SEMICONDUCTOR MANUFACTURING MEMBER AND MANUFACTURING METHOD THEREFOR

Abstract

The present invention relates to a semiconductor manufacturing member including a silicon carbide-containing boron carbide film at least on a surface thereof, in which the silicon carbide-containing boron carbide film has a content of silicon carbide of 5 wt % or more and 18 wt % or less and a balance being boron carbide.

Claims

1. A semiconductor manufacturing member comprising a silicon carbide-containing boron carbide film at least on a surface thereof, wherein the silicon carbide-containing boron carbide film has a content of silicon carbide of 5 wt % or more and 18 wt % or less and a balance being boron carbide.

2. The semiconductor manufacturing member according to claim 1, wherein the silicon carbide-containing boron carbide film has a porosity of 5% or less.

3. The semiconductor manufacturing member according to claim 1, wherein the silicon carbide-containing boron carbide film is formed on a surface of a base material comprising silicon.

4. The semiconductor manufacturing member according to claim 2, wherein the silicon carbide-containing boron carbide film is formed on a surface of a base material comprising silicon.

5. A method of manufacturing a semiconductor manufacturing member comprising: preparing a raw material comprising silicon carbide and boron carbide; and thermally spraying the raw material onto a base material to form a thermal-sprayed film comprising boron carbide comprising 5 wt % or more and 18 wt % or less of silicon carbide.

6. The method of manufacturing a semiconductor manufacturing member according to claim 5, further comprising removing the base material.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0033] FIG. 1 is a cross-sectional view schematically illustrating a configuration of a semiconductor manufacturing member.

[0034] FIG. 2A is a modification of the semiconductor manufacturing member of FIG. 1.

[0035] FIG. 2B is a modification of the semiconductor manufacturing member of FIG. 1.

[0036] FIG. 3 is a graph showing results of Examples and Comparative Examples of the present invention with respect to a sputtered amount of Ar.

[0037] FIG. 4 is a graph showing results of Examples and Comparative Examples of the present invention with respect to a consumed amount of oxygen plasma.

[0038] FIG. 5 is a graph showing results of Examples and Comparative Examples of the present invention with respect to a consumed amount of fluorine plasma.

DESCRIPTION OF EMBODIMENTS

[0039] Hereinafter, embodiments according to the present invention will be described with reference to FIGS. 1, 2A, and 2B. The present invention is not limited to the embodiments described below. As FIG. 1 is a cross-sectional view schematically illustrating a configuration of a semiconductor manufacturing member and FIGS. 2A and 2B illustrate modifications of the semiconductor manufacturing member of FIG. 1, dimension relationship of elements, ratios of the elements, and the like are different from actual ones.

[0040] A semiconductor manufacturing member 100 illustrated in the drawing is configured with a base material 1 and a silicon carbide-containing boron carbide film 2 formed so as to cover a surface of the base material 1.

[0041] The base material 1 may be any material having plasma resistance, and for example, silicon and alumina are suitable. In particular, when silicon is used as the base material 1, for example, in the case of forming a focus ring as the semiconductor manufacturing member 100, shape processing thereof can be easily performed by using existing techniques and apparatuses.

[0042] The silicon carbide-containing boron carbide film 2 is formed to have a thickness of, for example, 500 μm. The content of silicon carbide (SiC) in the silicon carbide-containing boron carbide film 2 is 5 wt % or more and 18 wt % or less. The silicon carbide is desirably contained at more than 5 wt %, and more preferably contained at 6 wt % or more and 10 wt % or less.

[0043] When the content of silicon carbide is less than 5 wt %, the corrosion resistance effect to the oxygen plasma is reduced, which is not preferable.

[0044] On the other hand, when the content of silicon carbide is 5 wt % or more and up to 18 wt %, the corrosion resistance to oxygen plasma is improved. When the content of silicon carbide exceeds 18 wt %, further corrosion resistance effect cannot be expected.

[0045] For Ar plasma, since Ar+ ions are sputtered due to physical corrosion, the corrosion resistance is related to the strength of atomic bonds.

[0046] Since silicon carbide has a smaller atomic bond than boron carbide, as the added amount relatively increases, the sputtering rate increases, and thus, the corrosion resistance decreases. When the content of silicon carbide is 18 wt % or less, the corrosion resistance increases, and when the content of silicon carbide is less than 5 wt %, the corrosion resistance does not change substantially.

[0047] The content of silicon carbide has almost no effect on the fluorine plasma.

[0048] In addition, in the dry etching process in semiconductor manufacturing, the processes used in the plasma atmosphere of a single gas are limited, and thus, in many cases, interaction occurs in the plasma atmosphere of a mixed gas. Considering an advanced process in which a very high frequency power is applied, it is more preferable that the content of silicon carbide for obtaining a stable corrosion resistance effect is 6 wt % or more and 10 wt % or less.

[0049] The silicon carbide-containing boron carbide film 2 is preferably formed by thermal spraying, but may be formed by a CVD method or a PVD method by adjusting the composition ratio of boron carbide and silicon carbide.

