Cu pillar 범프의 금속간화합물 성장과 계면접착에너지에 관한 연구
Study on the Intermetallic Compound Growth and Interfacial Adhesion Energy of Cu Pillar Bump
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열처리 및 electromigration에 따른 Cu pillar 범프 내 금속간화합물의 성장거동을 비교하기 위 해서 각각 150oC와 150oC, 5×104 A/cm2의 조건에서 실험을 실시하였다. 또한 금속간화합물의 성장이 Cu pillar 범프 접합부의 기계적 신뢰성에 미치는 영향을 평가하기 위해 4점굽힘강도실험을 실시하여 열처리 에 따른 계면접착에너지를 평가하였다. 리플로우 후에 Cu pillar/Sn 계면에서는 Cu6Sn5만이 관찰되었지 만, 열처리 및 electromigration 실험 시간이 경과함에 따라 Cu3Sn이 Cu pillar와 Cu6Sn5 사이의 계면에서 생성되어 Cu6Sn5와 함께 성장하였다. 전체(Cu6Sn5 + Cu3Sn)금속간화합물의 성장거동은 Cu pillar 범프 내 Sn이 모두 소모될 때 변화하였고, 이러한 금속간화합물 성장거동의 변화는 electromigration의 경우가 열처리의 경우보다 훨씬 빠르게 나타났다. 열처리 전 시편의 계면접착에너지는 3.37 J/m2이고, 180oC에 서 24시간동안 열처리한 시편의 계면접착에너지는 0.28 J/m2로 평가되었다. 따라서 금속간화합물의 성장 은 접합부의 기계적 신뢰성에 영향을 주는 것으로 판단된다.
Abstract
Thermal annealing and electromigration test were performed at 150oC and 150oC, 5×104 A/ cm2 conditions, respectively, in order to compare the growth kinetics of intermetallic compound (IMC) in Cu pillar bump. The quantitative interfacial adhesion energy with annealing was measured by using four-point bending strength test in order to assess the effect of IMC growth on the mechanical reliability of Cu pillar bump. Only Cu6Sn5 was observed in the Cu pillar/Sn interface after reflow. However, Cu3Sn formed and grew at Cu pillar/Cu6Sn5 interface with increasing annealing and stressing time. The growth kinetics of total (Cu6Sn5 + Cu3Sn) IMC changed when all Sn phases in Cu pillar bump were exhausted. The complete consumption time of Sn phase in electromigration condition was faster than that in annealing condition. The quantitative interfacial adhesion energy after 24h at 180oC was 0.28 J/m2 while it was 3.37 J/m2 before annealing. Therefore, the growth of IMC seem to strongly affect the mechanical reliability of Cu pillar bump.
참고문헌 (13)
- K. N. Chiang, "Current crowding-induced electromigration in SnAgCu microbumps", Appl. Phys. Lett, 88, pp.072102~ (2006)
- T. Y. Lee, "Electromigration of eutectic SnPb and SnAgCu flip chip solder bumps and under-bump metallization", J. Appl. Phys, 90, pp.4502~ (2001)
- V. S. Rao, "Bed of Nails-100 microns pitch wafer level interconnection process", 54th Electron. Comp. Technol. Conf., pp.449~ (2004)
- M. Ding, "Effect of contact metallization on electromigration reliability of Pb-free solder joints", J. Appl. Phys, 99, pp.094906~ (2006)
- 최재영, "공정 조성의 SnPb 솔더에서의 Electromigration 거동", 전기전자재료학회논문지, 16(1) (2003), 한국전기전자재료학회
- J. R. Lloyd, "Electromigration in integrated circuit conductors", J. Appl. Phys, 32, pp.109~ (1999)
- H. Y. Son, "Cu", SnAg double bump flip chip assembly as an alternative of solder flip chip on organic substrates for fine pitch applications, 2007, 864~
- K. Zeng, "Kirkendall void formation in eutectic Sn-Pb solder joint on bare Cu and its effect on joint reliability", J. Appl. Phys, 97, pp.024508~ (2005)
- Z. Huang, "Initiation and arrest of an interfacial crack in a four-point bend test", Eng. Fracture Mech, 72, pp.2584~ (2005)
- P. G. Charalambides, "A test specimen for determining the fracture resistance of bimaterial interfaces", J. Appl. Mech, 111, pp.77~ (1989)
- H. Gan, "Polarity effect of electromigration on kinetics of intermetallic compound formation in Pb-free solder V-groove samples", J. Appl. Phys, 97, pp.063514~ (2005)
- K. Yamanaka, "Electromigration effect on solder bump in Cu", Sn–3Ag– 0.5Cu, Scripta Mater, pp.2006, 55[DOI]
- J. M. Koo, "Mechanical and Electrical Properties of Cu", Sn-3.5Ag, J. Electron. Mater, pp.2008, 37[DOI]