Improving Semiconductor Reliability of Silver Sintering Die-Attach Adhesives for Large Die on Copper Lead Frames

Emerging trends like 6G Telecom and Electric Vehicles (EVs) are driving advancements in semiconductor packaging, specifically in back-end assembly. These enabling technologies are focused on achieving higher functionality, improved connectivity at higher frequencies, smaller form factors, efficient heat dissipation, and reduced power consumption. The instrumental role of Wide-Band Gap semiconductors to enable high-frequency RF transmissions, and efficient power switching necessitates advancements in thermal dissipation and the ability to withstand higher thermo-mechanical stresses in next-generation power devices. Concurrently, the semiconductor industry has been seeking a lead (Pb) solder replacement with improved automotive reliability for over two decades. The lead-free alternatives need to be compatible with larger die sizes on metal lead frames and must align with the high productivity demands of semiconductor back-end processing. However, finding a suitable, drop-in leadfree solution that can address these challenges has proven to be highly challenging [1]. This paper describes the ongoing product development and comprehensive testing of a new hybrid silver sintering die-attach development with stress- absorbing additives specifically designed for large die on lead frame based applications following close collaboration between Henkel and CITC. This development work has been the result of the dire need to meet the industry’s evolving trends and requirements towards higher power and sustainable products.