JP7630294B2 - Member for plasma processing apparatus, method for producing same, and plasma processing apparatus - Google Patents

Description

The present invention relates to a member for a plasma processing device, a manufacturing method thereof, and a plasma processing device.

Plasma processing equipment, such as plasma etching equipment and plasma CVD equipment used in semiconductor device manufacturing processes, is equipped with a pair of electrodes arranged vertically opposite each other in a vacuum chamber. Generally, the upper electrode has a vent hole for passing gas for generating plasma, and the lower electrode serves as a stand to which a substrate to be processed, such as a wafer, can be fixed. Gas for generating plasma is supplied from the vent hole in the upper electrode (also called the ceiling electrode plate) to the substrate to be processed fixed to the lower electrode, while a high-frequency voltage is applied between the upper and lower electrodes to generate plasma and perform processing such as etching on the substrate to be processed.

In the plasma processing apparatus configured as above, a cooling plate (also called a cooling plate) is arranged on the surface (back surface) of the upper electrode opposite the lower electrode, so that heat generated along with the plasma can be dissipated to the cooling plate via the upper electrode. In order to improve the thermal conductivity between the upper electrode and the cooling plate and ensure uniform heating of the electrodes, it has been considered to place a heat transfer material between the upper electrode and the cooling plate. For example, it has been considered to place a silicone resin containing alumina filler between the upper electrode and the cooling plate (Patent Document 1).

In addition, in order to suppress fluctuations in the etching conditions due to heat, it has been considered to place a heat transfer material (heat transfer sheet) with high thermal conductivity between a circular support ring (focus ring) that supports the peripheral portion of the workpiece and a stand (mounting table) on which the focus ring is placed (Patent Document 2). Patent Document 2 describes heat-resistant silicone rubber containing alumina particles as the heat transfer material.

Patent No. 5762798 JP 2012-9563 A

In order to ensure the thermal uniformity of the electrode plate for the plasma processing apparatus used as the upper electrode for a long period of time, it is important to efficiently transfer heat from within the plasma processing apparatus to the cooling plate via the electrode plate for the plasma processing apparatus for a long period of time. Therefore, it is preferable that the heat transfer material placed between the electrode plate for the plasma processing apparatus and the cooling plate is not easily deteriorated by heat, plasma, or by-product radicals (plasma in the broad sense) and has high heat transfer properties for a long period of time. In addition, in order to prevent contamination (contamination of the substrate to be processed) due to deterioration of the heat transfer material, it is preferable that the heat transfer material has high plasma resistance. The same applies to the heat transfer material placed between the pedestal and the annular focus ring that supports the peripheral portion of the object to be processed.

This invention has been made in consideration of the above-mentioned circumstances, and has an object to provide a plasma processing device component, such as an electrode plate for a plasma processing device or a focus ring, that has a heat transfer material with excellent heat resistance and plasma resistance and has high thermal uniformity over a long period of time, and a manufacturing method thereof. Another object of the present invention is to provide a plasma processing device that is less susceptible to contamination.

In order to solve the above problems, the member for a plasma processing apparatus of the present invention is a member for a plasma processing apparatus having a substrate and a heat transfer layer provided on one surface of the substrate, the heat transfer layer contains at least one of a fluorine-based resin and a fluorine-based elastomer, and a filler, the filler being one or more selected from alumina, alumina hydrate, aluminum nitride, silica, silicon carbide, titanium oxide, and boron nitride, and the filler content in the heat transfer layer is within the range of 50 mass % or more and 90 mass % or less .

In the member for a plasma processing apparatus having this configuration, the heat transfer layer contains at least one of a fluororesin and a fluoroelastomer, and therefore has excellent heat resistance and plasma resistance, and therefore the member for a plasma processing apparatus has high thermal uniformity over a long period of time and is less susceptible to contamination.
Furthermore, since the heat transfer layer contains a filler, the heat transfer layer has improved thermal conductivity, which further improves the thermal uniformity of the member for a plasma processing apparatus.

In the member for a plasma processing apparatus of the present invention, the material forming the substrate is preferably Si or SiC.
In this case, since the base material contains Si or SiC, the heat conductivity of the base material is improved, and therefore the thermal uniformity of the member for a plasma processing apparatus is improved.

In the electrode plate for a plasma processing apparatus of the present invention, the filler is preferably at least one of alumina and boron nitride.
In this case, since the heat transfer layer contains at least one of alumina and boron nitride, the thermal conductivity of the heat transfer layer is improved more reliably, and thus the thermal uniformity of the member for a plasma processing apparatus is further improved.

In the member for a plasma processing apparatus of the present invention, the fluororesin and the fluoroelastomer are preferably compounds having a perfluoropolyether group.
In this case, since the heat transfer layer contains a compound having a perfluoropolyether group, the heat resistance and plasma resistance of the heat transfer layer are further improved, and therefore the member for a plasma processing apparatus has high thermal uniformity for a long period of time and is less susceptible to contamination.

In the member for a plasma processing apparatus of the present invention, the heat transfer layer preferably has a thickness in the range of 20 μm to 1 mm.
In this case, since the thickness of the heat transfer layer is 20 μm or more, it is easy to make the heat transfer layer adhere to the cooling plate or the stand of the plasma processing apparatus, and the thermal conductivity between the heat transfer layer and the cooling plate or between the heat transfer layer and the stand is improved. In addition, since the thickness of the heat transfer layer is 1 mm or less, the thermal conductivity of the heat transfer layer is also high. Therefore, the thermal uniformity of the member for the plasma processing apparatus is further improved.

