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only types of failure modes seen are Mode 1, ductile solder ball failure, and Mode 2, pad li- ing, which are issues with the solder and lam- inate, respectively. ere are no failures at the surface finish in these samples. In conclusion, both solder ball pull and shear tests showed no failures related to the surface finish, so the strong intermetallics predicted by the thinner intermetallics seen in the previous sections are proven true. Since there are no brit- tle intermetallics failures, the Ni-less surface fin- ish creates a stronger solder joint than ENIG. Conclusions e Ni-less surface finish of cyanide-free immersion gold plated onto a nano-engineered barrier layer on top of copper is a viable solution for high-frequency HDI applications. e sur- Figure 11: Failure modes during pull tests and shear tests on solder balls on the Ni-less surface finish for one, three, and six reflow cycles and 1,000 hours of aging.