Investigation and Optimization of Ultrathin Buffer Layers Used in Cu/Sn Eutectic Bonding

Ya Sheng Tang; Hsiu Chi Chen; Yi Tung Kho; Yu Sheng Hsieh; Yao Jen Chang; Kuan-Neng Chen

doi:10.1109/TCPMT.2018.2838047

Investigation and Optimization of Ultrathin Buffer Layers Used in Cu/Sn Eutectic Bonding

Ya Sheng Tang, Hsiu Chi Chen, Yi Tung Kho, Yu Sheng Hsieh, Yao Jen Chang, Kuan-Neng Chen^*

^*Corresponding author for this work

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

8 Scopus citations

Abstract

Ultrathin buffer layers (UBLs) with varied thickness ranging from 10 to 100 nm and different materials were used in Cu/Sn eutectic bonding. A Cu/Sn film thinner than 2 μm could fully react and became stiff and rough Cu-Sn intermetallic compound layer, which leads to failure bonding. Four kinds of semiconductor compatible materials including Ti, Pd, Co, and Ni were inserted between Cu/Sn to delay interdiffusion prior to eutectic bonding. In addition to symmetric Cu/Sn bonding with UBL, asymmetric Cu/Sn-Cu bonding scheme with 50-nm Ni UBL was demonstrated. With good mechanical properties, bonding quality, and electrical characteristics, the application of submicrometer Cu/Sn wafer-level bonding by assistance of buffering layer gives a promising and flexible platform for future 3-D integration applications.

Original language	English
Article number	8373691
Pages (from-to)	1225-1230
Number of pages	6
Journal	IEEE Transactions on Components, Packaging and Manufacturing Technology
Volume	8
Issue number	7
DOIs	https://doi.org/10.1109/TCPMT.2018.2838047
State	Published - 1 Jul 2018

Keywords

3-D integration
eutectic bonding
ultrathin buffer layer (UBL)

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10.1109/TCPMT.2018.2838047

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title = "Investigation and Optimization of Ultrathin Buffer Layers Used in Cu/Sn Eutectic Bonding",

abstract = "Ultrathin buffer layers (UBLs) with varied thickness ranging from 10 to 100 nm and different materials were used in Cu/Sn eutectic bonding. A Cu/Sn film thinner than 2 μm could fully react and became stiff and rough Cu-Sn intermetallic compound layer, which leads to failure bonding. Four kinds of semiconductor compatible materials including Ti, Pd, Co, and Ni were inserted between Cu/Sn to delay interdiffusion prior to eutectic bonding. In addition to symmetric Cu/Sn bonding with UBL, asymmetric Cu/Sn-Cu bonding scheme with 50-nm Ni UBL was demonstrated. With good mechanical properties, bonding quality, and electrical characteristics, the application of submicrometer Cu/Sn wafer-level bonding by assistance of buffering layer gives a promising and flexible platform for future 3-D integration applications.",

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author = "Tang, {Ya Sheng} and Chen, {Hsiu Chi} and Kho, {Yi Tung} and Hsieh, {Yu Sheng} and Chang, {Yao Jen} and Kuan-Neng Chen",

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AU - Tang, Ya Sheng

AU - Chen, Hsiu Chi

AU - Kho, Yi Tung

AU - Hsieh, Yu Sheng

AU - Chang, Yao Jen

AU - Chen, Kuan-Neng

PY - 2018/7/1

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N2 - Ultrathin buffer layers (UBLs) with varied thickness ranging from 10 to 100 nm and different materials were used in Cu/Sn eutectic bonding. A Cu/Sn film thinner than 2 μm could fully react and became stiff and rough Cu-Sn intermetallic compound layer, which leads to failure bonding. Four kinds of semiconductor compatible materials including Ti, Pd, Co, and Ni were inserted between Cu/Sn to delay interdiffusion prior to eutectic bonding. In addition to symmetric Cu/Sn bonding with UBL, asymmetric Cu/Sn-Cu bonding scheme with 50-nm Ni UBL was demonstrated. With good mechanical properties, bonding quality, and electrical characteristics, the application of submicrometer Cu/Sn wafer-level bonding by assistance of buffering layer gives a promising and flexible platform for future 3-D integration applications.

AB - Ultrathin buffer layers (UBLs) with varied thickness ranging from 10 to 100 nm and different materials were used in Cu/Sn eutectic bonding. A Cu/Sn film thinner than 2 μm could fully react and became stiff and rough Cu-Sn intermetallic compound layer, which leads to failure bonding. Four kinds of semiconductor compatible materials including Ti, Pd, Co, and Ni were inserted between Cu/Sn to delay interdiffusion prior to eutectic bonding. In addition to symmetric Cu/Sn bonding with UBL, asymmetric Cu/Sn-Cu bonding scheme with 50-nm Ni UBL was demonstrated. With good mechanical properties, bonding quality, and electrical characteristics, the application of submicrometer Cu/Sn wafer-level bonding by assistance of buffering layer gives a promising and flexible platform for future 3-D integration applications.

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ER -

Investigation and Optimization of Ultrathin Buffer Layers Used in Cu/Sn Eutectic Bonding

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