Wafer holder and support pin for wafer holder

Abstract

To obtain a wafer holder to which a support pin can be surely attached by a simpler method.SOLUTION: A wafer holder includes a plate-shaped base having a plurality of bottomed holes on a top surface, and a support pin disposed in each of the plurality of bottomed holes. The bottomed hole has an opening on a top surface. The support pin has a main body portion and an arm portion. The main body portion and the arm portion are integral parts made of the same material. The main body portion has a first end portion protruding from the top surface and a second end portion facing the bottom surface of the bottomed hole. The arm portion has a cantilever structure in which a third end connected to the main body portion is a fixed end, and a fourth end opposite to the third end is a free end.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a wafer holder and support pins for the wafer holder. [Background technology]

[0002] Patent Document 1 relates to a ceramic heater in which a heating element is formed on the surface or inside of a ceramic substrate. Patent Document 1 discloses a structure in which a recess is provided on the heating surface of the ceramic substrate and a support pin is fixed in the recess. The support pin is fixed by fitting into the recess or by a C-ring. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-246286 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, a separate C-ring must be used to securely fasten the support pin. Methods that do not use a C-ring require a direct fit between the recess and the support pin's main body, resulting in variations in the fastening force and protrusion dimensions due to dimensional tolerances, thermal expansion, and other factors. Therefore, a simpler method for attaching a support pin that allows for reliable assembly is desired. [Means for solving the problem]

[0005] The wafer holder of the present disclosure comprises: a plate-like base having a plurality of bottomed holes on an upper surface thereof; a support pin disposed in each of the plurality of bottomed holes, the bottomed hole has an opening on the top surface, The support pin has a main body and an arm, the main body and the arm are integral parts made of the same material; the main body portion has a first end portion protruding from the upper surface and a second end portion facing a bottom surface of the bottomed hole, The arm has a cantilever structure in which a third end connected to the main body is a fixed end and a fourth end opposite the third end is a free end.

[0006] Furthermore, the support pin for a wafer holder according to the present disclosure comprises: It has a main body and an arm, the main body and the arm are integral parts made of the same resin material, the main body portion has a first end portion and a second end portion at opposite ends in a first direction; the arm portion has a curved cantilever structure extending from a third end portion to a fourth end portion in a plane perpendicular to the first direction, the third end is a fixed end connected to the main body portion, and the fourth end is a free end; the fourth end has a gripping portion; The gripping portion has a shape of a hole, a protrusion, or a notch, The resin material is any one of polyimide resin, polyether ether ketone resin, tetrafluoroethylene resin, and tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to obtain a wafer holder to which support pins can be reliably attached using a simpler method, and support pins that can be reliably attached to a wafer holder using a simpler method. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a plan view of a wafer holder according to this embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the wafer holder shown in FIG. [Figure 3A] FIG. 3A is a plan view showing an example of a support pin according to this embodiment. [Figure 3B] FIG. 3B is a plan view showing an example of a support pin according to this embodiment. [Figure 3C] FIG. 3C is a plan view showing an example of a support pin according to this embodiment. [Figure 3D] FIG. 3D is a plan view showing an example of a support pin according to this embodiment. [Figure 4A] FIG. 4A is a cross-sectional view illustrating the structure of the gripping portion of the support pin according to this embodiment. [Figure 4B] FIG. 4B is a cross-sectional view illustrating the structure of the gripping portion of the support pin according to this embodiment. [Figure 4C] FIG. 4C is a plan view illustrating the structure of the gripping portion of the support pin according to this embodiment. [Figure 5A] FIG. 5A is a cross-sectional view illustrating the shape of the main body of the support pin according to this embodiment. [Figure 5B] FIG. 5B is a cross-sectional view illustrating the shape of the main body of the support pin according to this embodiment. [Figure 5C] FIG. 5C is a cross-sectional view illustrating an example of the shape of the main body of the support pin according to this embodiment. [Figure 6A] FIG. 6A is a cross-sectional view illustrating an example of the tip shape of a support pin according to this embodiment. [Figure 6B] FIG. 6B is a cross-sectional view illustrating an example of the tip shape of the support pin according to this embodiment. [Figure 7A] FIG. 7A is a cross-sectional view illustrating the structure of the bottomed hole and the support pin according to this embodiment. [Figure 7B] FIG. 7B is a cross-sectional view illustrating the structure of the bottomed hole and the support pin according to this embodiment. [Figure 8] FIG. 8 is a schematic cross-sectional view illustrating an example of semiconductor manufacturing equipment that uses a wafer holder according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Description of the embodiments of the present disclosure] First, embodiments of the present disclosure will be listed and described.

[0010] (1) A wafer holder according to an embodiment of the present disclosure is a wafer holder comprising a plate-like base having a plurality of bottomed holes on its upper surface, and support pins arranged in each of the plurality of bottomed holes, wherein the bottomed holes have openings on their upper surface, the support pins have a main body portion and an arm portion, the main body portion and the arm portion being an integral part made of the same material, the main body portion having a first end portion protruding from the upper surface and a second end portion facing the bottom of the bottomed hole, and the arm portion having a cantilever structure with a third end portion connected to the main body portion as a fixed end and a fourth end portion opposite the third end portion as a free end.

