A new technical paper titled “Facilitating Small-Pitch Interconnects with Low-Temperature Solid-Liquid Interdiffusion Bonding” was published by researchers at Aalto University in Finland.
Abstract
“The trend for 3D heterogeneous integration drives the need for a low-temperature bonding process for high-density interconnects (HDI). The Cu-Sn-In based solid-liquid interdiffusion (SLID) is a promising option as a low-temperature bonding technique that offers better processing flexibility and relatively lower costs for chip-sized substrates when compared to hybrid bonding. In this work, the low-temperature process was applied in a chip-to-chip bonding process. The test structures contain microbumps with 5 μm width and 15 μm pitch, mimicking state-of-the-art small-pitch interconnects. At the bonding temperature of 170 °C the process was completed within 5 minutes, while at 150 °C extended bonding time was required to completely transform low-melting materials into intermetallic phases. Electrical characterization, performed using three test structures, estimated a single interconnect resistivity as low as 1.3E-7 Ωm. This work showcases the potential of the low-temperature SLID bond process for HDI applications.”
Find the technical paper here. February 2025.
O. Golim, V. Vuorinen and M. Paulasto-Kröckel, “Facilitating Small-Pitch Interconnects with Low-Temperature Solid-Liquid Interdiffusion Bonding,” in IEEE Transactions on Components, Packaging and Manufacturing Technology, doi: 10.1109/TCPMT.2025.3540665.
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