Aluminum nitride sintered substrate, manufacturing method thereof, and insulating substrate for electronic circuits

Abstract

The present invention aims to improve heat cycle resistance in an aluminum nitride sintered substrate by a method advantageous for improving partial discharge resistance. An aluminum nitride sintered substrate according to the present invention is made of a plate-shaped aluminum nitride sintered body; when a region from a surface to a depth of one-third of the plate thickness is called a surface layer portion, and a region other than the surface layer portion is called a plate thickness central portion, at least one of the surface layer portions is a zirconium-distributed surface layer portion containing a greater amount of zirconium atoms than the plate thickness central portion. The aluminum nitride sintered substrate can be obtained by a manufacturing method that includes the steps of: applying paste A containing aluminum nitride powder to a plate to obtain a base sheet; applying paste B containing aluminum nitride powder and powder of a zirconium-containing substance to at least one surface of the base sheet to obtain a multilayer sheet; and heating and sintering the multilayer sheet.

Images