JP2012121120A - Manufacturing method of wafer holder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a wafer holder having a spherical curvature, capable of manufacturing it more easily and more precisely than ever before.SOLUTION: A support body 1 has a convex surface 5 in a spherical shape. In a substrate fixing step S21, a substrate 100 is mounted on the surface 5 of the support body 1 and fixed to the support body 1. In a substrate grinding step S22, a surface of the substrate 100 is ground so that the ground surface of the substrate 100 fixed to the support body 1 becomes flat.

Description

  The present invention relates to a method for manufacturing a wafer holder for holding a wafer in a semiconductor device manufacturing process.

  Generally, a wafer holder for holding a wafer is used in a wafer film forming process which is one of semiconductor device manufacturing processes. The wafer may be bent due to thermal expansion of the wafer due to heating or due to its own weight. A wafer holder is known in which a concave portion that is recessed in a spherical shape is provided in order to make the heating of the wafer uniform even when the wafer is bent (see, for example, Patent Document 1). The wafer is uniformly heated by being placed in a concave portion that is recessed in a spherical shape.

  In order to manufacture the above-mentioned wafer holder, a method of grinding with a rotary grinder by CNC (Computerized Numerical Control) control is generally performed. By CNC control, the rotary grinding machine can be moved into a spherical shape, and a concave portion recessed in the spherical shape is provided in the wafer holder.

JP 2005-311290 A

  However, the above-described CNC grinding method of the rotary grinder has the following problems.

  A grinding jig used in a rotary grinding machine has a grinding plane (that is, a contact plane) of a certain size in order to shorten the grinding time. For this reason, even if the rotary grinder moves to a spherical shape, the vicinity of the center of the recess is ground to a flat surface. When a wafer is heated using such a wafer holder, the vicinity of the outer periphery of the wafer can be heated uniformly, but the vicinity of the center of the wafer may not be heated uniformly.

  In CNC control, since the program control range is limited, the rotary grinder may not be able to move the grinding jig corresponding to the manufacture of a wafer having a large diameter. In this case, the movement of the rotary grinding machine can be controlled by manual input, but since the coordinate value is inputted, the rotary grinding machine has a linear trajectory. For this reason, strictly speaking, a concave portion recessed in a spherical shape is not provided in the wafer holder, and the wafer cannot always be processed uniformly.

  Therefore, an object of the present invention is to provide a method for manufacturing a wafer holder that can manufacture a wafer holder having a spherical shape more easily and accurately than in the past.

  In order to solve the above-described problems, the present invention has the following features. A feature of the present invention is a method for manufacturing a wafer holder, which includes a step (substrate preparation step S1) of preparing a substrate (substrate 100) to be a wafer holder for holding a wafer and a step of grinding the substrate (grinding step S2). The step of grinding the substrate includes a substrate fixing step (substrate fixing step S21) for fixing the substrate to a support (supports 1, 2) and a grinding jig (grinding jig 50). Including a substrate grinding step (substrate grinding step S22) for grinding, and the support has a convex surface (surface 5) having a spherical shape, and in the substrate fixing step, the support is provided on the surface of the support. The substrate is mounted and the substrate is fixed to the support.In the substrate grinding step, the ground surface of the substrate is flat in a state where the substrate is fixed to the support. Sharpen the surface of the substrate And it is required to.

  According to the features of the present invention, in the substrate fixing step, the substrate is placed on a convex surface having a spherical shape, and the substrate is fixed to the support. In the substrate grinding step, the substrate is fixed to the support. In this state, the surface of the substrate is ground so that the ground surface of the substrate becomes a flat surface. Thus, the substrate is bent so as to have a spherical shape in accordance with the support. In this state, grinding is performed so that the substrate has a flat surface. That is, grinding can be performed only by moving the grinding jig on a flat surface. Therefore, it is not necessary to control the rotary grinder by CNC control and move the grinding jig into a spherical shape, so that the wafer holder can be manufactured more easily than before.

  By removing the substrate from the support, there is no deflection of the substrate. Thereby, the surface ground by the plane has a spherical shape. Since the grinding jig is only moved on a plane, a wafer holder having a curvature near the center can be manufactured regardless of the size of the grinding plane of the grinding jig. That is, the wafer holder can be manufactured more accurately than in the past.

  In the fixing step, a synthetic resin may be interposed between the support and the substrate, and the substrate may be fixed to the support.

  In the fixing step, the substrate may be fixed to the support by vacuum suction.

  The substrate may be made of a silicon carbide material.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the wafer holder which can manufacture the wafer holder which has a spherical shape more easily and correctly than before can be provided.

