Computational Lithography and Optics

The lithography simulation group develops physical/chemical models, numerical algorithms, and software for the simulation of lithographic processes. 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. Besides from model and software development, the lithography group offers also 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, including model calibration by local and global optimizers
  • evaluation and optimization of lithographic imaging, mask, and source optimization using genetic algorithms
Andreas Erdmann (4th from the right) and the Fraunhofer IISB Computational Lithography and Optics Team

Fraunhofer IISB Lithography Simulation Workshop


The Fraunhofer IISB Lithography Simulation Workshop brings together experts from various fields of computational lithography and applications of models and simulation for the fabrication and characterization of nano- and microstructures. In contrast to the large events, we focus on few special topics with invited talks from several experts and users of simulation software. We have typically around 40 attendees both from academics and industry. The talks present different methods to address certain problems and elaborate on some of the still unresolved problems as well. The workshop provides an excellent opportunity to exchange ideas and discuss results and developments in:

  • Computational EUV lithography: 3D mask, high NA and stochastic effects, resolution enhancement techniques, novel resist materials and phenomena
  • