Pattern transfer distortions in optical photomasks

For optical lithography to meet the high resolution and positioning accuracy required for sub-130 nm technology, it is essential to design and implement low distortion reticles. Using finite element modeling to simulate the processing steps of the optical photomask provides valuable insight into understanding and controlling the sources of distortion. The results presented here focus on the in-plane and out-of-plane distortions induced in the reticle due to pattern transfer, in particular illustrating how the pattern layout affects the induced image placement errors.