Controlled Diffusion Bonding in Multilevel Package
Original Publication Date: 1982-May-01
Included in the Prior Art Database: 2005-Feb-09
In the design and manufacturing of substrates on which integrated circuit chips are to be mounted, there are many instances where it is desirable to have a multiplicity of layers of metallization. One technique to accomplish this is to provide a first level of metallization on the ceramic substrate, apply a layer of plastic, such as polyimide, over this first level of metallization, and thereafter apply a second level of metallization. Conventionally, each layer of metallization includes Cr-Cu-Cr layers. In certain regions, vias are etched in the polyimide, and the second level and first level metallization contact each other in these vias. In the past, there has been a problem of obtaining good contact between the two levels of metallization.