Joint Property of Sn-Cu-Cr(Ca) Middle Temperature Solder for Automotive Electronic Module |
Junghwan Bang1, Dong-Yurl Yu1, Yong-Ho Ko1, Jeonghan Kim1, Chang-Woo Lee1 |
Correspondence:
Chang-Woo Lee, Email: cwlee@kitech.re.kr |
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Abstract |
Joint properties of vehicle ECU (Electric Control Unit) module which was manufactured by using Sn- Cu-Cr-Ca alloy were investigated. A new solder which has a middle melting temperature about 231℃ was fabricated as the type of 300um solder ball and paste type. The prototype modules were made by reflow process and measured spreadability, wettability shear strength and estimated interface reaction. The spreadability of the alloy was about 84% from the measurement of contact angle of the solder ball and the wetting force was measured 2mN. The average shear strength of the module which was manufactured by using the solder paste, was 1.9 kg/mm2. Also, the thickness of IMC(intermetallic compound) was evaluated with various aging temperature and time in order to understand Cr effect on Sn-0.7Cu solder. Cu6Sn5 IMC was formed between Cu pad and the solder alloy and the average thickness of the Cu6Sn5 IMC was measured about 4um and it was about 50% of thickness of Cu6Sn5 IMC in Sn-0.7Cu. It is expected to have a positive effect on reliability of the solder joint. |
Key Words:
Middle temperature solder, Environment-friendly solder, ECU, ELV(End-of-Life Vehicle), Cr effec |
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