| abstract |
The substrate is formed by a stack of sheets of dielectric material (10) at least some of which have conductive patterns thereon (21-24); the substrate has conductive emerging portions (31, 32) for connecting the terminals of the component (1) to at least one internal layer provided with conductive tracks (24) providing layer-to-layer interconnection and interconnection with emerging portions in accordance with a pre-established patterns. According to the invention, the composition of the dielectric material comprises 92% to 98% alumina, and preferably 96%, with a melting agent based on magnesia titanate enabling the maximum firing temperature to be reduced to about 1400° C. The conductive patterns are made of a non-oxidizable metal which is not meltable at high temperature, e.g. palladium or a silver-palladium alloy. The properties of the substrate obtained in this manner are comparable to those of a substrate made of 99.9% ultra-pure alumina. The invention is also applicable to multi-level chip carriers made of this material. |