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Title: Role of Cu-Sn intermetallics in wettability degradation

Abstract

Wettability of pretinned Cu decreases after long aging times. This work provides insight into the role Cu-Sn intermetallics play in wettability degradation. This study investigates the effects of aging in air and argon at 170{degree}C on Cu coupons which were pretinned with 75Sn-25Pb solder. Coating was applied using an electroplating technique. The coating thickness was controlled between 3 to 30 {mu}m and the specimens were aged for 0, 2, 24 h, and two weeks. Wetting balance tests were used to evaluate the wettability of the test specimens. Microstructural development was evaluated using x-ray diffraction, energy dispersive x-ray, and Auger spectroscopy, as well as optical and scanning electron microscopy. Results indicate that Cu-Sn intermetallics protected from oxidation do not contribute to a decrease in wettability. Oxidized intermetallics, however, significantly decrease the wettability of aged pretinned samples. The extent of degradation is determined by the type of oxide formed on the surface of the intermetallic. This study shows that a predominantly Cu oxide forms on Cu{sub 3}Sn, while a Sn oxide forms on Cu{sub 6}Sn{sub 5}. No evidence of internal oxidation was found. 20 refs., 9 figs., 1 tab.

Authors:
;  [1]
  1. Lawrence Berkeley Lab., CA (United States)|[Univ. of California, Berkeley, CA (United States)
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
171470
DOE Contract Number:  
AC03-76SF00098
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Electronic Materials; Journal Volume: 24; Journal Issue: 10; Other Information: PBD: Oct 1995
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 40 CHEMISTRY; INTERMETALLIC COMPOUNDS; OXIDATION; X-RAY DIFFRACTION; ELECTRON MICROSCOPY; WETTABILITY; COPPER ALLOYS; TIN ALLOYS; ELECTRON SPECTRA

Citation Formats

Reynolds, H.L., and Morris, J.W.. Role of Cu-Sn intermetallics in wettability degradation. United States: N. p., 1995. Web. doi:10.1007/BF02655460.
Reynolds, H.L., & Morris, J.W.. Role of Cu-Sn intermetallics in wettability degradation. United States. doi:10.1007/BF02655460.
Reynolds, H.L., and Morris, J.W.. Sun . "Role of Cu-Sn intermetallics in wettability degradation". United States. doi:10.1007/BF02655460.
@article{osti_171470,
title = {Role of Cu-Sn intermetallics in wettability degradation},
author = {Reynolds, H.L. and Morris, J.W.},
abstractNote = {Wettability of pretinned Cu decreases after long aging times. This work provides insight into the role Cu-Sn intermetallics play in wettability degradation. This study investigates the effects of aging in air and argon at 170{degree}C on Cu coupons which were pretinned with 75Sn-25Pb solder. Coating was applied using an electroplating technique. The coating thickness was controlled between 3 to 30 {mu}m and the specimens were aged for 0, 2, 24 h, and two weeks. Wetting balance tests were used to evaluate the wettability of the test specimens. Microstructural development was evaluated using x-ray diffraction, energy dispersive x-ray, and Auger spectroscopy, as well as optical and scanning electron microscopy. Results indicate that Cu-Sn intermetallics protected from oxidation do not contribute to a decrease in wettability. Oxidized intermetallics, however, significantly decrease the wettability of aged pretinned samples. The extent of degradation is determined by the type of oxide formed on the surface of the intermetallic. This study shows that a predominantly Cu oxide forms on Cu{sub 3}Sn, while a Sn oxide forms on Cu{sub 6}Sn{sub 5}. No evidence of internal oxidation was found. 20 refs., 9 figs., 1 tab.},
doi = {10.1007/BF02655460},
journal = {Journal of Electronic Materials},
number = 10,
volume = 24,
place = {United States},
year = {Sun Oct 01 00:00:00 EDT 1995},
month = {Sun Oct 01 00:00:00 EDT 1995}
}