The IMC formation and progress in the copper pillar Cu/Sn1.8Ag /OSP-Cu microbump structure upon current stressing

Chiao Wen Chen, Kwang-Lung Lin, Ying Ta Chiu, Chin Li Kao, Chiu Wen Lee, Ping Feng Yang

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The present study investigated the evolution of intermetallic compounds on a microbump structure upon electric current stressing. The incorporation of Cu pillar gives rise to the microbump structure of TiCuCu/Sn1.8Ag/OSP (organic solderability preservative)-Cu. The current stressing was conducted at a current density of 1.0 × 104 A/cm2 under 125°C for various durations of 24hr, 100hr, 200hr, 300hr, and tested to fail(566hr). In order to have a good understanding to the progress and mechanism of IMCs growth, the bumps were examined in perpendicular directions. The growth of intermetallic compounds within the microbump was found to segregate on certain corner in the beginning of current stressing. The intermetallic compounds grew from the segregated area as induced by electric current flow. The intermetallic compounds grew to almost completely occupy the entire solder bump in most of the joints investigated. Cu3Sn grew to occupy most of the solder volume of the microbump joint in the failed specimen, while the Cu6Sn5 and Ag3Sn IMCs gathered at the center of solder joint. Cracks penetrated through the central region of the joint between the upper and lower Cu3Sn IMC. The cross-section inspection revealed that the microbump structure failed through the voids and crack formation along the central region of the joints. The findings indicate the marvelous difference in intermetallic compounds formation behavior between flip solder bump and microbump as a result of the differences in current density and solder/UBM structure.

Original languageEnglish
Title of host publicationProceedings of the 16th Electronics Packaging Technology Conference, EPTC 2014
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages518-521
Number of pages4
ISBN (Electronic)9781479969944
DOIs
Publication statusPublished - 2014 Jan 30
Event2014 16th IEEE Electronics Packaging Technology Conference, EPTC 2014 - Singapore, Singapore
Duration: 2014 Dec 32014 Dec 5

Publication series

NameProceedings of the 16th Electronics Packaging Technology Conference, EPTC 2014

Other

Other2014 16th IEEE Electronics Packaging Technology Conference, EPTC 2014
CountrySingapore
CitySingapore
Period14-12-0314-12-05

All Science Journal Classification (ASJC) codes

  • Electrical and Electronic Engineering

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