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Taoyuan City, Taiwan

Wang I.-T.,National Tsing Hua University | Duh J.-G.,National Tsing Hua University | Cheng C.-Y.,Shenmao Technology Inc. | Wang J.,Shenmao Technology Inc.
Materials Science and Engineering B: Solid-State Materials for Advanced Technology | Year: 2012

Sn3.0Ag0.5Cu solder doped with 0, 100, and 500 ppm Pd was reflowed with electroless Ni/immersion Au substrate. As Pd concentration increased in the solder, formation and growth of (Cu,Ni) 6Sn 5 were suppressed. After thermal aging, Cu 4Ni 2Sn 5 and Cu 5NiSn 5 were observed at interface of Sn3.0Ag0.5Cu-xPd/Au/Ni systems. As compared to Cu 4Ni 2Sn 5, more Pd dissolved in Cu 5NiSn 5. In addition, Pd doping enhanced the growth of Cu 4Ni 2Sn 5 and slowed the formation of Cu 5NiSn 5, which would stabilize the intermetallic compound. Based on quantitative analysis by field emission electron probe microanalyzer, the correlation between Pd doping and elemental redistribution in solder joints was probed and discussed. This study described a possible mechanism of the formation of different intermetallic compounds in Pd-doped lead-free solder. © 2011 Elsevier B.V. All rights reserved.

Hsu H.-H.,National Central University | Wang C.-M.,Shenmao Technology Inc. | Lee H.-Y.,National Synchrotron Radiation Research Center | Wu A.T.,National Central University
2016 International Conference on Electronics Packaging, ICEP 2016 | Year: 2016

Warpage has become a very critical reliability problem for the advanced electronic packaging technique. One or more chips are stacked on the substrates for a device. The device thus contains materials that have different physical properties. The most prominent problem would be the differences in the thermal expansion coefficient for these materials. During fabrication, thermal energy was applied to the chips; the expansion of these materials would induce thermal stress and warpage on the chips that would be harmful to the long-term reliability. When a current is applied to the device, the Joule heating may further enhance the warpage of the chips. Si-on-Si interposer samples are introduced to minimize the issue. It is important to develop a quick and non-destructive method to insitu analyze the warpage level at different conditions. Synchrotron radiation X-ray is used for measuring the strain and the warpage of the Si dies. © 2016 The Japan Institute of Electronics Packaging.

Chen C.-H.,National Central University | Lee B.-H.,Shenmao Technology Inc. | Chen H.-C.,Shenmao Technology Inc. | Wang C.-M.,Shenmao Technology Inc. | Wu A.T.,National Central University
Journal of Electronic Materials | Year: 2015

A new ternary solder alloy Sn62Bi32Ga6 (in wt.%) with melting point of 128°C, which is 10°C lower than that of eutectic Sn-Bi, has been developed. The composition was obtained by adding the maximum possible amount of Ga without causing Ga segregation and the formation of a liquid phase inside the solder. Solders were reflowed on Cu substrates to investigate their interfacial morphologies during liquid reactions. The only intermetallic compound detected at the interfaces was CuGa2, which initially formed with a discrete basin type at the interfaces. As the reflow time was increased, the basin-type compound formed a continuous layer that inhibited Cu dissolution. Solid-state aging tests were also performed on the system, and the activation energy for the formation of CuGa2 was found to be 2.82 kJ/mol, which is much lower than that of the Cu-Sn compound. © 2015 The Minerals, Metals & Materials Society

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