Advanced CMP Optimization for Enhanced Cu/Polymer Hybrid Bonding in 3D IC

Cu/polymer hybrid bonding is a critical advanced packaging technology that overcomes the physical limitations of conventional solder-based packaging technologies. The technology enables higher-density input/output (I/O) counts, and finer pitch interconnects while maintaining wide process windows and cost efficiency. To enhance hybrid bonding quality, optimizing the chemical mechanical polishing (CMP) process and understanding its impact on bonding performance is critical in hybrid bonding technology. In this study, the CMP process is optimized by adjusting the applied pressure to control the Cu protrusion range. This approach ensures surface planarity and uniformity, thereby improving the reliability of Cu/polymer hybrid bonding. Through the optimized CMP process, Cu/polymer hybrid bonding with a fine pitch (10-μm) is demonstrated at low-temperature (150°C) for 10 seconds, achieving excellent bonding strength and bonding quality. These technological advancements significantly enhance interconnect density and reliability, enabling superior overall performance and laying a solid foundation for advanced packaging applications.