[0011] With the wafer holder according to this embodiment, the support pins are held in their bottomed holes by the cantilevered arms of the support pins, making it possible to reliably attach the support pins to the wafer holder using a simpler method without using any separate fixing parts.

[0012] (2) In a cross section perpendicular to the top surface, the bottomed hole has an intermediate portion whose width is narrower than the width of the bottom surface, and the arm portion is positioned between the bottom surface and the intermediate portion of the bottomed hole, and the minimum inscribed diameter of the intermediate portion in a cross section parallel to the top surface may be smaller than the maximum distance between two parallel straight lines circumscribing the arm portion of the support pin.

[0013] Because the minimum inscribed diameter of the intermediate portion is smaller than the maximum spacing between the arms of the support pin, the support pin will not easily fall out of the bottomed hole. The support pin can be securely held in the bottomed hole. Here, the minimum inscribed diameter of the intermediate portion is the smallest diameter of a circle inscribed on the inner wall surface, which is the side surface of the hole that constitutes the intermediate portion. Furthermore, the maximum spacing between the arms is the largest distance between two parallel straight lines that circumscribe the arms. "Circumscribing the arms" means that at least one straight line is tangent to the arms in a plane that includes the arms. This includes cases where both straight lines are tangent to the arms, and cases where one is tangent to the arms and the other is tangent to the main body.

[0014] (3) The arm may have a grip portion in a region including the fourth end portion, and may be configured to be elastically deformed by an external force applied to the grip portion in a direction parallel to the upper surface.

[0015] Applying force to the gripping portion causes the arms to elastically deform. Applying force to the gripping portion so as to reduce the distance between the arms or the distance between the arms and the main body reduces the maximum distance between the arms. The support pin is inserted into the bottomed hole in its deformed state, and then the force is released, causing the arms to remain in the bottomed hole. If the maximum distance between the arms before deformation is greater than the inner diameter of the inner wall surface of the bottomed hole, the elastic force of the arms will cause the arms to be fixed in a state of tension against the inner wall surface of the bottomed hole. If the maximum distance between the arms before deformation is smaller than the inner diameter of the inner wall surface of the bottomed hole and greater than the minimum inscribed diameter of the middle portion of the bottomed hole, the support pin will be held between the middle portion of the bottomed hole and the bottom surface. This allows the support pin to be reliably attached to the wafer holder using a simple method.

[0016] (4) The gripping portion may be any one of a hole, a protrusion, and a notch provided in the arm portion.

[0017] The gripping portion may have any shape that makes it easy to apply force to the arm in the direction in which the diameter of the arm decreases. Force can be applied to the gripping portion using a tool. Examples of such a gripping portion shape include a hole, protrusion, or notch provided in the arm. The hole here refers to a shape that becomes a recess or through-hole in the depth direction of the bottomed hole when the support pin is placed in the bottomed hole. The protrusion may have any shape that protrudes from the arm in the depth direction of the bottomed hole. The notch refers to a shape in which a portion of the arm is missing within the plane in which the arm extends.

[0018] (5) The wafer holder may include a plurality of the arms.

[0019] The arm may have multiple arms. For example, the arms can be easily deformed by applying force between grippers provided on two arms. For example, by applying force so as to pinch the gripper provided on a first arm and the gripper provided on a second arm with a tool, the first arm and the second arm are deformed so as to move closer to each other.

[0020] (6) When viewed from a direction perpendicular to the top surface, the arm portion may have an arc shape extending from the third end portion to the fourth end portion.

[0021] The arc-shaped arms give the support pin an overall shape that is close to a circle, making it easier to insert the support pin into the bottomed hole. In particular, if the bottomed hole is a circular hole, the arc-shaped arms that follow the side wall of the bottomed hole make it easier to insert the support pin into the bottomed hole and to hold it in the bottomed hole.

[0022] (7) The tip of the first end portion may have a curved or flat surface.

[0023] The first end of the support pin is the part that comes into contact with the wafer to be placed on it. The smaller the contact area between the support pin and the wafer, the less likely it is that a cool spot will occur in the temperature distribution within the wafer's surface. From this perspective, it is preferable that the first end has a sharp tip or be curved. If the tip is curved, the wafer and the first end will be in close to point contact. On the other hand, if the tip is too sharp, contact with the wafer will likely result in abrasion of the support pin itself or the wafer, generating dust. From this perspective, the first end may be flat.

[0024] (8) The first end portion may have a surface roughness Ra of 5 μm or less.

[0025] The smoother the first end that contacts the wafer, the less likely it is to generate dust upon contact with the wafer.

[0026] (9) The material constituting the support pin may be any one of polyimide resin, polyether ether ketone resin, tetrafluoroethylene resin, and tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin, and the thermal conductivity of the material may be 1.0 W / m·K or less.

[0027] The support pins may be made of a resin material. If a resin material is used, the main body and arms can be easily formed by integral molding. The above-mentioned resin material has the heat resistance required of a wafer holder, and also has sufficient thermal insulation performance between the wafer and the wafer holder. The lower the thermal conductivity of the support pins, the less likely hot spots will occur in the temperature distribution within the wafer surface.

