I am currently investigating ways to make a mold for hot-embossing. Normally this is done by for instance SU8 on a silicon wafer, or DRIE of a silicon wafer. But my design is deeper than a normal wafer, around 5 mm deep. Because the devices are actually fairly large (for microsystems) I would be happy having a resolution of only 25 micron (x, y, and z). I am wondering what the capability of CNC machines are. The structures aren't too complex, the smallest line required is 90 micron high and 175 micron in diameter, 5mm long. Is it possible to have this machined in steel?