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Vol.49, No.2, 180 ~ 187, 2011
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| Title |
| Intermetallic Compound Growth Characteristics of Cu/thin Sn/Cu Bump for 3-D Stacked IC Package |
| 박영배 Young Bae Park , 김재원 Jae Won Kim , 김병준 Byoung Joon Kim , 김재동 Jae Dong Kim , 주영창 Young Chang Joo , 이기욱 Ki Wook Lee , 정명혁 Myeong Hyeok Jeong , 곽병현 Byung Hyun Kwak |
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| Abstract |
| Isothermal annealing and electromigration tests were performed at 125℃ and 125℃, 3.6×104 A/cm2 conditions, respectively, in order to compare the growth kinetics of the intermetallic compound (IMC) in the Cu/thin Sn/Cu bump. Cu6Sn5 and Cu3Sn formed at the Cu/thin Sn/Cu interfaces where most of the Sn phase transformed into the Cu6Sn5 phase. Only a few regions of Sn were not consumed and trapped between the transformed regions. The limited supply of Sn atoms and the continued proliferation of Cu atoms enhanced the formation of the Cu3Sn phase at the Cu pillar/Cu6Sn5 interface. The IMC thickness increased linearly with the square root of annealing time, and increased linearly with the current stressing time, which means that the current stressing accelerated the interfacial reaction. Abrupt changes in the IMC growth velocities at a specific testing time were closely related to the phase transition from Cu6Sn5 to Cu3Sn phases after complete consumption of the remaining Sn phase due to the limited amount of the Sn phase in the Cu/thin Sn/Cu bump, which implies that the relative thickness ratios of Cu and Sn significantly affect Cu-Sn IMC growth kinetics. |
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| Key Words |
| Cu/thin Sn/Cu bump, intermatallics, annealing, electromigration, scanning electron microsopy, SEM |
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