Material development of polymer/metal paste for flip-chip attach interconnection technology. Quarterly report

In the last leg of the project the major thrust has been on the assembly process using the conductive adhesive, viz., the optimization of the process conditions and the bonding equipment. The past at this point is deemed optimum in terms of the three basic properties: adhesion, screenability and conductivity. The reliability and wafer level screening is proven reproducibly over several experiment constituting assembly of more than one part. Using the optimum paste the authors have provided an uninterrupted supply of reproducible (optimum) paste. By tweaking the compounding conditions a first-level scale-up was successfully achieved. The initial 30g batch to Endicott is increased to as high as 300 g batches with similar properties. The large batch material is shown to behave similar to the small batch materials. Also, it has been essential to do large wafer level studies: Endicott has scaled up their screening from 5 inch wafer to 8 inch wafer.