Low resistance and high reliable Cu-To-Cu joints using highly (111)-oriented nano-Twinned copper

Jing Ye Juang*, Kai Cheng Shie, Yu Jin Li, King-Ning Tu, Chih Chen

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

In this study, we present a chip-To-chip copper direct bonding technique in N2 ambient, without vacuum by using (111) oriented nano-Twinned copper. A well bonded copper joint was identified by the cross-sectioning process and microstructure observation. The cross-sectional images showed a void-less bonding interface in the bonded copper joint. In addition, we conducted resistance measurement using Kelvin probes on the bonded chip-To-chip test vehicle. The resistance for a daisy chain loop (400 joints) and the Kelvin structure (single joint) are 5.28 Ω and 4.14 mΩ, respectively. The contact resistivity is 3.98 × 10-8 Ω cm2. More than 30% resistance reduction in the single Cu joint has been confirmed as compared to the SnAg solder joint (6.32 mΩ). Besides, temperature cycling test shows that the daisy chain loop with 400 Cu joints can stand the 1,000 cycles without failure. In summary, the chip-To-chip copper direct bonding in no-vacuum ambient has been successfully achieved by using (111) oriented nt-Cu. The low resistance as well as a reliable Cu-To-Cu joint can be achieved.

Original languageEnglish
Title of host publication2019 International Conference on Electronics Packaging (ICEP)
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages212-215
Number of pages4
ISBN (Electronic)9784990218867
DOIs
StatePublished - Apr 2019
Event2019 International Conference on Electronics Packaging, ICEP 2019 - Niigata, Japan
Duration: 17 Apr 201920 Apr 2019

Publication series

Name2019 International Conference on Electronics Packaging, ICEP 2019

Conference

Conference2019 International Conference on Electronics Packaging, ICEP 2019
CountryJapan
CityNiigata
Period17/04/1920/04/19

Keywords

  • Cu joint resistance
  • Cu-To-Cu direct bonding
  • grain growth
  • nanotwinned Cu
  • temperature cycling test

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