Reliability studies of Sn-Ag-Cu BGA solder joints on Ni/Cu/Au surface finish for SMAFTI packaging technology

A novel pad metal stack structure for wafer-level 3-D packaging technology with fine and thin interposer is proposed. The purpose of this paper is to investigate the solder joint performance of SMAFTI (smart chip connection with feedthrough interposer) under impact shear test and board level reliability test. Using the prototype samples of SMAFTI packages, impact shear tests are performed, which show Sn-Ag-Cu solder joints on Ni/Cu/Au surface are superior to those on Ni/Au. Thermal cycle test, bending cyclic test and drop test are conducted to evaluate the fatigue life of this package. The 0.1% Weibull life of thermal cycle is 989 cycles, and the life cycles of more than 20,000 and 10 cycles are obtained for cyclic bending and drop tests, respectively.

[1]  L. Snugovsky,et al.  Phase equilibria in Sn rich corner of Cu–Ni–Sn system , 2006 .

[2]  M. Amagai,et al.  High drop test reliability: lead-free solders , 2004, 2004 Proceedings. 54th Electronic Components and Technology Conference (IEEE Cat. No.04CH37546).

[3]  Moshe Deutsch,et al.  Surface Oxidation of Liquid Sn , 2004, cond-mat/0407313.

[4]  K. Newman,et al.  BGA brittle fracture - alternative solder joint integrity test methods , 2005, Proceedings Electronic Components and Technology, 2005. ECTC '05..

[5]  K. Kondo,et al.  A 160Gb/s interface design configuration for multichip LSI , 2004, 2004 IEEE International Solid-State Circuits Conference (IEEE Cat. No.04CH37519).

[6]  M. Tago,et al.  A novel "SMAFTI" package for inter-chip wide-band data transfer , 2006, 56th Electronic Components and Technology Conference 2006.

[7]  Tomohiro Nishiyama,et al.  Development of CoC (Chip-on-Chip) Interconnection technology in hyperfine pitch : Packaging technology , 2003 .

[8]  H. Reichl,et al.  Effect of the Cu thickness on the stability of a Ni/Cu bilayer UBM of lead free microbumps during liquid and solid state aging , 2005, Proceedings Electronic Components and Technology, 2005. ECTC '05..

[9]  K. Tu,et al.  Six cases of reliability study of Pb-free solder joints in electronic packaging technology , 2002 .