The member for a plasma processing apparatus of the present invention may be an electrode plate for a plasma processing apparatus having a vent hole for passing a gas for generating plasma.
In this case, the electrode plate for a plasma processing apparatus may have a configuration in which the base material is a substrate having a large number of ventilation holes, and the heat transfer layer is provided on one surface of the substrate.
Furthermore, the substrate may be disk-shaped, have a thickness in the range of 1 mm or more and 20 mm or less, the diameter of the ventilation hole in the range of 0.1 mm or more and 1 mm or less, and the aspect ratio of the ventilation hole may be 3 or more.

In the member for a plasma processing apparatus of the present invention, the member for a plasma processing apparatus may be a focus ring.
In this case, the focus ring may be configured such that the base material is an annular base material having a circular flat portion and a protrusion portion formed on the outer circumferential side of one surface of the flat portion, and the heat transfer layer is provided on a surface of the flat portion opposite to the surface on which the protrusion portion is formed.

The method for producing a member for a plasma processing apparatus of the present invention includes: a preparation step of preparing a substrate; a coating step of applying a coating composition containing a filler and a fluorine -based compound that generates at least one of a fluorine-based resin and a fluorine-based elastomer by heating or irradiation with ultraviolet light onto one surface of the substrate to form a coating layer; and a heat transfer layer formation step of heating the coating layer or irradiating the coating layer with ultraviolet light to generate a heat transfer layer containing at least one of a fluorine-based resin and a fluorine-based elastomer.

According to this method for manufacturing a member for a plasma processing apparatus, a coating composition is applied to a substrate formed in advance into a predetermined shape to generate a heat transfer layer, so that members for plasma processing apparatuses of various shapes, such as electrode plates for plasma processing apparatuses and focus rings, can be efficiently manufactured. Furthermore, good contact between the heat transfer layer and the substrate can be achieved, and thermal resistance can be reduced. Furthermore, the obtained member for plasma processing apparatus has excellent heat resistance and plasma resistance because the heat transfer layer contains at least one of a fluororesin and a fluoroelastomer, and has high thermal uniformity over a long period of time, and is less susceptible to contamination.

Since the coating composition contains a filler, the formed heat transfer layer contains the filler and has improved thermal conductivity, making it possible to manufacture a member for a plasma processing apparatus with improved thermal uniformity.

In addition, in the manufacturing method of an electrode plate for a plasma processing apparatus of the present invention, the base material may be a substrate having a large number of ventilation holes, and the coating composition may be applied to one surface of the substrate.
In this case, since the heat transfer layer is formed on the substrate having a large number of ventilation holes, it is easy to align the ventilation holes of the substrate and the ventilation holes of the heat transfer layer. Therefore, an electrode plate for a plasma processing apparatus having ventilation holes can be efficiently manufactured. In addition, as a manufacturing method of an electrode plate for a plasma processing apparatus, a method of separately manufacturing a heat transfer material (heat transfer layer) having a large number of ventilation holes and placing this heat transfer material on the substrate is considered. In this case, misalignment is likely to occur when placing the heat transfer material on the substrate. For this reason, it is necessary to make the ventilation holes of the heat transfer material a size that can absorb the misalignment, but in that case, the contact surface between the cooling plate of the plasma processing apparatus and the heat transfer material and the contact area between the heat transfer material and the substrate become small, and heat is not efficiently transferred. Furthermore, when forming ventilation holes in an independent heat transfer material, if the heat transfer material has many ventilation holes, the mechanical strength of the heat transfer material itself becomes weak, making it difficult to handle as an independent heat transfer material. In particular, when the amount of filler filling is large, the mechanical strength of the heat transfer material itself becomes even weaker, so the amount of filler filling cannot be increased. In contrast, the above-mentioned manufacturing method does not require the heat transfer layer to be separated, and therefore it is possible to form a heat transfer layer with a large amount of filler. Therefore, the above-mentioned manufacturing method makes it possible to manufacture an electrode plate for a plasma processing apparatus having uniform temperature and thermal stability.

In addition, in the manufacturing method of an electrode plate for a plasma processing device of the present invention, the base material may be a circular substrate having a circular flat portion and a protrusion portion formed on the outer periphery of one surface of the flat portion, and the coating composition may be applied to the surface of the flat portion opposite to the surface on which the protrusion portion is formed.
In this case, since the base material is an annular substrate having a circular flat portion and a protrusion formed on the outer circumferential side of one surface of the flat portion, the focus ring can be manufactured efficiently.

The plasma processing apparatus of the present invention is a plasma processing apparatus comprising an electrode plate for a plasma processing apparatus having an air hole for passing a gas for generating plasma and a focus ring, wherein at least one of the electrode plate for the plasma processing apparatus and the focus ring has a heat transfer layer, the heat transfer layer contains at least one of a fluorine-based resin and a fluorine-based elastomer , and a filler, the filler being one or more selected from alumina, alumina hydrate, aluminum nitride, silica, silicon carbide, titanium oxide, and boron nitride, and the filler content in the heat transfer layer is within the range of 50 mass % or more and 90 mass % or less .
In the plasma processing apparatus having this configuration, at least one of the electrode plate for the plasma processing apparatus and the focus ring has a heat transfer layer containing at least one of a fluorine-based resin and a fluorine-based elastomer, and therefore has excellent heat resistance and plasma resistance, thereby providing high thermal uniformity and reducing the risk of contamination.

The present invention makes it possible to provide an electrode plate for a plasma processing device that has a heat transfer material with excellent heat resistance and plasma resistance and has high thermal uniformity over a long period of time, and a manufacturing method thereof. Furthermore, the present invention makes it possible to provide a plasma processing device that is less susceptible to contamination.

