Investigation of reactions between lead/tin solder and palladium surface finishes

The role of palladium as a surface finish for the electronics industry was investigated. Of particular interest were the metallurgical phases that form during and following soldering operations of palladium thin films. The formation of PdSn 4 intermetallics on composite substrates (gold/palladium/ni...

Full description

Saved in:
Bibliographic Details
Published in:Acta materialia 2002-10, Vol.50 (18), p.4667-4676
Main Authors: Kobe, B, McIntyre, N.S
Format: Article
Language:English
Subjects:
Applied sciences
Brazing. Soldering
Composite materials
Diffusion
Exact sciences and technology
Growth kinetics
Intermetallics
Joining, thermal cutting: metallurgical aspects
Lead
Metallurgy
Metals. Metallurgy
Palladium
Solder
Thin films
Tin
X ray analysis
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The role of palladium as a surface finish for the electronics industry was investigated. Of particular interest were the metallurgical phases that form during and following soldering operations of palladium thin films. The formation of PdSn 4 intermetallics on composite substrates (gold/palladium/nickel) with varying palladium chemistry and layer thickness were soldered at 220 °C and observed using scanning electron microscope combined with energy dispersive X-ray (SEM/EDX) analysis. Thin layers of palladium approximately 1 μm thick, combined with a fast dissolution rate also resulted in the formation of Ni 3Sn 4 intermetallics. The role of phosphorus in palladium thin films was also investigated. Its presence was found to increase the solubility of palladium in molten solder producing intermetallic crystals that are confined to the bulk. A thin gold layer, used to protect the palladium was found to dissolve rapidly into the solder and to redeposit, forming a thin layer just outside the PdSn 4 intermetallic structure.
ISSN:1359-6454
1873-2453
DOI:10.1016/S1359-6454(02)00319-1