摘要
Three important concepts about the mask error enhancement factor (MEEF) are proposed. From the definition of MEEF, it could be derived as a function of the image log slope and the aerial image variation caused by mask critical dimension (CD) errors. Second, a mask error common window indicator (MECWIN) is proposed to evaluate the MEEF and mask CD specification by knowing the wafer CD tolerance. This concept is used to define the mask CD specification without any ambiguity. Finally, we describe the complex 2-D response to the mask-making error around the line end by a mask error enhancement tensor. Both theoretical derivations and experiments to justify the theory are presented. © 2004 Society of Photo-Optical Instrumentation Engineers.