3D Grayscale Lithography Based on Exposure Optimization

Laser direct writing (LDW) lithography is a maskless lithography method of selectively photoresist exposure. This extremely flexible exposure method provides a possibility of arbitrary three-dimensional (3D) microstructure manufacturing. However, the accumulation of exposure energy during the overlapped laser scanning and the nonlinear effect of the photoresist absorption lead to distortions of the wafer images. Thus, it is necessary to compensate the wafer image distortion by optimizing the exposure energy. In this paper, the inverse lithography technology (ILT) is used to create a numerical model of the laser direct writing lithography and search for the optimal exposure profile, then an optimized exposure planning can be generated. And the simulation results show a greatly improvement of the pattern fidelity.