|
Vol.55, No.11, 798 ~ 806, 2017
|
| Title |
| Effect of Current Densities on the Electromigration Failure Mechanisms of Flip-Chip Sn-Ag Solder Bump |
| 김가희 Gahui Kim , 손기락 Kirak Son , 박규태 Gyu-tae Park , 박영배 Young-bae Park |
|
|
|
| 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.
(Received May 11, 2017; Accepted August 16, 2017) |
|
|
| Key Words |
| electrical/electron materials, soldering, diffusion, scanning electron microscopy(SEM), electromigration |
|
|
 |
|
