Block-based inverse lithography technology with adaptive level-set algorithm

• Published in: Optics and laser technology Vol. 182; p. 112211
• Main Authors: Huang, Chaojun, Ma, Xu, Zhang, Shengen, Lin, Mu, Porras-Díaz, Néstor, Arce, Gonzalo R.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.04.2025
• Subjects: Inverse lithography technology; Level-set; Mask manufacturability; Level-set; Inverse lithography technology; Mask manufacturability
• ISSN: 0030-3992
• DOI: 10.1016/j.optlastec.2024.112211

•An innovative inverse lithography method is proposed to improve the imaging performance of lithography system and mask manufacturability.•The Barzilai-Borwein gradient algorithm is used to effectively accelerate the convergence rate.•Different mask optimization methods are compared in terms of lithography image fidelity and mask manufacturability based on both simulations and real experiments.•A DMD-based digital lithography testbed is built up to verify the effectiveness of the proposed inverse lithography methods. Inverse lithography technology (ILT) is a key computational lithography approach aimed at inversely optimizing the photomask pattern to compensate for the image distortion in advanced optical lithography process. Traditional ILT algorithms, despite their capacity of significantly enhancing the image quality, bring challenges to the computational efficiency and mask manufacturability. To overcome those problems, this paper proposes a novel block-based ILT method driven by the level-set algorithm. This method leverages overlapped basis blocks with a level-set support area for mask representation, thus reducing the mask complexity. To circumvent the slow convergence rate dictated by the conventional Euler time step of the Courant-Friedrichs-Lewy condition, this research adopts the Barzilai-Borwein algorithm to update level set function using adaptive time step, which accelerates the optimization process. In addition, a testbed of digital lithography system is established to verify the proposed ILT method with a calibrated imaging model. It shows that the proposed method is superior over the widely-used and state-of-the-art ILT methods in terms of convergence speed and mask manufacturability.