1 is a perspective view of an example of an electrode plate for a plasma processing apparatus according to an embodiment of the present invention; 2 is a cross-sectional view taken along line II-II of FIG. 1. 1 is a schematic configuration diagram showing an example of a plasma etching apparatus according to an embodiment of the present invention. FIG. 2 is a perspective view of an example of a focus ring according to the embodiment. 5 is a cross-sectional view taken along line VV in FIG. 4. FIG. 2 is a schematic configuration diagram showing another example of a plasma etching apparatus according to the present embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a plasma processing apparatus member, a manufacturing method thereof, and a plasma processing apparatus according to embodiments of the present invention will be described with reference to the accompanying drawings.
The plasma processing apparatus according to the present embodiment is, for example, a plasma processing apparatus such as a plasma etching apparatus or a plasma CVD apparatus used in a semiconductor device manufacturing process. The member for the plasma processing apparatus according to the present embodiment is a member used inside the plasma processing apparatus, for example, an electrode plate for the plasma processing apparatus or a focus ring. The electrode plate for the plasma processing apparatus according to the present embodiment is used as the upper electrode of a pair of electrodes provided in a vacuum chamber of a plasma processing apparatus such as a plasma etching apparatus or a plasma CVD apparatus used in a semiconductor device manufacturing process. The focus ring according to the present embodiment is, for example, an annular support ring that supports a processing object placed in a vacuum chamber of the plasma processing apparatus at its periphery.

FIG. 1 is a perspective view of an example of an electrode plate for a plasma processing apparatus according to this embodiment, and FIG. 2 is a cross-sectional view taken along line II-II of FIG.
1 and 2, the electrode plate 10 for the plasma processing apparatus is disk-shaped and has a plurality of ventilation holes 11 for passing a gas for generating plasma. The electrode plate 10 for the plasma processing apparatus has a base material 12 and a heat transfer layer 13 formed on the surface of the base material 12.

The ventilation hole 11 may have a diameter, for example, in the range of 0.1 mm to 1 mm. The aspect ratio of the ventilation hole 11 in the substrate 12 (thickness of substrate 12/diameter of ventilation hole 11) may be 1 or more, but is preferably 3 or more. The aspect ratio of the ventilation hole 11 may be 200 or less.

The material constituting the substrate 12 is not particularly limited, but is preferably Si (silicon) or SiC (silicon carbide). The diameter of the substrate 12 may be, for example, in the range of 200 mm or more and 400 mm or less. The thickness of the substrate 12 may be, for example, in the range of 1 mm or more and 20 mm or less.

The heat transfer layer 13 contains at least one of a fluororesin (fluororesin, fluorine-containing resin) and a fluoroelastomer (fluoroelastomer, fluorine-containing elastomer). The heat transfer layer 13 may contain a fluororesin alone, a fluoroelastomer alone, or a mixture of a fluororesin and a fluoroelastomer. The fluororesin is preferably elastic. The heat transfer layer 13 preferably contains a filler. The heat transfer layer 13 preferably has a configuration in which at least one of a fluororesin and a fluorine-containing elastomer is used as a matrix binder, and a filler is dispersed in the matrix binder.

The fluorine-based resin preferably has a fluorine-containing group in the main chain. The fluorine-based elastomer is preferably a fluorine-containing three-dimensional crosslinking compound having a fluorine-containing group and a three-dimensional crosslinking structure. Examples of the fluorine-containing group include a perfluoroalkylene group -(CF ₂ ) _x - (x is an integer of 1 or more) and a perfluoropolyether group. Examples of the perfluoropolyether group include -(CF ₂ CF ₂ O) _m (CF ₂ O) _n - (m and n are integers of 1 or more), -(CF ₂ CF ₂ CF ₂ O) _p - (p is an integer of 1 or more), and -(CF ₂ CF(CF ₃ )O) q- (q is an integer of 1 or more). Examples of the three-dimensional crosslinking structure include an organosilicon structure having a silicon-carbon bond, a silicone structure having a siloxane bond, an epoxy structure having an epoxy bond, and a urethane structure having a urethane bond. The fluorine-containing three-dimensional cross-linking compound may be used alone or in combination of two or more kinds.

Examples of materials that can be used for the filler include alumina (Al ₂ O ₃ ), alumina hydrate, aluminum nitride (AlN), silica (SiO ₂ ), silicon carbide (SiC), titanium oxide (TiO ₂ ), and boron nitride (BN). Among these materials, alumina and boron nitride are preferred. The shape of the filler is not particularly limited, and may be, for example, spherical, flat, or fibrous. The alumina is more preferably α-alumina. The boron nitride is more preferably granular boron nitride.

The filler content of the heat transfer layer 13 is preferably in the range of 50% by mass to 90% by mass. When the filler content is 50% by mass or more, the thermal conductivity of the heat transfer layer 13 is improved, and when the filler content is 90% by mass or less (the matrix binder content is more than 10% by mass), the sheet formability is improved.
The thickness of the heat transfer layer 13 is preferably in the range of 20 μm to 1 mm, and particularly preferably in the range of 20 μm to 500 μm.

Next, a method for manufacturing the electrode plate 10 for a plasma processing apparatus according to this embodiment will be described.
The electrode plate 10 for a plasma processing apparatus can be manufactured by a method including the following steps.
(1) A preparation step of preparing a substrate 12 having a large number of ventilation holes 11.
(2) A coating step of coating one surface of the substrate 12 with a coating composition containing a fluorine-based compound that generates at least one of a fluorine-based resin and a fluorine-based elastomer upon heating or exposure to ultraviolet light to form a coating layer.
(3) A heat transfer layer forming step in which the coating layer is heated or irradiated with ultraviolet light to form a heat transfer layer 13 containing at least one of a fluorine-based resin and a fluorine-based elastomer.

