PCB mounting stand for PCB processing equipment

Abstract

The present invention provides a substrate mounting stand that can prevent heat generated for heating the substrate from escaping to the outside, and can also heat the substrate to a high temperature. [Solution] The substrate mounting stand (10) comprises a substrate mounting section (11) made of a predetermined metal material or a material containing said metal material, and a cylindrical support member (13) having a smaller diameter than the substrate mounting section (11) that supports the substrate mounting section (11) from below. The support member (13) is located on the substrate mounting section (11) side and consists of a first part (131) made of a first material which is a metal material, and a second part (132) made of a second material which is a metal material with lower thermal conductivity than the first material, and connected to the first part (131) by friction stir welding (FSW).

Description

Technical Field

[0001] The present invention relates to a substrate stage used in an apparatus for performing some kind of processing on a substrate, such as a plasma processing apparatus, an atomic layer deposition (ALD) processing apparatus, a heat treatment apparatus, etc.

Background Art

[0002] In the manufacturing process of semiconductor substrates using a plasma processing apparatus, etc., processing using plasma may be performed while heating the substrate to a temperature exceeding 400°C (for example, 450°C). A typical example is plasma CVD processing. When performing such processing, a substrate stage incorporating a heater is used.

[0003] Patent Document 1 discloses a plate-shaped substrate stage made of an aluminum alloy incorporating a resistance heating element (heater) in a CVD (chemical vapor deposition) apparatus. This substrate stage is supported from below by a cylindrical support also made of an aluminum alloy and is disposed substantially at the center in the reaction chamber. The substrate stage and the support are joined by TIG (Tungsten Inert Gas) welding. When performing CVD processing on a substrate with this apparatus, after placing the substrate on the upper surface of the substrate stage, an electric current is passed through the resistance heating element to heat the substrate through the substrate stage. However, in this apparatus, since the support is made of an aluminum alloy, which is the same material as the sample stage, there is a drawback that part of the heat generated by the heater escapes to the outside through the support.

[0004] Patent Document 2 describes a semiconductor manufacturing apparatus including a plate-shaped substrate stage incorporating a heater and a cylindrical support fixed to the lower surface of the substrate stage. Metals such as copper and aluminum are used for the material of the substrate stage, while metals such as nickel and nickel alloys having a lower thermal conductivity than the material of the substrate stage are used for the material of the support. By using these materials for the substrate stage and the support, it is possible to suppress the heat generated by the heater from escaping to the outside through the support.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Utility Model Registration No. 3122477 (Publication) [Patent Document 2] Japanese Patent Publication No. 2009-065033 [Patent Document 3] Japanese Patent Publication No. 2001-225179 [Patent Document 4] Japanese Patent Publication No. 2017-220327 [Overview of the project] [Problems that the invention aims to solve]

[0006] As described above, the support in the semiconductor manufacturing apparatus described in Patent Document 2 uses a different metal material from the substrate mounting table, making it difficult to join it to the substrate mounting table by conventional welding methods such as TIG welding. Therefore, a flange is formed on the upper part of this support, and the support is fixed to the substrate mounting table by abutting the flange against the lower surface of the substrate mounting table and passing screws through the flange. However, when fixing with a flange, it is necessary to interpose an O-ring between the flange and the substrate mounting table to ensure airtightness, but this results in low heat resistance, and the substrate can only be heated to a maximum of 300°C.

[0007] The problem that this invention aims to solve is to provide a substrate mounting stage for a substrate processing apparatus that can suppress the escape of heat used to heat the substrate to the outside, and can heat the substrate to a high temperature. [Means for solving the problem]

[0008] The substrate mounting stage for a substrate processing apparatus according to the present invention, which was developed to solve the above problems, A substrate mounting section made of a predetermined metal material or a material containing said metal material, A cylindrical support member having a smaller diameter than the substrate mounting portion supports the substrate mounting portion from below. Equipped with, The aforementioned support member is Located on the substrate mounting side, the first part is made of a first material which is a metallic material, The second part is made of a second material which is a metallic material having lower thermal conductivity than the first material, and is connected to the first part by friction stir welding. It consists of.

