Research And Implementation Of DMD Image Exposure Method For Lithography

Lithography technology is the basis of the semiconductor industry.With the continuous reduction of the feature size of IC(Integrated Circuit)devices,the cost of mask in traditional photolithography is increasing dramatically.Various maskless lithography technology has been developed rapidly in recent years.DMD(Digital Micromirror Device)based digital maskless lithography simplifies the process of traditional lithography,and reduces the difficulty and the high cost to manufacture the mask by using DMD instead of the traditional lithography mask.And it has great advantages such as high efficiency,low cost,flexibility and so on.Through the flexible control of DMD exposure images by computer for grayscale exposure,continuous complex microstructure processing can be easily completed.In the field of three dimensional(3D)lithography or 3D micro-structuring,DMD-based digital grayscale lithography is a promising tool.Compared with the traditional lithography,it has great advantages and very good application prospects in the industry of semiconductor integrated circuits,PCB manufacturing,micro-optical components processing,etc.In this paper,deep research is carried out around the DMD digital lithography system,aiming at the problems of exposure mode,efficiency and grayscale exposure in large area processing,some new solutions are proposed.Firstly,this paper studies the exposure mode of DMD in large area lithography.Aiming at the problem of low efficiency in the scanning exposure mode of existing DMD digital lithography system,a method of high-speed DMD image exposure is designed,to optimize the process of scanning exposure.Through the pre-storage of all image data,completing the exposure image processing and DMD exposure control in FPGA,high-speed scanning exposure of large area photolithography image is completed.Then,according to the grayscale modulation method of DMD,the study of control algorithm DMD grayscale exposure is completed.An improvement scheme of the DMD grayscale exposure frame rate based on binary pulse width modulation is proposed,and a method of DMD grayscale exposure for three dimensional scanning lithography is designed.The grayscale image is decomposed into bit planes by PC software.In FPGA,the grayscale exposure image processing and the grayscale modulation of DMD iscompleted,to realize DMD grayscale lithography,and obtain a higher gray frame frequency.Finally,based on FPGA,the methods of high-speed DMD image exposure and grayscale exposure are designed and implemented in the TI DLP4100 development platform.Through the high speed data transmission and powerful timing control capabilities of FPGA,the advantage of high speed of DMD image flip is utilized.A high performance DMD scanning exposure controller is implemented and applied to the development of digital lithography equipment.The results prove that the methods proposed in this paper effectively improve the scanning and grayscale exposure speed and the efficiency of DMD digital lithography system.