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Title: Gold-Tin Solder Wetting Behavior for Package Lid Seals

This study examined the cause of nonwetted regions of the gold (Au) finish on iron-nickel (Fe–Ni) alloy lids that seal ceramic packages using the 80Au-20Sn solder (wt %, abbreviated Au–Sn) and their impact on the final lid-to-ceramic frame solder joint. The Auger electron spectroscopy (AES) surface and depth profile techniques identified surface and through-thickness contaminants in the Au metallization layer. In one case, the AES analysis identified background levels of carbon (C) contamination on the surface; however, the depth profile detected Fe and Ni contaminants that originated from the plating process. The Fe and Ni could impede the completion of wetting and spreading to the edge of the Au metallization. The Au layer of lids not exposed to a Au–Sn solder reflow step had significant surface and through-thickness C contamination. Inorganic contaminants were absent. Subsequent simulated reflow processes removed the C contamination from the Au layer without driving Ni diffusion from the underlying solderable layer. Finally, an Au metallization having negligible C contamination developed elevated C levels after exposure to a simulated reflow process due to C contamination diffusing into it from the underlying Ni layer. However, the second reflow step removed that contamination from the Au layer, thereby allowingmore » the metallization to support the formation of lid-to-ceramic frame Au–Sn joints without risk to their mechanical strength or hermeticity.« less
Authors:
 [1] ;  [1] ;  [1]
  1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
Report Number(s):
SAND-2017-11856J
Journal ID: ISSN 1043-7398; 658329
Grant/Contract Number:
AC04-94AL85000
Type:
Accepted Manuscript
Journal Name:
Journal of Electronic Packaging
Additional Journal Information:
Journal Volume: 140; Journal Issue: 2; Journal ID: ISSN 1043-7398
Publisher:
ASME
Research Org:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA), Office of Defense Nuclear Security (NA-70)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE
OSTI Identifier:
1464180

Vianco, Paul T., Kilgo, Alice C., and McKenzie, Bonnie M.. Gold-Tin Solder Wetting Behavior for Package Lid Seals. United States: N. p., Web. doi:10.1115/1.4039749.
Vianco, Paul T., Kilgo, Alice C., & McKenzie, Bonnie M.. Gold-Tin Solder Wetting Behavior for Package Lid Seals. United States. doi:10.1115/1.4039749.
Vianco, Paul T., Kilgo, Alice C., and McKenzie, Bonnie M.. 2018. "Gold-Tin Solder Wetting Behavior for Package Lid Seals". United States. doi:10.1115/1.4039749.
@article{osti_1464180,
title = {Gold-Tin Solder Wetting Behavior for Package Lid Seals},
author = {Vianco, Paul T. and Kilgo, Alice C. and McKenzie, Bonnie M.},
abstractNote = {This study examined the cause of nonwetted regions of the gold (Au) finish on iron-nickel (Fe–Ni) alloy lids that seal ceramic packages using the 80Au-20Sn solder (wt %, abbreviated Au–Sn) and their impact on the final lid-to-ceramic frame solder joint. The Auger electron spectroscopy (AES) surface and depth profile techniques identified surface and through-thickness contaminants in the Au metallization layer. In one case, the AES analysis identified background levels of carbon (C) contamination on the surface; however, the depth profile detected Fe and Ni contaminants that originated from the plating process. The Fe and Ni could impede the completion of wetting and spreading to the edge of the Au metallization. The Au layer of lids not exposed to a Au–Sn solder reflow step had significant surface and through-thickness C contamination. Inorganic contaminants were absent. Subsequent simulated reflow processes removed the C contamination from the Au layer without driving Ni diffusion from the underlying solderable layer. Finally, an Au metallization having negligible C contamination developed elevated C levels after exposure to a simulated reflow process due to C contamination diffusing into it from the underlying Ni layer. However, the second reflow step removed that contamination from the Au layer, thereby allowing the metallization to support the formation of lid-to-ceramic frame Au–Sn joints without risk to their mechanical strength or hermeticity.},
doi = {10.1115/1.4039749},
journal = {Journal of Electronic Packaging},
number = 2,
volume = 140,
place = {United States},
year = {2018},
month = {5}
}