Patent ID: 7669171

Claim:
An apparatus for performing an exposure process, comprising: an exposure machine; and a process control system, outputting an optimized exposure dose of the exposure process to the exposure machine based on a prediction model for exposure dose, such that according to a mean of differences between actual critical dimensions and target values of a mask (MTT), a corresponding exposure dose compensation value is obtained and the exposure dose compensation value is used to correct the optimized exposure dose of the exposure process, and the prediction model is given by a formula, E=E 0 +E C , wherein E represents the optimized exposure dose, E 0 represents a preset exposure dose of the process control system, E C represents the exposure dose compensation value, given by a formula, E C =[( MTT diff /X )/( CD mask /X )]×( E S /A ′)×( W last +W avg ), wherein MTT diff represents differences between the MTT value of a previous lot and the MTT value of a next lot, CD mask represents the actual critical dimension of the mask, X represents a magnification of the mask, E S represents an actual exposure dose of a previous lot, A′ represents an experimental value obtained from results of different lots, W last represents a last batch of weights and W avg represents an average weight, and CD mask , E S , A′, W last and W avg are set parameters built into the process control system.