Flip-chip technology has been rapidly progressing in thelaboratory. But industrial use of flip-chip has not progressedsatisfactorily. Packaging materials are using low viscosity liquid typeunderfill epoxy resin, and packaging methods are using dispensersystems. These systems have many problems in mass production as follows.(1) This process needs to underfill epoxy resin many times. (2) Thisepoxy resin must use low viscosity epoxy resin to underfill under LSI,and it can't contain much filler. It is difficult to get low expansionepoxy resin system. Delamination between LSI and underfill epoxy resinsometimes occurs. We solved these problems using our PES process and PESepoxy resin. At the first step, we developed new type underfill epoxyresin. This epoxy resins has low expansion, high purity, high adhesivestrength, high Tg, high humidity resistance and high electricresistance. This underfill epoxy resin didn't have mismatching betweenLSI and board. At the secondary step, we developed the special PES forunderfill method of flip-chip. We can get no bubble process forunderfill packaging of flip-chip. This process is formed of flip-chipbumping→PES printing→vacuum process→heatcuring→test. This process is very simple and underfills many LSIchips at once
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