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Vol.55, No.4, 232 ~ 240, 2017
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| Title |
| Solder Joint Fatigue Life of Flexible Impact Sensor Module for Automotive Electronics |
| 박지연 Ji-yeon Park , 김미송 Mi-song Kim , 오철민 Chulmin Oh , 도상현 Sang Hyeon Do , 서종덕 Jong Dock Seo , 김대근 Dae Keun Kim , 홍원식 Won Sik Hong |
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| Abstract |
| To improve the sensitivity of impact sensor modules for automotive air bag systems, we developed a flexible module. The impact sensor was soldered with Sn-3.0Ag-0.5Cu (SAC305) solder on a flexible printed circuit board (FPCB) with an organic solderability preservative (OSP) surface finish. Thermal shock (TS) is one of the test methods used to accelerate the degradation of solder joints. To evaluate the solder joint fatigue life of the proposed flexible impact sensor module experienced with/without TS, TS test was conducted from -40 to 90 ℃ with a dwell time of 10 min for 1000 cycles. Then, high cycle fatigue tests were sequentially performed at a force range from 0 N and 20 N with a 1 Hz frequency sine wave. From these results, we determined that the mean life and B10 life of the solder joint fatigue after 1000 TS cycles were 4188.9 and 1864.8 cycles, respectively. Finally, we found that the fatigue life of the solder joint decreased with increasing TS cycles due to the growth of Cu6Sn5 + Cu3Sn, the thickness and the dispersion of Ag3Sn at the solder joint and matrix. Even though the mean life and B10 life of the solder joint fatigue life were reduced by 60% and 13.8% respectively, compared to their initial values, we confirmed the feasibility of using the flexible modules for automobile air bag systems. (Received September 19, 2016; Accepted October 19, 2016) |
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| Key Words |
| fatigue life, solder joint, flexible, air bag, automotive electronics |
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