Deposition of thick, adherent copper coatings on glass

Thick (1 mm), adherent copper was needed on low coefficient of expansion glass to serve as a heat sink for a laser calorimeter. Also, adherent, diamond-turnable coatings on glass approximately 75 μm thick were sought for possible improvements in the optics of systems currently fabricated from metal. To meet these requirements, vacuum deposition and electroplating were combined. An initial adherent, thin layer was deposited by magnetron sputtering and then thick copper was built-up by electroplating. This combined usage of these two different coating processes is but one example of applications wherein these technologies can complement one another. The conventional technology used by platers for metallizing non-conductors via stannous chloride/palladium chloride activation followed by electroless deposition prior to final electroplating is not acceptable for glass when thick coatings are required. With this process, deposits thicker than around 12.5 μm (0.5 mil) easily separate from the glass substrate