JP7619862B2 - Method for polishing substrate placement table and substrate processing apparatus - Google Patents

Description

This disclosure relates to a polishing method for a substrate placement table and a substrate processing apparatus.

Patent Document 1 discloses a substrate mounting table having a roughened portion on the 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.

JP 2011-119326 A

The technology disclosed herein reduces the occurrence of steps due to processing mismatches that occur when the processing tool tilts due to the effect of cutting load during processing of the substrate mounting table, thereby suppressing the occurrence of etching spots.

One aspect of the present disclosure is a polishing method for polishing a substrate mounting surface, which is an upper surface of a substrate mounting table having a base, a lower layer sprayed film provided on the base, and an upper layer sprayed film provided on an electrode layer, the method comprising the steps of: performing an impregnation treatment on the sprayed film with an impregnation agent; performing a planarization treatment on the substrate mounting surface by grinding; and performing a surface roughening treatment on a central portion of the substrate mounting surface excluding the peripheral portion , wherein the impregnation treatment is performed on the sprayed film by selecting at least one of a first impregnation agent and a second impregnation agent having a filling rate different from that of the first impregnation agent, the filling rate of the second impregnation agent being higher than the filling rate of the first impregnation agent, and the planarization treatment is performed on a bank sprayed film formed only on the peripheral portion of the substrate mounting surface after the impregnation treatment with the second impregnation agent has been performed .

According to the present disclosure, it is possible to suppress the occurrence of steps due to processing mismatches caused by tilting of the processing tool due to the effect of cutting load during processing of the substrate placement table, thereby suppressing the occurrence of etching spots.

FIG. 11 is an explanatory diagram regarding processing mismatch. 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. 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. 5A to 5C are explanatory diagrams of a polishing method for a mounting table according to the present embodiment. 10A to 10C are explanatory diagrams of a polishing method for a mounting table according to a first alternative embodiment. 11A to 11C are explanatory diagrams of a polishing method for a mounting table according to a second alternative embodiment.

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

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) into a more suitable shape (for example, flat on the macro scale and rough on the micro scale). 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 portion, leaving the surrounding area smooth.

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 a processing mismatch, is a concern. Figure 1 is an explanatory diagram of processing mismatch. As shown in Figure 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 Figure 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) will occur 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.

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

The configuration of a plasma processing apparatus equipped with 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 will be assigned the same reference numerals to avoid redundant description.

<Plasma Processing Apparatus>
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.

The plasma processing apparatus 1 in FIG. 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 processes, electronic devices such as light-emitting elements and driving circuits for the light-emitting elements are formed on the substrate G.

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, such as aluminum, and is electrically grounded. Since corrosive gases are often used in plasma processing, the inner wall surface of the container body 10 is subjected to a corrosion-resistant coating treatment such as anodizing 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 sealed by a rectangular metal window 20 that is insulated from the container body 10, specifically, 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 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 are provided on the side wall of the container body 10 on the negative side in the X direction (the left side in FIG. 2).

On the bottom wall 10a of the container body 10, a substrate mounting table (hereinafter also simply referred to as the mounting table) 30 on which the substrate G is mounted is provided so as to face the metal window 20. The mounting table 30 is formed, for example, in a rectangular shape in a plan view. 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 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.

A power supply member 44 is connected to the underside of the substrate 36. A high frequency power supply 41, which is a bias power supply, is connected to the power supply member 44 via a matching unit 40. The high frequency power supply 41 supplies high frequency power for bias, for example, high frequency power with 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 way, the mounting table 30 forms a bias electrode that generates an RF bias.

As shown in FIG. 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 table is covered by the outer periphery of the substrate G.

The substrate 36 is provided with a temperature control medium flow path 47a that is serpentine so as to cover the entire area of the plane. At both ends of the temperature control medium flow path 47a, 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 are connected. 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, and the feed flow path 51 and the return flow path 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 (both not shown). In addition, a refrigerant is used as the temperature control medium, and Galden (registered trademark) or Fluorinert (registered trademark) is used as the refrigerant. The illustrated example shows a temperature control form in which a temperature control medium is circulated through the substrate 36, but the substrate 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, temperature control involving heating may be performed by circulating a high-temperature temperature control medium. The heater, which is a resistor, is made of tungsten or molybdenum, or a compound of one of these metals with alumina, titanium, or the like. Also, in the illustrated example, the temperature control medium flow path 47a is formed in the substrate 36, but for example, the table body 31 may have a temperature control medium flow path.