[0028] (10) The height that the first end portion protrudes from the upper surface may be 30 μm or more and 200 μm or less.

[0029] The above protruding height allows the support pins to be used for proximity heating, a method of heating a wafer by thermal radiation from the substrate, which is effective in ensuring uniform temperature distribution across the wafer and preventing the wafer from being affected by dust particles.

[0030] (11) Furthermore, a support pin according to an embodiment of the present disclosure may have a main body and an arm, the main body and the arm being an integral part made of the same resin material, the main body having a first end and a second end at opposite ends in a first direction, the arm having a curved cantilever structure extending from a third end to a fourth end in a plane perpendicular to the first direction, the third end being a fixed end connected to the main body, and the fourth end being a free end, the fourth end having a gripping portion, the gripping portion having a shape of a hole, a protrusion, or a notch, and the resin material may be any one of polyimide resin, polyether ether ketone resin, tetrafluoroethylene resin, and tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin.

[0031] With the support pin described above, the support pin is held in the bottomed hole by the cantilevered arm portion of the support pin, making it possible to reliably attach the support pin to the wafer holder using a simpler method without using any additional parts.

[0032] [Details of the embodiments of the present disclosure] Wafer holders and support pins according to embodiments of the present disclosure will be described below with reference to the drawings. In the following description, identical or corresponding elements will be designated by the same reference numerals, and the same description will not be repeated. The sizes and positional relationships of the members shown in each drawing are depicted for the purpose of clarifying the description and do not necessarily represent the actual dimensional relationships, etc. Furthermore, directions are depicted with the side on which the wafer is placed being the upper side and the opposite side being the lower side.

[0033] [Wafer holder] The configuration of a wafer holder 1 according to this embodiment will be described with reference to Figures 1 and 2. The wafer S here is typically a semiconductor wafer. Figure 1 is a plan view showing an example of a wafer holder. Figure 2 is a cross-sectional view schematically showing the AA cross section of the wafer holder 1 shown in Figure 1. The wafer holder 1 has a base 10 and support pins 20. The base 10 is a plate-like body that is circular in plan view. The wafer S is placed on the upper surface of the base 10. The upper surface 11 of the base 10 is flat, and is provided with a plurality of bottomed holes 30. The bottomed holes 30 are holes that have an opening 31 in the upper surface 11 and a bottom surface 32 within the base 10.

[0034] A support pin 20 is disposed within the bottomed hole 30. The support pin 20 is composed of a main body 21 and an arm 22. The tip of the main body 21 protrudes from the opening 31. Most of the main body 21, excluding the tip, and the arm 22 are housed within the bottomed hole 30. The height by which the tip of the main body 21 protrudes from the top surface 11 may be 30 μm or more and 200 μm or less, and may be 50 μm or more and 100 μm or less. If the height is too small, the wafer S will bend due to its own weight, causing local contact between the wafer S and the base 10. If the gap between the top surface 11 and the wafer S varies greatly in this way, it becomes difficult to maintain uniform heating across the entire surface of the wafer S. If the height is too large, heat from the base 10 will not be easily transferred to the wafer S.

[0035] In this embodiment, the bottomed hole 30 is provided in seven locations: one at the center of the base 10 and six locations concentrically arranged with the base 10. The six bottomed holes 30 are arranged in a regular hexagonal shape at 60° intervals on a circumference with a radius of two-thirds the radius of the base 10 from the center of the base 10. The number and arrangement of the bottomed holes 30 and support pins 20 on the upper surface 11 are not limited as long as they can hold the wafer S on the upper surface 11 while maintaining the flatness of the wafer S and maintaining a constant distance between the upper surface 11 and the wafer S. For example, the wafer S may be held by three support pins 20 arranged in an equilateral triangle. A smaller number of support pins 20 has the effect of suppressing heat conduction between the wafer S and the base 10. Alternatively, the wafer S may be supported by a larger number of support pins 20. Evenly arranging a large number of support pins 20 on the upper surface 11 makes it easier to maintain the flatness of the wafer S.

[0036] The material of the substrate 10 is a material with high thermal conductivity to achieve high temperature uniformity. The size of the substrate 10 can be selected depending on the size of the wafer S to be placed on it. Typically, the diameter of the substrate 10 is 200 mm to 500 mm, and the thickness is 1 mm to 10 mm. The material of the substrate 10 may be a metal such as copper (Cu) or aluminum (Al). The material of the substrate 10 may also be a ceramic such as aluminum nitride, silicon carbide, aluminum oxide, or silicon nitride, or a composite of these ceramics and silicon. Using these materials makes it possible to maintain a high level of flatness at all times.

[0037] [Support pin] The support pin 20 has a main body 21 and an arm 22. The main body 21 and the arm 22 are an integral part made of the same material. That is, the main body 21 and the arm 22 are a continuous, integrated part. With reference to FIGS. 3A to 3D and 5A to 5C , the main body 21 has a first end 211 protruding from the upper surface 11 of the base 10 and a second end 212 facing the bottom surface 32 of the blind hole 30. The arm 22 has a cantilever structure in which a third end 221 connected to the main body 21 is a fixed end and a fourth end 222 opposite the third end 221 is a free end. Specific structural examples of the support pin 20 will be described below with reference to the drawings. The support pin 20 is not limited to the structure described below and may have other modified examples.

