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66 PCB007 MAGAZINE I NOVEMBER 2019 Article by Rick Nichols, Sandra Nelle, Robert Spreemann, and Gustavo Ramos ATOTECH DEUTSCHLAND GMBH A key discussion topic within the electronics industry in recent years has been about the im- pact of real estate pressure on lines and spaces. However, looming in the background is a very real issue that will not go away by simply be- ing ignored. The monster in the closet is envi- ronmental awareness. The Tianjin chemical blast in August 2015 sensitized the Chinese authorities to the use of cyanide in production. As a consequence, the authorities have introduced licensing with regard to the use of cyanide. In turn, this has motivated Chinese PCB manufacturers to ask suppliers for a competent cyanide-free immer- sion gold solution (CNF Au). To achieve authenticity, the gold data for this article has all been generated in a 19-liter pro- duction simulation tank (Figures 1 and 2). Bea- ker testing can potentially result in non-repre- sentative findings. To ascertain the relevance of any data generated, statistical tools will be ap- plied where suitable. Background Although the main drive of this article is a benchmarking exercise, due to the applica- tion complexity, some of the elements stud- ied need to be considered on their own merit. In the field, electroless nickel chemistries are normally combined with complementary im- mersion gold chemistries to provide a robust and reliable system. This article has main- tained this approach, in that the immersion gold baths that will be compared to the CNF Figure 1: 19-liter lab setup for Au bath. Figure 2: Diagrammatic plan view of gold plating cell. The Viability of a Cyanide-free Immersion

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