Patent ID: 7737065

Claim:
A process of producing an aluminum nitride sintered body comprising sintering a non-fired molded body of a powder mixture comprising an aluminum nitride powder and a sintering aid, wherein the aluminum nitride sintered body has a thermal conductivity of at least 190 W/m·K and a shrinkage factor represented by the percentage of {(dimensions of the molded body before sintering)−(dimensions of the sintered body after sintering)}/(dimensions of the molded body before sintering) of at most 15%, and wherein the aluminum nitride powder comprises: from 40 to 70% of coarse particles having a size of 3 to 15 μm, from 25 to 40% of medium particles having a size of 0.5 to 1.5 μm, and from 0.5 to 20% of fine particles having a size of 0.3 μm or less, the percentages being on a volume basis; and the aluminum nitride powder has an oxygen amount of from 0.5 to 1.5 mass %.