In-die mask registration measurement with existing inspection tools

The demand for aggressive image placement accuracy for each generation is being increasingly accelerated by DPT deployment. The method of the correction with the scanner is in effect devised by obtaining the CD and IP maps of each mask after the mask pattern is drawn, We are developing a technology that generates CD and IP maps for each mask from the image data of inspection equipment with the ultimate goal of "in-die overlay improvement" optimizing scanner as well as writer performances. We have reported in-die CD and registration metrology capability of mask inspection equipment. However existing inspection machines, which are already in use, do not have such features to perform this function, as they are not designed for such purpose. We are developing a method to improve measurement accuracy by incorporating registration mark data obtained by conventional metrology tool, and will report the result of evaluation of this method.