Title :
Fine pitch low-cost bumping for flip chip technology
Author :
Lu, Szu-Wei ; Uang, Ruoh-Huey ; Chen, Kuo-Chum ; Hu, Hsu-Tien ; Kung, Ling-Chen ; Huang, Hsin-Chien
Author_Institution :
Dept. for Packaging Process, Ind. Technol. Res. Inst., Hsinchu, Taiwan
Abstract :
In this paper, a low-cost and fine pitch bumping process by electroless Ni-Au bumping for the UBM (under bump metallurgy) and stencil printing for the solder bump is studied. The solder bumps are made of eutectic SnPb. The pitches of the solder bumps range from 300 μm to 200 μm for various stencil openings from 210 μm to 125 μm. The regular bump height is 90 μm for the 200 μm pitch. The pad opening size is also controlled as a variable. The kinetics of zincating on an Si-Cu surface and on an Al surface are compared. It is found that zincating replacement on the Al-Si-Cu surface is much more rapid than on the Al surface and the dissolution rate of Al-Si-Cu is also faster than that of Al. Finally, the quality of the low-cost solder bumping process is evaluated by shear tests and reliability tests
Keywords :
assembling; dissolving; fine-pitch technology; flip-chip devices; integrated circuit interconnections; integrated circuit metallisation; integrated circuit packaging; integrated circuit reliability; integrated circuit testing; reaction kinetics; soldering; surface chemistry; surface treatment; 125 to 210 micron; 200 to 300 micron; 90 micron; Al; Al surface; AlSiCu; Ni-Au; Si-Cu; Si-Cu surface; bumping cost; dissolution rate; electroless Ni-Au bumping under bump metallurgy; eutectic SnPb solder bumps; fine pitch bumping; fine pitch bumping process; flip chip technology; regular bump height; reliability tests; shear tests; solder bump; solder bump pitch; solder bumping process; solder bumps; stencil openings; stencil printing; zincation kinetics; Adhesives; Aluminum; Costs; Electronics packaging; Flip chip; Nickel; Passivation; Printing; Testing; Zinc;
Conference_Titel :
Electronics Manufacturing Technology Symposium, 1999. Twenty-Fourth IEEE/CPMT
Conference_Location :
Austin, TX
Print_ISBN :
0-7803-5502-4
DOI :
10.1109/IEMT.1999.804806
