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

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Volume Title

A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

2024-03-01

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Mcode

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Language

en

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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