Substrate used for fabrication of thick film circuit.

摘要

An insulating substrate is used for fabrication of a thick film circuit and comprises a foundation (1) of aluminum nitride and a surface film structure (2) provided on the foundation, in which the foundation contains at least one oxidizing agent selected from the group consisting of an yttrium oxide and a calcium oxide ranging from 0.1 % to 10 % by weight for enhancing a stiffness of the foundation, and in which the surface film structure is of the multi-level surface film structure having a lower surface film (3) of an aluminum oxide rapidly grown on the foundation in the presence of the oxidizing agent and an upper surface film (4) containing a silicon oxide and a substance selected from the group consisting of a zirconium oxide, a titanium oxide and a boron oxide for enhancing the resistivity against a firing operation.