Edge placement error measurement in lithography process with die to database algorithm

摘要

The control of edge placement error (EPE) is playing key role in the patterning of advanced technology node insemiconductor industry. EPE is evaluated by the metric of overlay, distance of patterns between two layers in multipatterning, and patterning error in local area. In past instance, overlay between upper layer and underlayer was measuredby electron beam (e-beam) metrology system with scanning electron microscopy (SEM) image.EPE which is caused by local patterning error on photoresist layer is influenced by scanner tool parameters such as focusand exposure. Technology and method of EPE measurement on photoresist layer is highly required to optimize scannertool performance.This study provides the measurement method of EPE on photoresist layer resulting from variation of scanner toolcondition. Definition of EPE in this study is the distance between contour of SEM pattern and contour of target layout. Dieto Database (D2DB) technology which compares image and layout data was applied to this study with large image sizewhich include huge number of patterns. The advantage of the method was confirmed by the experiment on the verificationof local patterning error.The result of the experiment shows scanner tool conditions are well represented by these local patterning errors. Inaddition, optimizing scanner parameters and monitoring scanner condition by these local patterning errors are proposed.