Fast Lithography Image Simulation By Exploiting Symmetries in Lithography Systems

Lithography simulation has been widely used in many applications, such as optical proximity correction, in the semiconductor industry. It is important to reduce the runtime of such simulations. Dedicated hardware and parallel computation have been used to reduce the runtime. For full chip simulation, the simulation method, optimal coherent approximations (OCAs), is widely used. But, it has not been improved since its first inception. In this paper, we improve it by considering the symmetric properties of lithography systems. The new method could speed up the runtime by 2X without loss of accuracy. We demonstrate the speedup is applicable to vectorial imaging model as well. In case the symmetric properties do not hold strictly, the new method can be generalized such that it could still be faster than the old method.