The SU-8 XFT series is a high contrast, epoxy-based photoresist designed for micromachining and other microelectronic applications, where an ultra-thick, chemically and thermally stable image is desired. SU-8 XFT has been formulated for ultra thick film processes with improved adhesion and lower coating stresses. Film thicknesses of 50 to >200 microns can be achieved with a single coat process. The SU-8 XFT series has excellent imaging characteristics and is capable of producing very high, over 5:1 aspect ratio structures, with near vertical sidewalls.