[0009] The material of the substrate mounting portion may contain metal, and may be a single metal or alloy, or a mixture of metal and non-metallic material (such as a metal oxide). On the other hand, the first part of the support member uses a first material, which is a metallic material that does not contain non-metallic materials, so that it can be connected to the second part by friction stir welding (FSW). The metallic material used for the first part may be the same as or different from the metallic material used for the substrate mounting portion. The second part uses a second material, which is a metallic material, for connection with the first part by FSW, and which has a lower thermal conductivity than the first material for reasons described later.

[0010] The shape of the support member is typically cylindrical, but it may also have a cross-sectional shape other than a circle, such as an ellipse or polygon, as long as it is cylindrical, i.e., a columnar shape with a hollow interior.

[0011] Friction stir welding, used to join the first and second parts, is a joining method in which a cylindrical tool having a protruding probe made of a harder material than the first and second parts is rotated and the probe is pressed against the boundary between the first and second parts before joining and penetrated, thereby softening the first and second parts near the boundary with frictional heat and causing plastic flow due to the rotational force of the probe, thereby integrating them (see, for example, Patent Document 3). According to FSW, it is possible to join two members made of different materials, such as the first and second parts in the present invention, which was difficult with conventional welding methods.

[0012] The substrate mounting section and the first section can be joined, for example, by a conventional welding method. To ensure more reliable welding, it is desirable that the material of the first section (first material) contains at least 50% of the same metal material as the substrate mounting section.

[0013] In the substrate mounting stage for a substrate processing apparatus according to the present invention, a material (second material) with lower thermal conductivity than the material (first material) of the first part is used for the second part of the support member. Therefore, heat from the substrate mounting section is prevented from escaping to the outside through the support member, while the substrate placed on the substrate mounting section can be heated effectively. Furthermore, since the second part is joined to the first part by a FSW (Fiber Switching Weld), there is no need to use an O-ring to ensure airtightness at the connection between the two, and the heating temperature is not limited by the O-ring. As a result, the substrate on the substrate mounting section can be heated to a high temperature of 400°C or higher.

[0014] The substrate mounting platform for a substrate processing apparatus according to the present invention can be suitably used in a plasma processing apparatus. In addition to plasma processing apparatuses, it can also be suitably used in apparatuses that perform processing involving heating or heat generation of substrates, such as atomic layer deposition apparatuses and heat processing apparatuses. Furthermore, in order to suppress the inflow of heat from the outside into the substrate mounting section, the substrate mounting platform according to the present invention may be used in apparatuses equipped with a cooling mechanism instead of a heating mechanism.

[0015] If two cylindrical members made of different materials are joined directly by FSW, as in the support member of the substrate mounting stand for the substrate processing apparatus according to the present invention, there is a risk that the cylindrical members will deform when a probe is pressed against the boundary. Therefore, it is preferable to manufacture the cylindrical body formed by joining two cylindrical members by FSW using the following method.

[0016] First, a first (solid) rod-shaped member made of the first material and a second (solid) rod-shaped member made of the second material are joined together using FSW (Fiber Stabilization Welding). Then, the first and second rod-shaped members thus joined are machined to hollow out their centers axially, forming cylindrical bodies.

[0017] As a result, a cylindrical body in which two cylindrical members are joined by FSW can be obtained. According to this method, since the first rod-shaped member and the second rod-shaped member are solid during FSW joining, it is difficult to deform even when a probe is pressed against their boundary portion, and they can be easily joined.

Advantages of the Invention

[0018] According to the present invention, it is possible to suppress heat for heating the substrate from escaping to the outside, and it is possible to obtain a substrate mounting table for a substrate processing apparatus that can heat the substrate to a high temperature.

Brief Description of the Drawings

[0019] [Figure 1] A longitudinal sectional view showing an embodiment of a substrate mounting table for a substrate processing apparatus according to the present invention. [Figure 2] A photograph of the substrate mounting table of this embodiment taken around the joint portion between the first part and the second part of the support member. [Figure 3] A diagram showing a manufacturing process of a cylindrical member which is a component of the substrate mounting table of this embodiment. [Figure 4] A diagram showing a state where the substrate mounting table of this embodiment is fixed to the bottom plate of the chamber of a plasma processing apparatus.

