A novel flip chip technology using non-conductive resin sheet

摘要

A novel flip chip packaging technology using non-conductive resin sheet has been studied. The process flow of this new packaging system is as follows. First, epoxy base resin sheet is laminated onto substrate to cover the substrate surface including land electrodes. Bumped chip alignment and attachment has done through the resin sheet, in the second stage with pressure and temperature. The bumps under the chip penetrate with removing resin sheet material and eventually reaching to the metal land of the substrate in this process. Metal connection and curing of the interface resin have completed in the third stage. This new process has big potential to make flip chip package simple compared with current flip chip packaging process using liquid resin with dispensing system. The through put time can be reduced to less than 10 seconds/units in actual model case even large flip chip package which has over 15/spl times/15 (mm) square area IC chip. The other advantages are thermal stability of material in the process, moisture related performance, and warpage control performance. For current underfill process we have only choice to use anhydride type resin system which has many disadvantaged on that. This new process made it possible to introduce moisture and thermally stable epoxy resin with phenol curing system for flip chip packaging. Drastic process ability improvement can be achieved by the new process and material. As a typical improvement of thermal shock performance, it was confirmed that the life of chip damage becomes over 10 times longer by flip chip bonding parameters which can be controlled only by this new flip chip packaging process.