Issue link: https://iconnect007.uberflip.com/i/1293772
OCTOBER 2020 I SMT007 MAGAZINE 65 It exhibited stable soldering characteristics, such as printability with the 0.4-mm pitch QFP board pads after 200 print strokes (Figure 13) and good melting properties on the 0.25-mm diameter CSP board pads and the 0603 chip resistor components (Figure 14). In addition, there was found to be low voiding behavior with this solder paste with soldered power transistor/BTC, 6330 chip, and BGA compo- nents (Figure 15), allowing its use as a gen- eral-purpose solder paste product. It was also found to be an effective solder paste for the assembly of sensor components and camera modules; these application areas are expected to expand in the future. Conclusions This article discussed the mechanism of flux splattering during soldering, preventive measures Figure 13: Fine-pitch printing on 0.4-mm pitch QFP board pad (left: initial; right: after 200 print strokes). Figure 14: Reflow behavior on 0.25-mm diameter CSP board pads (L) and 0603 chip components (R). Figure 11: No flux splattering with Type 4 Sn3Ag0.5Cu no-clean Paste Product C using a reflow simulator. Figure 12: Flux splattering with no-clean Type 4 Sn3Ag0.5Cu conventional Paste Product A using a reflow simulator. Figure 15: Low voiding behavior on soldered power transistor (L), 6330 chip (center), and 1-mm pitch BGA components (R).