Improving the PCB Assembly Manufacturing Process by an ALTERNATIVE SOLDER PASTE: A Statistical Evaluation, Part II

摘要

Although significant differences in performance were observed across the different pastes, a number of common trends were documented. As aperture size increases, the deposit volume distributions typically narrow (C_p increases), eventually stabilizing for component apertures of 0402 and above. All pastes exhibited a reduction in process capability (C_(pk) decreases) with increasing aperture size due to a shift in the center of the deposit volume distribution to above the 100% target. This is a result of the hydrostatic characteristics of solder pastes and yields deposits that are higher than the thickness of the stencil. The extra paste may also contribute to mid-chip solder balling. Paste A consistently yields the greatest C_p and C_k values compared to the other pastes.