The Effect of Wetting Gravity Regime on Shear Strength of SAC and Sn-Pb Solder Lap Joints
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Date
2017
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Springer New York LLC barbara.b.bertram@gsk.com
Abstract
The failure of solder joints due to imposed stresses in an electronic assembly is governed by shear bond strength. In the present study, the effect of wetting gravity regime on single-lap shear strength of Sn-0.3Ag-0.7Cu and Sn-2.5Ag-0.5Cu solder alloys reflowed between bare copper substrates as well as Ni-coated Cu substrates was investigated. Samples were reflowed for 10 s, T<inf>gz</inf> (time corresponding to the end of gravity regime) and 100 s individually and tested for single-lap shear strength. The single-lap shear test was also carried out on eutectic Sn-Pb/Cu- and Sn-Pb/Ni-coated Cu specimens to compare the shear strength values obtained with those of lead-free alloys. The eutectic Sn-Pb showed significantly higher ultimate shear strength on bare Cu substrates when compared to Sn-Ag-Cu alloys. However, SAC alloys reflowed on nickel-coated copper substrate exhibited higher shear strength when compared to eutectic Sn-Pb/Ni-coated Cu specimens. All the substrate/solder/substrate lap joint specimens that were reflowed for the time corresponding to the end of gravity regime exhibited maximum ultimate shear strength. © 2017, ASM International.
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Keywords
Binary alloys, Copper, Copper alloys, Eutectics, Joints (structural components), Lead, Lead alloys, Lead-free solders, Nickel, Nickel alloys, Nickel coatings, Plasma theory, Shear flow, Silver, Silver alloys, Soldered joints, Soldering alloys, Substrates, Ternary alloys, Tin, Wetting, Bare copper substrate, Copper substrates, Electronic assemblies, Lead-free alloy, Shear bond strengths, Single lap shears, Single-lap shear tests, Ultimate shear strength, Tin alloys
Citation
Journal of Materials Engineering and Performance, 2017, 26, 9, pp. 4177-4187