Classical control theory applied to OPC correction segment convergence

Model based Optical Proximity Correction work is currently performed by segmenting patterns in a layout and iteratively applying corrections to these segments for a set number of iterations. This is an open loop control methodology that relies on a finely tuned algorithm to arrive at a proper correction. A goal of this algorithm is to converge in the fewest number of iterations possible. As technology nodes become smaller, different correction areas tend to correct at different rates, and these correction rates are diverging with process node. This leads to more iterations being required to converge to a final OPC solution, the consequence of which is an increased runtime and tapeout cost. The current solution to this problem is to use proportional damping factors to attempt to bring different structure types to a solution. Classical control theory provides tools to optimize the convergence of these processes and to speed up convergence in physical systems. Introducing derivative and integral control while continuing use of proportional control should reduce the number of iterations needed to converge to a final solution as well as optimize the convergence for varied configurations.