Warpage Mitigation through Diebond Process Improvement with Enhanced Leadframe Configuration

This paper presents an improvement in the design of quad flat no-leads (QFN) leadframe material to reduce the amount of unit rejection due to excessive leadframe warpage observed after die attach curing (DAC) process. The enhanced leadframe design includes modification through increasing the number of unit panels from 2 maps structure into 4-panel configuration to integrate mechanical relief for coefficient thermal expansion (CTE) mismatch between different material composition present inside the device. The implementation of this design in the assembly of QFN successfully reduced the amount of leadframe warpage into manufacturable level with positive impact in production output and assembly yield.