Method for polishing substrate placement table and substrate placement 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 polishing method for a substrate table and a substrate table. [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. With such a substrate mounting table, the occurrence of etching spots can be effectively suppressed without damaging the substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-119326 A Summary of the Invention [Problem to be solved by the invention]

[0004] The technology disclosed herein suppresses the occurrence of steps associated with processing mismatches that occur when a processing tool tilts due to the effect of 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 substrate and a sprayed film provided on the substrate, the method comprising the steps of forming a bank sprayed film on a peripheral portion of the sprayed film, subjecting the bank sprayed film to an impregnation treatment with an impregnation agent, subjecting the impregnated bank sprayed film to a planarization treatment by grinding, and masking the planarized bank sprayed film, and subjecting a central portion of the sprayed film excluding the peripheral portion to a roughening treatment. Effect of the Invention

[0006] According to the present disclosure, the occurrence of steps due to processing mismatches caused by tilting of a processing tool due to the effect of cutting load during processing of a substrate table can be suppressed, and the occurrence of etching spots can be suppressed. [Brief description of the drawings]

[0007] [Figure 1] FIG. 11 is an explanatory diagram regarding processing mismatch. [Diagram 2] 1 is a vertical cross-sectional view showing an outline of a configuration of a plasma processing apparatus according to an embodiment of the present invention. [Diagram 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 diagrams of a polishing method for a mounting table according to the present embodiment. [Diagram 5] 5A to 5C are explanatory views of a polishing method for a mounting table according to a first alternative embodiment. [Figure 6] 11A to 11C are explanatory views of a polishing method for a mounting table according to a second alternative embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] In the manufacturing process of plasma panel displays (FPDs), plasma etching is performed on a substrate, which is a target object. In the plasma etching process, for example, in a processing vessel in which a pair of parallel plate electrodes (upper electrode and lower electrode) are arranged, a substrate is placed on a substrate placement stage that functions as a lower electrode, and 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 forms plasma of a processing gas, and the material film on the substrate is etched by the plasma. When the plasma etching process is repeatedly performed, etching products are generated, which may adhere to and accumulate on the surface of the substrate placement stage. In this case, due to the presence of the deposits, a region where the deposits are present between the back surface of the substrate and the surface of the substrate placement stage is generated on the surface of the substrate placement stage, and a difference occurs in thermal conductivity and electrical conductivity between the region where the deposits are not present. As a result, a portion with a high etching rate and a portion with a low etching rate are formed within the surface of the substrate, resulting in unevenness called etching spots.

[0009] In recent years, in FPD manufacturing equipment, the production of flexible panels has increased, 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) into a more suitable shape (for example, flat in the macroscopic sense and rough in the microscopic sense). 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 blasted to form a roughened part, and the surrounding area is made smooth.

[0010] In the prior art, machining using a processing tool is known as a method for processing a sprayed film on the surface of a substrate mounting table. In machining, the processing tool tilts due to the effect of cutting load during processing, and a step is formed on the surface, which is called processing mismatch, is a concern. 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 cutting resistance, which causes a fine step 203 to be formed on the surface of the substrate mounting table 202. Then, as shown in FIG. 1(b), if an etching product 204 adheres to the surface of the substrate mounting table 202 with the step 203 formed on it, a temperature difference (temperature unevenness) occurs due to the difference in heat transfer depending on the position of the substrate caused by the step (see the large and small arrows in the figure), and etching spots may occur.

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

[0012] Hereinafter, the configuration of a plasma processing apparatus including a substrate mounting table according to the present embodiment will be described with reference to the drawings. In this specification, elements having substantially the same functional configurations are denoted by the same reference numerals, and duplicated descriptions will be omitted.

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

[0014] 2 performs substrate processing using plasma of a processing gas, i.e., plasma processing, 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 processing, 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 bottom and a rectangular cylindrical shape. The container body 10 is made of a conductive material, for example, aluminum, and is electrically grounded. Since corrosive gas is often used in plasma processing, the inner wall surface of the container body 10 is subjected to a corrosion-resistant coating treatment such as anodization treatment in order to improve corrosion resistance. In addition, an opening is formed on the upper surface of the container body 10. This opening is airtightly closed by a rectangular metal window 20 provided insulated from the container body 10, specifically, airtightly closed by the metal window 20 and a metal frame 14 described later. The space surrounded by the container body 10 and the metal window 20 becomes 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 becomes an antenna chamber S2 in which a high-frequency antenna (plasma antenna) 90 described later is arranged. A load / unload port 11 for loading / unloading the substrate G into / from the processing space S1 and a gate valve 12 for opening / closing the load / unload port 11 are provided on a side wall of the container body 10 on the negative side in the X direction (the left side in FIG. 2).

[0016] A substrate mounting table (hereinafter, also simply referred to as a mounting table) 30 on which a substrate G is mounted 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 a mounting surface for the substrate G. A base material 36 made of a conductive material, for example, aluminum or an aluminum alloy, is provided on the lower part of 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 lower surface of the base material 36. A high frequency power supply 41, which is 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 table body 31. This generates an RF bias, and ions in the plasma generated in the processing space S1 can be attracted to the substrate G. In this manner, the mounting table 30 forms a bias electrode that generates an RF bias.

