Image tone optimization in advanced mask making for DUV lithography

Abstract

Deep-UV (DUV) lithography has been developed to define minimum feature sizes of sub-100 nm dimensions of devices semiconductor. In response to this trend, DUV mask technology has been proposed as an effective technique for considering the reduction of mask making cost, especially, in low volume designs. However, the requirement of tight CD control of the mask features in advanced devices is resulted in increasing of mask cost. In this research, we discussed two different typed image tones comparison, positive and negative tone, in DUV lithography. The choice of final mask tone needs to be selected as function of pattern density and shape. The evaluation items to judge if the mask is good are the OPC model accuracy, resolution and mask throughput. Both mask process and manufacturing throughput are affected by image tone type of positive and negative. This paper will show the procedures and results of experiment.