The present invention provides for a method and an apparatus for using scatterometry to perform feedback and feed-forward control. A processing run of semiconductor devices is performed. Metrology data from the processed semiconductor devices is acquired. Error data is acquired by analyzing the acquired metrology data. A determination is made whether the error data merits modification to the processing of semiconductor devices. A feedback modification of the processing of semiconductor devices is performed in response to the determination that the error data merits modification to the processing of semiconductor devices. A feed-forward modification of the processing of the semiconductor devices is performed in response to the determination that the error data merits modification to the processing of semiconductor devices.