Degradation Characteristics of Eutectic and Pb-free Solder Joint
of Electronics mounted for Automotive Engine

Kim, A Young; Hong, Won Sik

doi:2014.32.3.288

J Weld Join > Volume 32(3); 2014 > Article

Special Issue

Journal of Welding and Joining 2014;32(3):288-294.
DOI: https://doi.org/10.5781/JWJ.2014.32.3.74 Published online June 30, 2014.

Degradation Characteristics of Eutectic and Pb-free Solder Joint of Electronics mounted for Automotive Engine

A Young Kim^*, Won Sik Hong^*,†

Correspondence: Won Sik Hong,
Email: wshong@keti.re.kr

Abstract

Due to environmental regulations (RoHS, WEEE and ELV) of the European Union, electronics and automotive electronics have to eliminate toxic substance from their devices and system. Especially, reliability issue of lead-free solder joint is increasing in car electronics due to ELV (End-of-Life Vehicle) banning from 2016. We have prepared engine control unit (ECU) modules soldered with Sn-40Pb and Sn-3.0Ag-0.5Cu (SAC305) solders, respectively. Degradation characteristics of solder joint strength were compared with various conditions of automobile environment such as cabin and engine room. Thermal cycle test (TC, -40 ℃ ~ (85 ℃ and 125 ℃), 1500 cycles) were conducted with automotive company standard. To compare shear strength degradation rate with eutectic and Pb-free solder alloy, we measured shear strength of chip components and its size from cabin and engine ECU modules. Based on the TC test results, finally, we have known the difference of degradation level with solder alloys and use environmental conditions. Solder joints degradation rate of engine room ECU is superior to cabin ECU due to large CTE (coefficient of thermal expansion) mismatch in field condition. Degradation rate of engine room ECU is 50~60% larger than cabin room electronics.

Key Words: Automotive, Solder joint, Degradation, Failure mechanism, Electronic control unit (ECU)