In the preparation process, there is no particular limitation on the method of forming the vent hole 11 in the substrate 12. For example, various methods that are used as methods for forming the vent hole 11 in the electrode plate 10 for plasma processing equipment, such as a method of mechanically forming the vent hole 11 using a drill, a method of thermally forming the vent hole 11 by irradiating a laser, etc., can be used. In the substrate 12 in which the vent hole 11 is formed, burrs may occur around the vent hole, and the flatness of the surface in which the vent hole is not formed may decrease. If burrs exist around the vent hole or the flatness of the surface in which the vent hole is not formed decreases, this may cause uneven coating in the next coating process. For this reason, it is preferable to remove burrs from the substrate 12 in which the vent hole 11 is formed by etching before the coating process, and then polish the upper and lower surfaces of the substrate 12 to improve flatness.

The coating composition used in the coating step is preferably a composition containing a fluorine-based compound and a filler. The coating composition may further contain a fluorine-based oil and a volatile solvent.

The fluorine-based compound is a compound that generates a fluorine-based resin and/or a fluorine-based elastomer when heated or irradiated with ultraviolet light. The fluorine-based compound is preferably a fluorine-containing crosslinkable compound that generates a fluorine-containing three-dimensional crosslinkable compound when heated or irradiated with ultraviolet light. As the fluorine-containing crosslinkable compound, a fluorine-containing crosslinkable organosilicon compound, a fluorine-containing crosslinkable silicone compound, a fluorine-containing crosslinkable epoxy compound, or a fluorine-containing crosslinkable urethane compound can be used. An example of a commercially available fluorine-based compound is SHIN-ETSU SIFEL (registered trademark) manufactured by Shin-Etsu Chemical Co., Ltd.

The fluorine-based oil acts as a viscosity modifier for the coating composition. The fluorine-based oil is preferably a liquid polymer having a perfluoropolyether group. Examples of the perfluoropolyether group are the same as those of the fluorine-based resin and the fluorine-based elastomer. The fluorine-based oil polymer may have a perfluoropolyether group bonded to a linear or branched saturated or unsaturated hydrocarbon group, an aromatic group, or a hydrocarbon group containing a heteroatom. Examples of commercially available fluorine-based oils include Fomblin (registered trademark) sold by Solvay, Demnum (registered trademark) sold by Daikin Industries, Ltd., and Krytox (registered trademark) sold by Chemours. Examples of commercially available volatile solvents include Novec (registered trademark) sold by 3M.

In the coating step, it is preferable to use a screen printing method as a method for coating one surface of the substrate 12 with the coating composition. It is also preferable to place a masking material in the ventilation holes 11 of the substrate 12 before applying the coating composition. The masking material used in the screen printing may be a metal mask or a mesh mask. Instead of placing a masking material in the ventilation holes 11 of the substrate 12, a mask patterned to block the ventilation holes 11 may be used.

In the heat transfer layer formation process, the coating layer is heated or irradiated with ultraviolet light to generate a heat transfer layer 13 containing at least one of a fluorine-based resin and a fluorine-based elastomer. The heating temperature or the amount of ultraviolet light irradiation is the condition under which the fluorine-based compound generates a fluorine-based resin and/or a fluorine-based elastomer.

The above steps produce the electrode plate 10 for the plasma processing device of this embodiment.

The electrode plate 10 for a plasma processing apparatus is used as an upper electrode in a vacuum chamber of the plasma processing apparatus. Figure 3 is a schematic diagram showing an example of a plasma etching apparatus using the electrode plate 10 for a plasma processing apparatus according to this embodiment.

As shown in FIG. 3, the plasma etching apparatus 100 has a vacuum chamber 30, an etching gas introduction section 1 provided on the upper side in the vacuum chamber 30, and a workpiece support section 2 provided on the lower side in the vacuum chamber 30. The etching gas introduction section 1 is provided so that the electrode plate 10 (upper electrode) for the plasma processing apparatus according to this embodiment faces the heat transfer layer 13 upward. In addition, a vertically movable stand (lower electrode) 20 is provided in parallel with the electrode plate 10 for the plasma processing apparatus at a distance from each other in the workpiece support section 2. In this case, the upper electrode plate 10 for the plasma processing apparatus is supported in an insulated state against the wall of the vacuum chamber 30 by an insulator 14, and an electrostatic chuck 21 and a focus ring (support ring) 22 made of Si (silicon) or SiC (silicon carbide) surrounding the electrostatic chuck 21 are provided on the stand 20, and a wafer (substrate to be processed) 40 is placed on the electrostatic chuck 21 with the peripheral portion supported by the focus ring 22. An etching gas supply pipe 31 is provided above the vacuum chamber 30, and the etching gas sent from this etching gas supply pipe 31 passes through a diffusion member 32, then flows toward the wafer 40 through a vent hole 11 provided in the electrode plate 10 for the plasma processing device, and is exhausted to the outside from an exhaust port 33 on the side of the vacuum chamber 30. Meanwhile, a high-frequency voltage is applied between the electrode plate 10 for the plasma processing device and the stand 20 by a high-frequency power source 50.

A cooling plate 15 is fixed to the back surface of the electrode plate 10 for the plasma processing apparatus via a heat transfer layer 13. The material of the cooling plate 15 is aluminum or the like, which has excellent thermal conductivity. The cooling plate 15 also has through holes 16 formed at the same pitch as the ventilation holes 11 so as to communicate with the ventilation holes 11 of the electrode plate 10 for the plasma processing apparatus. The electrode plate 10 for the plasma processing apparatus is then fixed in the plasma etching apparatus 100 by screws or the like with the back surface in contact with the cooling plate 15.