[0050] While the CVD method can easily form a high-purity film, the thermal-sprayed film has a feature that the film can be easily formed on various substrates.

[0051] In the embodiment illustrated in FIG. 1, the silicon carbide-containing boron carbide film 2 is configured to be formed on the surface of the base material 1, but by forming the silicon carbide-containing boron carbide film 2 to be thick on the upper surface of the base material 1 as illustrated in FIG. 2A and by removing the base material 1 as illustrated in FIG. 2B, the semiconductor manufacturing member 100 including only the silicon carbide-containing boron carbide film 2 may be formed.

[0052] In addition, when the silicon carbide-containing boron carbide film 2 is a thermal-sprayed film, the temperature and collision rate of the raw material particles deposited on the base material 1 in the film forming process by thermal spraying become important factors that determine the density of the film and the adhesion to the base material 1.

[0053] In the present invention, the temperature and collision rate of the raw material particles are not limited, but in the case of forming, a thermal spraying method according to the physical properties of a to-be-coated material and the application thereof may be employed. For example, since boron carbide has a high melting point of 2763° C. and is oxidized under an oxygen atmosphere, a reduced pressure plasma spraying method or an electromagnetically accelerated plasma spraying method is preferable.

[0054] The sublimation temperature of silicon carbide is 2545° C. to 2730° C. which is lower than the melting point of boron carbide of 2763° C., and thus the silicon carbide is usually volatilized during the thermal spraying. For this reason, depending on the thermal spraying method, it is necessary to adjust the particle size and the mixing amount of silicon carbide, and the silicon carbide has a structure dispersed as particles in the thermal-sprayed film.

[0055] As described above, according to the embodiment of the present invention, since the silicon carbide-containing boron carbide film 2 is formed on the base material 1, and 5 wt % or more and 18 wt % or less, more preferably 6 wt % or more and 10 wt % or less of silicon carbide is contained in boron carbide, it is possible to improve the corrosion resistance to oxygen plasma and Ar plasma.

[0056] In addition, when the base material 1 includes silicon, since an existing manufacturing technique can be used, shape processing of a semiconductor manufacturing member such as a focus ring can be easily performed.

EXAMPLE

[0057] The semiconductor manufacturing member and the manufacturing method therefor according to the present invention will be further described based on Examples.

Example 1

[0058] In Example 1, a silicon carbide-containing boron carbide (B.sub.4C) film having a thickness of 500 μm was formed onto a silicon substrate by thermal spraying to prepare a sample. A content of silicon carbide (SiC) in a boron carbide film after thermal spraying was set to 5 wt %. In the measurement of the silicon carbide content of the silicon carbide-containing boron carbide film, the silicon substrate was polished and removed, the remaining silicon substrate was melted and removed using an acid, and only the silicon carbide-containing boron carbide film was taken out. Then, the amount of boron and silicon was detected by ICP-MS, and the amount of SiC was calculated from the ratio. A surface after the thermal spraying was mirror-finished.

[0059] Further, the porosity of the silicon carbide-containing boron carbide film, which was observed with an optical microscope and was calculated by image editing software, was 3.9%.

[0060] The sputter rate for Ar ions was measured for the sample. The measurement conditions were that an Ar ion beam capable of generating high energy was used, a voltage was set to 3 kV, a beam current was set to 25 μA, and an irradiation time was set to 3 hours. Then, a sputtered consumed amount was measured.

Example 2

[0061] In Example 2, a content of silicon carbide in a silicon carbide-containing boron carbide film of a sample was set to 7 wt %. Other conditions are the same as those in Example 1. The porosity of the silicon carbide-containing boron carbide film was 4.1%. Similarly to Example 1, for this sample, the sputter rate for Ar ions was measured.

Example 3

[0062] In Example 3, a content of silicon carbide in a silicon carbide-containing boron carbide film of a sample was set to 18 wt %. Other conditions are the same as those in Example 1. The porosity of the silicon carbide-containing boron carbide film was 5.0%. Similarly to Example 1, for this sample, the sputter rate for Ar ions was measured.

Comparative Example 1

[0063] In Comparative Example 1, a content of silicon carbide in a silicon carbide-containing boron carbide film of a sample was set to 0 wt %. Other conditions are the same as those in Example 1. The porosity of the boron carbide film was 3.5%. Similarly to Example 1, for this sample, the sputter rate for Ar ions was measured.

Comparative Example 2

[0064] In Comparative Example 2, a silicon carbide film (100%) having a thickness of 500 μm was formed on a silicon substrate by a CVD method to prepare a sample. Other conditions are the same as those in Example 1. The porosity of the silicon carbide film was 0%. Similarly to Example 1, for this sample, the sputter rate for Ar ions was measured.

Comparative Example 3

[0065] In Comparative Example 3, a silicon substrate having no film formed on a surface was used as a sample. Other conditions are the same as those in Example 1. Similarly to Example 1, for this sample, the sputter rate for Ar ions was measured.

