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characteristics of epig deposits for fine-line applications continues poorer WBR was caused when Au and Pd thickness was thinner. In order to keep WBR of the EPIG film after heat treatment, it was suggested that it will be necessary to prevent Cu diffusion and Pd diffusion. For EPIG film, the effect of Pd and Au thickness was confirmed as shown in Figure 16 and 17 by using wide scan and depth profile of AES after heat treatment. From the result of wide scan, the peak of Cu was detected when Pd film was thinner. Howev- Figure 14: Wide scan results by AES; EPIG (Pd 0.1 µm, Au 0.1 µm), ENEPIG (Ni-P 6 µm, Pd 0.1 µm, Au 0.1 µm) as plated and with heat treatment. Figure 15: Depth profile results by AES; EPIG (Pd 0.1 µm, Au 0.1 µm), ENEPIG (Ni-P 6 µm, Pd 0.1 µm, Au 0.1 µm) as plated and with heat treatment. 24 The PCB Magazine • January 2014