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摘要

"The Effect of Solder Paste Reflow Conditions on Surface Insulation Resistance" Three different reflow temperature vs. time profiles - a 1.5℃/s ramp to 230℃, a 1.5℃/s ramp to 250℃ and a 90s soak at 175℃ with a 230℃ peak - were used to reflow three lead-free solder pastes in air and nitrogen atmospheres. Fourier transform IR spectra of the reflowed flux residues show how reflow profile conditions and atmosphere affects the decrease of a peak around 1700 cm~(-1) and the appearance and increase of another peak at 1600 cm~(-1). The 1700 cm~(-1) is smaller for flux residues reflowed under hotter conditions and for those reflowed in air. The peak at 1600 cm~(-1) is larger for residues exposed to hotter reflow profiles in air, but is hardly present for residues reflowed in nitrogen. The effect of these reflow conditions on surface insulation resistance per IPC-TM-650 Method 2.6.3.7 at 40℃/90% RH and 12V bias has been studied. This measurement shows that hotter reflow conditions result in higher SIR values for two of the pastes, as would be expected, but has a smaller affect on the third paste.