[0038] 3A to 3D are plan views showing an example of a support pin 20 according to this embodiment. Referring to FIG. 3A, in this example, two arms 22 are provided on a main body 21. The main body 21 and each arm 22 are continuous at a third end 221 of the arm 22. A grip 23 is provided at a fourth end 222, which is the other end of the arm 22. The arm 22 has a cantilever structure with the third end 221 as a fixed end and the fourth end 222 as a free end. Therefore, when an external force is applied to the fourth end 222, the arm 22 is deformed so as to bend with respect to the third end 221. If the applied external force is equal to or less than a certain magnitude, the arm 22 returns to its original shape when the external force is released. In other words, the arm 22 is elastically deformed. The purpose of providing the arms 22 is to prevent the support pin 20 from coming out of the bottomed hole 30. The positional relationship between the support pin 20 and the bottomed hole 30 will be described later.

[0039] When the bottomed hole 30 is a circular hole in a plan view seen from a direction perpendicular to the top surface, the support pin 20 can easily fit inside the hole if it is also shaped like a circle. The arm portion 22 may have an arc shape extending from the third end 221 to the fourth end 222 when seen from a direction perpendicular to the top surface, but is not limited to this.

[0040] The support pin 20 shown in FIG. 3A has two arms 22 connected to a main body 21 in opposite directions, forming an overall C-shape. By applying an external force to bring two gripping portions 23 closer together, the arms 22 deform toward the main body 21. That is, the arms 22 deform toward the main body 21. That is, the arms 22 of the support pin 20 deform toward the main body 21. Here, the outer diameter of the support pin 20 is the maximum spacing between the arms 22, as described above. Then, by releasing the external force, the shape of the arms 22 returns to its original state. Note that the spacing between the arms 22 is the distance Wp between two parallel lines circumscribing the arms 22, as illustrated in FIG. 3A. One of the two lines may be a line circumscribing the main body 21. The distance Wp is calculated for all combinations of two parallel lines circumscribing the arms, and the largest of these distances is determined as the maximum spacing between the arms 22.

[0041] 3B has two arms 22 connected to a main body 21 in the same direction, and has an overall S-shape. When an external force is applied to bring the two gripping portions 23 closer together, the arms 22 deform in a direction approaching the main body 21. In other words, the support pin 20 deforms in a direction that reduces the outer diameter of the support pin 20. Thereafter, when the external force is released, the arms 22 return to their original shape.

[0042] 3C, only one arm 22 is connected to a main body 21. The main body 21 extends on the opposite side of the arm 22, and a gripping portion 23 is also provided on the main body 21. When an external force is applied so as to bring the main body 21 and the gripping portion 23 of the arm 22 closer together, the arm 22 deforms in a direction approaching the main body 21. In other words, the support pin 20 deforms in a direction reducing the outer diameter. Thereafter, when the external force is released, the arm 22 returns to its original shape.

[0043] 3D has four arms 22 connected to a main body 21. When an external force is applied so as to bring the four gripping portions 23 closer together, the arms 22 deform in a direction approaching the main body 21. In other words, the arms 22 deform in a direction that reduces the outer diameter of the support pin 20. When the external force is then released, the arms 22 return to their original shape. The number and shape of the arms 22 are not limited to these examples, and any shape may be used as long as they have the function of elastically deforming when subjected to a force in a direction parallel to the top surface 11 of the base 10.

[0044] 4A to 4C are diagrams illustrating the structure of the gripping portion 23 of the support pin 20 according to this embodiment. The cross sections shown in FIGS. 4A and 4B are examples of the CC cross section shown in FIG. 3A. FIG. 4A shows a structure in which a hole is provided as the gripping portion 23 at the fourth end 222 of the arm portion 22. In this figure, the hole is a through hole, but it may also be a bottomed hole. For example, by inserting a tool such as tweezers into the hole as the gripping portion 23, a force can be applied to bring the two gripping portions 23 closer together.

[0045] 4B is a diagram illustrating a structure in which protrusions are provided as gripping portions 23 at fourth end portion 222 of arm portion 22. The planar shape of the protrusions is not limited, but may be any shape that is easy to grasp with a tool such as tweezers. A force can be applied with the tool to bring two gripping portions 23 closer together.

[0046] FIG. 4C is a diagram illustrating another structure for the gripping portion 23. Similar to FIG. 3A, FIG. 4C shows an example of the support pin 20 in a plan view. Notches are provided on the outer edges of the arms of the arm portion 22 as gripping portions 23. For example, a force can be applied with a tool to bring the two gripping portions 23 closer together. The shape of the notch is not limited, and may be any shape that is easy to grasp with the tool. Examples of the shape of the notch include an arc shape, a rectangle shape, and a V-shape.

[0047] 5A to 5C are cross-sectional views illustrating the shape of the main body 21 of the support pin 20 according to this embodiment. The cross sections of the support pin 20 shown in Fig. 5A to 5C are examples of the BB cross section shown in Fig. 3A.

