Focus ring and method for producing focus ring

Patent metadata

Field	Value
Publication number	US-10273190-B2
Application number	US-201615742421-A
Country	US
Kind code	B2
Filing date	Aug 23, 2016
Priority date	Sep 3, 2015
Publication date	Apr 30, 2019
Grant date	Apr 30, 2019

Abstract

The present invention provides a focus ring having favorable plasma resistance. In addition, the present invention provides a method for producing a focus ring which enables the easy production of focus rings having favorable plasma resistance. The focus ring of the present invention is a focus ring made of a sintered body of silicon carbide, in which the sintered body includes a plurality of first crystal grains having an α-SiC-type crystal structure and a plurality of second crystal grains having a β-SiC-type crystal structure, a content of the first crystal grains is 70% by volume or more of a total of the first crystal grains and the second crystal grains, and a volume-average crystallite diameter of the first crystal grains is 10 μm or less.

First claim

The invention claimed is:

1. A focus ring comprising:
a sintered body of silicon carbide, the sintered body including a plurality of first crystal grains having an α-SiC-type crystal structure and a plurality of second crystal grains having a β-SiC-type crystal structure, in which
a content of the first crystal grains is 70% by volume or more of a total of the first crystal grains and the second crystal grains, and
a volume-average crystallite diameter of the first crystal grains is 10 μm or less.

2. The focus ring according to claim 1 ,
wherein a volume-average crystallite diameter of the second crystal grains is smaller than the volume-average crystallite diameter of the first crystal grains.

3. The focus ring according to claim 1 ,
wherein an average volume intrinsic resistance of the sintered body is 0.1 Ω·cm or more and 100 Ω·cm or less.

4. The focus ring according to claim 1 ,
wherein a thermal conductivity of the focus ring is 100 W/mK or more, and
thermal conductivities of the focus ring in a circumferential direction and in a radial direction are greater than a thermal conductivity in a thickness direction.

5. The focus ring according to claim 1 ,
wherein a relative density of the sintered body is 95% or more.

6. The focus ring according to claim 1 ,
wherein a ratio of a mass of impurities in the sintered body to a mass of the entire focus ring is 500 ppm or less.

7. A method for producing a focus ring, the method comprising:
mixing first particles which have an α-SiC-type crystal structure and an average particle diameter of 5 μm or less and second particles which have a β-SiC-type crystal structure and an average particle diameter of 0.1 μm or less so that a content of the first particles reaches 70% by volume or more of a total of the first particles and the second particles; and
sintering a mixture including mixed particles of the first particles and the second particles using a hot press,
wherein, in the sintering, the mixture is heated and pressurized at 2,200° C. or higher and 2,500° C. or lower and 20 MPa or more and 50 MPa or less, and a heating temperature-rise rate from 1,400° C. to 2,000° C. is 10° C./minute or more and 30° C./minute or less.

8. The method for producing a focus ring according to claim 7 , further comprising, prior to the mixing:
synthesizing the second particles using a thermal plasma CVD method.

9. The method for producing a focus ring according to claim 7 ,
wherein, in the mixing, the first particles and the second particles are respectively sprayed at a high speed and caused to collide with each other.

10. The method for producing a focus ring according to claim 7 ,
wherein, in the mixing, a compound including impurity elements which are elements other than silicon and carbon is further mixed thereinto, and a ratio of a mass of the impurity elements to a mass of the entire mixed particles is 500 ppm or less.

Assignees

• Sumitomo Osaka Cement Co Ltd

Inventors

• Nagatomo Hiroaki

Classifications

• H10P72/722

  Details of electrostatic chucks · CPC title

• H10P50/242

  of Group IV materials · CPC title

• C04B2235/786

  Micrometer sized grains, i.e. from 1 to 100 micron · CPC title

• H01B1/04

  mainly consisting of carbon-silicon compounds, carbon or silicon · CPC title

• C04B35/565 Primary

  based on silicon carbide · CPC title