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During the process of scanning maskless lithography, exposure speed determines the efficiency and productivity of lithography fabrication. In this paper, a novel Digital Micromirror Device(DMD) based high-speed exposure method is proposed to optimize the exposure process and improve speed of scanning maskless lithography system. At first, structure and working principle of the DMD based maskless exposure system is presented. Then, fundamental principle of the proposed method is proposed. Exposure process of the proposed method and each module in the process including in scan stride pretreatment module, scan stride data storage module, high-speed real-time exposure image processing module and micromirror arrays control module are designed. Finally, the proposed method is implemented in the exposure experiment with TI DMD based scanning maskless lithography system and the results demonstrated the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Abstract: Maskless lithography (ML) provides a fast and low-cost method for projecting the images of IC or micro features onto photoresist. However, it needs an efficient simulation method to evaluate the performance of lithography process. In this paper, a pixel-based partially coherent image method for digital micro-mirror device (DMD) based ML is proposed based on the linear invariant theory. In our method, the mask is sampled by DMD pixel (each pixel corresponding to each micro-mirror) and expressed by rect function. Using the shift theory of Fourier transform and the stacked pupil operator approach, we build a matrix Φ for system response function of rect function. If the DMD pixel state matrix is S, then the aerial image can be calculated with two matrix multiplication I(x,y)= SΦ. [Copyright &y& Elsevier]