Use of overlay misalignment error estimates in imaging overlay measurements

摘要

A system and method are provided, which calculate an overlay misalignment error estimate from the analyzed measurements of each region of interest (ROI) in at least one metrology imaging target, and an overlay corresponding to the calculated overlay misalignment error estimate. Incorporate within the misalignment estimate. The disclosed embodiments provide a step-by-step, weighted analysis of target quality that can be incorporated in a continuous manner into the metrology measurement process, and also evaluates the target quality in terms of overlay misalignment, which is different from sources, e.g., manufacturing. It forms a common basis for evaluating errors from the characteristics of the step, measurement parameters, and target characteristics. This common basis then combines various sources of error to provide a single number associated with measurement fidelity, analyzing various errors at wafer, lot and process levels, and/or reducing the number of measurements. This makes it possible to trade-off the resulting accuracy over throughput in a controlled manner.