ENEPIG 표면처리에서의 Sn-Ag-Cu 솔더조인트 신뢰성: 1. 무전해 Ni-P도금의 두께와 표면거칠기의 영향
Reliability of Sn-Ag-Cu Solder Joint on ENEPIG Surface Finish: 1. Effects of thickness and roughness of electroless Ni-P deposit
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전자 제품의 경박 단소화 및 고집적화가 이루어 지면서 실리콘 집과 인쇄회로기판의 인터커넥션의 고신뢰도가 요구되고 있다. 본 연구는 Sn-4.0wt%Ag-0.5wt%Cu (SAC405) 솔더와 다양한 무전해 Ni-P 도금 두께에서의 high speedshear 에너지 및 파괴 모드를 연구하였다. 파괴 모드 분석을 위하여 집속이온빔(FIB) 분석이 이용되었다. 질산 기상 처리하지 않은 1 μm Ni-P 시편에서 낮은 shear 에너지가 나왔으며, 이는 솔더레지스트 선단에서 파단의 원인을 제공하는 것이 확인되었다. 질산 기상 처리한 시편에서 무전해 Ni-P 도금 두께가 커질수록 취성 파괴 모드는 감소한다. 또 Ni-P 도금두께와 표면 거칠기(Ra)는 반비례 관계를 가진다. 이는 Ni-P 도금의 표면 거칠기를 낮추면 SAC405 솔더 조인트의 신뢰도를 향상시킨다는 사실을 나타낸다.
Abstract
By the trends of electronic package to be smaller, thinner and more integrative, the reliability ofinterconnection between Si chip and printed circuit board is required. This paper reports on a study of high speed shearenergy of Sn-4.0wt%Ag-0.5wt%Cu (SAC405) solder joints with different the thicknesses of electroless Ni-P deposit. Ahigh speed shear testing of solder joints was conducted to find a relationship between the thickness of Ni-P deposit andthe brittle fracture in electroless Ni-P deposit/SAC405 solder. A focused ion beam (FIB) was used to polish the crosssections to reveal details of the microstructure of the fractured pad surface with and without HNO3 vapor treatment. Thehigh speed shear energy of SAC405 solder joint with 1 μm Ni-P deposit was found to be lower without HNO3 vapor,compared to those of over 3 μm Ni-P deposit. This could be due to the edge of solder resist in 1 μm Ni-P deposit, whichprovides a fracture location for the weakened shear energy of solder joints and brittle fracture in high speed shear test. With HNO3 vapor, the brittle fracture mode in high speed shear test decreased with increasing the thickness of Ni-P deposit. Then the roughness (Ra) of Ni-P deposits decreased with increasing its thickness. Thus, this gives the evidence that thedecrease in roughness of Ni-P deposit for Eelectroless Ni/ Electroless Pd/ Immersion Au (ENEPIG) surface play a criticalrole for improving the robustness of SAC405 solder joint.
참고문헌 (20)
- D. Cullen, "A study on interfacial fracture phenomenon of solder joints formed using the electroless nickel", immersion gold surfaces finish, 2000, s03~
- 손윤철, "계면 화학반응과 무전해 니켈 금속층에서 나타나는 취성파괴와의 연관성에 관한 연구", 마이크로전자 및 패키징학회지, 12(1), pp.41~46 (2005), 한국마이크로전자및패키징학회
- Z. Mei, "Brittle interfacial fracture of PBGA packages on electroless Ni", immersion Au, 1998, 952~
- G. M. Wenger, "Case studies of brittle interfacial fractures in area array solder intercommnects", Proc. 26th International Symposium for testing and failure analysis, pp.355~ (2000)
- T. I. Eijim, "Assembly and reliability of thermally enhanced high I", O BGA packages, 1997, 25~
- J. W. Jang, "Morpholgy of interfacial reaction between lead-free solders and electroless Ni-P under bump metallization", J. Appl. Phys., 88(11), pp.6359~ (2000)
- D. Goyal, "Failure mechanism of brittle solder joint fracture in the presence of electroless Ni immersion gold (ENIG) interface", Proc. 52nd Electronic Component and Technology Conference, pp.732~ (2002)
- K. Zeng, "The root cause of black pad failure of solder joints with electroless Ni", immersion gold plating, 2006, 75~
- D. G. Lee, "New surface finish of the substrate for the flip chip packaging", SEMICON Korea 2007, pp.255~ (2007)
- 이지혜, "무전해 Ni-P 두께와 Assembly Process가 Solder Ball Joint의 신뢰성에 미치는 영향", 대한용접접합학회지, 32(3), pp.60~67 (2014), 대한용접접합학회
- A. Kumar, "Effect of Ni-P thickness on the tensile strength of Cu", Electroless Ni-P, 7th Electronics Packaging Technology Conference, pp.2005[DOI]
- K. Pun, "Effect of Ni layer thickness on intermetallic formation and mechanical strength of Sn-Ag-Cu solder joint", 10th Electronics Packaging Technology Conference, pp.487~ (2008), IEEE
- S. H. Huh, "A novel high speed shear test for lead free flip chip package, Electron", Mater. Lett., 8(1), pp.53~ (2012)
- W. L. Liu, "Growth behavior of Ni-P film on Fe", Si substrate in an acid electroless plating bath, 2008, pp.155(3), D192~
- D. K. Lee, "Influence of Doping on Ni Electroless Deposition at Single Crystalline Si", JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 158(8), pp.490~494 (2011), ELECTROCHEMICAL SOC INC
- J. W. Yoon, "Flip-chip bonding technology and reliability of electronic packaging", J. KWS, 25, pp.6~ (2007)
- S. S. Ha, "Thermo-mechanical reliability of lead-free surface mount assemblies for automobile application", J. KWS, 24, pp.21~ (2006)
- Min-Ho Park, "TEM Study on the Interfacial Reaction between Electroless Plated Ni-P", Au UBM and Sn-3.5Ag Solder, 2007, pp.13(3), 235~238[DOI]
- 임지연, "BGA Type 유·무연 솔더의 기계적 충격에 대한 보드레벨 신뢰성 평가", 마이크로전자 및 패키징학회지, 15(4), pp.77~86 (2008), 한국마이크로전자및패키징학회
- 장임남, "리플로우 횟수와 표면처리에 따른 Sn-Ag-Cu계 무연 솔더 범프의 고속전단 특성평가", 마이크로전자 및 패키징학회지, 16(3), pp.11~17 (2009), 한국마이크로전자및패키징학회