INFLUENCE OF COEFFICIENT OF THERMAL EXPANSION OF ADHESIVE RESIN IN A RESIN PRESSURE CONTACT FLIP CHIP
Author: Mitsuru Mura Company: Sony Corporation Date Published: 2/2/1999
Pan Pacific Symposium
Abstract: Epoxy resin adhesive is an extremely important element for ensuring the reliability of connection in the resin pressure contact flip-chip method. Up to now, it was considered sufficient, for the pressure contact flip-chip method, to use the same epoxy resin adhesive as in the solder-bonding flip-chip attach (FCA) method. In other words, the physical properties of such as epoxy resin adhesive had been examined in order to ease thermal stress generated by the difference in thermal expansion between the chip and the substrate. Accordingly, the coefficient of thermal expansion (CTE) of the epoxy resin adhesive used in the solder-bonding FCA method is designed to be the same as that of the bump solder. However, unlike in the solder-bonding FCA method, a flip-chip bonding method, which uses epoxy resin adhesive, does not bond bumps to the substrate land and retains a connection through contact between bumps and the substrate land. Since the breaking mode in the heat cycle is different between the flip-chip bonding method and the solder-bonding FCA method, effective thermal fatigue life cannot be achieved when the same epoxy resin adhesive as used in the solder-bonding FCA method is used in the flip-chip bonding method.
In this study, the relationship between the adhesive resin’s coefficient of thermal expansion and its thermal fatigue life (heat cycle test) in a resin pressure contact flip chip is investigated.