Patent ID: 7018494

Claim:
A method of producing a composite sheet comprising: a step of preparing a first ceramic sheet from a ceramic powder, and a different kind of sheet made of a material different from that of the first ceramic sheet, both of said sheets having substantially the same thickness; a step of forming a through hole in a predetermined portion of said first ceramic sheet; a step of laminating said different kind of sheet on said first ceramic sheet in which said through hole is formed; a step of preparing a composite sheet by pressing the portion of said first ceramic sheet where the through hole is formed from the side of said different kind of sheet, such that a portion of said different kind of sheet is buried in the through hole in a manner that said first ceramic sheet and said different kind of sheet are integrated together; and a step of applying a paste onto the boundary portion between the first ceramic sheet and the different kind of sheet to form a coating layer on said portion, wherein said different kind of sheet is a burn-and-extinguish sheet made of a material that extinguishes by burning through the heat treatment.