Joined ceramic article, substrate holding structure and apparatus for treating substrate

A substrate holding structure (1) holding a substrate when processing the substrate, comprising:

• a ceramic base (2) for holding the substrate;
• an airtight sealing member (7) joined to said ceramic base;
• and
• a joining layer (8) positioned between said ceramic base (2) and said airtight sealing member (7) for joining said ceramic base (2) and said airtight sealing member (7) to each other, wherein
• said joining layer (8) is formed by heating/calcining a joining material containing 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, and
• said rare earth oxide or said aluminum oxide has the largest ratio among said three types of components in said joining layer (8).

A ceramic joined body comprising:

• a first ceramic body (2);
• a second ceramic body (7) joined to said first ceramic body (2);
• and
• a joining layer (8) positioned between said first ceramic body (2) and said second ceramic body (7) for joining said first ceramic body (2) and said second ceramic body (7) to each other, wherein
• said joining layer (8) contains:
• 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, and
• said rare earth oxide or said aluminum oxide has the largest ratio among said three types of components in said joining layer (8).

A ceramic joined body (1) comprising:

• a first ceramic body (2);
• a second ceramic body (7) joined to said first ceramic body (2);
• and
• a joining layer (8) positioned between said first ceramic body (2) and said second ceramic body (7) for joining said first ceramic body (2) and said second ceramic body (7) to each other, wherein
• said joining layer (8) is formed by heating/calcining a joining material containing 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, and
• said rare earth oxide or said aluminum oxide has the largest ratio among said three types of components in said joining layer (8).