Selective Metallization of Cured Su-8 Microstructures Using Electroless Plating Method

In this talk, we report a research work on fabrication and metallization of high aspect ratio polymer microstructures fabricated using UV lithography of SU-8 on silicon substrate. Electroless plating of metal film on both the top and sidewall surfaces of microstructures were achieved while the silicon substrate was not plated. The primary chemical mechanisms and possible applications were also discussed. The detailed procedures, from the surface modification of cured SU-8 microstructures to electroless plating copper on the polymer microstructures, were successfully developed and presented. In the surface modification of cured SU-8 microstructures, Au colloidal film is attached to amine group that forms the seed layer on cured SU-8 polymer for electroless plating copper. Other metals may also be plated after the polymer surface modification by using different baths. Our experiments found that UV exposure dosage and illumination direction played significant rules in selective electroless plating of metal films on cured SU-8 polymer.