Embodiments for Carrying Out the Invention

[0020] Embodiments of a substrate mounting table for a substrate processing apparatus according to the present invention (hereinafter abbreviated as "substrate mounting table") will be described with reference to FIGS. 1 to 4.

[0021] FIG. 1 shows the configuration of the substrate mounting table 10 of this embodiment. Further, FIG. 2 shows a photograph of the manufactured substrate mounting table 10. The substrate mounting table 10 of this embodiment has a substrate mounting portion 11, a heater 12, and a support member 13.

[0022] The substrate mounting section 11 is made of an aluminum (Al) plate, a composite material plate made of aluminum mixed with alumina (Al2O3), or a composite material plate (aluminum composite material) made by impregnating an alumina support with aluminum as described in Patent Document 4. In the case of the aluminum composite material, the outer surface of the support is made of aluminum without alumina. Therefore, the lower surface of the substrate mounting section is also made of aluminum. This configuration allows for greater strength at high temperatures than aluminum alone, while maintaining the temperature uniformity obtained due to the high thermal conductivity of aluminum, and suppressing deformation. Furthermore, this configuration increases the plasma resistance of the substrate mounting section, so the substrate mounting stand of the present invention can be used in a plasma processing apparatus. In addition, this configuration improves the throughput when cleaning the substrate mounting stand compared to when the substrate mounting stand is made of SUS (stainless steel). Generally, when the substrate mounting table is made of SUS (stainless steel), the temperature of the substrate mounting table must be lower than that during film deposition to prevent cleaning gases such as NF3 from corroding the SUS. This reduces throughput due to the time required for heating and cooling. However, since the substrate mounting section 11 made of aluminum or aluminum composite material has high plasma resistance, cleaning can be performed at the film deposition temperature without reducing throughput. In this embodiment, a disc-shaped substrate mounting section 11 with a diameter of 260 mm and a thickness of 37 mm was used, but the shape and size are not limited to this example. A cooling mechanism 17 consisting of a heater 12 and a flow path for a refrigerant is embedded inside the substrate mounting section 11.

[0023] The support member 13 is a hollow cylindrical member made of the material described later, with one end fixed to the lower surface of the substrate mounting section 11. Wiring for supplying current to the heater 12 and a pipe for supplying refrigerant to the cooling mechanism 17 are passed through the hollow portion of the support member 13 (not shown). The outer diameter of the support member 13 is 14 mm, which is smaller than the diameter of the substrate mounting section 11. The wall thickness of the support member 13 is 3 mm. Note that the support member 13 is not limited to the above shape and size as long as it is cylindrical.

[0024] The support member 13 consists of a first portion 131 located on the substrate mounting portion 11 side (the one end side) and a second portion 132 located on the opposite side (the other end side). The material of the first portion 131 (first material) is preferably aluminum, which is the same metallic material as that contained in the substrate mounting portion 11, as it can be joined to the lower surface of the substrate mounting portion 11 by conventional welding methods such as TIG welding. The material of the second portion 132 (second material) can be any metallic material with a lower thermal conductivity than the first material, but if the first material is aluminum, a nickel alloy called Inconel (registered trademark) is preferred. This nickel alloy is an alloy in which chromium (Cr), iron (Fe), carbon (C), etc. are added to nickel (Ni), which is the main constituent element. The thermal conductivity of nickel alloy (generally 12-15 W / m·K) is lower than that of aluminum (220 W / m·K). By using Inconel material for the second material, corrosion resistance at high temperatures can be provided compared to stainless steel, etc.

[0025] The joint 151 between the substrate mounting section 11 and the first section 131 of the support member 13 is joined by TIG welding. The joint 152 between the first section 131 and the second section 132 is joined by FSW, which is suitably used for joining members made of dissimilar metal materials. TIG welding is a joining method commonly used for joining members made of the same type of metal material, while FSW is a joining method that can be suitably used for joining members made of dissimilar metal materials.