The gas for generating plasma passes through the ventilation holes 11 from top to bottom (in the direction of the arrow), and the plasma is generated below the electrode plate 10 for the plasma processing device. The heat generated along with the plasma is transferred from the substrate 12 of the electrode plate 10 for the plasma processing device through the heat transfer layer 13 to the cooling plate 15, and is then dissipated to the outside.

Next, the focus ring according to the present embodiment will be described.
FIG. 4 is a perspective view of an example of the focus ring according to the present embodiment, and FIG. 5 is a cross-sectional view taken along line VV of FIG.

In Figures 4 and 5, the focus ring 22 has an annular base material 23 with a circular opening in the center, and a heat transfer layer 24. The annular base material 23 has an annular flat portion 23a and a protrusion 23b formed on the outer periphery of one surface of the flat portion 23a. The heat transfer layer 24 is provided on the surface of the annular base material 23 opposite the surface on which the protrusion 23b is formed.

The annular base material 23 may have a diameter in the range of 350 mm to 500 mm, for example. The central opening diameter of the annular base material 23 may be in the range of 295 mm to 298 mm. The protrusion 23b of the annular base material 23 may have a thickness in the range of 2 mm to 8 mm, for example. There are no particular restrictions on the material constituting the annular base material 23, but it is preferably Si (silicon) or SiC (silicon carbide).

The heat transfer layer 24 contains at least one of a fluorine-based resin and a fluorine-based elastomer. The heat transfer layer 24 preferably contains a filler. Examples of the fluorine-based resin, fluorine-based elastomer, and filler contained in the heat transfer layer 24 are the same as those in the electrode plate 10 for plasma processing equipment described above. In addition, the thickness of the heat transfer layer 24 is preferably in the range of 20 μm to 1 mm, and particularly preferably in the range of 20 μm to 500 μm, as in the case of the electrode plate 10 for plasma processing equipment described above.

The focus ring 22 can be manufactured by a method including the following steps.
(1) A preparation step of preparing an annular base material 23 having an annular flat portion 23a and a protrusion portion 23b formed on the outer periphery of one surface of the flat portion 23a.
(2) A coating step in which a coating composition containing a fluorine-based compound that produces at least one of a fluorine-based resin and a fluorine-based elastomer by heating or irradiating with ultraviolet light is applied to the surface of the annular base material 23 opposite to the surface on which the protrusions 23b are formed, thereby forming a coating layer.
(3) A heat transfer layer forming step in which the coating layer is heated or irradiated with ultraviolet light to generate a heat transfer layer 24 containing at least one of a fluorine-based resin and a fluorine-based elastomer.

In the preparation step, the method for forming the annular base material 23 is not particularly limited. For example, a method of mechanically processing the base material into an annular shape using a drill can be used. In addition, the annular base material 23 may be formed by bonding multiple arc-shaped members in a ring shape in the circumferential direction. A focus ring formed by bonding multiple arc-shaped members is described in JP 2011-3730 A. In a focus ring of this configuration, the above-mentioned fluorine-based resin and/or fluorine-based elastomer may be used as the adhesive for bonding the multiple arc-shaped members.

There are no particular limitations on the method of applying the coating composition in the application process and the method of generating the heat transfer layer 24 in the heat transfer layer formation process. For example, the same method as in the case of the electrode plate 10 for the plasma processing device described above can be used.

Figure 6 is a schematic diagram showing another example of a plasma etching apparatus according to this embodiment. The plasma etching apparatus 200 shown in Figure 6 is the same as the plasma etching apparatus 100 shown in Figure 3, except that a focus ring 22 having the above-mentioned annular base material 23 and heat transfer layer 24 is used. For this reason, parts of the plasma etching apparatus 200 shown in Figure 6 that are common to the plasma etching apparatus 100 shown in Figure 3 are given the same reference numerals and detailed descriptions are omitted.

In the plasma etching apparatus 200 shown in FIG. 6, the workpiece support unit 2 includes a stand 20 , an electrostatic chuck 21 , a focus ring 22 , and a heat extraction plate 25 .
The pedestal 20 has a circular shape in a plan view. A focus ring 22 is disposed on the outer periphery of the pedestal 20. The focus ring 22 supports the peripheral portion of the wafer 40 by means of an annular base material 23. A heat extraction plate 25 is disposed in the center of the pedestal 20, and an electrostatic chuck 21 is disposed on the heat extraction plate 25. The pedestal 20 has a coolant flow path 27 therein and also functions as a cooling portion. The pedestal 20 is also connected to an earth 28 and also functions as an electrode portion. The electrostatic chuck 21 may be connected to a high-frequency power source (not shown).

Between the mount 20 and the focus ring 22, an O-ring 26 is arranged. The O-ring 26 is arranged in a circular ring shape in a plan view around the O-ring 26. The material of the O-ring 26 may be, for example, a heat-resistant elastic body such as silicone rubber or a fluorine-based elastomer. An intermediate layer may be provided at least on one side between the mount 20 and the focus ring 22. The intermediate layer may be a sintered ceramic body such as alumina, yttria, silicon carbide, aluminum nitride, or silicon nitride.

According to the plasma processing apparatus member of this embodiment (electrode plate 10 for plasma processing apparatus, focus ring 22) configured as described above, the heat transfer layer contains at least one of a fluorine-based resin and a fluorine-based elastomer, and therefore has excellent heat resistance and plasma resistance. Therefore, the plasma processing apparatus member has high thermal uniformity for a long period of time and is less susceptible to contamination.

