Joule heating induced thermomigration failure in un-powered microbumps due to thermal crosstalk in 2.5D IC technology

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

18 Scopus Citations
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Author(s)

  • Menglu Li
  • Dong Wook Kim
  • Sam Gu
  • Dilworth Y. Parkinson
  • Harold Barnard

Detail(s)

Original languageEnglish
Article number075105
Journal / PublicationJournal of Applied Physics
Volume120
Issue number7
Publication statusPublished - 21 Aug 2016
Externally publishedYes

Abstract

Thermal-crosstalk induced thermomigration failure in un-powered microbumps has been found in 2.5D integrated circuit (IC) circuit. In 2.5D IC, a Si interposer was used between a polymer substrate and a device chip which has transistors. The interposer has no transistors. If transistors are added to the interposer chip, it becomes 3D IC. In our test structure, there are two Si chips placed horizontally on a Si interposer. The vertical connections between the interposer and the Si chips are through microbumps. We powered one daisy chain of the microbumps under one Si chip; however, the un-powered microbumps in the neighboring chip are failed with big holes in the solder layer. We find that Joule heating from the powered microbumps is transferred horizontally to the bottom of the neighboring un-powered microbumps, and creates a large temperature gradient, in the order of 1000 °C/cm, through the un-powered microbumps in the neighboring chip, so the latter failed by thermomigration. In addition, we used synchrotron radiation tomography to compare three sets of microbumps in the test structure: microbumps under electromigration, microbumps under thermomigration, and microbumps under a constant temperature thermal annealing. The results show that the microbumps under thermomigration have the largest damage. Furthermore, simulation of temperature distribution in the test structure supports the finding of thermomigration.

Bibliographic Note

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Citation Format(s)

Joule heating induced thermomigration failure in un-powered microbumps due to thermal crosstalk in 2.5D IC technology. / Li, Menglu; Kim, Dong Wook; Gu, Sam et al.
In: Journal of Applied Physics, Vol. 120, No. 7, 075105, 21.08.2016.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review