Shaping intensity behind amplitude masks for proximity correction lithography: Design, measurement and realization
Proximity exposure techniques in lithography are getting more and more popular because of the cost of ownership advantage of mask aligners compared to projection systems. In this paper a gap between simulation and the final result, the prints will be closed. We compare high resolution measurements of intensity field behind amplitude masks with proximity correction structures with simulations gain insight in limitation of proximity lithography. The final goal is to develop techniques that allow enhancing the resolution by using advanced optical correction structures. The correction structures are designed with Layout Lab (GenISys GmbH), prints are done and characterized and the results are compared with measured light intensity distributions. The light intensity distributions behind the mask are recorded using a High Resolution Interference Microscopy (HRIM). We concentrate on an example study of edge slope improvement and we explore possibilities of improved parameters like edge slope at different proximity distances. Simulations and measurements are compared and discussed.