In the plasma processing apparatus member of this embodiment, when the material forming the substrate (substrate 12, annular substrate 23) is Si or SiC, the thermal conductivity of the substrate is improved. This improves the thermal uniformity of the plasma processing apparatus member.

In the plasma processing apparatus member of this embodiment, when the heat transfer layers 13 and 24 contain a filler, the thermal conductivity of the heat transfer layers is improved. Therefore, the thermal uniformity of the plasma processing apparatus member is further improved. Furthermore, when the filler is at least one of alumina and/or boron nitride, the thermal conductivity of the heat transfer layers 13 and 24 is more reliably improved. Therefore, the thermal uniformity of the plasma processing apparatus member is further improved. Furthermore, in the plasma processing apparatus member of this embodiment, when the fluororesin and the fluoroelastomer are compounds having a perfluoropolyether group, the heat resistance and plasma resistance of the heat transfer layers 13 and 24 are further improved. Therefore, the plasma processing apparatus member has high thermal uniformity for a longer period of time and is less likely to become contaminated. Furthermore, in the plasma processing apparatus member of this embodiment, when the thickness of the heat transfer layers 13, 24 is within the range of 20 μm or more and 1 mm or less, the heat transfer layers 13, 24 are easily attached to the cooling plate 15 and the stand 20 of the plasma processing apparatus, and the thermal conductivity between the heat transfer layer 13 and the cooling plate 15 and between the heat transfer layer 24 and the stand 20 is improved. In addition, since the thickness of the heat transfer layer is 1 mm or less, the thermal conductivity of the heat transfer layer is also high. This further improves the thermal uniformity of the plasma processing apparatus member.

The plasma processing device member of this embodiment may also be an electrode plate 10 for a plasma processing device having a vent hole 11 for passing a gas for generating plasma. In this case, the electrode plate 10 for a plasma processing device may be configured such that the base material 12 is a substrate having a large number of vent holes 11, and the heat transfer layer 13 is provided on one surface of the base material 12. Furthermore, the base material 12 may be disc-shaped, have a thickness in the range of 1 mm to 20 mm, have a diameter of the vent hole 11 in the range of 0.1 mm to 1 mm, and have an aspect ratio of 1 or more, preferably 3 or more. In this case, the electrode plate 10 for a plasma processing device has high adhesion to the cooling plate 15 of the plasma etching device 100, has high thermal uniformity for a long period of time, and is less likely to be contaminated, so that plasma processing can be performed stably for a long period of time.

The plasma processing apparatus member of this embodiment may be a focus ring 22. In this case, the focus ring 22 may be configured such that the base material is an annular base material 23 having an annular flat portion and protrusions formed on the outer periphery of one surface of the flat portion, and the heat transfer layer 24 is provided on the surface opposite to the surface on which the protrusions of the flat portion are formed. In this case, the focus ring 22 has high adhesion to the stand 20 of the plasma etching apparatus 200, has high thermal uniformity for a long period of time, and is less susceptible to contamination, so that plasma processing can be performed stably for a long period of time.

According to the manufacturing method for plasma processing equipment members of this embodiment, a coating composition is applied to a substrate formed in advance into a predetermined shape to generate a heat transfer layer, so that plasma processing equipment members of various shapes, such as electrode plates 10 for plasma processing equipment and focus rings 22, can be efficiently manufactured. Furthermore, good contact between the heat transfer layer and the substrate can be achieved, and thermal resistance can be reduced. In addition, the obtained plasma processing equipment member has excellent heat resistance and plasma resistance because the heat transfer layer contains at least one of a fluororesin and a fluoroelastomer, and has high thermal uniformity over a long period of time, and is less susceptible to contamination.

In the manufacturing method of the plasma processing device member of this embodiment, the substrate may be a substrate 12 having a large number of ventilation holes 11, and the coating composition may be applied to one surface of the substrate 12. In this case, the heat transfer layer 13 is formed on the substrate 12 having a large number of ventilation holes 11, so that it is easy to align the positions of the ventilation holes 11 of the substrate 12 and the ventilation holes 11 of the heat transfer layer 13. Therefore, the electrode plate 10 for the plasma processing device having the ventilation holes 11 can be manufactured efficiently. In addition, as a manufacturing method of the electrode plate 10 for the plasma processing device, a method is considered in which a heat transfer material (heat transfer layer) having a large number of ventilation holes 11 is separately manufactured and this heat transfer material is placed on the substrate. In this case, the positional deviation is likely to occur when the heat transfer material is placed on the substrate. For this reason, it is necessary to make the ventilation holes of the heat transfer material a size that can absorb the positional deviation, but in that case, the contact surface between the cooling plate of the plasma processing device and the heat transfer material and the contact area between the heat transfer material and the substrate are small, and heat is not transferred efficiently. Furthermore, when forming ventilation holes in an independent heat transfer material, if the heat transfer material has many ventilation holes, the mechanical strength of the heat transfer material itself is weakened, making it difficult to handle as an independent heat transfer material. In particular, if the filler loading amount is large, the mechanical strength of the heat transfer material itself is further weakened, so the filler loading amount cannot be increased. In contrast, according to the above manufacturing method, it is not necessary to separate the heat transfer layer independently, so it is possible to form a heat transfer layer with a large filler loading amount. Therefore, according to the above manufacturing method, it is possible to manufacture an electrode plate 10 for a plasma processing device that has thermal uniformity and thermal stability.

