Issue link: https://iconnect007.uberflip.com/i/239245
characteristics of epig deposits for fine-line applications continues When using LF35 as the solder ball, the result of HSS was shown in Figure 7. And the observation of IMC and the analysis of IMC composition by EDS were shown in Figure 8 and Figure 9. The broken energy of HSS for EPIG film was better, compared with the result with M705. From the results of EDS shown in Figure 7, (Cu,Ni)6Sn5 was formed as layer 1 and Cu3Sn was formed as layer 2. Ni was supplied for the solder ball of LF35. It was considered that layer 1 became uniform and thinner because its Ni inhibited the growth of layer 1. Thinner and uniform layer 1 will result in better broken energy of HSS. Layer 1 became thicker after heat treatment, but layer 2 still kept thinner. It was considered that (Cu, Ni)6Sn5 inhibited the growth of layer 2 by making the supply of Sn slower into layer 2. As the results of IMC formation, the broken energy of 300hrs HT was worse than that of as-plated for EPIG film. On the other hand, the result of HSS for ENEPIG film was similar with that of M705 regardless of as-plated sample and 300hrs HT sample. It was considered that similar tendency was observed because similar IMC was formed even if the different type of the solder ball was used. From these results, it will be possible that SJR of EPIG film was significantly improved by using LF35 as the solder ball. However, there will be possibility that SJR after long term heat treatment become worse. It's necessary to confirm the influence of longer heat treatment. Gold Wire Bonding The strength and failure mode of wire pull test for as-plated sample of an EPIG and ENEPIG film were shown in Figure 10 and Figure Figure 7: HSS result with LF35 as the solder ball; EPIG (Pd 0.05–0.2 µm, Au 0.1 µm) and ENEPIG (Ni-P 6 µm, Pd 0.05–0.2 µm, Au 0.1 µm). January 2014 • The PCB Magazine 19