Colaminated single and multichip package development

Next generation single and multichip packages must support flip chip assembly of die with a very high number of I/O. Cofire ceramic technology has been the traditional solution. We report on a new packaging technology that, in many ways, is an organic version Cofire ceramic. This “Colamination” process leverages recent developments in adhesiveless flex circuitry and low temperature sinterable materials to produce multilayer structures with sintered blind and buried vias in a single lamination step. This paper describes the fabrication of a 6-metal layer 751 I/O flip chip test vehicle with the Colamination process. Novaclad^TM flex circuit layer pairs, ViaPly^TM bond ply layers, and a metal stiffener are colaminated to form the package substrate. The package design takes advantage of Novaclad^TM design rules, which includes microvias in die attach and BGA pads. Test vehicle design, substrate fabrication, flip chip assembly, thermomechanical, and environmental test results are described