Cu–(Sn–Bi) SLID Bond Microstructure Under Different Temperatures
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2024Metadata
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Original version
Gonzalez, L. H., Aasmundtveit, K. E., & Nguyen, H. V. (2024, September). Cu-(Sn-Bi) SLID Bond Microstructure Under Different Temperatures. In 2024 IEEE 10th Electronics System-Integration Technology Conference (ESTC) (pp. 1-6). IEEE. https://doi.org/10.1109/ESTC60143.2024.10712096Abstract
Bi is introduced to a common Cu–Sn metal system for solid-liquid interdiffusion (SLID) bonding, allowing for lower process temperature. Cu–(Sn–Bi) SLID bonds were realized by using a eutectic Sn–Bi sandwiched between Cu layers. The microstructure of the bonds at different temperatures was studied to understand the behavior of the metal system and the role of Bi. Cross-sectional microscopy using scanning electron microscope and energy dispersive X-ray analysis was performed to identify the microstructure of different bonds. The results showed a higher concentration of Sn at the edges and more Bi concentration in the middle of the chip. The bond-lines generally had a layered structure of Cu / Cu–Sn IMC / Cu, with pockets of Bi enclosed by Cu–Sn bridges connecting the top and bottom Cu layers. The samples bonded at the highest temperature, 300 ºC, showed a dissimilar structure, with Bi inclusions in the Cu layers.