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

Volume

22

Issue

4

fYear

1999

fDate

11/1/1999 12:00:00 AM

Firstpage

568

Lastpage

574

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;

fLanguage

English

Journal_Title

Advanced Packaging, IEEE Transactions on

Publisher

ieee

ISSN

1521-3323

Type

jour

DOI

10.1109/6040.803447

Filename

803447