[0048] The second end 212 is a surface that faces the bottom surface 32 of the bottomed hole 30 when placed in the bottomed hole 30. The second end 212 shown in both Figures 5A and 5B has a flat shape. In Figure 5A, the second end 212 and the lower surface of the arm portion 22 are in the same plane. In Figure 5B, the arm portion 22 is located closer to the first end 211 than the second end 212. That is, in the shape of Figure 5B, the arm portion 22 does not contact the bottom surface 32 within the bottomed hole 30. The second end 212 shown in Figure 5C has a recess. Only the portion of the second end 212 other than the recess contacts the bottom surface 32.

[0049] In FIG. 5A, the shape of the first end 211 is a part of a hemisphere. FIGS. 6A and 6B are cross-sectional views illustrating other tip shapes of the first end 211. The main body 21 has a columnar shape having a first end 211 and a second end 212. The first end 211 protrudes from the upper surface 11 of the base 10 and has a tip that supports the wafer S. The shape of the first end 211 can be a hemisphere as shown in FIG. 5A, a cone with the tip rounded with an arbitrary curvature as shown in FIG. 6A, or a flat shape as shown in FIG. 6B. The tip of the first end 211 is the portion that comes into contact with the supported wafer S.

[0050] When the tip is curved as shown in Figures 5A and 6A, ideally the support pin 20 and wafer S will be in point contact. The smaller the contact area, the less heat is transferred from the support pin 20 to the wafer S by thermal conduction, improving the temperature uniformity of the wafer S. On the other hand, if the tip is too sharp, the support pin 20 will be scraped off by contact with the wafer S, which is likely to generate dust. There is a concern that the dust will act as foreign matter and adversely affect wafer processing.

[0051] To avoid sharp edges and achieve point contact, if the tip is arc-shaped, the radius of curvature should be 0.5 mm to 3 mm. The radius of curvature of the tip may be 1.5 mm or less. Alternatively, the tip may be flat, as shown in Figure 6B. The corners of the flat surface are chamfered to prevent them from becoming too sharp. The chamfered shape should be a curve with a radius of 10 μm to 1 mm. By flattening the tip, the contact area can be freely designed. In either case, to reduce dust generated by contact between the support pin 20 and the wafer S, the surface roughness Ra of the tip should be 5 μm or less, preferably 1 μm or less. The surface roughness can be adjusted by adjusting the surface roughness of the molding die or by polishing after molding. The surface roughness Ra is the arithmetic mean roughness specified in JIS B 0601-2001.

[0052] The material constituting the support pins 20 is a material that is compatible with the operating temperature range required for the wafer holder 1 to be used. A material with a thermal conductivity of 1.0 W / m·K or less is preferable. A thermal conductivity of 0.5 W / m·K or less, or even 0.3 W / m·K or less, is acceptable. It is easier to maintain a uniform in-plane temperature of the wafer placed on it if heat from the wafer holder 1 is not directly transmitted through the support pins 20. Depending on the application, the support pins 20 may be required to be made of an insulating material. Ceramics and resin materials can be used as materials for the support pins 20. Resin materials have excellent processability. Resin materials generally have a lower hardness than the wafer S and base 10 to be placed on them. The low hardness of the support pins 20 can prevent the support pins 20 from damaging the wafer S and generating particles due to the damage.

[0053] Examples of resin materials that satisfy these conditions include polyimide resin (PI), polyether ether ketone resin (PEEK), tetrafluoroethylene resin (PTFE), and tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin (PFA). Alternatively, the same ceramic material as the base 10 may be used for the support pin 20. The thermal conductivity of PI is typically 0.3 W / m·K. The thermal conductivity of PEEK is 0.2 W / m·K to 0.9 W / m·K. The thermal conductivity of PTFE is typically 0.23 W / m·K, and the thermal conductivity of PFA is typically 0.19 W / m·K. The thermal conductivities of ceramic materials are typically 200 W / m·K for silicon carbide, 150 W / m·K for aluminum nitride, 32 W / m·K for alumina, and 27 W / m·K for silicon nitride.

[0054] [Bottomed hole] 7A and 7B are schematic cross-sectional views illustrating the shape of the bottomed hole 30 and the positional relationship with the support pin 20 according to this embodiment. FIGS. 7A and 7B correspond to enlarged cross sections of one of the portions of the bottomed hole 30 in the cross-sectional view of FIG. 2 where the support pin 20 is housed. A bottomed hole 30 is provided in the base 10. The bottomed hole 30 has an opening 31 with a circular opening edge, a bottom surface 32, and an inner wall surface 33 connecting the opening edge to the bottom surface 32. Also, in FIG. 7A, the bottomed hole 30 has an intermediate portion 34, which is a portion where the inner wall surface 33 protrudes inward. In FIG. 7A, the width W2 of the intermediate portion 34 is smaller than the width W1 of the bottom surface 32. Here, the width of the bottom surface 32 is the distance between the connection points of the inner wall surface 33 and the bottom surface 32. In FIG. 7A, the width of the bottom surface 32 is equal to the width of the opening 31. The intermediate portion 34 does not need to protrude around the entire circumference of the inner wall surface 33, and may have a structure in which only a portion protrudes. The minimum inscribed diameter of the intermediate portion is the diameter of the smallest circle inscribed in the protruding portion in a plan view. The bottomed hole 30 in FIG. 7B does not have an intermediate portion 34. The inner wall surface 33 in FIG. 7B is a surface that extends from the edge of the opening 31 toward the bottom surface 32 and is perpendicular to the top surface 11.

