전류밀도에 따른 플립칩 Sn-Ag 솔더 범프의 Electromigration 손상기구 분석 |
김가희1, 손기락1, 박규태2, 박영배1 |
1안동대학교 신소재공학부, 청정에너지소재기술연구센터 2앰코테크놀로지 코리아 |
Effect of Current Densities on the Electromigration Failure Mechanisms of Flip-Chip Sn-Ag Solder Bump |
Gahui Kim1, Kirak Son1, Gyu-Tae Park2, Young-Bae Park1 |
1School of Materials Science and Engineering, Andong National University, Andong 36729, Republic of Korea 2Amkor Technology Korea Inc, Gwangju 61006, Republic of Korea |
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Received: 11 May 2017; Accepted: 16 August 2017. Published online: 31 October 2017. |
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ABSTRACT |
The effect of current densities on the electromigration (EM) failure mechanism of flip chip Cu/Ni/Sn-Ag/Cu solder bumps was investigated under stressing conditions at current densities ranging from 5.0~6.9 × 103 A/cm2 at 150 ℃. The EM failure times at 5.0 × 103 A/cm2 were around 11 times longer than at 6.9 × 103 A/cm2. A systematic failure analysis considering stressing time showed that a current density of 5.0 × 103 A/cm2 induced pancake void propagation near the Cu6Sn5 intermetallic compound/solder interface at the cathode, while a current density of 6.9 × 103 A/cm2 produced severe Joule heating due to high current crowding near the solder/Cu6Sn5 interface. This was due to electrons entering the location at the cathode, which led to local melting of the solder and fast Cu consumption. It was determined that the EM failure mechanisms of flip chip Sn-Ag solder strongly depend not only on the Ni barrier effect but also on current density, which drives the dominant failure mechanisms of pancake voiding and local Joule-heating melting. |
Keywords:
electrical/electron materials, soldering, diffusion, scanning electron microscopy(SEM), electromigration |
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