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

Obert Golim; Vesa Vuorinen; Tobias Wernicke; Marta Pawlak; Mervi Paulasto-Kröckel

doi:10.1016/j.mee.2024.112140

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

Obert Golim^*, Vesa Vuorinen, Tobias Wernicke, Marta Pawlak, Mervi Paulasto-Kröckel

^*Corresponding author for this work

EV Group E. Thallner GmbH

Research output: Contribution to journal › Article › Scientific › peer-review

2 Citations (Scopus)

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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.

Original language	English
Article number	112140
Journal	Microelectronic Engineering
Volume	286
DOIs	https://doi.org/10.1016/j.mee.2024.112140
Publication status	Published - 1 Mar 2024
MoE publication type	A1 Journal article-refereed

Keywords

Hermeticity
Intermetallics
Low-temperature
SLID
Wafer-level bonding

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10.1016/j.mee.2024.112140Licence: CC BY

1-s2.0-S0167931724000091-mainFinal published version, 5.56 MBLicence: CC BY

Cite this

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

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.",

keywords = "Hermeticity, Intermetallics, Low-temperature, SLID, Wafer-level bonding",

author = "Obert Golim and Vesa Vuorinen and Tobias Wernicke and Marta Pawlak and Mervi Paulasto-Kr{\"o}ckel",

note = "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: {\textcopyright} 2024 The Author(s) | openaire: EC/H2020/826588/EU//APPLAUSE",

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doi = "10.1016/j.mee.2024.112140",

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AU - Vuorinen, Vesa

AU - Wernicke, Tobias

AU - Pawlak, Marta

AU - Paulasto-Kröckel, Mervi

N1 - 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

PY - 2024/3/1

Y1 - 2024/3/1

N2 - 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.

AB - 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.

KW - Hermeticity

KW - Intermetallics

KW - Low-temperature

KW - SLID

KW - Wafer-level bonding

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DO - 10.1016/j.mee.2024.112140

M3 - Article

AN - SCOPUS:85183467491

SN - 0167-9317

VL - 286

JO - Microelectronic Engineering

JF - Microelectronic Engineering

M1 - 112140

ER -

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

Abstract

Keywords

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APPLAUSE: Advanced packaging for photonics, optics and electronics for low cost manufacturing in Europe

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

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Keywords

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APPLAUSE: Advanced packaging for photonics, optics and electronics for low cost manufacturing in Europe

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