Copper-On-Ceramic Microelectronic Technology

My COPPER-ON-CERAMIC MICRO- ELECTRONIC TECHNOLOGY by Harry Cole, CEng, MIERE As the technology of modern micro-electronic circuitry advances, so too does the need to convey digitally coded signals at ever increasing rates. This requirement assumes considerable importance in the multi-layer type of circuit board where many widely spaced ICs have to be interconnected with negligible loss of amplitude. Traditionally, gold has been used for in- terconnection purposes in chip carriers intended for military and aerospace ap- plications where high reliability is of prime importance. Unfortunately, the relatively high electrical resistivity of gold (0.02 p52 m) and the need for thin- ner interconnections makes this material unsuitable for the interconnection of densely packed ICs. Copper, although lacking some of the desirable properties of gold, has a resis- tivity of 0.016 p52 m which is con- siderably lower and has good solder- ability. It is much cheaper and has good adhesion properti...