Warpage Mitigation in 2.5D Chiplets Packaging through Heterogeneous Integration of Diamond Heat Spreaders

Interposer-based 2.5D chiplets integration has emerged as a crucial technology for high-performance chip packaging and has played a pivotal role in advancements of artificial intelligence (AI) in recent years. However, thermal expansion coefficient mismatches among glass, silicon, and molding materials induce warpage and deformation during packaging, compromising subsequent processing steps and device reliability. This study employs finite element simulations and experiments to investigate the warpage mitigation effect of integrating a diamond heat spreader into 2.5D chiplet packaging, while analyzing the impact of substrate size, stiffener ring dimensions, and design parameters. Results demonstrate that the diamond heat spreader significantly reduces warpage, with greater effectiveness at elevated temperatures. Additionally, smaller substrate sizes and wider, taller stiffener rings contribute to further warpage reduction. These findings offer valuable insights and practical guidelines for warpage control in high-performance, high-power multi-chiplet packaging, thereby enhancing structural stability and interconnection reliability.