Cu/photosensitive-BCB thin-film multilayer technology for high-performance multichip modules

A new MCM-D technology which enables reliable fabrication of high-performance and low cost MCM´s has been developed. The technology is based on Cu/photosensitive-BCB thin-film multilayer structure. The fabrication process is reduced by using the newly developed photosensitive-BCB, with a conventional photolithography process. The flexibility on design rules is allowed, because the Cu/BCB structure has the advantages of excellent planarization and low electrical resistance of signal line. The following long-term reliability tests were successfully done: thermal cycle (-45°C/125°C), high-temperature aging at 125°C, and high-temperature/humidity (85°C/85%). A prototype of the high density RISC module fabricated with the developed technology passed all the long-term reliability tests. The excellent electrical performance was also proved through the signal transmission tests with the prototype module