Fast imaging algorithm for DMD-based photolithography with partially coherent illumination

In the paper, the characteristic of imaging with digital micro-mirror device (DMD) illuminated by a partially coherent light is discussed using Abbe's method. When a mask is sampled by DMD, the intensity in the substrate is modulated by sinc function and cut off by pupil function, according to oblique illumination theory and Fourier transform property of exponential function, a fast partially coherent imaging algorithm for DMD-based dynamic projection photolithography is proposed to combine Hopkins's method with Abbe's method. In the algorithm, the transmission cross coefficient (TCC) matrix of DMD projection photolithography is constructed as two-matrix multiplication according to illuminate source points. The new development presented in this paper utilizes matrix multiplication technique to speed up the computation of TCC matrix by tenfold on an average, which is beneficial to real time mask shift and mask optimization in DMD-based gray-tone photolithography.