Modeling and Improving Geometric Accuracy in Projection Multiphoton Lithography

Projection multiphoton lithography (PMPL) is a promising alternative to conventional voxel‐by‐voxel serial writing lithography, offering significant gain in fabrication speed. However, this high throughput can come at the expense of geometric accuracy, as printed structures can deviate from the intended patterns displayed on the digital micromirror device (DMD). To uncover the origins of these deviations, a numerical framework is developed that solves coupled 3D reaction‐diffusion equations and captures the underlying photochemical processes of projection‐based printing. Simulations of elementary geometries such as circles and rectangles, which serve as building blocks of complex architectures, reveal that oxygen inhibition, oxygen diffusion from surrounding regions, and intensity variations due to DMD diffraction are the dominant sources of geometric distortion. Guided by these insights, pre‐exposure and asymmetric compensation strategies are proposed that modify the projected patterns to counteract these effects. Simulations and experiments indicate that these approaches hold promise for mitigating distortions and improving the fidelity of printed structures, offering a pathway toward more accurate, high‐throughput 3D microfabrication.