Adaptive modeling and H/sub /spl infin// control for photolithography manufacturing process

A run-by-run feedback controller is designed for Intel manufacturing fabs to stabilize the critical dimension in the process of photolithography, in the presence of unpredictable process drift and unknown non-Gaussian disturbances. The controller is a combination of an adaptive model with an H/sub /spl infin// feedback. The model described here is a discrete-time model based on real data from the shallow trench isolation area in one of the Intel flash manufacturing fabs.