[0026] According to the substrate mounting stand 10 of this embodiment, since the material of the second portion 132 of the support member 13 is a nickel alloy with a lower thermal conductivity than the material of the first portion 131, when heating a substrate placed on the substrate mounting section 11 with the heater 12, the heat generated by the heater 12 is prevented from escaping to the outside through the support member 13, and the substrate can be heated with uniform heat distribution.

[0027] Furthermore, because the second part 132 is joined to the first part 131 by the FSW, there is no need to use an O-ring to ensure airtightness at the connection between the two parts, and the heating temperature is not restricted by the O-ring. Therefore, the substrate on the substrate mounting part 11 can be heated to a high temperature.

[0028] The support member 13 can be suitably manufactured by the following method. First, a first rod-shaped member 21 is prepared, which is a solid rod-shaped member made of a first material, and a second rod-shaped member 22 is prepared, which is a solid rod-shaped member made of a second material and has the same cross-sectional shape as the first rod-shaped member 21 (for example, a circle with the same diameter) (Figure 3(a)).

[0029] Next, with one end of the first rod-shaped member 21 and one end of the second rod-shaped member 22 in contact, the probe 31 is pressed against the boundary portion 23 between them and penetrated, and the probe 31 is rotated (ibid. (b), arrow A). As a result, the first rod-shaped member 21 and the second rod-shaped member 22 soften due to frictional heat near the sides of the boundary portion 23 and undergo plastic flow due to the rotational force of the probe 31. In this way, the first rod-shaped member 21 and the second rod-shaped member 22 are joined near the sides of the boundary portion 23. While performing FSW joining at one point on the boundary portion 23, the first rod-shaped member 21 and the second rod-shaped member 22 are slowly rotated coaxially in synchronization (ibid. (b), arrow B).

[0030] Subsequently, the outer circumferences of the first rod-shaped member 21 and the second rod-shaped member 22, which have been joined in this manner, are removed by cutting to smooth the joint, and the center is hollowed out in the axial direction (ibid. (c)). This results in a support member 13, which is a cylindrical body in which the first part 131 and the second part 132 are joined at the joint 152 by FSW (ibid. (d)).

[0031] Generally, when attempting to join two hollow cylindrical bodies using FSW (Fiber Switching Welding), there is a risk of deformation when a probe is pressed against the joint. In contrast, by joining solid rod-shaped members using FSW as described above, and then hollowing out the center to form a cylindrical body, such deformation can be prevented.

[0032] The substrate mounting stand 10 of this embodiment can be used as a substrate mounting stand for a plasma processing apparatus. For example, as described below, the substrate mounting stand 10 of this embodiment can be fixed to the bottom plate 40 of the chamber of the plasma processing apparatus (see Figure 4). In this example, a through hole 41 is provided in the bottom plate 40 of the chamber, and the other end of the second portion 132 (the end opposite to the joint 151) is inserted into this through hole 41. Wiring to the heater 12 is routed to the outside of the chamber through the hollow portion of the support member 13 and the through hole 41 in the bottom plate 40 of the chamber. In addition, a flange 16 made of the same material as the second portion 132 is welded to a position closer to the joint 151 than the other end of the second portion 132 of the support member 13 (joint 161). The flange 16 has screw holes for screws to be fixed to the bottom plate 40 of the chamber, and an O-ring 162 for maintaining airtightness inside the chamber is provided on its lower surface, that is, the surface that contacts the upper surface of the bottom plate 40 of the chamber. Although the O-ring 162 is a component with low heat resistance, in this embodiment, the material of the second part 132 is a nickel alloy with lower thermal conductivity than the material of the first part 131. Therefore, the heat from the heater 12 does not conduct to the O-ring 162, preventing it from becoming too hot and degrading.

[0033] Although the substrate mounting stand 10 of this embodiment has been described above, the present invention is not limited to the above embodiment.

