Papers by Author: Jong Soo Cho

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Authors: Jae Hyung Cho, Jong Soo Cho, Jung Tak Moon, J. Lee, Young Hee Cho, Anthony D. Rollett, Kyu Hwan Oh
Authors: Suk Hoon Kang, Jae Hyung Cho, Joon Sub Hwang, Jong Soo Cho, Yong Jin Park, Jung Tak Moon, Kyu Hwan Oh
Abstract: Cold drawn gold wires are widely applied in electronic packaging process to interconnect micro-electronic components. They basically provides a conducting path for electronic signal transfer, and experience thermo-mechanical loads in use. The mechanical stability of drawn gold wires is a matter of practical concern in the reliable functioning of electronic devices. It is known that mechanical properties of materials are deeply related to the microstructure. With appropriate control of deformation and heat processes, the mechanical properties of final products, such as tensile strength and elongation can be improved. Severe plastic deformation by torsion usually contributes to grain refinement and increment of strength. In this study, microstructure variations with torsion strain followed by drawing and heat treatment were investigated. Analyses by focused ion beam (FIB) and electron backscattered diffraction (EBSD) were carried out to characterize the effect of deformation and heat treatment on the drawn gold wires. Pattern quality of EBSD measurements was used as a quantitative measure for plastic deformation.
Authors: Suk Hoon Kang, Hee Suk Jung, Woong Ho Bang, Jae Hyung Cho, Kyu Hwan Oh, Dong Sup Kim, Jong Soo Cho, Yong Jin Park, Sang Hoon Park
Abstract: This paper studies the microstructure of drawn gold wires to equivalent strain of 10 and to equivalent strain of 8.5 then heat-treated. The texture of gold wire drawn to strain of 10 is mainly composed of <100> and <111> fibers. Tensile strength of the gold wire increases with <111> fiber fraction, while the grain size does not appear to affect the tensile property. With an exception at heat treatment at 600oC, the texture of gold wire drawn the strain of 8.5 is replaced with <100> fiber component by heat treatment process at 400~700oC. Heat treatment at 600oC produces <110> fiber or <112> fiber, depending upon annealing time.
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