Patent ID: 7211153

Claim:
A substrate holding structure adapted to hold a substrate when processing the substrate, comprising: a ceramic base adapted to hold the substrate and including a ceramic member and an electric circuit element; an electricity feeding conductive member connected to said electric circuit element; an airtight sealing member joined to said ceramic base and enclosing said conductive member; and a joining layer that is positioned between said ceramic base and said airtight sealing member and joins said ceramic base and said airtight sealing member to each other, and that exhibits a helium leak rate of less than 1.0×10 −8 Pa·m 3 /s therethrough; wherein: said joining layer consists of: at least 2 mass % and not more than 70 mass % of a rare earth oxide, at least 10 mass % and not more than 78 mass % of aluminum oxide, and at least 2 mass % and not more than 50 mass % of aluminum nitride including aluminum nitride grains formed by precipitation of said aluminum nitride resulting from dissolution-reprecipitation; said aluminum oxide has the largest proportional content among said rare earth oxide, said aluminum oxide and said aluminum nitride in said joining layer.