The table body 31 includes a lower sprayed film 33 formed of a dielectric material, for example, a ceramic 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 is a substrate mounting surface 35 on which a substrate G is placed. 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.

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. 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.

The surface roughness Ra refers to the arithmetic mean roughness as defined in JIS B0601-1994, which 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).

The table body 31 is 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 in which it is placed on the table body 31 by this Coulomb force.

In addition, exhaust ports 13 are 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 is rectangular in plan view. 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 this 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.

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 container body 10. A seal member 15 is provided between the container body 10 and the metal frame 14 to keep the processing space S1 airtight. The container body 10, the metal frame 14, and the metal window 20 together form a processing container with a mounting table 30 provided inside.

The metal window 20 is divided into multiple partial windows 21, which are arranged inside the metal frame 14 to form a rectangular metal window 20 as a whole.

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 connected to each other.

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 is equipped with a flow rate control valve (not shown) and an on-off valve (not shown), and supplies the process gas 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.

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 facing the processing space S1.

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 plate portion 80 via a suspension member (not shown).

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

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. The high-frequency antenna 90 is formed concentrically, for example in a spiral shape, along the surface corresponding to each partial window 21 and going around the circumferential direction of the rectangular metal window 20, forming a multi-ring antenna.

A high-frequency power supply 43 is connected to each high-frequency antenna 90 via a matching device 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 device 42. As a result, eddy currents are induced on the surface of each partial window 21 during plasma processing, and these eddy currents form an induced electric field inside the processing space S1. The processing gas discharged from the gas discharge hole 21a is turned into plasma inside the processing space S1 by the induced electric field.

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 from the storage medium into the control unit U. A part or all of the program may be realized by dedicated hardware (circuit board). Furthermore, the above-mentioned storage medium may be temporary or non-temporary.

<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 carried 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.

Next, the processing gas is supplied from the processing gas supply unit 71 into the processing space S1 through the diffusion chamber 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 the desired pressure.

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, 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 source 41 to the table body 31 of the mounting table 30, and plasma processing is performed on the substrate G.

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.

<Method of polishing 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 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, 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, silicate, etc. may be used, or a second impregnation agent having a high filling rate such as acrylic, epoxy, urethane, etc. may be used.

Then, as shown in FIG. 4(b), a grinding machine (not shown) having, for example, 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 less than 2 μm.

Next, as shown in FIG. 4(c), while the peripheral portion 35b of the substrate mounting surface 35 is protected by the mask 103, a roughening process is performed on the central portion 35a. The roughening process 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. This roughening process makes the surface roughness Ra of only the central portion 35a of the substrate mounting surface 35 1 μm or more and 6 μm or less. Examples of blasting materials used in the blasting process include alumina, silicon carbide, and zirconia.

Through the above process, 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.

<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 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.

In addition, 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 a convex portion is 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 of the substrate G, improving the heat transfer efficiency.

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 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. In the following other embodiments, components having the same functional configuration as the above-described embodiment are illustrated with the same reference numerals, and their description will be omitted.

<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 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 in order to prevent the penetration of the 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.

As shown in FIG. 5(b), the entire substrate mounting surface 35 is ground as a flattening process using 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 the bank sprayed film 120 is impregnated with an impregnating agent to prevent the grinding fluid from seeping in during the next process and to prevent the bank sprayed film 120 from peeling off. The impregnating agent used here is a second impregnating agent with a high filling rate, such as acrylic, epoxy, or urethane.

As shown in FIG. 5(d), a grinding device (not shown) having a surface grinder 100 is used to grind the surface of the bank sprayed film 120 as a flattening process. Next, as shown in FIG. 5(e), the flattened bank sprayed film 120 is protected by a mask 125 and the central portion 35a is roughened. The roughening process is performed, for example, by a thermal spraying device 130 using a thermal spraying method called in-plane roughening thermal spraying. 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. The impregnation agent used here is a second impregnation agent with a high filling rate, such as acrylic, epoxy, or urethane.

