JP2011168426A - Silicon carbide ceramics, and fixture for semiconductor process using the silicon carbide ceramics - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a silicon carbide ceramics in which cracks caused by thermal stress can be suppressed, and a fixture for a semiconductor process using the silicon carbide ceramics. <P>SOLUTION: In the silicon carbide ceramics, purity of silicon carbide is ≥99.9999 wt.%, and also, density is 2.0 to 3.0 g/cm<SP>3</SP>. Further, the fixture for a semiconductor process is composed of the silicon carbide ceramics. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to silicon carbide ceramics and a semiconductor process jig using the silicon carbide ceramics.

  Conventionally, a jig for manufacturing a semiconductor or performing various processes on the semiconductor has been developed (for example, see Patent Document 1). In addition, among semiconductors, a silicon (Si) semiconductor is processed at a temperature lower than the melting point of Si (about 1400 ° C.), which is relatively low.

JP 2008-308373 A

  However, in recent years, processing of compound semiconductors performed at high temperatures has become popular, and there has been a problem that jigs are easily cracked by thermal stress under such high temperature environments.

  Accordingly, an object of the present invention is to provide silicon carbide ceramics capable of suppressing cracking due to thermal stress, and a semiconductor process jig using the silicon carbide ceramics.

In order to solve the above-described problems, the present invention has the following features. The gist of the silicon carbide ceramic according to the first feature of the present invention is that the purity of silicon carbide is 99.9999% by weight or more and the density is 2.0 to 3.0 g / cm ³ .

  In this way, by making the density lower than the theoretical density of SiC, the crystal has a porous structure and becomes an assembly of micro defects, so when heat is applied, thermal stress is dispersed and generated for each defect. By reducing the stress value, the toughness is improved and cracking against thermal stress is less likely to occur. Note that ceramics having a high density and a dense crystal structure have low toughness, and when thermal stress is applied, stress concentrates on micro defects, so that brittle fracture is easily caused.

  The gist of the semiconductor process jig according to the second feature of the present invention is the silicon carbide ceramics according to the first feature.

  The gist of the semiconductor process jig according to the third feature of the present invention is that it is used in a thermal environment to which a thermal stress of 100 MPa or more is applied.

  According to the silicon carbide ceramic according to the present invention and the semiconductor process jig using the silicon carbide ceramic, cracking due to thermal stress can be suppressed.

The wafer support jig | tool which concerns on embodiment of this invention is shown, (a) is a top view of a wafer support jig | tool, (b) is sectional drawing by the AA line of (a).

  Hereinafter, details of silicon carbide ceramics according to an embodiment of the present invention and a semiconductor process jig using the same will be described with reference to the drawings. Specifically, (1) the overall configuration of a wafer support jig that is an example of a semiconductor process jig according to the present embodiment, (2) physical properties of the silicon carbide ceramics according to the present embodiment, (3) operational effects, (4) Other embodiments will be described. However, it should be noted that the drawings are schematic, and the thicknesses and ratios of the material layers are different from actual ones. Therefore, specific thicknesses and dimensions 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 is contained.

(1) Overall Configuration of a Wafer Support Jig that is an Example of a Semiconductor Process Jig According to the Present Embodiment First, a diagram illustrating an overall configuration of a wafer support jig that is an example of a semiconductor process jig according to the present embodiment. This will be described with reference to FIG. FIG. 1 shows a susceptor 1 that is specifically a wafer support jig.

As shown in FIGS. 1 (a) and 1 (b), the susceptor 1 is formed in a disk shape and is formed of silicon carbide ceramics. As shown in FIG. 1A, the outer shape of the susceptor 1 is circular in plan view, and a wafer holder 2 having a circular shape in plan view is formed at the center side. As shown in FIG. 1B, the wafer holding unit 2 has a bottom surface configured as a wafer holding surface 3, and a semiconductor wafer (not shown) is held by the wafer holding unit 2. The susceptor 1 is used in a thermal environment where a thermal stress of 100 MPa or more is applied. Moreover, the silicon carbide in the silicon carbide ceramics used for the susceptor 1 has a purity of 99.9999% by weight or more and a density of 2.0 to 3.0 g / cm ³ as described later. Note that the wafer support jig is not limited to the susceptor 1, and includes all jigs for supporting a semiconductor wafer such as a soaking plate and a tray.

(2) Physical property of silicon carbide ceramic Next, the physical property of the silicon carbide ceramic which concerns on this embodiment is demonstrated.

