CU-CU MECHANICAL BONDING FOR 3D INTEGRATION OF THE NEXT GENERATION ELECTRONIC CHIPS: INTERFACIAL MECHANISMS, SURFACE ENGINEERING, AND EMERGING LOW-TEMPERATURE STRATEGIES

Three-dimensional integrated circuit (3D IC) technology is essential for ultra-high-density integration, and Cu-Cu direct mechanical bonding has emerged as a promising alternative due to the limitations of traditional soldering methods. This technology offers excellent power efficiency, high-density packaging, faster processing speeds, and improved heat dissipation. However, existing research has limitations in systematically analyzing the relationship between key parameters affecting Cu-Cu bonding quality such as bonding layer thickness, temperature, grain size, and surface roughness. A comprehensive review, particularly under the low-temperature conditions necessary for 3D IC processes, has been lacking. Therefore, this review introduces the fundamental theory of Cu-Cu bonding and systematically discusses the effects of the parameters on bonding quality. By integrating these factors with a specific focus on low-temperature Cu-Cu interfaces, this review aims to provide a practical and up-to-date guide on Cu-Cu bonding technologies.