FIG. 1 is a perspective view of a support 1 according to the present embodiment. FIG. 2 is an explanatory diagram for explaining a method of manufacturing the wafer holder. FIG. 3A to FIG. 3C are schematic cross-sectional views for explaining the manufacturing process of the wafer holder. Drawing 4 is an explanatory view for explaining the adsorption state of support 2 concerning other embodiments.

  An example of a method for manufacturing a wafer holder according to the present invention will be described with reference to the drawings. Specifically, (1) a schematic configuration of the support 1, (2) a method for manufacturing a wafer holder, (3) actions and effects, and (4) other embodiments will be described.

  In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. It should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones. Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, the part from which the relationship and ratio of a mutual dimension differ also in between drawings may be contained.

(1) Schematic Configuration of Support 1 The schematic configuration of the support 1 according to the present embodiment will be described with reference to FIG. FIG. 1 is a perspective view of a support 1 according to the present embodiment.

  As shown in FIG. 1, the support 1 has a disk shape. It has a convex surface 5 having a spherical curvature R1. That is, one main surface of the support 1 has a spherical shape. Examples of the material for the support 1 include metals, resins, ceramics, and carbon. The size of the support 1 and the spherical curvature R1 are appropriately adjusted according to the wafer holder to be manufactured.

(2) Manufacturing Method of Wafer Holder A manufacturing method of the wafer holder according to the present embodiment will be described with reference to FIGS. FIG. 2 is an explanatory diagram for explaining a method of manufacturing the wafer holder. FIG. 3A to FIG. 3C are schematic cross-sectional views for explaining the manufacturing process of the wafer holder. As shown in FIG. 2, the method for manufacturing a wafer holder according to the present embodiment includes a substrate preparation step S1 and a grinding step S2.

(2.1) Substrate preparation step S1
The substrate preparation step S1 is a step of preparing a substrate 100 that serves as a wafer holder for holding a wafer. As the substrate 100, for example, a disk-shaped substrate made of a silicon carbide material is prepared. Specific examples of silicon carbide materials include silicon carbide sintered bodies.

(2.2) Grinding step S2
The grinding step S2 is a step of grinding the substrate 100. The grinding step S2 includes a substrate fixing step S21 for fixing the substrate 100 to the support 1, and a substrate grinding step S22 for grinding the substrate 100 using the grinding jig 50.

  In the substrate fixing step S <b> 21, the substrate 100 is placed on the surface 5 of the support 1. As shown in FIG. 3A, an adhesive layer 20 is interposed between the support 1 and the substrate 100. Thereby, the substrate 100 is fixed to the support 1. As the adhesive layer 20, for example, a synthetic resin is used. A synthetic resin melted by heating is applied to the surface 5 of the support 1 and the surface of the substrate 100 on the support 1 side. Thereafter, the substrate 100 is placed on the support 1. When the temperature of the synthetic resin decreases, it solidifies and bonds the support 1 and the substrate 100 together. As a result, the substrate 100 is fixed to the support 1. Examples of the synthetic resin include resin wax (acrylic resin, urethane resin).

  As an example, when a silicon carbide sintered body having a diameter of 350 mm and a thickness of 4 mm is used as the substrate 100, the substrate 100 is bent by 40 to 50 μm.

  In the substrate grinding step S22, the surface of the substrate 100 is ground so that the ground surface of the substrate 100 becomes a flat surface in a state where the substrate 100 is fixed to the support 1.

  Specifically, as shown in FIGS. 3A and 3B, the surface of the substrate 100 is ground by moving the grinding jig 50 on a plane. Specifically, the grinding jig 50 is moved in a plane so that the height along the central axis C of the support 1 including the convex vertex of the support 1 is the highest along the central axis C. Thereby, the grinding surface 105 becomes a flat surface. The grinding height at which the substrate 100 is ground along the central axis C (that is, the height along the central axis C between the surface of the substrate 100 before grinding and the ground surface 105 after grinding) is on the central axis C. Becomes the highest (height h). As the distance from the central axis C increases, the grinding height decreases. A ground surface 105 of the substrate 100 generated by grinding has a circular shape. Since the diameter of the grinding surface 105 is substantially equal to the recess 120 of the wafer holder, it is preferable to adjust the height h as appropriate depending on the diameter of the wafer to be manufactured. Note that the center of the grinding surface 105 coincides with the center of the recess 120 of the wafer holder.

  As shown in FIG. 3A, grinding is performed by moving the grinding jig 50 in a plane, but grinding may be performed by moving the support 1. The grinding jig 50 may be rotated about an axis perpendicular to the grinding surface 105. The support 1 may be rotated around the central axis C for grinding.

  The ground substrate 100 is removed from the support 1. Specifically, the adhesive layer 20 is melted by heating, and the substrate 100 is removed from the support 1. As a result, as shown in FIG. 3A, the substrate 100 from which the deflection is released includes a spherical recess 120. The grinding surface 105 is the surface of the recess 120.