[0055] The support pin 20 is disposed inside the bottomed hole 30, and only the first end 211 of the body 21 of the support pin 20 protrudes above the upper surface 11 from the opening 31 of the bottomed hole 30. As described above, the arm 22 of the support pin 20 is elastically deformable.

[0056] The placement of the support pin 20 in the bottomed hole 30 will be described for the structure of the bottomed hole 30 shown in FIG. 7B . In a plan view perpendicular to the top surface 11, the outer diameter of the arm 22 before deformation is larger than the inner diameter of the opening 31. Here, the outer diameter of the arm 22 refers to the maximum spacing between the arms, and the inner diameter of the opening 31 refers to the minimum inscribed diameter, and so on. An external force is applied to the arm 22 using a tool or the like to deform the arm 22 so that its outer diameter becomes smaller than the inner diameter of the opening 31, and the support pin 20 is inserted into the bottomed hole 30. When the external force is released after the support pin 20 reaches the bottom surface 32 of the bottomed hole 30, an elastic force acts on the arm 22 to return it to its original shape. In other words, the arm 22 comes into contact with the inner wall surface 33 of the bottomed hole 30 and is in a tensioned state. This tension force secures the support pin 20 so that it does not easily fall out of the bottomed hole 30.

[0057] In the structure of the bottomed hole 30 shown in FIG. 7A , an external force is applied to the arm portion 22 using a tool or the like to deform the arm portion 22 so as to reduce its outer diameter, and then the support pin 20 is inserted into the bottomed hole 30. Unlike the structure of FIG. 7B , the structure of FIG. 7A requires that the outer diameter be deformed so as to be smaller than the inner diameter of the intermediate portion 34. Furthermore, the arm portion 22 of the support pin 20 after insertion only needs to be larger than the inner diameter of the intermediate portion 34. That is, in a plan view seen from a direction perpendicular to the top surface 11, the outer diameter of the arm portion 22 before deformation is larger than the inner diameter of the intermediate portion 34, but does not necessarily have to be larger than the inner diameter of the opening 31. After insertion, the arm portion 22 may be in contact with and protruding from the inner wall surface 33 of the bottomed hole 30, or it may not be protruding from the inner wall surface 33 of the bottomed hole 30. In either case, since the outer diameter of the arm portion 22 is larger than the inner diameter of the intermediate portion 34, it does not easily fall out of the bottomed hole 30.

[0058] Although manufacturing is easier when the bottomed hole 30 has a circular shape in plan view, polygonal shapes are also acceptable. The smaller the opening size, the less adverse effects on in-plane uniformity can be. On the other hand, if the opening is too small, it becomes difficult to insert the support pin 20. The circle-equivalent diameter of the opening 31 of the bottomed hole 30 is 3 mm or more and 15 mm or less, and may further be 6 mm or more and 10 mm or less. The cross-sectional shape of the bottomed hole 30 is not limited to the shapes exemplified above. The inner wall surface 33 does not have to be perpendicular to the top surface 11. For example, the inner wall surface 33 may have a tapered shape that widens from the opening 31 toward the bottom surface 32.

[0059] The depth of the bottomed holes 30 can be selected arbitrarily depending on the thickness of the base 10 and the shape of the support pin 20. If the depth of the bottomed holes 30 is ¾ or less, or even ⅔ or less, of the thickness of the base 10, the strength of the base 10 is easily maintained. Specifically, the depth of the bottomed holes 30 is preferably 1 mm or more and 5 mm or less.

[0060] [Semiconductor manufacturing equipment] 8 is a schematic diagram illustrating an example of a semiconductor manufacturing apparatus 100 that uses a wafer holder according to this embodiment. The wafer holder 1 of the present disclosure can be used as part of the semiconductor manufacturing apparatus 100.

[0061] Referring to FIG. 8, semiconductor manufacturing equipment 100 includes a wafer holder 1. Wafer holder 1 has the structure described above. Bottomed holes 30 and support pins 20 are arranged in the upper surface 11 of base 10. The tips of support pins 20 protrude from upper surface 11 and support wafer S. A heater 50 contacts the lower surface of base 10. Heater 50 is a sheet-shaped heating element. Heater 50 has a structure in which a heater circuit 51 that generates heat when current is applied is sandwiched between two insulating sheets 52. Power for energizing is supplied from the outside through current-carrying terminals and electrodes (not shown). Support plate 60 holds sheet-shaped heater 50 between base 10 and also serves to supplement the rigidity of base 10. Base 10 and support plate 60 are fixed together by a fastening structure such as bolts (not shown). With the above structure, a wafer S placed on wafer holder 1 is held flat and heated by heat from heater 50. The lower surface of the support plate 60 is supported by support columns 81 provided on the cooling stage 80. The cooling plate 70 has holes through which the support columns 81 pass, and can change its position between a state in contact with the cooling stage 80 and a state in contact with the support plate 60. The fixing structure of the support columns 81 and the driving structure of the cooling plate 70 are not shown, and known structures are applied.

