Applications of micro hot embossing for optical switch formation

This paper demonstrates applications of micro hot embossing process for fabricating vertical micromirrors and optical switch platforms using polycarbonate as the process material. The effect of process parameters upon the height of mirrors, the thickness of cantilevers and the deflection of switch platforms was investigated. Micromirrors with a dimension of 500 μm (width) ×100 μm (thickness) × 200 μm (height) were embossed at 180 °C under a pressure of 1.75 kg/mm². Cantilevers with a thickness around 120 μm were obtained at 200 °C and a pressure of 1.75 kg/mm ². Considering both the mirror height and the thickness of cantilever, the process temperature and pressure were chosen as ≥185 °C and ≥1.75 kg/mm², respectively. Annealing the embossed sample in 140 °C can reduce its deflection to 50-60% of its original value. Measurement using a scanning force microscope illustrated that surface roughness (R_a) of the embossed polymer mirror was around 0.1 μm.