By the above process, 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 125 after the planarization process is configured as a smooth portion 35b that is flatter than the roughened portion 35a.

According to the polishing method of the first alternative embodiment, in the early polishing steps 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, or silicate, to improve the interfacial adhesion between the upper sprayed film 34 and the bank sprayed film 120. In addition, in the later polishing steps 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, or urethane, to improve the corrosion resistance and voltage resistance of the substrate mounting table 30. This realizes a mounting table 30 with a substrate mounting surface that has superior corrosion resistance and voltage resistance in addition to the effects described in the above embodiment.

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 structure 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 having a high filling rate, such as acrylic, epoxy, or urethane.

As shown in FIG. 6(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. 6(c), a blasting machine 105 is used to blast the central portion 35a of the substrate mounting surface 35, thereby digging out the upper sprayed film 34 at the central portion 35a (pool digging process).

Then, as shown in FIG. 6(d), while the peripheral portion 35b is protected by the mask 135, the central portion 35a is roughened. The roughening is performed, for example, by a thermal spraying method called in-plane roughening thermal spraying using a thermal spraying device 130. After the roughening, an impregnation process is performed with an impregnation agent to seal the 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.

By the above process, 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.

The polishing method according to the second alternative embodiment achieves the effects described in the above embodiment, as well as a mounting table 30 equipped with a substrate mounting surface that is more corrosion-resistant and has better voltage resistance.

Reference Signs List 1 Plasma processing apparatus 30 Substrate mounting table 31a Electrode layer 33 Lower thermal sprayed film 34 Upper thermal sprayed film 35 Substrate mounting surface 35a Central portion (roughened portion)
35b peripheral portion (smooth portion)
36 Base material 103 Mask G Substrate

Claims (4)

A polishing method for polishing a substrate mounting surface, which is an upper surface of a substrate mounting table including a substrate, a lower layer sprayed film provided on the substrate, and an upper layer sprayed film provided on an electrode layer, comprising the steps of:
impregnating the thermal sprayed film with an impregnation agent;
a step of performing a planarization process on the substrate mounting surface by grinding;
a step of masking a peripheral portion of the substrate mounting surface and roughening a central portion of the substrate mounting surface excluding the peripheral portion ,
the impregnation treatment is performed on the thermal sprayed coating by selecting at least one of a first impregnation agent and a second impregnation agent having a filling rate different from that of the first impregnation agent;
the loading rate of the second impregnating agent is higher than the loading rate of the first impregnating agent;
The method for polishing a substrate mounting table , wherein the planarization treatment is performed on a bank sprayed film formed only on the peripheral portion of the substrate mounting surface after the impregnation treatment with the second impregnation agent has been performed . 2. The method for polishing a substrate supporting table according to claim 1, further comprising the step of: after planarizing the bank sprayed film, impregnating the entire surface including the bank sprayed film with the second impregnating agent. 2. The method for polishing a substrate supporting member according to claim 1, wherein the surface roughening treatment is performed by thermal spraying. A substrate processing apparatus including a substrate mounting table,
the substrate mounting table has a base material, a lower layer sprayed film provided on the base material, and an upper layer sprayed film provided on an electrode layer, and an upper surface of the substrate mounting table is configured as a substrate mounting surface;
impregnating the thermal sprayed film with an impregnation agent;
a step of performing a planarization process on the substrate mounting surface by grinding;
a step of masking a peripheral portion of the substrate mounting surface and performing a surface roughening treatment on a central portion of the substrate mounting surface excluding the peripheral portion, thereby polishing the substrate mounting surface;
the impregnation treatment is performed on the thermal sprayed coating by selecting at least one of a first impregnation agent and a second impregnation agent having a filling rate different from that of the first impregnation agent;
the loading rate of the second impregnating agent is higher than the loading rate of the first impregnating agent;
The substrate processing apparatus, wherein the planarization treatment is performed on a bank sprayed film formed only on the peripheral portion of the substrate mounting surface after the impregnation treatment with the second impregnation agent has been performed.

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