[0034] For example, in the above embodiment, a composite material (aluminum composite material) made by impregnating an alumina support with aluminum was used as the material for the substrate mounting portion 11, with aluminum used for the first material (material for the first portion 131) and a nickel alloy used for the second material (material for the second portion 132). However, the substrate mounting portion, the first material, and the second material are not limited to the above example. For example, the support material of the aluminum composite material for the substrate mounting portion may be a ceramic material other than alumina, such as graphite, silicon carbide, silicon nitride, or aluminum borate. Also, the material for the substrate mounting portion may be a support made of the above material (alumina may also be used) impregnated with a metal material other than aluminum, such as copper (thermal conductivity 398 W / m·K), magnesium (same 155 W / m·K), or nickel (same 90 W / m·K). In this case, the first material can be the same metal material as the metal material impregnated in the substrate mounting portion, or a different metal material may be used. Furthermore, in addition to pure aluminum, an aluminum alloy (with a thermal conductivity of approximately 30-60 (W / m·K)) can be used as the first material. In this case, pure aluminum may be used for both the first part 131 and the substrate mounting part 11, or pure aluminum may be used for one of them and an aluminum alloy for the other. Pure aluminum and aluminum alloy are different materials, but since both contain aluminum, which is a metallic material, it is preferable that the components made of these two types of materials (the substrate mounting part 11 and the first part 131 in this embodiment) can be joined by conventional welding methods. In addition to the metallic materials described above, various metallic materials can be used for the first material, and these metallic materials may be the same as or different from the metallic materials contained in the substrate mounting part 11. In addition to the metallic materials described above, various metallic materials can be used for the first material, and these metallic materials may be the same as or different from the metallic materials contained in the substrate mounting part 11.

[0035] The second material may be any metallic material with a lower thermal conductivity than the first material, such as the nickel alloy material used in the above embodiment. For example, pure nickel may be used as the second material. In addition, brass (an alloy of copper and zinc (thermal conductivity 10⁶ (W / m·K))) and stainless steel (an alloy of iron and chromium, etc. (thermal conductivity 84 (W / m·K))) also have lower thermal conductivity than aluminum and its alloys and can be used as the second material.

[0036] The substrate mounting stage of the above embodiment and its modified form can be used as a substrate mounting stage for a plasma processing apparatus, and can also be suitably used for atomic layer deposition processing apparatuses and heat processing apparatuses. Furthermore, if the purpose is to cool the substrate when performing some processing on the substrate, the heater 12 may be omitted (while providing the cooling mechanism 17). [Explanation of symbols]

[0037] 10...Substrate mounting stand for substrate processing equipment 11... Circuit board mounting section 12… Heater 13…Support member 131…Part 1 132…Second part 151... Joint between the substrate mounting section and the first section 152... Joint between the first and second parts 16…Flange 161...Joint between the second section and the flange 162... O-ring 17…Cooling mechanism 21...First rod-shaped member 22...Second rod-shaped member 23... Boundary 31…Probe 40…Bottom plate 41…Through hole

Claims

1. A substrate mounting section made of a predetermined metal material or a material containing said metal material, A cylindrical support member having a smaller diameter than the substrate mounting portion supports the substrate mounting portion from below. Equipped with, The aforementioned support member is Located on the substrate mounting side, the first part is made of a first material which is a metallic material, The second part is made of a second material which is a metallic material having a lower thermal conductivity than the first material, and is connected to the first part by friction stir welding. A substrate mounting stand for a substrate processing apparatus, consisting of the following components.

2. The substrate mounting stand for a substrate processing apparatus according to claim 1, wherein the first material is pure aluminum or a composite material containing an aluminum alloy, and the second material is pure nickel or a nickel alloy.

3. The substrate mounting stand for a substrate processing apparatus according to claim 1, wherein the substrate mounting portion and the first portion are joined by welding.

4. A method for manufacturing a cylindrical body that is a support member for supporting a substrate mounting portion in a substrate mounting table for a substrate processing apparatus, wherein two cylindrical members made of different metal materials are joined together, A step of joining a first rod-shaped member made of a first material which is a metallic material and a second rod-shaped member made of a second material which is a metallic material having a lower thermal conductivity than the first material by friction stir welding, The first rod-shaped member and the second rod-shaped member joined by the above process are subjected to a process of machining, which involves hollowing out the center of the first rod-shaped member and the second rod-shaped member in the axial direction. A method for manufacturing a cylindrical body having the following characteristics.

Images