Electrostatic chuck and manufacturing method thereof

• US 20080100985A1
• Filed: 10/30/2007
• Published: 05/01/2008
• Est. Priority Date: 11/01/2006
• Status: Active Grant

• Current Assignee: NGK Insulators Limited
• Original Assignee: NGK Insulators Limited
• Inventors: Hattori, Akiyoshi
• Granted Patent: US 7,633,738 B2
• Time in Patent Office: Days
• US Class Current: 361/234
• CPC Class Codes: H01L 21/6831 using electrostatic chucks

Abstract

An electrostatic chuck includes a base, and includes an electrode embedded in the base in parallel to a substrate mounting surface of the base. A terminal loaded into a terminal hole drilled into a back surface of the base toward the electrode is bonded to the electrode having a protruded portion with a substantially conical trapezoidal shape, which is formed on a flat surface on the terminal side of the electrode toward the terminal hole. In the protruded portion, an angle made by the flat surface on the terminal side of the electrode and an inclined surface of the protruded portion is 40° or less, and a distance from the flat surface of the electrode to a terminal-bonding surface of the protruded portion is 0.01 to 0.8 mm.

Claims

1. An electrostatic chuck, comprising:

a base made of substantially disc-like alumina ceramics and having a substrate mounting surface;

an electrode embedded in the base in parallel to the substrate mounting surface of the base; and

a terminal loaded into a terminal hole drilled toward the electrode from the opposite side surface of the substrate mounting surface of the base,

wherein the electrode has approximately constant thickness and includes, at a portion thereof going toward the terminal hole, a protruded portion with a substantially conical trapezoidal shape, the protruded portion being made of the same type of material as a material of the electrode, being bonded to the terminal, and

in the protruded portion, an angle made by a flat surface on the terminal side of the electrode, from which the protruded portion is protruded, and an inclined surface of the protruded portion is 40°

or less, and a distance from the flat surface on the terminal side of the electrode to a terminal-bonding surface of the protruded portion is 0.01 mm or more to less than 0.8 mm.

2. The electrostatic chuck according to claim 1, wherein the distance from the flat surface on the terminal side of the electrode to the terminal-bonding surface of the protruded portion is 0.02 to 0.4 mm.

3. The electrostatic chuck according to claim 1, wherein, in the protruded portion with the substantially conical trapezoidal shape, a diameter of a bottom surface thereof is 2 to 6 mm.

4. The electrostatic chuck according to claim 1, wherein a diameter of the end surface of the terminal is larger than a diameter of a top surface of the protruded portion with the substantially conical trapezoidal shape.

5. The electrostatic chuck according to claim 1, wherein the electrode contains conductive powder and alumina powder, and an addition amount of the alumina powder to the conductive powder is 5 to 20 vol %.

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

fabricating an alumina sintered body of a portion of a dielectric layer including a substrate mounting surface, the portion belonging to a base;

forming a flat electrode having approximately constant thickness, on a surface of the alumina sintered body;

forming a protruded portion made of the same type of material as a material of the electrode on a part of the flat electrode so that a thickness of the protruded portion can be 0.8 mm or less and that an angle made by the flat surface on the terminal side of the electrode and an inclined surface of the protruded portion can be 40°

or less;

forming a support portion of the base to cover the alumina sintered body and the electrode, and then integrally sintering the support portion and the portion of the dielectric layer;

drilling a terminal hole from the opposite side surface of the substrate mounting surface of the base toward the protruded portion, exposing the protruded portion to a bottom surface of the terminal hole, and setting a distance of the protruded portion from the flat surface on the terminal of the electrode to a bottom surface of a terminal hole at 0.01 mm or more to less than 0.8 mm; and

loading the terminal into the terminal hole, and bonding the terminal to the protruded portion by brazing.