Computational lithography uses various techniques of resolution enhancement technology (RET) to create more perfect images on the chip as the elements of the transistor get smaller and smaller.
For example, optical proximity correction (OPC) alters the shape of the elements on the mask, which winds up creating the perfect shape after the light shines through to the chip. Off-axis illumination (OAI) modifies the angle of the light and a phase-shift mask (PSM) changes the phase of the light on the sides of the lines being created. In addition, the polarization of the illumination can be controlled. See
photolithography and
chip manufacturing. See also
computational photography and
computational imaging.