METHOD OF PHOTOLITHOGRAPHIC EXPOSURE DOSE CONTROL AS A FUNCTION OF RESIST SENSITIVITY

A predictive method is used to compensate for intermediate batch sensitivities which inevitably occur during resist batch changeover. The compensation is applied to historical dose levels to arrive at a new dose level estimating an optimum dose. When the system discovers that a new batch of resist is loaded to a tool, historical data is used to calculate a reference dose for each tool. A batch factor is continuously calculated and using historical data along with the batch factor, a dose adjustment is made to maintain proper image size.