关键词：光掩模；边缘效应；相位成像；散焦
摘 要：In this work it is shown that the thin mask boundary layers used to characterize these effects can be directly measured by capturing through-focus aerial images, a routine procedure for local quality inspection during mask fabrication. The Transport of Intensity phase imaging method is used to recover quantitative phase from a stack of intensity images, the phase near feature edges directly corresponding to edge effects at the mask. We discover that the Transport of Intensity solver produces errors in the solved phase near sharp corners due to strong curl effects in the power flow, and an iterative solver is developed to remedy the artifacts.