ELECTROSTATIC CHUCK

• US 20070217114A1
• Filed: 01/30/2007
• Published: 09/20/2007
• Est. Priority Date: 01/31/2006
• Status: Active Grant

• Current Assignee: Sumitomo Osaka Cement Company Limited, Tokyo Electron Limited
• Original Assignee: Sumitomo Osaka Cement Company Limited, Tokyo Electron Limited
• Inventors: Nakagawa, Yusuke, Nagayama, Nobuyuki, Sasaki, Yasuharu, Ueda, Takehiro, Kosakai, Mamoru, OKajo, Taketoshi
• Granted Patent: US 7,646,581 B2
• Time in Patent Office: Days
• US Class Current: 361/145
• CPC Class Codes: C23C 14/505 for rotation of the substrates
• CPC Class Codes: C23C 16/4581 characterised by material of construction or surface finish of the means for supporting the substrate
• CPC Class Codes: C23C 16/4586 Elements in the interior of the support, e.g. electrodes, heating or cooling devices
• CPC Class Codes: H01L 21/6831 using electrostatic chucks
• CPC Class Codes: H01L 21/6875 characterised by a plurality of individual support members, e.g. support posts or protrusions

Abstract

The invention provides an electrostatic chuck capable of widening a temperature range when the temperature of a flat substrate is controlled and reducing a variation in thermal conductivity between the electrostatic chuck and the flat substrate over time. According to an aspect of the invention, an electrostatic chuck includes: a body that has an internal electrode for attracting a flat substrate by an electrostatic force provided therein; a plurality of protrusions that are formed on one surface of the body, serving as an electrostatic attraction surface; and one or more minute projections that are provided on each of top surfaces of some or all of the plurality of protrusions. In the electrostatic chuck, a region of the top surface of each of the minute projections on which the flat substrate is loaded is referred to as a mounting surface, and the total area of the mounting surfaces of the minute projections is equal to or larger than 0.01% and equal to or smaller than 2% of the area of the electrostatic attraction surface.

Claims

1. An electrostatic chuck comprising:

a body that has an internal electrode for attracting a flat substrate by an electrostatic force provided therein;

a plurality of protrusions that are formed on one surface of the body, serving as an electrostatic attraction surface; and

one or more minute projections that are provided on each of top surfaces of some or all of the plurality of protrusions,

wherein a region of the top surface of each of the minute projections on which the flat substrate is loaded is referred to as a mounting surface, and

the total area of the mounting surfaces of the minute projections is equal to or larger than 0.01% and equal to or smaller than 2% of the area of the electrostatic attraction surface.

2. The electrostatic chuck according to claim 1,

wherein the area of the mounting surface of the minute projection is equal to or larger than 2×

10<sup>−

3</sup> mm² and equal to or smaller than 0.8 mm².

3. The electrostatic chuck according to claim 1,

wherein the height of the minute projection from the top surface of the protrusion is equal to or larger than 1 μ

m and equal to or smaller than 10 μ

m.

4. The electrostatic chuck according to claim 1,

wherein the height of the minute projection from the one surface of the body is equal to or larger than 10 μ

m and equal to or smaller than 60 μ

m.

5. The electrostatic chuck according to claim 1,

wherein the area of the mounting surface of the minute projection is equal to or larger than 0.05% and equal to or smaller than 50% of the area of the protrusion.

6. The electrostatic chuck according to claim 1,

wherein the total area of the plurality of protrusions is equal to or larger than 15% and equal to or smaller than 60% of the area of the electrostatic attraction surface.

7. The electrostatic chuck according to claim 1,

wherein a curved portion having a curvature radius of equal to or larger than 0.5 μ

m and equal to or smaller than 5 μ

m is formed in the circumference of the top surface of the minute projection.

8. The electrostatic chuck according to claim 1,

wherein the protrusions and the minute projections are formed of a composite sintered material of aluminum oxide and silicon carbide that includes equal to or larger than 1% by weight and equal to or smaller than 12% by weight of silicon carbide,

the average diameter of aluminum oxide particles is equal to or smaller than 2 μ

m, and

the average diameter of silicon carbide particles is equal to or smaller than 0.2 μ

m.

9. The electrostatic chuck according to claim 1,

wherein a wall portion is provided in a ring shape along the circumference of the electrostatic attraction surface, and

the flat substrate is loaded on the top surface of the wall portion and the top surfaces of the minute projections.

10. The electrostatic chuck according to claim 9,

wherein a step portion is provided in the top surface of the wall portion along the inner circumference of the wall portion, and

the flat substrate is loaded on portions of the top surface other than the step portion.

11. The electrostatic chuck according to claim 10,

wherein one or more second minute projections are provided on the step portion, and

the flat substrate is loaded on the top surfaces of the second minute projections.

12. The electrostatic chuck according to claim 10,

wherein a second wall portion is provided in a ring shape on the step portion along the circumference of the step portion, and

the flat substrate is loaded on the top surface of the second wall portion.

13. The electrostatic chuck according to claim 12,

wherein the height of the second wall portion from the step portion is in the range of equal to or larger than 1 μ

m and equal to or smaller than 10 μ

m.