Lightfields behind amplitude and phase masks applications in high resolution proximity lithography

Fabrication of microstructures is often based on photolithography that uses amplitude masks and works in contact exposure mode. Recently non-contact or proximity exposure methods become popular. This is mainly triggered by the fact that one can work in a non-contact process, not touching the sensitive surface of the mask, having at the same time excellent resolution due to a technique called optical proximity correction and still keeping the very high throughput in production volume. The optical proximity technique introduces fine correction structures that allow feature sizes of only a few microns at exposure distance that easily reach 50 microns. In our contribution we analyze light behind such structures to understand better possible high level design rules. We show for the first time measurements and simulations of amplitude and phase fields behind optical proximity correction structures.