ELECTROSTATIC CHUCK WITH HEATER AND MANUFACTURING METHOD THEREOF

• US 20080174930A1
• Filed: 09/12/2007
• Published: 07/24/2008
• Est. Priority Date: 09/13/2006
• Status: Active Grant

• Current Assignee: NGK Insulators Limited
• Original Assignee: NGK Insulators Limited
• Inventors: Nobori, Kazuhiro, Hattori, Akiyoshi
• Granted Patent: US 7,701,693 B2
• Time in Patent Office: Days
• US Class Current: 361/234
• CPC Class Codes: B29C 43/006 Pressing and sintering powders, granules or fibres
• CPC Class Codes: B29C 67/04 Sintering combined with compression B29C43/00
• CPC Class Codes: B32B 18/00 Layered products essentially comprising ceramics, e.g. refractory products
• CPC Class Codes: C04B 2235/3217 Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
• CPC Class Codes: C04B 2235/6562 Heating rate
• CPC Class Codes: C04B 2235/6584 at an oxygen percentage below that of air
• CPC Class Codes: C04B 2235/721 Carbon content
• CPC Class Codes: C04B 2235/77 Density
• CPC Class Codes: C04B 2235/96 Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
• CPC Class Codes: C04B 2235/9607 Thermal properties, e.g. thermal expansion coefficient
• CPC Class Codes: C04B 2237/34 Oxidic
• CPC Class Codes: C04B 2237/343 Alumina or aluminates
• CPC Class Codes: C04B 35/111 Fine ceramics
• CPC Class Codes: C04B 35/505 based on yttrium oxide
• CPC Class Codes: C04B 35/5626 based on tungsten carbides
• CPC Class Codes: C04B 35/62695 Granulation or pelletising devices for shaping artificial aggregates from ceramic mixtures B28B1/004
• CPC Class Codes: C04B 35/645 Pressure sintering
• CPC Class Codes: C04B 37/001 directly with other burned ceramic articles
• CPC Class Codes: H01L 21/6831 using electrostatic chucks

Abstract

An electrostatic chuck includes a base. The base has a support portion made of alumina ceramics, and a surface portion made of yttria ceramics. The surface portion forms at least a substrate mounting surface and side surface of the base on a surface of the support portion. Carbon contents in alumina ceramics of the support portion and yttria ceramics of the surface portion are 0.05 wt % or less.

Claims

1. An electrostatic chuck, comprising:

a plate-like base that is made of ceramics and has a substrate mounting surface on which a substrate is to be mounted; and

a dielectric electrode embedded in the base,

wherein the base includes a support portion made of alumina ceramics, and a surface portion that is made of yttria ceramics and forms at least the substrate mounting surface of the base on a surface of the base, and

a carbon content in alumina ceramics in a vicinity of the dielectric electrode is 0.05 wt %.

2. The electrostatic chuck according to claim 1,

wherein volume resistivity of alumina ceramics concerned is 1×

10¹⁶ Ω

·

cm or more at room temperature, and is 1×

10¹⁴ Ω

·

cm or more at 150°

C., and volume resistivity of yttria ceramics concerned is 1×

10¹⁶ Ω

·

cm or more at the room temperature, and is 1×

10¹⁵ Ω

·

cm or more at 150°

C.

3. The electrostatic chuck according to claim 1, wherein an at least one of a YAG phase and a YAM phase, which contains yttrium and aluminum, is formed by a thickness of 10 μ

m or more to 100 μ

m or less between alumina ceramics and yttria ceramics.

4. The electrostatic chuck according to claim 1, wherein the dielectric electrode is embedded between alumina ceramics and yttria ceramics that forms the substrate mounting surface of the base.

5. The electrostatic chuck according to claim 1, wherein yttria ceramics is formed on the substrate mounting surface of the base and a side surface thereof, a thickness of a portion of the base, which forms the substrate mounting surface, is 0.2 mm to 0.5 mm, and a thickness of a portion of the base, which forms the side surface of the base, is 0.2 mm to 10 mm.

6. The electrostatic chuck according to claim 1, further comprising:

a heater that is a resistance heating body that contains niobium as a main component and is embedded in a support portion of a base,

wherein a carbon content in alumina ceramics on a periphery of the resistance heating body is 0.05 wt % to 0.25 wt %, and the carbon content is higher than a carbon content in alumina ceramics in a vicinity of the dielectric electrode.

7. A manufacturing method of an electrostatic chuck, comprising the steps of:

forming a plate-like alumina sintered body with a carbon content of 0.05 wt % or less from a raw material of alumina ceramics;

forming a dielectric electrode on one surface of the alumina sintered body;

forming an yttria member so as to cover the dielectric electrode and the surface of the alumina sintered body, on which the dielectric electrode is formed; and

sintering the alumina sintered body and the yttria member while integrally pressing the alumina sintered body and the yttria member in a uniaxial direction, thereby forming a base.

8. The manufacturing method of an electrostatic chuck according to claim 7, wherein the plate-like alumina member has a cutaway portion on an upper circumferential edge portion thereof, and a raw material of yttria ceramics is filled onto the cutaway portion in a case of forming the yttria member.

9. The manufacturing method of an electrostatic chuck according to claim 7, further comprising the step of:

forming a resistance heating body on the other surface of the alumina sintered body before the step of forming an yttria member,

wherein, in the step of forming an yttria member, the yttria member is formed so as to cover the resistance heating body and the surface of the alumina sintered body, on which the resistance heating body is formed.

10. The manufacturing method of an electrostatic chuck according to claim 7, wherein a carbon amount in the raw material of yttria ceramics of the yttria member is 0.001 wt % or more to less than 0.05 wt %.