Hello all, i need to perform front and back photolitography. On each side of a 4'' silicon wafer i need to realize geometries of size 10um. Geometries on the opposite wafer faces must be aligned with the best possible accuracy. Here we don't have the possibility to realize front-back photolitography and so i plan to ask to some company to do the job for me. Which is the best precision accuracy which can be obtained on the market ? Best regards, Andrea