Achieving low-temperature wafer level bonding with Cu-Sn-In ternary at 150 °C
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Date
2023-01-01
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Language
en
Pages
3
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Scripta Materialia, Volume 222
Abstract
In this work, a low-temperature wafer-level bonding process at 150 °C was carried out on Si wafers containing 10 µm-sized microbumps based on the Cu-Sn-In ternary system. Thermodynamic study shows that addition of In enables low-melting temperature metals to reach liquid phase below In melting point (157 °C) and promotes rapid solidification of the intermetallic layer, which are beneficial for achieving low-temperature bonding. Microstructural observation shows high bonding quality with low amount of defect. SEM and TEM characterization concludes that a single-phase intermetallic formed in the bond and identified as Cu6(Sn,In)5 with a hexagonal lattice. Mechanical tensile test indicates that the bond has a mechanical tensile strength of 30 MPa, which are adequate for 3D heterogeneous integration.Description
Keywords
SLID bonding, Micro-bump, Solder joint technology, Intermetallics, Interdiffusion
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Citation
Golim, O, Vuorinen, V, Ross, G, Wernicke, T, Pawlak, M, Tiwary, N & Paulasto-Kröckel, M 2023, ' Achieving low-temperature wafer level bonding with Cu-Sn-In ternary at 150 °C ', Scripta Materialia, vol. 222, 114998 . https://doi.org/10.1016/j.scriptamat.2022.114998