Suppressing interfacial voids in Cu/In/Cu microbump with Sn and Cu addition

Song, Rui-Wen; Fleshman, Collin; Chen, Hao; Tsai, Su-Yueh; Duh, Jenq‐Gong

doi:10.1016/j.matlet.2019.126855

Cited by 9 publications

(1 citation statement)

References 13 publications

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“…In an investigation of Cu addition to In-48Sn solder, the observed Cu-rich IMC was reported to be η-Cu 6 (Sn,In) 5 [16,17]. In the Cu/In-48Sn/Cu interfacial reaction, where the In-48Sn is completely consumed, Cu 6 (Sn,In) 5 and Cu 3 (Sn,In) were observed at the interface after 250 • C bonding; only Cu 6 (Sn,In) 5 was observed after 200 • C to 160 • C bonding [18][19][20][21][22]. The results of previous works imply that there is extremely fast formation of IMCs at the In-48Sn/Cu interface, which makes In-48Sn a promising SLID material [23].…”

Section: Introductionmentioning

confidence: 99%

Artifact-Free Microstructures in the Interfacial Reaction between Eutectic In-48Sn and Cu Using Ion Milling

2023

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Eutectic In-48Sn was considered a promising candidate for low-temperature solder due to its low melting point and excellent mechanical properties. Both Cu2(In,Sn) and Cu(In,Sn)2 formation were observed at the In-48Sn/Cu interface after 160 °C soldering. However, traditional mechanical polishing produces many defects at the In-48Sn/Cu interface, which may affect the accuracy of interfacial reaction investigations. In this study, cryogenic broad Ar+ beam ion milling was used to investigate the interfacial reaction between In-48Sn and Cu during soldering. The phase Cu6(Sn,In)5 was confirmed as the only intermetallic compound formed during 150 °C soldering, while Cu(In,Sn)2 formation was proven to be caused by room-temperature aging after soldering. Both the Cu6(Sn,In)5 and Cu(In,Sn)2 phases were confirmed by EPMA quantitative analysis and TEM selected area electron diffraction. The microstructure evolution and growth mechanism of Cu6(Sn,In)5 during soldering were proposed. In addition, the Young’s modulus and hardness of Cu6(Sn,In)5 were determined to be 119.04 ± 3.94 GPa and 6.28 ± 0.13 GPa, respectively, suggesting that the doping of In in Cu6(Sn,In)5 has almost no effect on Young’s modulus and hardness.

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