Analysis of the line pattern width and exposure efficiency in maskless lithography using a digital micromirror device

In this study, we calculate the exposure intensity of line/space patterns recorded with a DMD (digital micromirror device) digital maskless lithography system using the point array method. With a diffracted beam spot with a radius of 4 μm, we simulate the line space patterns over a spot overlap section ranging from 85% to 95%. From the results of the simulation, we analyze the relationships among the exposure intensity, the width of the line pattern, and the exposure efficiency, which are process parameters used in maskless lithography. From a numerical analysis of the relationship between the line pattern width and the exposure efficiency, it is estimated that the practical acceptable minimum width of the line pattern recorded with a maskless lithography system using a 4-μm radius diffracted beam spot array is approximately 4.5 μm, which is 11% larger than the spot radius with the exposure efficiency of 73%.