Improving speed and pattern quality of DMD-based maskless lithography

Abstract

Development of maskless lithography enables micropatterning without the cost and time fabricating photomasks. The cost-and-time saving helps to test prototypes and to produce multiple varieties in microfabrication fields. In order to apply maskless patterning in the actual manufacturing process, continuous production, such as roll-to-roll, is considered for high-throughput production. Scanning the images of a digital micromirror device (DMD) is one of the methods to implement continuous maskless patterning. This method has the advantage of being able to create pattern shapes of high flexibility with a simple system configuration. However, since the minimum size of each DMD pixel is several microns, high-resolution patterning of few- or sub-micron has to use a high-magnification lens, which causes a low throughput due to a small illuminated area and a limited data transfer rate. In addition, DMD images have pixelated edges that limit pattern quality, which is problematic in many applications having curved pattern shapes. To overcome these problems of DMD-based maskless lithography, a patterning method utilizing pulse exposure and oblique scanning is proposed. This method improves the maximum scanning speed of DMD images and pattern quality in continuous DMD patterning.