Patent ID: 7819995

Claim:
A method of manufacturing a multilayer ceramic substrate, the method comprising: providing a non-sintered multilayer ceramic substrate having a plurality of low temperature sintering green sheets laminated therein; disposing a hard-to-sinter constraining green sheet on at least one of top and bottom surfaces of the non-sintered multilayer ceramic substrate; sintering the non-sintered multilayer ceramic substrate having the hard-to-sinter constraining layer disposed thereon; immersing the sintered multilayer ceramic substrate into an acidic solution; and activating a contact between the hard-to-sinter constraining layer and the acidic solution such that the hard-to-sinter constraining layer is removed, wherein the hard-to-sinter constraining layer comprises a graphite powder as a main material and has a silicon carbide powder and pyrolytic boron nitride added thereto.