Browsing by Author "Tang, Ya-Sheng"

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Development and Investigation of Ultra-Thin Buffer Layers Used in Symmetric Cu/Sn Bonding and Asymmetric Cu/Sn-Cu Bonding for Advanced 3D Integration Applications
(2017-01-01)
Chen, Hsiu-Chi
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Kho, Yi-Tung
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Huang, Yen-Jun
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Hsieh, Yu-Sheng
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Chang, Yao-Jen
In this work, a particular ultra-thin buffer layer (UBL) with various thickness ranging from 10 nm to 100 nm and different materials including Co, Ni, Pd and Ti is inserted between Cu/Sn to delay the interdiffusion prior to eutectic bonding. The efficacy of the buffer layer and the bonding quality are systematically conferred using microstructure imaging, material analysis, and electrical performance. In addition to symmetric Cu/Sn bonding with UBL, an asymmetric Cu/Sn-Cu bonding which is proposed to relieve the heat enhanced interdiffUsion issues thereby enhancing the reliability performance is demonstrated with the assistance of UBL technology.
Investigation and Optimization of Ultrathin Buffer Layers Used in Cu/Sn Eutectic Bonding
(2018-07-01)
Tang, Ya-Sheng
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Chen, Hsiu-Chi
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Kho, Yi-Tung
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Hsieh, Yu-Sheng
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Chang, Yao-Jen
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 mu m 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.
Investigation of Co Thin Film as Buffer Layer Applied to Cu/Sn Eutectic Bonding and UBM With Sn, SnCu, and SAC Solders Joints
(2017-11-01)
Tang, Ya-Sheng
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Derakhshandeh, Jaber
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Kho, Yi-Tung
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Chang, Yao-Jen
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Slabbekoorn, John
The demand of small-feature-size, high-performance, and dense I/O density applications promotes the development of fine-pitch vertical interconnects for 3-D integration where microbumps are fabricated with Cu through-silicon via and under-bump metallization. Small dimension Cu/Sn bonding has to be developed to address the needs of increasing I/O density and shrinking pitch and size for future applications. For fine-pitch microbumps, it is important to select right UBM and solder materials to obtain lower UBM consumption, which means lower intermetallic compound (IMC) thickness. To find the best binary system material for fine-pitch microbumps with a different annealing temperature and time, we investigate the interfacial reaction and intermetallic compound morphologies of Co UBM with Sn, SnCu, and SAC solders. A thin, uniform, and single-phase IMC between solder and UBM facilitates finer pitch and more reliable microbumps development; the higher activation energies imply longer solder lifetime. Co, as an ultrathin buffer layer (UBL), is also used in Cu/Sn bonding. A comparison between Cu-Sn bonding with and without UBL is conducted. From this study, Co as UBL and UBM is explored and could be applied in semiconductor applications.
Wafer-level Cu-Cu bonding technology
(2012-02-01)
Tang, Ya-Sheng
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Chang, Yao-Jen
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Chen, Kuan-Neng
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
Semiconductor industry currently utilizes copper wafer bonding as one of key technologies for 3D integration. This review paper describes both science and technology of copper wafer bonding with regard to present applications. The classification of Cu bonding, bonding mechanisms, process developments, its microstructure evolution, as well as other characterizations are reviewed. Researches about patterned Cu bonding, future prospects, and 3D integration using Cu bonding are discussed in this paper. (C) 2011 Elsevier Ltd. All rights reserved.