In the manufacturing method of the electrode plate for plasma processing equipment of this embodiment, if the substrate is an annular substrate 23 having a circular flat portion and a protrusion formed on the outer periphery of one surface of the flat portion, and the coating composition is applied to the surface of the flat portion opposite the surface on which the protrusion is formed, the focus ring 22 can be manufactured efficiently.

According to the plasma etching apparatus 100, 200 of this embodiment, at least one of the electrode plate 10 for the plasma processing apparatus and the focus ring 22 has excellent heat resistance and plasma resistance because the heat transfer layers 13, 24 contain at least one of a fluorine-based resin and a fluorine-based elastomer, so that the electrode plate 10 for the plasma processing apparatus and the focus ring 22 have high thermal uniformity and are less susceptible to contamination.

Although the embodiment of the present invention has been described above, the present invention is not limited thereto, and can be modified as appropriate within the scope of the technical concept of the invention. For example, in the plasma etching apparatus 200 of this embodiment shown in FIG. 6, both the heat transfer layer 13 of the electrode plate 10 for plasma processing apparatus and the heat transfer layer 24 of the focus ring 22 are configured to contain at least one of a fluorine-based resin and a fluorine-based elastomer, but as long as the heat transfer layer 24 of the focus ring 22 is configured to contain at least one of a fluorine-based resin and a fluorine-based elastomer, the heat transfer layer 13 of the electrode plate 10 for plasma processing apparatus does not need to contain a fluorine-based resin or a fluorine-based elastomer.

[Example 1]
(1) Preparation of coating composition 8.7 parts by mass of rubber agent I (X-71-6053-6A, manufactured by Shin-Etsu Chemical Co., Ltd.) having perfluoropolyether group and thermal crosslinking property, 9.0 parts by mass of rubber agent II (X-71-6053-6B, manufactured by Shin-Etsu Chemical Co., Ltd.) having perfluoropolyether group and thermal crosslinking property, 57.2 parts by mass of large particle size alumina filler (AA-18, manufactured by Sumitomo Chemical Co., Ltd., average particle size (d50): 18 μm), and 25.1 parts by mass of small particle size alumina filler (AA-3, manufactured by Sumitomo Chemical Co., Ltd., average particle size (d50): 3 μm) were mixed in a ratio of 82.3% by mass. The obtained mixture was kneaded while defoaming using a rotating/revolving vacuum mixer (Awatori Rentaro ARV-310, manufactured by Thinky Corporation) to prepare a coating composition.

(2) Preparation of electrode plate substrate for plasma processing device An air hole was formed in a Si substrate using a drill. Burrs generated around the air hole on the upper and lower surfaces of the Si substrate were then removed by etching, and the upper and lower surfaces of the Si substrate were polished to prepare an electrode plate substrate for plasma processing device.

(3) Preparation of electrode plate for plasma processing device A masking material was placed in the ventilation hole on one surface of the electrode plate substrate for plasma processing device prepared in (2) above. Next, the coating composition prepared in (1) above was applied to the surface of the electrode plate for plasma processing device by screen printing using a metal mask having an opening with the same diameter as the diameter of the electrode plate substrate for plasma processing device, and a coating layer having a thickness of 0.3 mm after heating was formed. The electrode plate substrate for plasma processing device on which the coating layer was formed was placed in a heating furnace and heated at 150 ° C. for 30 hours. Next, the electrode plate substrate for plasma processing device was removed from the heating furnace and allowed to cool to room temperature. After confirming that the coating layer had hardened and a heat transfer layer had been formed, the masking material was removed. In this way, an electrode plate for plasma processing device was prepared.

(4) Evaluation (Thickness of heat transfer layer of electrode plate for plasma processing device)
The electrode plate for plasma processing equipment after the heat transfer layer was formed was cut, and the thickness was measured from a SEM photograph of the cross section. As a result, it was confirmed that the average thickness of the heat transfer layer was 0.3 mm.

(Radical irradiation weight loss rate)
The heat transfer layer of the electrode plate for plasma processing equipment was subjected to O2-rich conditions in which _O2 and _CF4 were used as reactive gases, with their flow rates of 500 ml/min and 10 ml/min, respectively, the reaction pressure of 40 Pa, and the radical irradiation time of 1 hour, and the radical irradiation weight loss rate after radical irradiation was calculated based on the following formula under _{CF4- rich} conditions in which _O2 and _CF4 were used as reactive gases, with their flow rates of 100 ml/min and 410 ml/min, respectively, the reaction pressure of 100 Pa, and the radical irradiation time of 1 hour. As a result, the radical irradiation weight loss rate was 0 mass% for both the O2 _- rich condition and the _CF4- rich condition.
Radical irradiation weight loss rate (mass%)=[(mass before irradiation−mass after irradiation)/mass before irradiation]×100 (where the mass before irradiation is the mass of the electrode plate for a plasma processing apparatus before radical irradiation, and the mass after irradiation is the mass of the electrode plate for a plasma processing apparatus after radical irradiation.)

(Loss on Heat)
The weight loss rate of the electrode plate for plasma processing equipment after heating in air at 240° C. for 5 hours was calculated based on the following formula. The weight loss rate of the electrode plate for plasma processing equipment after heating in air at 240° C. for 75 hours was calculated in the same manner. As a result, the weight loss rate of the electrode plate for plasma processing equipment after heating in air at 240° C. for 5 hours was 0.8 mass %, and the weight loss rate of the electrode plate for plasma processing equipment after heating in air at 240° C. for 75 hours was 3.2 mass %.
Heating loss rate (mass%) = [(mass before heating - mass after heating) / mass before heating] x 100
(Note that the mass before heating is the mass of the electrode plate for a plasma processing apparatus before heating, and the mass after heating is the mass of the electrode plate for a plasma processing apparatus before heating.)

