Apparatus and process for determination of dynamic scan field curvature

摘要

A process for the determination of focal plane deviation uniquely due to the scanning dynamics associated with a photolithographic scanner is described. A series of lithographic exposures is performed on a resist coated silicon wafer using a photolithographic scanner. The lithographic exposures produce an array of focusing fiducials that are displaced relative to each other in a unique way. The resulting measurements are fed into a computer algorithm that calculates the dynamic scanning field curvature in an absolute sense in the presence of wafer height variation and other wafer/reticle stage irregularities. The dynamic scan field curvature can be used to improve lithographic modeling, overlay modeling, and advanced process control techniques related to scanner stage dynamics.