This paper describes an evaluation technique for solder pasteprintability using a solder paste inspection system and optimization ofprinting parameters. In a Surface Mount Assembly (SMA), it is veryimportant to evaluate printability of solder paste precisely, becauseprintability of solder paste directly influences reflow solderingquality. We established quite reliable inspection criteria for printquantity of solder paste. So it was found that about 90% of reflowsoldering defects could be reduced by prevention of printing defects.Furthermore, since package types have been varied in a SMA, highsoldering quality demands stable printability for all patterns. Thispaper presents a printability evaluation adopted procedure based on thequality engineering (TAGUCHI method). As a result of optimizing squeegeeshape and printer condition by this evaluation method, printability wasimproved better than 20% in the production process. And optimization ofsolder paste and stencil added to printer condition resulted in goodprintability for 0.3 mm pitch patterns on the optimum condition
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