[Example 2]
A ring-shaped base material made of Si having a ring-shaped flat portion and a protrusion formed on the outer periphery of one surface of the flat portion was prepared. The coating composition prepared in (1) of Example 1 of the present invention was applied to the surface of the ring-shaped base material opposite to the surface on which the protrusion was formed by screen printing to form a coating layer having a thickness of 0.3 mm after heating. The ring-shaped base material on which the coating layer was formed was placed in a heating furnace and heated at 150° C. for 30 hours. The ring-shaped base material was then removed from the heating furnace and allowed to cool to room temperature, and it was confirmed that the coating layer had hardened and a heat transfer layer had been formed. In this way, a focus ring for a plasma processing device was produced.

The thickness of the heat transfer layer, the weight loss rate due to radical irradiation, and the weight loss rate due to heating of the obtained focus ring for plasma processing equipment were measured in the same manner as in Example 1 of the present invention. As a result, the thickness of the heat transfer layer was 0.3 mm, the weight loss rate due to radical irradiation was 0 mass%, the weight loss rate upon heating at 240°C for 5 hours was 0.8 mass%, and the weight loss rate upon heating at 240°C for 75 hours was 3.2 mass%.

REFERENCE SIGNS LIST 1 Etching gas inlet 2 Processing object support 10 Electrode plate for plasma processing apparatus 11 Ventilation hole 12 Substrate 13 Heat transfer layer 14 Insulator 15 Cooling plate 20 Stand (lower electrode)
21 electrostatic chuck 22 focus ring 23 annular base material 23a flat portion 23b protrusion portion 24 heat transfer layer 25 heat extraction plate 26 O-ring 27 coolant flow path 28 earth 30 vacuum chamber 31 etching gas supply pipe 32 diffusion member 33 exhaust port 40 wafer (substrate to be processed)
50 High frequency power supply 100, 200 Plasma etching device

Claims (14)

A member for a plasma processing apparatus,
The heat transfer layer includes a substrate and a heat transfer layer provided on one surface of the substrate.
The heat transfer layer contains at least one of a fluorine-based resin and a fluorine-based elastomer, and a filler,
the filler is one or more selected from alumina, alumina hydrate, aluminum nitride, silica, silicon carbide, titanium oxide, and boron nitride;
A member for a plasma processing apparatus, wherein the heat transfer layer has a filler content in the range of 50% by mass to 90% by mass . The member for a plasma processing apparatus according to claim 1, wherein the material forming the substrate is Si or SiC. 3. The member for a plasma processing apparatus according to claim 1, wherein the filler is at least one of alumina and boron nitride. 4. The member for a plasma processing apparatus according to claim 1, wherein the fluorine-based resin and the fluorine-based elastomer are compounds having a perfluoropolyether group. 5. The member for a plasma processing apparatus according to claim 1, wherein the heat transfer layer has a thickness in the range of 20 [mu]m to 1 mm. 6. The member for a plasma processing apparatus according to claim 1, which is an electrode plate for a plasma processing apparatus having a vent hole for passing a gas for generating plasma. 7. The member for a plasma processing apparatus according to claim 6, wherein the base material of the electrode plate for a plasma processing apparatus is a substrate having a large number of ventilation holes, and the heat transfer layer is provided on one surface of the substrate. 8. The member for a plasma processing apparatus according to claim 7, wherein the substrate is disk-shaped, has a thickness in the range of 1 mm or more and 20 mm or less, the diameter of the ventilation hole is in the range of 0.1 mm or more and 1 mm or less, and the aspect ratio of the ventilation hole is 3 or more. The member for a plasma processing apparatus according to claim 1 , wherein the member for a plasma processing apparatus is a focus ring. 10. The member for a plasma processing apparatus according to claim 9, wherein the focus ring is an annular base material having a circular flat portion and protrusions formed on an outer circumferential side of one surface of the flat portion, and the heat transfer layer is provided on a surface of the flat portion opposite to the surface on which the protrusions are formed. A preparation step of preparing a substrate;
a coating step of coating one surface of the substrate with a coating composition containing a fluorine-based compound that generates at least one of a fluorine-based resin and a fluorine-based elastomer by heating or irradiating with ultraviolet light, and a filler to form a coating layer;
a heat transfer layer forming step of heating the coating layer or irradiating the coating layer with ultraviolet light to generate a heat transfer layer containing at least one of a fluorine-based resin and a fluorine-based elastomer;
A method for producing a member for a plasma processing apparatus comprising the steps of: The base material is a substrate having a large number of ventilation holes,
The method for producing a member for a plasma processing apparatus according to claim 11 , wherein the coating composition is applied to one surface of the substrate. The base material is an annular substrate having a flat portion and a protrusion portion formed on an outer circumferential side of one surface of the flat portion,
The method for producing a member for a plasma processing apparatus according to claim 11 , wherein the coating composition is applied to a surface of the flat portion opposite to a surface on which the protrusions are formed. A plasma processing apparatus including an electrode plate for a plasma processing apparatus having a vent hole for passing a gas for generating plasma therethrough, and a focus ring,
At least one of the electrode plate for the plasma processing apparatus and the focus ring has a heat transfer layer,
the heat transfer layer contains at least one of a fluorine-based resin and a fluorine-based elastomer, and a filler, the filler being one or more selected from alumina, alumina hydrate, aluminum nitride, silica, silicon carbide, titanium oxide, and boron nitride;
A plasma processing apparatus, characterized in that the heat transfer layer has a filler content in the range of 50 mass % to 90 mass % .

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