In this investigation, a novel idea had been proposed to expand the process window and reduce the optical proximity effect (OPE) by employing post-exposure delay (PED). Our previous work presented a model to specify the resist linewidth according to PED time based on the neutralization mechanism of organic base and photogenerated acid. Based on the model, the exposure latitude and depth of focus can be extended for various pattern sizes by applying PED on linewidth broadening. Moreover, the dense-iso critical dimension bias, which is caused by OPE, can also be reduced when PED is performed.