Low-temperature aluminum thermo-compression wafer bonding with tin antioxidation layer for hermetic sealing of MEMS

Shiro Satoh, Hideyuki Fukushi, Masayoshi Esashi, Shuji Tanaka

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

7 Citations (Scopus)

Abstract

Hermetic Al-Al thermo-compression bonding was demonstrated at the lowest temperature ever reported, 370-390°C, using a thin antioxidation capping layer of Sn. A key factor of hermetic sealing is bonding pressure enough to compress the bonding interlayer metal. From the same point of view, a narrower sealing frame for stress concentration, thicker Al and a higher bonding temperature within the allowable range (<400°C) are favorable for high yield hermetic sealing. Judging from Al-Sn phase diagram, Sn should uniformly and sparsely exist among Al grains as Al-Sn eutectic, which was also supported by the cross-sectional observation of the bonding interlayer. In such a microstructure, Al-Al direct metal bonding, which is stable at Pb-free solder reflow temperature, should be created. Al is the standard metal of CMOS backend, free from the risk of metal contamination and inexpensive, and thus the bonding technology described in this paper is useful for MEMS-CMOS integration.

Original languageEnglish
Title of host publicationMEMS 2016 - 29th IEEE International Conference on Micro Electro Mechanical Systems
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages581-584
Number of pages4
ISBN (Electronic)9781509019731
DOIs
Publication statusPublished - 2016 Feb 26
Event29th IEEE International Conference on Micro Electro Mechanical Systems, MEMS 2016 - Shanghai, China
Duration: 2016 Jan 242016 Jan 28

Publication series

NameProceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS)
Volume2016-February
ISSN (Print)1084-6999

Other

Other29th IEEE International Conference on Micro Electro Mechanical Systems, MEMS 2016
Country/TerritoryChina
CityShanghai
Period16/1/2416/1/28

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Mechanical Engineering
  • Electrical and Electronic Engineering

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