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JUNE 2021 I SMT007 MAGAZINE 39 Foreign Object Debris (FOD) (Case Study 3) Defect observed De-wetting occurred at the SOT (small out- line transistor) component lead. By observ- ing the SOT solder joint having de-wetting issues by optical microscope the foreign object debris was found. FT-IR (Fourier Transform Infra-Red) analysis was performed on the for- eign object debris. e solder paste reflowed at the SOT component solder joint was no-clean Type 3 62Sn36Pb2Ag tin-lead-silver. Type of analysis equipment used to observe and characterize defect Optical microscope and FT-IR (Fourier Transform Infra-Red) analysis was performed. Damaged plating (Case Study 4) Defect observed Solder de-wetting occurred on the Sn-plated component. A no-clean flux was used with the solder. Type of analysis equipment used to observe and characterize defect e plated surface of the good and inferior solder wetted components was observed by SEM (scanning electron microscope) with EDX (energy dispersive X-ray) analysis. Improper process condition setting (Case Study 5) Defect observed Solder de-wetting occurred on the pad sub- strate. e no-clean solder paste material sol- dered on the pad was Sn3Ag0.5Cu Type 4. Type of analysis equipment used to observe and characterize defect Pad substrates with good and poor solder wetting were observed by optical microscope. e following section discusses the defects observed with the analysis equipment used for the different case studies reported. Results and Discussion Inferior board plating/surface finish quality (Case Study 1) Analysis of board plating/surface finish qual- ity results An uneven HAL (hot air solder levelled) treatment layer thickness can be observed. e composition of the HAL surface treatment was Sn3Ag0.5Cu on the copper pad substrate. e area with the HAL treatment can cause de- wetting due to the Cu (copper) board pad sub- strate oxidation which is shown in Figures 4 through 7. Figure 3: X-ray equipment. Figure 4: SEM image on HAL treatment.