  As an example, when a silicon carbide sintered body having a diameter of 350 mm and a thickness of 4 mm is used as the substrate 100, a concave portion having a spherical curvature R2 having a diameter of 305 mm and an SR of 230,000 mm is set by setting the height h to 50 to 100 μm. The provided wafer holder can be manufactured.

(3) Action / Effect According to the method for manufacturing a wafer holder in the present embodiment, in the substrate fixing step S21, the substrate 100 is placed on the surface 5 of the support 1, and the substrate 100 is fixed to the support 1. In the grinding step S22, the surface 5 of the substrate 100 is ground so that the ground surface 105 of the substrate 100 is flat in a state where the substrate 100 is fixed to the support 1. If the grinding jig 50 is moved in a plane, a flat grinding surface 105 is obtained. Therefore, it is not necessary to control the rotary grinding machine by CNC control and move the grinding jig 50 into a spherical shape. Therefore, since it can grind more easily than before, a wafer holder can be manufactured easily.

  By removing the substrate 100 from the support body 1, the substrate 100 is not bent and the substrate 100 is provided with the recess 120. Since the substrate 100 is ground on a flat surface and not ground to the shape of the recess 120, a wafer holder having an accurate spherical shape near the center can be manufactured regardless of the grinding plane of the grinding jig 50.

  According to the method for manufacturing a wafer holder in the present embodiment, the substrate 100 is fixed to the support 1 with a synthetic resin interposed between the support 1 and the substrate 100. Since the substrate 100 can be easily fixed to the support 1 by heating or the substrate 100 can be detached from the support 1, the wafer holder can be easily manufactured.

  According to the method for manufacturing a wafer holder in the present embodiment, substrate 100 is made of a silicon carbide material. Since the silicon carbide material has a high hardness, it is difficult to grind the silicon carbide material to have a spherical shape. According to the present embodiment, it is possible to manufacture the wafer holder including the recess 120 only by moving the grinding jig 50 on a plane, and therefore the wafer holder can be manufactured more easily than in the past.

(4) Other Embodiments Although the contents of the present invention have been disclosed through the embodiments of the present invention, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. The present invention includes various embodiments not described herein. Accordingly, the present invention includes various embodiments not described herein.

  Specifically, in the above-described embodiment, the substrate 100 is fixed to the support 1 by the adhesive layer 20, but the present invention is not limited to this. For example, as shown in FIG. 4, the substrate 100 may be fixed to the support 1 by vacuum suction. Similar to the support 1, the support 2 has a convex surface 5 having a spherical curvature R <b> 1. The support 2 is formed with a vacuum hole 2a that can be vacuum-sucked. The substrate 100 is placed on the surface 5 of the support 2 and is vacuum-adsorbed by the vacuum hole 2 a, whereby the substrate 100 is pushed toward the support 2 by atmospheric pressure, and the support 1 is fixed to the substrate 100. For this reason, the support 1 can be fixed to the substrate 100 without using the adhesive layer 20. Other steps are the same as those in the above-described embodiment.

In order to fix the substrate 100 to the support 2, the vacuum chucking force is preferably 500 g / cm ² or more. When using a material having brittleness as the substrate 100, the substrate 100 may be damaged if the vacuum chucking force is too large. Therefore, the amount of deformation (deflection) that does not reach the breaking stress is adjusted. Is preferred.

  As described above, the present invention includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

  DESCRIPTION OF SYMBOLS 1, 2 ... Support body, 2a ... Vacuum hole, 5 ... Surface, 20 ... Adhesive layer, 50 ... Grinding jig, 100 ... Substrate, 105 ... Grinding surface, 120 ... Recess

Claims (4)

A method for manufacturing a wafer holder, comprising a step of preparing a substrate to be a wafer holder for holding a wafer and a step of grinding the substrate,
The step of grinding the substrate comprises:
A substrate fixing step of fixing the substrate to a support;
A substrate grinding step of grinding the substrate using a grinding jig,
The support has a convex surface having a spherical shape,
In the substrate fixing step, the substrate is placed on the surface of the support, and the substrate is fixed to the support.
In the substrate grinding step, a method for manufacturing a wafer holder, wherein the surface of the substrate is ground so that the ground surface of the substrate is flat in a state where the substrate is fixed to the support.   The method for manufacturing a wafer holder according to claim 1, wherein in the fixing step, a synthetic resin is interposed between the support and the substrate to fix the substrate to the support.   The method for manufacturing a wafer holder according to claim 1, wherein in the fixing step, the substrate is fixed to the support by vacuum suction.   The method for manufacturing a wafer holder according to claim 1, wherein the substrate is made of a silicon carbide material.

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