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characteristics of epig deposits for fine-line applications continues thickness of 0.1 µm and with Pd thickness of 0.1 µm, the results of wide scan and depth profile by AES were analyzed as shown in Figure 14 and Figure 15. From the result of wide scan for EPIG film after heat treatment, the peak of Cu was detected, but no Cu peak was detected for ENEPIG film. It was considered that one of the factors, which EPIG film had poorer WBR after heat treatment, was Cu diffusion to the Au surface. Also, the peak of Pd was detected for EPIG film and ENEPIG film after heat treatment. From the result of depth profile, it was observed that Pd exists in Au film layer fully. It was considered that the solid solution layer of Au and Pd was formed and this was second factor, when Figure 12: Wire pull test results; ENEPIG (Ni-P 6 µm, Pd 0.05–0.3 µm, Au 0.05–0.3 µm) as-plated. Figure 13: Wire pull test results; ENEPIG (Ni-P 6 µm, Pd 0.05–0.3 µm, 0.05–0.3 µm) after heat treatment. January 2014 • The PCB Magazine 23