Research Of Digital Lithography Resolution Enhanced Technology Based On Super-pixelation Modulation

The development of maskless digital lithography technology has brought innovation to the field of optical lithography. Its technical principle is to display digital mask pattern on the DMD. It can effectively avoid the problem of high cost of mask fabrication. But the process of fabricating micro-optical elements by using digital lithography technology, the problems such as unneat structure, rough edge and low lithography resolution appear. Therefore, according to the principle characteristics of DMD digital lithography technology, we propose super-pixelation modulation lithography technology, mainly study two methods including the axial super-pixelation modulation and multi-pixelation moving modulation, to promote digital lithography resolution and improve the image quality of digital lithography.1. Axial super-pixelation modulation method is based on graphic pixel subdivision, by projecting a single micromirror of DMD to form sub-pixel on the substrate, and then the super-pixel array can be form sub-pixel superposition along the axial direction, so the lithography resolution can be improved. Its technical idea is to project the mask pattern on the photoresist-coated substrate by fine reduction lens and then realize the exposure modulation in the way of axial super-pixelaiton moving. The substrate is driven by high-precision stepper motor, and the DMD pattern is flexibly controlled by the computer. We first introduce the theory of the method. Then the axial super-pixel modulation lithography system is set up according to the characteristics of the method. A lot of experiments are carried out by using this system, which proves that the quality of digital lithography can be improved by adopting the axial super-pixelation modulation method.2. Multi-pixelation move modulation method is to project the grayscale mask pattern on the photoresist-coated substrate by fine reduction lens, and there is a certain angle between the substrate and DMD plane, and the DMD image is flexibly controlled by the stage, then realize the exposure modulation in the way of multi-pixelation moveing in substrate. In order micro structure get smaller lithography resolution. The method is based on graphic multi-pixel subdivision. By projecting a single micromirror to form same size sub-pixel on the substrate, and then the method improve the image quality by the sub-pixel superposition form multi pixel array. In the research, the method is analyzed in theory. Then lithography system is set up according to the characteristics of multi pixel shifting modulation method. The characteristics of the system is can flexibly driving and move at any angle. Finally, the example of making the micro lens, the design method of multi-pixelation move modulation digital mask is proposed, which proves that the quality of digital lithography can be improved by adopting the multi-pixelaiton moving modulation method.