Aerial image analysis for defective masks in optical lithography

The quality of photomasks in optical lithography is important for the quality of the wafer printing process. Lithography simulation software can be used to compute the influence of mask defects on the aerial or resist image of lithographic processes. The influence of various defect types and defect sizes can be compared and defect severity lists can be established. To investigate the quality of wafer images in current optical lithography different experimental tools such as AIMS and SEM are used to measure mask and wafer structures. Furthermore, it is possible to compare experimental and computational investigations and to calibrate the simulation models for future technology nodes.