LITHOGRAPHIC PERFORMANCE ENHANCEMENT USING DUMMY DIFFRACTION MASK

The basic lithographic characteristics of the dummy diffraction mask w hich has two (dummy and main) mask layers, are investigated by simulat ion and experiment. The basic principle and theoretical details of the dummy diffraction mask are explained. Influences on the aerial image by the gap size and misorientation between two mask layers and by the nonideal phase grating, are simulated. Also, results of the lithograph ic performances for the simple patterns (line/space, isolated line, is olated space) and the complex patterns (V-shape active pattern in dyna mic random access memory core cell) are presented.