Bump & underfill free flip-chip technology for VLSI/MCM assembly, based on Universal Contact Unit

Microelectronics Assembly Innovations (MAINn), is introducing an innovative and patented test, assembly and packaging (TAP) technology and presenting the results of relevant theoretical and experimental studies. MAINn's proprietary Universal Contact Unit (UCU) technology is applicable for VLSI, MCM and multiplayer manufacturing and enables simpler and lower cost implementation as compared with conventional bump/ball techniques. UCU- technology has the following attributes: do not required bump and underfill for flip- chip attachment, a guaranteed optical observability of each contact point that enables precise, rugged and reliable interconnection of numerous multilayers; technology is applicable for VLSI, MCM and other package structures; a wide variety of in-place semiconductor assembly and SMT processes and equipment (welding. evaporation, plating, etc.) can be easily upgraded to support the new UCU- processes; the flexibility of the UCU intermediate interconnection chip carrier allows for inexpensive KGD testing; UCU allows for approximately double the density of pad-pin interconnections of bump designs due to smaller size and pitch requirements. UCU- technology performance is explored by DCA with 1600pads:sqcm under pitch 250 mu and via D=50 mu. Test results are disclosed from the following studies: thermo mechanical reliability analysis, based upon computer simulation and experimental thermo cycle testing: quality optimization. based on linear/nonlinear resistivity measurements.