Unitho: A Unified Multi-Task Framework for Computational Lithography

Abstract--Reliable, generalizable data foundations are critical for enabling large-scale models in computational lithography. However, essential tasks--mask generation, rule violation detection, and layout optimization--are often handled in isolation, hindered by scarce datasets and limited modeling approaches. T o address these challenges, we introduce Unitho, a unified multi-task large vision model built upon the Transformer architecture. Trained on a large-scale industrial lithography simulation dataset with hundreds of thousands of cases, Unitho supports end-to-end mask generation, lithography simulation, and rule violation detection. As process nodes continue to shrink, geometric distortions induced by photolithography, such as optical proximity effects (OPE), pose a growing challenge to device performance and manufacturing yield. To ensure that design layouts are transferred to the wafer with high fidelity, optical proximity correction (OPC) and subsequent lithography verification have become indispensable steps in the chip design workflow [1]. However, the industry-standard physics-based simulation, while accurate, is computationally intensive and time-consuming, as shown in Figure 1 This bottleneck is severely exacerbated during process window (PW) analysis, which requires validating design robustness under variations in focus and exposure dose. Since simulations must be repeated across the entire process matrix, the resulting computational overhead significantly prolongs design iteration cycles and severely impedes early-stage Design-Technology Co-Optimization (DTCO), as shown in Figure 1.