Computational Lithography and Optics

The computational lithography and optics group develops physical and chemical models, numerical algorithms, and software for the simulation of lithographic processes and for the fabrication and characterization of nanophotonic components. This covers the process steps pre-bake, exposure, post-exposure bake, and chemical development of the photoresist.

Our lithography simulation algorithms are available in the software Dr.LiTHO of Fraunhofer IISB. Additional modules of Dr.LiTHO are used for the evaluation and optimization of lithographic processes and for the simulation of non-standard lithographic exposures such as interferometric exposures.

Models from the field of artificial intelligence are used in various areas such as prediction of lithographic imaging performance, resist pattern collapse, and defect detection.

Besides from model and software development, the lithography group offers support for industrial and governmental partners in process development and feasibility studies.

Current topics of the lithography group include:

  • Rigorous simulation of light diffraction from advanced masks, including defect-free and defective EUV masks
  • Modeling of modern chemical amplified resists, and novel EUV resists including model calibration by local and global optimizers
  • Evaluation and optimization of lithographic imaging, mask, and source optimization using genetic algorithms
  • Modeling of two-photon lithography for the fabrication of optical metasurfaces
  • Application of AI models in EUV lithography, two-photon lithography
Andreas Erdmann (4th from the right) and the Fraunhofer IISB Computational Lithography and Optics Team at the IISB Lithography Simulation Workshop 2023

Fraunhofer IISB Lithography Simulation Workshop


The 19th Fraunhofer IISB Lithography Simulation Workshop will be held on June 6-8, 2024 in Behringersmühle, a typical Franconian village about 50 km north of Nuremberg. Further information can be found here.

© Fraunhofer IOF
Valeriia Sedova

Applied Photonics Award 2023 for Valeriia Sedova


Valeriia Sedova, PhD student in the lithography group at Fraunhofer IISB, was honored with the Applied Photonics Award 2023 for the best master thesis. In her thesis, supervised by Dr. Andreas Erdmann, Valeriia addresses a critical challenge in the fabrication of micro-optical components: the lack of a well-established model for thick photoresists in grayscale lithography. Her work focuses on developing a special method for producing the components with improved precision and efficiency. At the same time, her research lays the foundation for the integration of deep learning techniques into the manufacturing process. With their help, predictions can be made about individual structural shapes, optimizing the accuracy of the product.

Valeriia's research realizes an important step towards faster and more cost-effective production of micro-optical components for a variety of application areas, e.g., telecommunications or medical imaging.


ZEISS Award for Talents in Photomask Industry for Sean D'Silva


Sean D'Silva, PhD student in the lithography group at Fraunhofer IISB, received the ZEISS Award for Talents in Photomask Industry for his paper “Predicting resist pattern collapse in EUV lithography using machine learning”. It was selected as the best student paper at the 38th European Mask and Lithography Conference in Dresden. In the paper, Sean and his co-authors R. Arava, A. Erdmann, T. Mülders, and H.-J. Stock employ machine learning to predict the dependence of the probability for resist pattern collapse on resist material properties, feature density, and profile shape.

Here you can download the poster presentation.

The conference paper can be accessed through the SPIE digitial library (requires subscription).

The book

A. Erdmann, Optical and EUV Lithography - A Modeling Perspective, SPIE, 2021

is intended to introduce students with backgrounds in physics, optics, computational engineering, mathematics, chemistry, material science, nanotechnology, and other areas to the fascinating field of lithographic techniques for nanofabrication. It is also suitable for helping senior engineers and managers expand their knowledge of alternative methods and applications. The material for the book was compiled during many years of lecturing on optical lithography technology, physical effects, and modeling at the Universität Erlangen-Nürnberg, as well as in preparation for dedicated courses on special aspects of lithography.

More info