Patent ID: 6569514
Filing Date: 2003-05-27
Classification: H01L,H05K,Y10T

Abstract:
A ceramic circuit board comprising:a ceramic substrate and a metal circuit portion bonded to a main surface of said ceramic substrate; a ratio of Ra1/Ra2 ranging from 1/1.5 to 1.5 in which a surface roughness in terms of arithmetical average surface roughness in one arbitrary direction of said main surface of said ceramic substrate is Ra1 while a surface roughness in a direction normal to said one arbitrary direction is Ra2, wherein a chipping flaw having a diameter of 1 &mgr;m or more is not formed on the surface of said ceramic substrate; a breakdown voltage of said ceramic substrate being 20 kV/mm or more; said metal circuit portion being bonded to said ceramic substrate through a brazing material layer containing at least one active metal selected from the group consisting of Ti, Zr, Hf, Al, and Nb; said metal circuit portion comprising a metal circuit plate such that a bonding strength between the metal circuit plate and the ceramic substrate is 12 kN/m or more; and said ceramic substrate having a thickness of 0.7 mm or less.