Utilizing Co as a contact metallization for wafer-level Cu-Sn-In SLID bonding used in MEMS and MOEMS packaging

Fahimeh Emadi*, Vesa Vuorinen, Mervi Paulasto-Kröckel

*Corresponding author for this work

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

1 Citation (Scopus)
25 Downloads (Pure)

Abstract

Many MEMS and MOEMS devices require hermetic packaging with preferably no postprocessing after the MEMS device's releasing. Wafer-level Solid-Liquid Interdiffusion (SLID) bonding can provide simultaneous hermetic packaging and better electrical interconnects. Moreover, employing a physically deposited contact metallization on the device wafer instead of chemically deposited layers (such as electrochemical Cu) is of utmost importance as far as reducing the complexity of the MEMS/MOEMS packaging process integration is concerned. The current work studied the possibility of utilizing Co as a contact metallization layer for the low-temperature Cu-Sn-In-based SLID bonding. In order to guarantee the long-term reliability of the devices, a fundamental understanding of the formation and evolution of interconnection microstructures and mechanical characterization of the joint is of utmost importance. In this work, Cu-Sn-In electroplated Si chips were bonded to Co substrates at a temperature range 160-250°C. During the bonding process, a single intermetallic compound (IMC) (Cu,Co)6(Sn,In)5 formed at the bonding area, with no detectable Cu3Sn phase that causes voids formation. The Young's modulus and hardness of (Cu,Co)6(Sn,In)5 and Cu6Sn5, as a reference, were measured as 124.8±0.5 and 6.2±0.5, 114±1 and 6.7±0.5 MPa, respectively. Furthermore, the current study was able to produce a fully IMC joint of Cu-Sn-In/Co SLID system at 220°C for bonding time as short as 20 minutes.

Original languageEnglish
Title of host publication2022 IEEE 9th Electronics System-Integration Technology Conference, ESTC 2022 - Proceedings
PublisherIEEE
Pages359-363
Number of pages5
ISBN (Electronic)978-1-6654-8947-8
DOIs
Publication statusPublished - 2022
MoE publication typeA4 Conference publication
EventElectronics System-Integration Technology Conference - Sibiu, Romania
Duration: 13 Sept 202216 Sept 2022

Publication series

Name2022 IEEE 9th Electronics System-Integration Technology Conference, ESTC 2022 - Proceedings

Conference

ConferenceElectronics System-Integration Technology Conference
Abbreviated titleESTC
Country/TerritoryRomania
CitySibiu
Period13/09/202216/09/2022

Keywords

  • Co contact metallization
  • Cu-Sn SLID bonding
  • Cu-Sn-In SLID bonding
  • Reliability
  • TLP bonding

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