a surface grinder 100. This makes the entire substrate mounting surface 35 uniformly smooth, and the surface roughness Ra of the top surface of the upper-layer sprayed film 34 is made less than 2 μm.

[0041] Next, as shown in FIG. 4(c), while the peripheral portion 35b of the substrate mounting surface 35 is protected by the mask 103, the central portion 35a is roughened. The roughening process is performed, for example, as a blasting process using a blasting device 105. In this blasting process, the upper sprayed film 34 in the central portion 35a may be dug out. The amount of dug out of the upper sprayed film by this dug out process is, for example, 30 to 50 μm. By this roughening process, only the central portion 35a of the substrate mounting surface 35 has a surface roughness Ra of 1 μm or more and 6 μm or less. Examples of blasting materials used in the blasting process include alumina, silicon carbide, and zirconia.

[0042] Through the above steps, the central portion 35a of the substrate mounting surface 35 is configured as a roughened portion 35a having a predetermined surface roughness, and the peripheral portion 35b protected by the mask 103 is configured as a smooth portion 35b that is flatter than the roughened portion 35a.

[0043] <Effects of the disclosed technology> According to the polishing method of this embodiment, the substrate mounting surface 35 has a roughened portion 35a with a predetermined surface roughness and a smooth portion 35b around its periphery. Because no machining using a processing tool is used during polishing, there is no risk of the processing tool tilting due to the cutting load during processing, resulting in the formation of steps on the surface, a phenomenon known as processing mismatch. This means that it is possible to suppress the occurrence of etching spots due to processing mismatch.

[0044] Furthermore, when the substrate G is placed on the substrate placement surface 35, the substrate G is in close contact with the smooth portion 35b, and the convex portions are formed on the roughened portion 35a, so that an enclosed space is formed between the substrate G and the roughened portion 35a of the upper-layer sprayed film 34. As a result, when a heat transfer gas is supplied to the back surface of the substrate G to control the temperature, the heat transfer gas can be confined to the back surface side of the substrate G, thereby improving heat transfer efficiency.

[0045] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims. Other embodiments of the present disclosure will be described below with reference to the drawings, etc. In the following other embodiments, components having the same functional configuration as those in the above-described embodiments are illustrated with the same reference numerals, and their description will be omitted.

[0046] <First Alternative Embodiment of the Present Disclosure> Next, a first alternative embodiment of the present disclosure will be described with reference to FIG. 5. FIG. 5 is an explanatory diagram of a method for polishing a mounting table (substrate mounting surface) according to the first alternative embodiment. First, as shown in FIG. 5(a), a structure A2 is prepared, which includes a lower-layer sprayed film 33, an electrode layer 31a, and an upper-layer sprayed film 34 formed on the upper surface of the structure by thermal spraying. Then, the lower-layer sprayed film 33, the electrode layer 31a, and the upper-layer sprayed film 34 are impregnated with an impregnating agent to prevent penetration of a grinding fluid in the next process and to improve interfacial adhesion with the bank sprayed film 120, which will be described later. The impregnating agent used here is a first impregnating agent with a low filling rate, such as a fluororesin, silicone, or silicate.

[0047] Then, as shown in FIG. 5(b), a grinding process as a planarization process is performed on the entire substrate mounting surface 35 using, for example, a grinding device (not shown) having a surface grinder 100. Next, as shown in FIG. 5(c), while the central portion 35a is protected by a mask 110, ceramics such as alumina or a metal-ceramic composite is sprayed onto the peripheral portion 35b to form a bank sprayed film 120. The entire surface, including this bank sprayed film 120, is impregnated with an impregnating agent to prevent penetration of the grinding fluid in the next process and to prevent peeling of the bank sprayed film 120. The impregnating agent used here is a second impregnating agent with a high filling rate, such as acrylic, epoxy, or urethane.

[0048] Then, as shown in FIG. 5(d), a grinding machine (not shown) having a surface grinder 100 is used to grind the surface of the bank sprayed film 120 as a planarization process. Next, as shown in FIG. 5(e), the planarized bank sprayed film 120 is protected by a mask 125, and the central portion 35a is roughened. The roughening process is performed using, for example, a thermal spraying device 130 by a thermal spraying method known as in-plane roughening thermal spraying. After the roughening process, an impregnation process is performed with an impregnation agent to seal the pores and ensure corrosion resistance and voltage resistance. The impregnation agent used here is a second impregnation agent with a high filling rate, such as acrylic, epoxy, or urethane.

[0049] Through the above steps, the central portion 35a of the substrate mounting surface 35 is configured as a roughened portion 35a having a predetermined surface roughness, and the peripheral portion 35b that was protected by the mask 125 after the planarization process is configured as a smooth portion 35b that is flatter than the roughened portion 35a.

