Test and Repair of Direct Chip Attach Modules
Original Publication Date: 1988-Aug-01
Included in the Prior Art Database: 2005-Feb-15
Several attempts have been made in recent years to expand IBM's C4 chip joining technology to production of cost effective, multi-chip modules. Some of the problem encountered involve the inability both to test the chips after they have been mounted and replacement of the bad chips if test has been accomplished through test points, module pins, etc. This is a serious problem since wafer test of the chips does not detect all failures and inspection of the C4 joints is difficult at best since they are under the chip. Yields for modules containing more than 1 chip are not commensurate with good economics. For example, yield on a 4-chip module with a single chip yield of 90% would be approximately 65%.