No abstract

The effect of dipping time to the intermetallic compound and free solder thickness of Sn-Cu-Ni (SN100C) lead-free solder has been investigated. Dipping of copper strips in molten solder was carried out using GEN3 solderability test machine with 20 s, 60 s, 120 s, 180 s, and 240 s of dipping time. Scanning Electron Microscope (SEM) was used to observe the solder coating on the copper strips. Thickness of IMC, free solder and total solder coating was calculated. The influence of dipping time was established. The results indicated that longer dipping time produced high IMC thickness while the free solder thickness reduced with the growth of IMC. Solderability test was also conducted to know the wettability of SN100C coating for the lowest dipping time which had resulted in 1.571 s of wetting time and 4.066 mN of maximum force.

SN100C lead-free solder coating wettability on SN100C solder has been investigated on as soldered samples and exposed intermetallic compound (IMC). In addition, the effect of oxidation on its wettability has also been investigated. Oxidation layer on the coated copper surface was developed after 120 hours of exposure on as soldered samples and exposed IMC samples. GEN3 solderability test machine in globule mode was used to determine the wettability of each sample. The influence of oxidation and the effect of exposed IMC were established. Results show that oxidation affected wettability by increasing the wetting time. On the other hand, exposed IMC had increased the wetting time and decreased the maximum force.

The wettability of Sn-Cu-Ni with Germanium (Ge) additions of 0 ppm, 10 ppm, 60 ppm, 100 ppm and 200 ppm were investigated with Gen3 machine. The range of the wettability shows the lowest and the highest reading of wetting time and maximum force. Three different conditions were investigated which consist of as soldered, reflowed and aged. Further interfacial IMC observation was done for 0 ppm and 60 ppm of Ge to investigate the growth of interfacial IMC after thermal aging. From the measurement, the thickness of IMC for 0 ppm Ge is 2.075μm, 3.936μm and 4.502μm with aging time at 24,120 and 240 hours respectively. While for 60 ppm Ge, the IMC thickness are much lower with 1.8μm, 3.11μm and 4.154μm at the same aging time with 0ppm Ge. The results indicate that 60 ppm of Ge in Sn-Cu-Ni has the lowest wetting time, higher maximum force and slow IMC growth.