[0018] 2, a step is formed by the table 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 table body 31, the end of the upper surface of the focus ring 36 on the side of 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 passage 47a that is serpentine so as to cover the entire area of ​​the plane. A feed pipe 47b that supplies the temperature control medium to the temperature control medium flow passage 47a and a return pipe 47c that discharges the temperature control medium that has been heated by flowing through the temperature control medium flow passage 47a are connected to both ends of the temperature control medium flow passage 47a. As shown in FIG. 2, a feed pipe 51 and a return pipe 52 are connected to the feed pipe 47b and the return pipe 47c, respectively, and the feed pipe 51 and the return pipe 52 are connected to a chiller 50. The chiller 50 has a main body that controls the temperature and discharge flow rate of the temperature control medium, and a pump that pressure-feeds the temperature control medium (neither is shown). A refrigerant is used as the temperature control medium, and Galden (registered trademark) or Fluorinert (registered trademark) is used as the refrigerant. The illustrated temperature control form is a form in which a temperature control medium is circulated through the base material 36, but the base material 36 may have a built-in heater or the like and the temperature may be controlled by the heater, or the temperature may be controlled by both the temperature control medium and the heater. Also, instead of a heater, a high-temperature temperature control medium may be circulated to control the temperature with heating. The heater, which is a resistor, is made of tungsten or molybdenum, or a compound of any one of these metals with alumina, titanium, or the like. In addition, in the illustrated example, the temperature control medium flow path 47a is formed in the base material 36, but for example, the table main body 31 may have a temperature control medium flow path.

[0020] The table body 31 includes a lower sprayed film 33 formed of a dielectric material, for example, ceramics such as alumina, and an upper sprayed film 34 provided on the lower sprayed film 33. The upper sprayed film 34 is formed by a spraying method in which a ceramic such as alumina or a metal-ceramic composite is 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 has a roughened portion 35a having a rough surface with a surface roughness Ra of 1 μm or more and 6 μm or less, 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 (hereinafter also referred to as the central portion) as a central portion, and the smooth portion 35b (hereinafter also referred to as the peripheral portion) as a peripheral portion.

[0021] The roughened portion 35a has fine projections and recesses, and the projections contact the substrate G at multiple points, thereby supporting the substrate G without scratching the rear surface 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 rear surface of the peripheral portion of the substrate G is in close contact with the surface of the smooth portion 35b, so that the substrate G can be stably placed on the mounting table 30. With this configuration, it is possible to form an enclosed space between the substrate G and the roughened portion 35a of the upper sprayed film 34, and in particular, when a heat transfer gas is supplied to the rear surface of the substrate G to control the temperature, the heat transfer gas can be confined to the rear surface of the substrate G, improving the heat transfer efficiency.

[0022] Surface roughness Ra means 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 body 31 is provided with an electrode layer 31a constituting 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 in which it is placed on the table body 31 by this Coulomb force.

[0024] Further, an exhaust port 13 is formed in the bottom wall 10a of the container body 10. A plurality of exhaust ports 13 are provided along each side of the mounting table 30, which has a rectangular shape in a plan view. As shown in FIG. 2, an exhaust unit 60 having a vacuum pump or the like is connected to the exhaust port 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 side of the side wall of the container body 10. A seal member 15 for keeping the processing space S1 airtight is provided between the container body 10 and the metal frame 14. The container body 10, the metal frame 14, and the metal window 20 together form a processing container 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 to form the metal window 20 having a rectangular shape as a whole.

[0027] Each of the partial windows 21 functions as a shower head that supplies a processing gas to the processing space S1. For example, each of the partial windows 21 is formed with a number of gas discharge holes 21a that discharge the 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 control valve (not shown) and an on-off valve (not shown) and supplies process gases required for film formation, etching, ashing, and other processes 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] Moreover, 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, which covers the surface of the insulating member 22 facing the processing space S1.

[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 .

[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 surfaces corresponding to the respective partial windows 21, thereby constituting a multi-ring antenna.

[0033] A high frequency power supply 43 is connected to each high frequency antenna 90 via a matching box 42. A 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 an induced electric field is formed inside the processing space S1 by the eddy currents. The processing gas discharged from the gas discharge hole 21a is turned into plasma inside the processing space S1 by the induced electric field.

[0034] Furthermore, the plasma processing apparatus 1 is provided with a control unit U. The control unit U is, for example, a computer equipped with a CPU, a 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 in a computer-readable storage medium and installed from the storage medium into the control unit U. A part or all of the program may be realized by dedicated hardware (circuit board). Moreover, 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 substrate processing described below 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 load / unload port 11 and placed on the mounting table 30. Thereafter, the gate valve 12 is closed.

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

[0037] Next, high frequency power is supplied from the high frequency power source 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, and high density inductively coupled plasma is generated. Then, ions in the plasma are attracted to the substrate G by the bias high frequency power supplied from the high frequency power source 41 to the table body 31 of the mounting table 30, and the substrate G is subjected to plasma processing.

