Patent ID: 6086990
Filing Date: 2000-07-11
Classification: C04B,H01L,H05K,Y10T

Abstract:
A high thermal conductivity silicon nitride circuit substrate which comprises:a silicon nitride ceramic plate having a thermal conductivity at 25.degree. C. of 60 W/m.multidot.K or more, which contains a rare earth element in an amount of 1.0 to 12.5% by weight calculated on oxide, and contains lithium, sodium, potassium, iron, calcium, magnesium, strontium, barium, manganese and boron in a total amount of 0.3% or less by weight as impurity cationic elements; anda metal circuit plate joined to the silicon nitride ceramic plate through an intermediate layer containing oxygen and at least element selected from the group consisting of titanium, zirconium, hafnium and niobium.