Micro-mold fabrication by PET anisotropic ultra-violet assisted etching suitable for 3D structures on Si

Ultra-violet assisted vertical etching of PET polymers has been successfully exploited for the realization of micro-molds on silicon substrates. Vertical etching of PET substrate with an aspect ratio of 10:1 has been achieved, using DMF as a strong solvent in the presence of ultra-violet illumination. Etch rates as high as 80 μm/h are obtained at a substrate temperature of 120 °C and in the presence of solvent vapors. These PET molds are suitable for fabrication of various 3D structures like vertical posts. Electroplating is employed to deposit chromium onto the exposed holes in the PET mold. We have also used a ultra-violet cured adhesive to realize vertical patterns suitable for the fabrication of 3D structures.