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

[0039] <Method of 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 is made up of a lower-layer sprayed film 33, an electrode layer 31a, and an upper-layer sprayed film 34 formed as an upper layer on the upper surface of the lower-layer sprayed film 33 by spraying. Then, in order to prevent the lower-layer sprayed film 33, the electrode layer 31a, and the upper-layer sprayed film 34 from being soaked with a grinding fluid in the next process, an impregnation process is performed with an impregnation agent. As the impregnation agent, a first impregnation agent having a low filling rate such as fluororesin, silicone, or silicate may be used, or a second impregnation agent having a high filling rate such as acrylic, epoxy, or urethane may be used.

[0040] 4(b), for example, a grinding device (not shown) having a surface grinder 100 is used to perform grinding as a flattening process on the entire substrate mounting surface 35. This makes the entire substrate mounting surface 35 uniformly smooth, and the surface roughness Ra of the upper surface of the upper 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 is performed, for example, as a blasting process using a blasting device 105. In this blasting process, a process of digging into the upper sprayed film 34 in the central portion 35a may be performed. The amount of digging into the upper sprayed film by this digging 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 having a predetermined surface roughness and a smooth portion 35b at its periphery. Since no machining process 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, i.e., so-called processing mismatch. In other words, 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 mounting 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 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, improving the heat transfer efficiency.

[0045] 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. Other embodiments of the present disclosure will be described below with reference to the drawings. In the following other embodiments, components having the same functional configuration as those in the above-described embodiment 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 is made up of a lower layer sprayed film 33, an electrode layer 31a, and an upper layer sprayed film 34 formed as an upper layer on the upper surface of the lower layer sprayed film 33 by 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 a grinding fluid in the next process and to improve the interface adhesion with the bank sprayed film 120 described later. The impregnating agent used here is a first impregnating agent with a low filling rate, such as fluororesin, silicone, silicate, etc.

[0047] Then, as shown in Fig. 5(b), a grinding machine (not shown) having a surface grinder 100 is used to grind the entire substrate mounting surface 35 as a flattening process. Then, 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. To prevent the penetration of the grinding fluid in the next process and to prevent the bank sprayed film 120 from peeling off, the entire surface including the bank sprayed film 120 is impregnated with an impregnating agent. 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 perform grinding as a flattening process on the surface of the bank sprayed film 120. Next, as shown in FIG. 5(e), a roughening process is performed on the center portion 35a while the flattened bank sprayed film 120 is protected by a mask 125. The roughening process is performed, for example, by a thermal spraying method called in-plane roughening thermal spraying using a thermal spraying machine 130. After the roughening process, an impregnation process is performed with an impregnation agent to seal the formed pores and ensure corrosion resistance and voltage resistance performance. 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 (b), an impregnation process is performed using a first impregnation agent with a low filling rate, such as fluororesin, silicone, silicate, etc., in order 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 (e), an impregnation process is performed using a second impregnation agent with a high filling rate, such as acrylic, epoxy, urethane, etc., in order to improve the corrosion resistance and voltage resistance performance of the substrate mounting table 30. This realizes a mounting table 30 having a substrate mounting surface with better corrosion resistance and voltage resistance performance in addition to the effects described in the above embodiment.

[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 is composed of a lower layer sprayed film 33, an electrode layer 31a, and an upper layer sprayed film 34 formed as an upper layer on the upper surface of the lower layer sprayed film 33 by 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 the 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), for example, a grinding device (not shown) having a surface grinder 100 is used to perform grinding as a flattening process on the entire substrate mounting surface 35. Then, 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 to perform a process of digging out the upper sprayed film 34 at 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 center portion 35a is roughened. The roughening is performed by a thermal spraying method called in-plane roughening thermal spraying, for example, using a thermal spraying device 130. After the roughening, an impregnation process is performed with an impregnation agent to seal the pores 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 which 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, it is possible to realize the mounting table 30 having a substrate mounting surface with superior corrosion resistance and voltage resistance. [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 Periphery (smooth part) 36 Base material 103 Mask G board

Claims

1. A method for polishing a substrate support including a substrate and a thermal sprayed film provided on the substrate, 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; 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 a central portion of the sprayed film excluding a peripheral portion thereof.

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

3. 3. The method for polishing a substrate supporting member according to claim 2, wherein the impregnating agent for the bank 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 supporting 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 support including a substrate and a thermal sprayed film provided on the substrate, a central portion of the thermal sprayed film, the central portion having first pores formed therein; a bank portion which is a peripheral portion formed on the peripheral edge of the central portion and in which a second pore is 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. The substrate supporting member according to claim 5 , wherein the first impregnating agent is any one of a fluororesin, a silicone, and a silicate.

7. The substrate supporting 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 supporting member according to claim 5, wherein the bank portion has a surface roughness Ra of less than 2 [mu]m.

10. 6. The substrate supporting member according to claim 5, wherein the recessed depth from the bank portion to the central portion is 30 μm to 50 μm.

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

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

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