A new paradigm for high resolution 3D lithography

A new gray-scale lithography method and modeling approach are reported, providing a technique for high-resolution 3D micromachining. A double-exposure grayscale technique was developed showing a significant improvement in the vertical resolution compared to single- exposure gray-scale lithography. This technique increased the number of gray-scale height levels from n levels to n levels, which decreased the average step height from 0.19 mum to 0.02 mum. An empirical model was formulated, enabling precise mask designs and investigation of critical fabrication tolerances. One critical tolerance, mask misalignment, has been simulated and characterized using the model to minimize surface roughness.