Optimization of the Wire Bonding Process for Enhanced Thermomechanical Performance of Quad Flat No-Lead (QFN) Packages in Automotive Applications

This study investigates how local warpage and stress near the sawing lines of Quad Flat No-lead (QFN) packages, under stringent automotive conditions, influence the wire bonding process. A finite element model, validated through experimental measurements, was developed to quantify deformation and stress distributions along the cutting paths. Three lead frame strip designs—1 Row 1 Block, Multi-Block, and 1 Block—were comparatively assessed under both thermal and mechanical loads. Results show that the 1 Row 1 Block design can reduce local deformation by up to 70–75% (e.g., 45 μm vs. 159 μm) compared to the 1 Block configuration, significantly mitigating alignment errors and fatigue risk. Concurrently, its peak local stress is about 212 MPa—a 70% reduction relative to the 708 MPa observed in the 1 Block design. These combined improvements highlight the necessity of balanced structural design in sawing regions to enhance wire bonding stability. Overall, these findings provide a robust framework for optimizing QFN packages under stringent automotive conditions, particularly by refining wire bonding design.