(2-1) Purity The purity of silicon carbide in the silicon carbide ceramic according to the present embodiment is 99.9999% by weight or more, and preferably 99.99995% by weight or more. Here, “purity” indicates the proportion of the main component determined by quantitative analysis in the sample, and in this specification, purity is indicated by “weight ratio”. Quantitative analysis is chemical analysis performed to determine the amount of a component in a sample, and includes gravimetric analysis, volumetric analysis, and colorimetric analysis. In the present embodiment, the value (weight%, wt%) of gravimetric analysis for measuring the weight of the component is the purity.

(2-2) Density The density of the silicon carbide ceramics according to the present embodiment is 2.0 to 3.0 g / cm ³ . Here, the density (g / cm ³ ) is a numerical value calculated by the Archimedes method according to JIS R1634.

In addition, since the theoretical density of silicon carbide is 3.21, the density of silicon carbide ceramics according to the present embodiment is 2.0 to 3.0 g / cm ³ is lower than the theoretical density. Therefore, since the crystal has a porous structure and becomes an aggregate of microscopic defects, when heat is applied, the thermal stress is dispersed to reduce the stress value generated for each defect, thereby improving toughness and thermal stress. It becomes difficult for the crack to occur.

(2-3) Other physical properties Silicon carbide powder is used as a raw material for the silicon carbide ceramics of the present invention. Examples of the silicon carbide powder include α-type, β-type, amorphous, and mixtures thereof. In particular, β-type silicon carbide powder is preferably used. The grade of this β-type silicon carbide powder is not particularly limited, and for example, commercially available β-type silicon carbide powder can be used.

The jig | tool using the silicon carbide ceramics concerning this embodiment has the following physical properties in a preferable aspect. For example, the thermal conductivity is 60 to 100 W / m · K, the bending strength at room temperature is about 200 MPa, the Vickers hardness (HV) is about 400, and the Young's modulus is about 120 GPa. The Poisson's ratio is 0.17, the linear expansion coefficient is 4.5E-6 / K, and the specific heat is 0.68 J / g · K. Of these physical properties, thermal conductivity is the most important.

(3) Operational Effects The operational effects according to the present invention will be described below.

(3-1) The silicon carbide ceramic according to the present embodiment has a purity of silicon carbide of 99.9999% by weight or more and a density of 2.0 to 3.0 g / cm ³ .

  Usually, since SiC has low toughness, cracking due to thermal stress during high-temperature processes tends to occur. However, as in this embodiment, by setting the density lower than the theoretical density of SiC, the crystal has a porous structure and becomes an aggregate of microscopic defects. Therefore, when heat is applied, thermal stress is dispersed. By reducing the stress value generated for each defect, toughness is improved and cracking against thermal stress is less likely to occur. Note that ceramics having a high density and a dense crystal structure have low toughness, and when thermal stress is applied, stress concentrates on micro defects, so that brittle fracture is easily caused.

  (3-2) Since the semiconductor process jig according to the present embodiment is made of the silicon carbide ceramic described in (3-1), it has high toughness and hardly causes thermal stress cracking and is suitable for use in a high-temperature process. It becomes.

  (3-3) According to the semiconductor process jig of (3-2) used in a thermal environment where a thermal stress of 100 MPa or more is applied, it should be used without causing thermal stress cracking even in a high temperature environment. Can do.

(4) Other Embodiments It should not be understood that the descriptions and drawings constituting a part of the disclosure of the above-described embodiments limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  As a silicon carbide ceramic jig in the present embodiment, a susceptor that is a wafer support jig has been described as an example. However, the semiconductor carbide jig of the silicon carbide ceramics obtained by the present invention has the physical properties described above, and is therefore used for semiconductor manufacturing parts and the like. Further, for example, it is suitably used for a dry etching apparatus, a heat treatment apparatus, an ion implantation apparatus, a CVD apparatus, a PVD apparatus, and the like. Examples of parts include susceptors, holders, trays, and soaking plates that support semiconductor wafers, plasma electrodes for dry etching equipment, protective rings (focus rings), slit parts (apertures) for ion implantation equipment, and ion generation The present invention can be applied to a protective plate for a part or a mass analysis part, a dummy wafer used at the time of wafer processing in a heat treatment apparatus or a CVD apparatus, or the like.

  As described above, the present invention naturally includes various embodiments that are 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 ... Susceptor, 2 ... Wafer holding part, 3 ... Wafer holding surface

Claims (3)

Silicon carbide ceramics characterized in that the purity of silicon carbide is 99.9999% by weight or more and the density is 2.0 to 3.0 g / cm ³ .   A semiconductor process jig comprising the silicon carbide ceramic according to claim 1.   The semiconductor process jig according to claim 2, wherein the jig is used in a thermal environment to which a thermal stress of 100 MPa or more is applied.

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