초록 ▼

A conductor pattern is formed on at least one surface of an AlN- or Si.sub.3 N.sub.4 -based ceramic substrate which is such that the ratio between the principal metal component binding with N to form the ceramic mass and the B in the BN remaining on the surface layer is no more than 50.times.10.sup.

A conductor pattern is formed on at least one surface of an AlN- or Si.sub.3 N.sub.4 -based ceramic substrate which is such that the ratio between the principal metal component binding with N to form the ceramic mass and the B in the BN remaining on the surface layer is no more than 50.times.10.sup.-6 as either B/Al or B/Si, wherein B/Al represents the ratio of I.sub.B to I.sub.Al where I.sub.B is the X-ray diffraction intensity of boron present on the surface layer and I.sub.Al is the X-ray diffraction intensity of aluminum, and B/Si represents the ratio of I.sub.B to I.sub.Si where I.sub.B is as defined above and I.sub.Si is the X-ray diffraction intensity of silicon. The thus produced circuit board has both a peel strength of at least 30 kg/mm.sup.2 and a capability of withstanding at least 30 heat cycles and, hence, satisfies the performance requirements of the recent models of power module ceramic circuit boards.

대표청구항 ▼

[ What is claimed is:] [1.] A power module circuit board comprising an AlN-based ceramic substrate having carried on at least one surface thereof a conductor pattern, said AlN-based ceramic substrate being mass-produced by sintering a plurality of stacked AlN-based ceramic substrates in the presence

[ What is claimed is:] [1.] A power module circuit board comprising an AlN-based ceramic substrate having carried on at least one surface thereof a conductor pattern, said AlN-based ceramic substrate being mass-produced by sintering a plurality of stacked AlN-based ceramic substrates in the presence of a release agent comprising boron nitride, said boron nitride preventing one substrate from adhering to an adjacent substrate, a ratio of I.sub.B to I.sub.Al being no more than 50.times.10.sup.-6, wherein I.sub.B represents the X-ray diffraction intensity of boron present on the surface of the AlN-based ceramic substrate and I.sub.Al represents the X-ray diffraction intensity of aluminum of the AlN-based ceramic substrate.