[0066] The graph of FIG. 3 shows the results of Examples 1, 2, and 3, and Comparative Examples 1, 2, and 3. In the graph of FIG. 3, the vertical axis is the etching amount (μm/h).

[0067] As shown in the graph of FIG. 3, it was found that the etching amount was suppressed by forming the silicon carbide-containing boron carbide film on the silicon surface (Comparative Example 1, Examples 1, 2, and 3).

Example 4

[0068] The etching rate for oxygen plasma was measured for the sample prepared by the same method as that in Example 1. In the measurement of the etching rate for oxygen plasma, the sample was exposed to the oxygen plasma under a reduced pressure of 2.66 Pa at a high frequency power of 800 W, O.sub.2=50 sccm, and at 200° C. for 30 minutes by using an ICP plasma etching apparatus. Then, the consumed amount was measured.

Example 5

[0069] The same experiment as that in Example 4 was performed on the sample prepared by the same method as that in Example 2.

Example 6

[0070] The same experiment as that in Example 4 was performed on the sample prepared by the same method as that in Example 3.

Comparative Example 4

[0071] The experiment of Example 4 was performed on the sample prepared by the same method as that in Comparative Example 1.

Comparative Example 5

[0072] The experiment of Example 4 was performed on the sample prepared by the same method as that in Comparative Example 2.

Comparative Example 6

[0073] The experiment of Example 4 was performed on the sample prepared by the same method as that in Comparative Example 3.

[0074] The graph of FIG. 4 shows the results of Examples 4, 5, and 6, and Comparative Examples 4, 5, and 6. In the graph of FIG. 4, the vertical axis is the etching amount (μm/h).

[0075] As shown in the graph of FIG. 4, it was found that, when the boron carbide film was formed on the silicon surface, etching amount was suppressed by setting the content of silicon carbide to 5% (Example 4), 7% (Example 5), and 18% (Example 6).

Example 7

[0076] The etching rate for fluorine plasma was measured for the sample prepared by the same method as that in Example 1. In the measurement of the etching rate for fluorine plasma, the sample was exposed to the fluorine plasma under a reduced pressure of 2.66 Pa at a high frequency power of 500 W/bias power of 40 W, CF.sub.4=100 sccm, and at room temperature for 4 hours by using an ICP plasma etching apparatus. Then, the consumed amount was measured.

Example 8

[0077] The experiment of Example 7 was performed on the sample prepared by the same method as that in Example 2.

Example 9

[0078] The experiment of Example 7 was performed on the sample prepared by the same method as that in Example 3.

Comparative Example 7

[0079] The experiment of Example 7 was performed on the sample prepared by the same method as that in Comparative Example 1.

Comparative Example 8

[0080] The experiment of Example 7 was performed on the sample prepared by the same method as that in Comparative Example 2.

Comparative Example 9

[0081] The experiment of Example 7 was performed on the sample prepared by the same method as that in Comparative Example 3.

[0082] The graph of FIG. 5 shows the results of Examples 7, 8, and 9, and Comparative Examples 7, 8, and 9. In the graph of FIG. 5, the vertical axis is the etching amount (μm/h).

[0083] As shown in the graph of FIG. 5, no difference in effectiveness was admitted when the boron carbide film, silicon carbide film and boron carbide film changing in the content of silicon carbide were formed on the silicon surface.

Example 10

[0084] The semiconductor manufacturing member was manufactured by the same method as that in Example 1. However, the thermal-sprayed film was thickened up to 2.0 mm, and then the silicon substrate was polished and removed. When the same experiments as those in Examples 1, 4, and 7 were performed, the corrosion resistance to various plasmas was the same as those in Examples 1, 4, and 7.

Comparative Example 10

[0085] The semiconductor manufacturing member was manufactured by the same method as that in Example 1. However, the thickness of the thermal-sprayed film was changed to 100 μm, 200 μm, and 300 μm. As a result, at thicknesses of 100 μm and 200 μm, the thermal-sprayed film was slightly non-uniform and the porosity was about 10 to 20%. At a thickness of 300 μm, the thermal-sprayed film was formed to be almost uniform, and the porosity was 5% or less.

[0086] As a result of Examples 1 to 10 above, it was confirmed that the corrosion resistance to the Ar plasma and the oxygen plasma can be improved by the content of silicon carbide in the boron carbide film at 5 wt % or more and 18 wt % or less. In particular, it was found that the effect is great when the content of silicon carbide in the boron carbide film is 6 wt % or more and 10 wt % or less.

[0087] Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made in the limitation disclosed in the claims. This application is based on and claims the benefit of priority from Japanese Patent Application No. 2020-144771, filed Aug. 28, 2020, and Japanese Patent Application No. 2021-097822, filed Jun. 11, 2021, the entire contents of which are incorporated herein by reference. [0088] 1 Base material [0089] 2 Silicon carbide-containing boron carbide film [0090] 100 Semiconductor manufacturing member