[0062] The wafer S is held floating above the upper surface 11 by support pins 20. Heat generated by the heater 50 is transferred to the base 10 and then transferred to the wafer S by thermal radiation from the upper surface 11. As one step in manufacturing a semiconductor device, the wafer S is subjected to a desired process in a heated state. After the wafer is processed, the cooling plate 70, which is kept at a low temperature while in contact with the cooling stage 80, moves upward and comes into contact with the support plate 60. The low-temperature cooling plate 70 comes into contact with the support plate 60, thereby cooling the base 10 in a short period of time.

[0063] The support plate 60 can be made of a known ceramic material that is used in similar devices. To prevent scattering of components during heating, it is preferable that the support plate 60 contain as few low-melting-point metals as possible, such as alkali metal elements and lead. Specifically, the support plate 60 should be mainly made of ceramics such as aluminum nitride, silicon carbide, aluminum oxide, and silicon nitride, or a composite of these ceramics and silicon.

[0064] The heater 50 has a heater circuit 51 extending in a plane. The heater circuit 51 is covered on both the top and bottom surfaces with insulating sheets 52 such as polyimide sheets to electrically insulate it from the base 10 and the support plate 60. The heater circuit 51 is formed by patterning a metal foil such as a stainless steel foil by etching or laser processing, and generates heat when electricity is applied to the circuit.

[0065] The above describes the basic structure of one example of semiconductor manufacturing apparatus 100. However, semiconductor manufacturing apparatus 100 in which wafer holder 1 of the present disclosure is used is not limited to the illustrated apparatus. Wafer holder 1 of the present disclosure can also be suitably used in apparatus for other purposes, such as proximity heating, that have a structure for holding semiconductor wafers at a distance from the mounting surface.

[0066] [Example of semiconductor manufacturing equipment] (Making support pins) Support pins 20 were fabricated with the shapes shown in Figures 3A, 4A, and 5A. The arms 22 were C-shaped, and the support pin 20 was circular overall. The outer diameter of the arms 22 was 7 mm in plan view, and the first end 211 of the main body 21 was hemispherical with a diameter of 2 mm. The distance from the first end 211 to the second end 212 of the main body 21, i.e., the height of the support pin 20, was 2.2 mm. The thickness of the arms 22 was 0.8 mm, and the width of the arms in plan view was 1 mm at their smallest point. The gripping portions 23 provided on the arms 22 were through-holes with a diameter of 0.7 mm. PEEK was used as the material for the support pin 20, and the main body 21 and arms 22 were molded together using a mold. The thermal conductivity of the PEEK used was 0.3 W / m K. The shape and surface condition of the fabricated support pin 20 were determined by the shape of the mold. The surface roughness Ra near the tip of the fabricated first end portion 211 was 0.2 μm.

[0067] (Preparation of the substrate) The substrate 10 was fabricated as follows. A circular aluminum nitride plate with a diameter of 320 mm and a thickness of 3 mm was prepared. Seven bottomed holes 30 were formed on the surface of this aluminum nitride plate, as shown in FIG. 1. The bottomed holes 30 had the structure shown in FIG. 7A. The diameter of the opening edge of the opening 31 of the bottomed hole 30 was 6.9 mm, and the diameter of the bottom surface 32 was 6.9 mm. The depth of the bottomed hole 30 was 2 mm. The bottomed hole 30 had an intermediate portion 34, and the inner diameter of the intermediate portion 34 was 6.5 mm. The distance between the intermediate portion 34 and the bottom surface 32 was 1 mm.

[0068] (Fabrication of wafer holder) A support pin 20 was fitted into each of the seven blind holes 30 of the base 10. The two gripping portions 23 of the support pin 20 were pinched with tweezers, and the support pin 20 was inserted into the blind hole 30 while holding the gripping portions 23 so that the outer diameter of the gripping portions 23 was reduced. As the outer diameter of the arm portions 22 was reduced, the support pin 20 passed through the middle portion 34 of the blind hole 30 and was inserted so that it contacted the bottom surface 32. The gripping portions 23 were then released, and the arm portions 22 returned to their original shape. In this example, the outer diameter of the support pin 20 and the inner diameter of the blind hole 30 were designed to be the same. Therefore, if the outer diameter of the support pin 20 is larger than the inner diameter of the blind hole 30 within the tolerance range, the arm portions 22 will be fixed so as to push against the inner wall surface 33 of the blind hole 30. If the outer diameter of the support pin 20 is smaller than the inner diameter of the blind hole 30, a gap will be created between the arm portions 22 and the inner wall surface 33 of the blind hole 30. In either case, the intermediate portion 34 prevents the support pin 20 from falling out of the bottomed hole 30 .

[0069] (Semiconductor manufacturing equipment manufacturing) The semiconductor manufacturing apparatus 100 was assembled as follows. The heater 50 was fabricated as follows. A 20 μm-thick stainless steel foil was etched to prepare a heater circuit 51. This heater circuit 51 was covered on both the top and bottom with a 50 μm-thick polyimide sheet as an insulating sheet 52 and thermocompressed to form a flat heater 50 with a diameter of 320 mm. Power supply cables (not shown) were attached to both ends of the heater circuit 51.

