Low-temperature bonding of silicon/glass enabled by micro–nano-structures and nano-silver paste

For the demand of low-temperature, high-strength joining between silicon and glass in semiconductor packaging, a composite joining method based on femtosecond laser micro/nano-fabrication and low-temperature sintering of silver nanoparticle paste is proposed. Conventional anodic bonding technology is prone to device performance degradation due to thermal stress introduced by high-temperature processes. This research employs femtosecond lasers to fabricate a multi-level structure composed of micron-scale cones and nanoparticles on the substrate surface. Combined with silver nanoparticle paste, a high-strength joint is achieved under 300 °C. The results indicate that surface micro–nano-structures provide abundant mechanical anchor points for silver particles, enhancing interfacial joining strength through mechanical interlocking. Meanwhile, the increased contact area enhances the thermal diffusion coefficient at the interface, facilitating heat dissipation from the chip. The influence of microstructure dimensions, sintering temperature, and pressure on joining strength is also analyzed. This method of enhancing interfacial bonding strength through micro–nano-structures provides a pathway for addressing thermal stress issues in semiconductor packaging.