[0050] According to the polishing method of the first alternative embodiment, in the early stage of polishing shown in Figures 5(a) and 5(b), an impregnation process is performed using a first impregnation agent with a low fill rate, such as fluororesin, silicone, or silicate, to improve the interfacial adhesion between the upper sprayed film 34 and the bank sprayed film 120. In addition, in the later stage of polishing shown in Figures 5(c) to 5(e), an impregnation process is performed using a second impregnation agent with a high fill rate, such as acrylic, epoxy, or urethane, to improve the corrosion resistance and voltage resistance of the substrate mounting table 30. This achieves the effects described in the above embodiment, as well as a mounting table 30 with a substrate mounting surface that is more excellent in corrosion resistance and voltage resistance.

[0051] <Second Alternative Embodiment of the Present Disclosure> Next, a second embodiment of the present disclosure will be described with reference to FIG. 6. FIG. 6 is an explanatory diagram of a method for polishing a mounting table (substrate mounting surface) according to the second embodiment. First, as shown in FIG. 6(a), a structure A3 is prepared, which includes a lower-layer sprayed film 33, an electrode layer 31a, and an upper-layer sprayed film 34 formed on the upper surface of the lower-layer sprayed film 33 by thermal spraying. Then, the lower-layer sprayed film 33, the electrode layer 31a, and the upper-layer sprayed film 34 are impregnated with an impregnating agent to prevent the penetration of grinding fluid in the next process. The impregnating agent used here is a second impregnating agent with a high filling rate, such as acrylic, epoxy, or urethane.

[0052] 6(b), a grinding process as a flattening process is performed on the entire substrate mounting surface 35 using, for example, a grinding device (not shown) having a surface grinder 100. Next, as shown in FIG. 6(c), a blasting process is performed on the central portion 35a of the substrate mounting surface 35 using a blasting device 105, thereby performing a process of digging out the upper sprayed film 34 in the central portion 35a (pool digging process).

[0053] Then, as shown in FIG. 6(d), while the peripheral portion 35b is protected by a mask 135, the central portion 35a is roughened. The roughening treatment is performed using, for example, a thermal spraying method called in-plane roughening thermal spraying using a thermal spraying device 130. After the roughening treatment, an impregnation treatment is performed with an impregnation agent to seal any pores that have formed and ensure corrosion resistance and voltage resistance. The impregnation agent used here is a second impregnation agent with a high filling rate, such as acrylic, epoxy, or urethane.

[0054] Through the above steps, the central portion 35a of the substrate mounting surface 35 is configured as a roughened portion 35a having a predetermined surface roughness, and the peripheral portion 35b is configured as a smooth portion 35b that is flatter than the roughened portion 35a.

[0055] According to the polishing method of the second alternative embodiment, in addition to the effects described in the above embodiment, the mounting table 30 having a substrate mounting surface with better corrosion resistance and voltage resistance performance is realized. [Explanation of symbols]

[0056] 1. Plasma processing equipment 30 Board mounting table 31a Electrode layer 33 Lower layer spray coating 34 Upper layer spray coating 35 Substrate mounting surface 35a Center part (roughened part) 35b Peripheral part (smooth part) 36 Base material 103 Mask G board

Claims

1. 1. A polishing method for a substrate table including a base material and a thermal sprayed film provided on the base material, comprising: forming a bank sprayed film on the peripheral edge of the sprayed film; a step of subjecting the bank sprayed film to an impregnation treatment with an impregnation agent; a step of performing a planarization treatment by grinding the bank sprayed film that has been impregnated; a step of masking the planarized bank sprayed film and roughening the central portion of the sprayed film excluding the peripheral portion.

2. 2. The method for polishing a substrate table according to claim 1, wherein the thermal sprayed film is formed by performing a planarization process by grinding after an impregnation process with a first impregnation agent.

3. 3. The method for polishing a substrate table according to claim 2, wherein the impregnating agent for the bank thermal sprayed film is a second impregnating agent, and the first impregnating agent and the second impregnating agent have different filling rates.

4. 4. The method for polishing a substrate table according to claim 3, wherein a filling rate of the second impregnating agent is higher than a filling rate of the first impregnating agent.

5. A substrate mounting table including a base material and a thermal sprayed film provided on the base material, a central portion of the thermal sprayed film in which first pores are formed; a bank portion which is a peripheral portion formed on the periphery of the central portion and in which second pores are formed, The first pores in the central portion contain a first impregnating agent, and the second pores in the bank portion contain a second impregnating agent different from the first impregnating agent.

6. 6. The substrate stage according to claim 5, wherein the first impregnating agent is any one of a fluororesin, a silicone, and a silicate.

7. The substrate support member according to claim 5 , wherein the second impregnating agent is any one of acrylic, epoxy, and urethane.

8. 6. The substrate supporting member according to claim 5, wherein the surface roughness Ra of the central portion is 1 [mu]m or more and 6 [mu]m or less.

9. 6. The substrate mounting table according to claim 5, wherein the bank portion has a surface roughness Ra of less than 2 [mu]m.

10. 6. The substrate mounting table according to claim 5, wherein the depth of the recess from the bank portion to the central portion is 30 μm to 50 μm.

11. 6. The substrate support according to claim 5, wherein the thermally sprayed film is made of ceramic or a ceramic-metal composite.

12. 12. The substrate support according to claim 11, wherein the ceramic is alumina.

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