TY - JOUR
T1 - High-strength and thermal stable Cu-to-Cu joint fabricated with transient molten Ga and Ni under-bump-metallurgy
AU - Lin, Shih kang
AU - Wang, Mei jun
AU - Yeh, Che yu
AU - Chang, Hao miao
AU - Liu, Yu chen
N1 - Publisher Copyright:
© 2017 Elsevier B.V.
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2017
Y1 - 2017
N2 - Copper (Cu)-to-Cu bonding is an essential process for most advanced electronic devices, such as Cu-pillar joining in flip-chip packaging, through-silicon-via interconnections in three-dimensional integrated circuits, and die attachments in wide band-gap electronics. Here we propose an approach for fabricating face-centered cubic solid-solution joints without formation of intermetallic compounds by using a trace amount of gallium (Ga) and nickel (Ni) under-bump-metallurgy (UBM) for the reactive diffusion bonding at 300 °C. The formation of solid-solution joints involves interactions with the Ni[sbnd]Cu[sbnd]Ga mixture at the bonding interface. A shear-strength of 43.5 MPa was achieved in the as-bonded joint due to the formation of grains across the bonding interface, while it does not degrade after prolonged post-annealing at 300 °C for 200 h. Instead, an even stronger joint with a shear-strength of 48.2 MPa was obtained. We demonstrate the fabrication of strong, thermally stable Cu-to-Cu joints using transient molten Ga and Ni UBM.
AB - Copper (Cu)-to-Cu bonding is an essential process for most advanced electronic devices, such as Cu-pillar joining in flip-chip packaging, through-silicon-via interconnections in three-dimensional integrated circuits, and die attachments in wide band-gap electronics. Here we propose an approach for fabricating face-centered cubic solid-solution joints without formation of intermetallic compounds by using a trace amount of gallium (Ga) and nickel (Ni) under-bump-metallurgy (UBM) for the reactive diffusion bonding at 300 °C. The formation of solid-solution joints involves interactions with the Ni[sbnd]Cu[sbnd]Ga mixture at the bonding interface. A shear-strength of 43.5 MPa was achieved in the as-bonded joint due to the formation of grains across the bonding interface, while it does not degrade after prolonged post-annealing at 300 °C for 200 h. Instead, an even stronger joint with a shear-strength of 48.2 MPa was obtained. We demonstrate the fabrication of strong, thermally stable Cu-to-Cu joints using transient molten Ga and Ni UBM.
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U2 - 10.1016/j.jallcom.2016.12.444
DO - 10.1016/j.jallcom.2016.12.444
M3 - Article
AN - SCOPUS:85012240360
SN - 0925-8388
VL - 702
SP - 561
EP - 567
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
ER -