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Title: Lead-free solders for electronics applications: Wetting analysis

Abstract

The fabrication of electronic systems has relied upon eutectic tin-lead solder for the attachment of components to printed wiring boards. Higher service temperatures are approaching the durability limits of the eutectic solder. The tin-rich, lead-free solders are being actively studied as alternate alloys. Experiments that examined the wettability of 95Sn-5Sb (wt %), 95.5Sn-4.0Cu-0.5Ag, 96.5Sn-3.5Ag, and the control solder, 60Sn-40Pb, on oxygen-free, high conductivity copper were performed. A rosin-based, mildly activated (RMA) flux and three water soluble, organic acid fluxes were used in the wetting balance/meniscometer measurements. The 95.5Sn-4.0Cu-0.5Ag and 95Sn- 5Sb alloys exhibited good wetting, with contact angles of 35{degree} < {theta}{sub c} < 55{degree} as compared to the excellent performance of the 60Sn-40Pb material (20{degree} < {theta}{sub c} < 35{degree}). The fair wettability observed with the 96.5Sn-3.5Ag solder (60{degree} < {theta}{sub c} < 75{degree}) was due in large part to the inability of the fluxes to significantly lower the solder-flux interfacial tension. The wetting rates of the 95.5Sn-4.0Cu-0.5Ag and 95Sn-5Sb solders were comparable to those of the control; the 96. 5Sn-3.5Ag alloy wetting rate was slower than the other candidates. The solder film formed on the substrate surface by the 95.5Sn-4.0Cu-0. 5Ag alloy was very grainy. The water solublemore » fluxes exhibited a larger degree of residue formation than did the RMA flux. 8 refs., 12 figs.« less

Authors:
; ;
Publication Date:
Research Org.:
Sandia National Labs., Albuquerque, NM (United States)
Sponsoring Org.:
USDOE; USDOE, Washington, DC (United States)
OSTI Identifier:
5494227
Report Number(s):
SAND-91-0031C; CONF-9108110-1
ON: DE91014900
DOE Contract Number:  
AC04-76DP00789
Resource Type:
Conference
Resource Relation:
Conference: 4. Electronic materials processing congress, Montreal (Canada), 19-23 Aug 1991
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 42 ENGINEERING; ANTIMONY ALLOYS; WETTABILITY; COPPER ALLOYS; LEAD ALLOYS; TIN BASE ALLOYS; ELECTRONIC EQUIPMENT; OPTICAL MICROSCOPY; SOLDERED JOINTS; ALLOYS; EQUIPMENT; JOINTS; MICROSCOPY; TIN ALLOYS; 360101* - Metals & Alloys- Preparation & Fabrication; 426000 - Engineering- Components, Electron Devices & Circuits- (1990-)

Citation Formats

Vianco, P T, Hosking, F M, and Frear, D R. Lead-free solders for electronics applications: Wetting analysis. United States: N. p., 1991. Web.
Vianco, P T, Hosking, F M, & Frear, D R. Lead-free solders for electronics applications: Wetting analysis. United States.
Vianco, P T, Hosking, F M, and Frear, D R. 1991. "Lead-free solders for electronics applications: Wetting analysis". United States.
@article{osti_5494227,
title = {Lead-free solders for electronics applications: Wetting analysis},
author = {Vianco, P T and Hosking, F M and Frear, D R},
abstractNote = {The fabrication of electronic systems has relied upon eutectic tin-lead solder for the attachment of components to printed wiring boards. Higher service temperatures are approaching the durability limits of the eutectic solder. The tin-rich, lead-free solders are being actively studied as alternate alloys. Experiments that examined the wettability of 95Sn-5Sb (wt %), 95.5Sn-4.0Cu-0.5Ag, 96.5Sn-3.5Ag, and the control solder, 60Sn-40Pb, on oxygen-free, high conductivity copper were performed. A rosin-based, mildly activated (RMA) flux and three water soluble, organic acid fluxes were used in the wetting balance/meniscometer measurements. The 95.5Sn-4.0Cu-0.5Ag and 95Sn- 5Sb alloys exhibited good wetting, with contact angles of 35{degree} < {theta}{sub c} < 55{degree} as compared to the excellent performance of the 60Sn-40Pb material (20{degree} < {theta}{sub c} < 35{degree}). The fair wettability observed with the 96.5Sn-3.5Ag solder (60{degree} < {theta}{sub c} < 75{degree}) was due in large part to the inability of the fluxes to significantly lower the solder-flux interfacial tension. The wetting rates of the 95.5Sn-4.0Cu-0.5Ag and 95Sn-5Sb solders were comparable to those of the control; the 96. 5Sn-3.5Ag alloy wetting rate was slower than the other candidates. The solder film formed on the substrate surface by the 95.5Sn-4.0Cu-0. 5Ag alloy was very grainy. The water soluble fluxes exhibited a larger degree of residue formation than did the RMA flux. 8 refs., 12 figs.},
doi = {},
url = {https://www.osti.gov/biblio/5494227}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Jan 01 00:00:00 EST 1991},
month = {Tue Jan 01 00:00:00 EST 1991}
}

Conference:
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