[0070] Heater 50 was sandwiched between the wafer holder 1 and a ceramic plate serving as support plate 60, and fixing screws were inserted into through-holes previously provided in support plate 60 to fasten it to base 10 of wafer holder 1. Support plate 60 is a circular plate made of aluminum nitride, 320 mm in diameter and 3 mm thick. Fixing screws equipped with bearings on their bearing surfaces were used to prevent deformation of base 10 and support plate 60 due to differences in the amount of thermal expansion. In this way, wafer holder 1 and support plate 60 were mechanically joined together with heater 50 sandwiched between them to form a heating unit.

[0071] A circular aluminum alloy plate with a diameter of 320 mm and a thickness of 12 mm was prepared as the cooling plate 70. A flexible silicone sheet was placed on the upper surface of the aluminum alloy plate, which would come into contact with the ceramic plate of the substrate heating unit, in order to improve adhesion to the ceramic plate.

[0072] A circular aluminum alloy plate with a diameter of 320 mm and a thickness of 12 mm was prepared as the cooling stage 80. A phosphorus-deoxidized copper pipe with an outer diameter of 6 mm and a thickness of 1 mm was attached to the underside of the aluminum alloy plate for the cooling stage 80 as a coolant flow path. Joints were attached to both ends of the pipe for supplying and discharging the coolant. A support pillar 81 was attached between the cooling stage 80 and the support plate 60 that constitutes the underside of the substrate heating unit. The support pillar 81 passed through a through-hole provided in the cooling plate 70. The cooling plate 70 was raised and lowered by the rod of a separately provided air cylinder.

[0073] It should be noted that the embodiments disclosed herein are illustrative in all respects and should not be considered restrictive. The present invention is not limited to these examples, but is defined by the scope of the claims, and is intended to include all modifications within the scope and meaning equivalent to the claims. [Explanation of symbols]

[0074] 1 Wafer holder 10 Base 11 Top side 20 support pin 21 Main body 211 First end 212 Second end 22 Arm 221 Third end 222 Fourth end 23 Gripping part 30 Bottomed hole 31 Opening 32 bottom 33 Inner wall surface 34 Middle section 50 Heater 51 Heater circuit 52 Insulation sheet 60 Support plate 70 Cooling plate 80 Cooling stage 81 Post 100 Semiconductor manufacturing equipment S wafer

Claims

1. a plate-like base having a plurality of bottomed holes on an upper surface thereof; a support pin disposed in each of the plurality of bottomed holes, the bottomed hole has an opening on the top surface, The support pin has a main body and an arm, the main body and the arm are integral parts made of the same material; the main body portion has a first end portion protruding from the upper surface and a second end portion facing a bottom surface of the bottomed hole, the arm portion extends from a third end to a fourth end in a plane perpendicular to a first direction from the first end to the second end, and has a cantilever structure in which the third end connected to the main body portion is a fixed end and the fourth end opposite the third end is a free end.

2. In a cross section perpendicular to the top surface, the bottomed hole has an intermediate portion having a width narrower than a width of the bottom surface, and the arm portion is disposed between the bottom surface and the intermediate portion of the bottomed hole, a minimum inscribed diameter of the intermediate portion in a cross section parallel to the upper surface is smaller than a maximum distance between two parallel straight lines circumscribing the arm portion of the support pin; 2. The wafer holder of claim 1.

3. the arm portion has a grip portion in a region including the fourth end portion, The arm portion is elastically deformed by an external force applied to the grip portion in a direction parallel to the upper surface.

3. The wafer holder according to claim 1.

4. The gripping portion is any one of a hole, a protrusion, and a notch provided in the arm portion.

4. The wafer holder according to claim 3.

5. A plurality of the arm portions are provided. The wafer holder according to any one of claims 1 to 4.

6. When viewed from a direction perpendicular to the top surface, the arm portion has an arc shape extending from the third end portion to the fourth end portion. The wafer holder according to any one of claims 1 to 5.

7. The tip shape of the first end portion is a curved surface or a flat surface. The wafer holder according to any one of claims 1 to 6.

8. The surface roughness Ra of the first end portion is 5 μm or less. The wafer holder according to any one of claims 1 to 7.

9. The material constituting the support pin is polyimide resin, polyether ether ketone resin, It is either tetrafluoroethylene resin or tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin, The thermal conductivity of the material is 1.0 W / m K or less. The wafer holder according to any one of claims 1 to 8.

10. The height by which the first end portion protrudes from the upper surface is 30 μm or more and 200 μm or less. The wafer holder according to any one of claims 1 to 9.

11. It has a main body and an arm, the main body and the arm are integral parts made of the same resin material, the main body portion has a first end portion and a second end portion at opposite ends in a first direction; the arm portion has a curved cantilever structure extending from a third end portion to a fourth end portion in a plane perpendicular to the first direction, the third end is a fixed end connected to the main body portion, and the fourth end is a free end; the fourth end has a gripping portion; The gripping portion has a shape of a hole, a protrusion, or a notch, the resin material is any one of polyimide resin, polyether ether ketone resin, tetrafluoroethylene resin, and tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin; Support pins for wafer holders.

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