Title :
Reflow and property of Al/Cu/electroless nickel/Sn-Pb solder bumps
Author :
Lin, Kwang-Lung ; Liu, Yi-Cheng
Author_Institution :
Dept. of Mater. Sci. & Eng., Nat. Cheng Kung Univ., Tainan, Taiwan
fDate :
11/1/1999 12:00:00 AM
Abstract :
Materials interaction, shearing strength, and bump growth of Al/Cu/electroless nickel/Sn-Pb solder bumps were investigated with respect to reflow conditions. Shearing strength of the solder bump is as high as 64 g/bump for a bump pad dimension of 100×100 μm. Reflow temperature enhances the shearing strength while repeating reflow downgrades the shearing strength to a lowest value of 35 g/bump. A greater bump height is achieved when reflow was conducted at a slower heating rate. Cu penetrates the electroless nickel (EN) layer after reflow, while Al remains unmoved. The diffusion behavior of Cu through the EN layer is discussed. Ni-Sn and Cu-Sn intermetallic compounds form during reflow
Keywords :
aluminium; copper; diffusion; electroplating; flip-chip devices; lead alloys; nickel; reflow soldering; shear strength; tin alloys; 100 mum; Al-Cu-Ni-SnPb; bump growth; bump height; bump pad dimension; diffusion behavior; heating rate; intermetallic compounds; reflow conditions; reflow temperature; shearing strength; solder bumps; Adhesives; Atherosclerosis; Chromium; Flip chip; Gold; Intermetallic; Nickel; Shearing; Thermal stresses; Tin;
Journal_Title :
Advanced Packaging, IEEE Transactions on
DOI :
10.1109/6040.803447
