시효 처리에 의한 42Sn-58Bi 솔더와 무전해 Ni-P/치환 Au UBM간의 계면 반응
Interfacial Reaction between 42Sn-58Bi Solder and Electroless Ni-P/ImmersionAu UBM during Aging
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42Sn-58Bi 솔더(이하 wt.%에 의한 표기)와 무전해 Ni-P/치환 Au under bump metallurgy (UBM)간의 계면 반응을 intermetallic compound (IMC)의 형성과 성장, UBM의 감소, 그리고 범프 전단 강도의 영향 관점에서 시효 처리 전 후에 어떠한 변화가 생기는 지를 알아보고자 하였다. 치환 Au 층을 5m 두께의 무전해 Ni-P (14~15 at.% P) 위에 세 가지 각기 다른 두께, 즉 0 m(순수한 무전해 Ni-P UBM), 0.1 m, 1 m로 도금하였다. 그 후 42Sn-58Bi 솔더 범프를 세 가지 다른 UBM 구조에 스크린 프린팅 방식으로 형성하였다. 범프 형성 직후에는 세 가지 다른 UBM 구조에서 솔더와 UBM사이에 공통적으로 Ni3Sn4 IMC (IMC1) 만이 형성됐다. 하지만, 이를 125?에서 시효 처리를 할 경우 특이하게 Au를 함유한 UBM 구조에서는 Ni3Sn4 위로 또 다른 4원계 화합물 (IMC2)이 관찰 되었다. 원자 비로 Sn77Ni15Bi6Au2인 4원계 화합물로 확인되었다. Sn77Ni15Bi6Au2 층은 솔더 조인트의 접합성에 매우 치명적인 영향을 미쳤다. 시효 처리를 거친 Au를 함유한 UBM 구조에서 솔더 범프의 전단 강도 값은 시효 처리 전에 비해 40% 이상의 감소를 보였다.
Abstract
The interfacial reaction between 42Sn-58Bi solder (in wt.% unless specified otherwise) and electroless Ni-P/immersion Au has been investigated before and after thermal aging, with a focus on formation and growth of an intermetallic compound (IMC) layer, consumption of under bump metallurgy (UBM), and bump shear strength. The immersion Au layer with thicknesses of 0 (bare Ni), 0.1, and 1 m was plated on the 5m thick electroless Ni-P (14~15 at.% P) layer. Then, the 42Sn-58Bi solder balls were fabricated on three different UBM structures by screen-printing and pre-reflow. The Ni3Sn4 layer (IMC1) was formed at the joint interface after pre-reflow for all the three UBM structures. On aging at 125C, a quaternary phase (IMC2) was observed above the Ni3Sn4 layer in the Au-containing UBM structures, which was identified as Sn77Ni15Bi6Au2 (in at.%). The thick Sn77Ni15Bi6Au2 layer deteriorated the integrity of the solder joint and the shear strength of the solder bump was decreased by about 40% compared with non-aged joints.
참고문헌 (18)
- "Thermodynamics-Aided Alloy Design and Evaluation of Pb-free Solders for High-Temperature Applications", 43, pp.1873~ (2002)
- "Role of Tin Content in the Wetting of Cu and Au by Tin-Bismuth Solders", 23, pp.773~ (1994)
- "The Effect of Gold-Nickel Metallization Microstructure on Fluxless Soldering", 23, pp.533~ (1994)
- "Interfacial Reaction and Microstructural Evolution for Electroplated Ni and Electroless Ni in the Under Bump Metallurgy with 42Sn58Bi Solder during Annealing", 30, pp.878~ (2001)
- "Phenomena of Electroless Ni-P and Intermetallic-Compound Stripping and Dissolving in Sn-Bi and Sn-Pb Solder Joints with Au", EN, pp.2002, 31[DOI]
- "Solderability of Electroless Nickes Alloys Using Wetting Balance Technique", 33, pp.4708~ (1994)
- "Six Cases of Reliability Study of Pb-free Solder Joints in Electronic Packaging Technology", 38, pp.55~ (2002)
- "Interfacial Microstructure Evolution in Pb-Free Solder Systems", 32, pp.906~ (2003)
- "Growth and ripening of Sn4 phase in Pb-free and Pb-containing solders on Ni", Au metallization, 2003, pp.18, 2562~
- "Reflow Soldering and Isothermal Solid-State Aging of Sn-Ag Eutectic Solder on Au", Ni Surface Finish, 2001, pp.30, 1152~
- "Interactions between Solder and Metallization During Long-Term Aging of Advanced Microelectronic Packages", 30, pp.379~ (2001)
- "Formation of Intermetallic Compounds in SnPbAg and SnAgCu Solders on Ni", Au Metallization, 2001, pp.32A, 2666~
- "Thermal expansion of tin in the b-g transition region", 15, pp.294~ (1962)
- "The crystal structure of Bi and of solid solutions of Pb Sb and Te in Bi", 15 (1962)
- "Crystal structure of Au Ni Sn intermetallic alloys", 334, pp.79~ (2002)
- "Compound Formation for Electroplated Ni and Electroless Ni in the Under-Bump Metallurgy with Sn-58Bi Solder during Aging", 32, pp.1463~ (2003)
- "The Microstructure Characterization of Ultrasmall Eutectic Bi-Sn Solder Bumps on Au", Cu, Ni, pp.Ti Under-Bump Metallization[DOI]
- "Mechanical Behavior of Solder Joint Interfacial Intermetallics", pp.229~