Low-Temperature Wafer-Level Bonding with Cu-Sn-In Solid Liquid Interdiffusion for Microsystem Packaging

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Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2024-03-01
Major/Subject
Mcode
Degree programme
Language
en
Pages
Series
Microelectronic Engineering, Volume 286
Abstract
This work demonstrates the potential use of Cu-Sn-In metallurgy for wafer-level low-temperature solid-liquid interdiffusion (LT-SLID) bonding process for microelectromechanical system (MEMS) packaging. Test structures containing seal-ring shaped SLID bonds were employed to bond silicon and glass wafers at temperatures as low as 170 °C. Scanning acoustic microscopy (SAM) was utilized to inspect the quality of as-bonded wafers. The package hermeticity was characterized by cap-deflection measurements and evaluated through finite element modelling. The results indicate the bonds are hermetic, but residual stresses limit the quantitative analysis of the hermeticity. The microstructural studies confirm the bonds contain a single-phase intermetallic Cu6(Sn,In)5 that remains thermally stable up to 500 °C. This work shows Cu-Sn-In based low-temperature bonding method as a viable packaging option for optical MEMS or other temperature-sensitive components.
Description
Funding Information: The project has received funding from the ECSEL Joint Undertaking (JU) under grant agreement No 826588. The JU receives support from the European Union's Horizon 2020 research and innovation program. The authors acknowledge the provision of facilities as well as technical support by Aalto University at Micronova nanofabrication cleanroom. The authors also would like to acknowledge the facilities of Nanomicroscopy Center for EBSD and FIB characterization. Funding Information: The project has received funding from the ECSEL Joint Undertaking (JU) under grant agreement No 826588 . The JU receives support from the European Union's Horizon 2020 research and innovation program. The authors acknowledge the provision of facilities as well as technical support by Aalto University at Micronova nanofabrication cleanroom. The authors also would like to acknowledge the facilities of Nanomicroscopy Center for EBSD and FIB characterization. Publisher Copyright: © 2024 The Author(s) | openaire: EC/H2020/826588/EU//APPLAUSE
Keywords
Hermeticity, Intermetallics, Low-temperature, SLID, Wafer-level bonding
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Citation
Golim, O, Vuorinen, V, Wernicke, T, Pawlak, M & Paulasto-Kröckel, M 2024, ' Low-Temperature Wafer-Level Bonding with Cu-Sn-In Solid Liquid Interdiffusion for Microsystem Packaging ', Microelectronic Engineering, vol. 286, 112140 . https://doi.org/10.1016/j.mee.2024.112140