High density microelectronic packaging with thick film hermetic packages

A high-density packaging approach has been developed that uses hermetic ceramic packages made with thick-film techniques. The overall packaging density, at the printed circuit (PC) board level, is comparable to or better than that achieved with some multichip packaging approaches. Low-cost thick-film ceramic packages are produced with no hard tooling from multiple sources. Chips are packaged, burned in, and tested in these packages with standard processes and production lines. The ceramic packages are then cut down to a smaller size by laser scribing and are mounted on printed circuit boards. The packages are then interconnected to the board by automatic gold-to-gold wire bonding. The author describes practical aspects of this packaging approach with respect to the design and fabrication of the thick-film ceramic packages, chip packaging and test using these packages, PC board design and fabrication, and PC board assembly. The issues of procurement costs, design, fabrication cycle times, parts screening, packaging density, rework, electrical considerations, thermal performance, process maturity, and reliability are also discussed