Flip-chip interconnection technology for advanced thermalconduction modules

摘要

Area array solder bumps on silicon devices, known as C4 balls,have been successfully used in terminating logic and memory devices toceramic substrates in numerous IBM products over two decades. With theIBM System 390/ES9000 series of mainframe computers, this highlyreliable chip termination technology has achieved improvedinterconnection density and total number of chip I/O connections permodule. In addition, in the models 820 and 900 of ES9000 series, a novelmaterials set, namely glass-ceramic with Cu internal metallization alongwith thin-film redistribution wiring on top, has been introduced formultilayered ceramic substrates. Key elements of advanced glass-ceramicsubstrate technology relevant to flip-chip joining are reviewed. This isfollowed by a discussion of device join and replace processes used inadvanced thermal conduction modules which also have decouplingcapacitors which are attached by C4 solder reflow. Optimization of thetop surface metallurgy and device join parameters necessary to achievereliable joining of more than 70000 solder balls per module is discussed