Fig. 1. SMT scope images of a solder paste. (a) 50℃ , (b) 150℃, and (c) 250℃.
Fig. 2. Wetting balance curves of fluxes with carbon number (n) of dicarboxylic acids (HOOC(CH2)nCOOH).
Fig. 3. Zero cross time (t0) and maximum wetting force (Fmax) of fluxes with carbon number (n) of dicarboxylic acids (HOOC(CH2)nCOOH).
Fig. 4. SMT scope images of solder pastes at 250℃. The activators in the solder pastes were (a) oxalic acid, (b) malonic acid, (c) succinic acid, (d) glutaric acid, (e) adipic acid, and (f) pimelic acid.
Fig. 5. Slump ratio of solder pastes with carbon number (n) of dicarboxylic acids (HOOC(CH2)nCOOH).
Fig. 6. Spreadability of solder pastes with carbon number (n) of dicarboxylic acids (HOOC(CH2)nCOOH).
Fig. 7. DSC curves of solder pastes with varying dicarboxylic acid activators. (a) oxalic acid, (b) malonic acid, (c) succinic acid, (d) glutaric acid, (e) adipic acid, and (f) pimelic acid.
Fig. 8. Enthalpy of fluxes calculated from the activation peak of DSC.
Table 1. Properties and structure of dicarboxylic activators in this study.
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