ALUMINA SINTERED BODY

Abstract

An alumina sintered body comprises an alumina substrate having a first main surface and a second main surface opposing each other, an embedded film electrode made of a metal and embedded in the alumina substrate at a depth HD of 0.4 mm or less from a first main surface SF1, and an embedded terminal formed of a metal, embedded in the alumina substrate nearer a second main surface SF2 side than the embedded electrode. The embedded terminal is in contact with the embedded electrode and a film thickness HE of the embedded electrode is 25 μm or less.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the invention will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only exemplary embodiments and are, therefore, not to be considered limiting of the invention's scope, the exemplary embodiments of the invention will be described with additional specificity and detail through use of the accompanying drawings in which:

FIG. 1 is a sectional view showing an entire structure of an electrostatic chuck shown as an example of an alumina sintered body according to an embodiment of the present invention;

FIG. 2 is an enlarged sectional view of a center portion of an alumina substrate shown in FIG. 1;

FIG. 3 is a table showing results of experiments conducted by the present inventors (Part 1);

FIG. 4 is a table showing results of experiments conducted by the present inventors (Part 2);

FIG. 5 is a sectional view showing an alumina sintered body having a mesh-type electrode embedded in an alumina substrate;

FIG. 6 is an enlarged sectional view of a center portion of the alumina substrate shown in FIG. 5; and

FIG. 7 is a sectional view for explaining generated cracks in a dielectric layer of an alumina substrate.

Claims

1. An alumina sintered body comprising: an alumina substrate having a first main surface and a second main surface opposing each other;an embedded film electrode made of a metal and embedded in the alumina substrate at a depth of 0.4 mm or less from the first main surface; andan embedded terminal formed of a metal, embedded in the alumina substrate nearer the second main surface side than the embedded electrode, whereinthe embedded terminal is in contact with the embedded electrode and a film thickness of the embedded electrode is 25 μm or less.

2. The alumina sintered body according to claim 1, wherein an outer peripheral portion of the embedded terminal is chamfered at a contact surface at which the embedded terminal is in contact with the embedded electrode.

3. The alumina sintered body according to claim 2, wherein a radius of curvature of the outer peripheral portion chamfered is 0.2 mm or more.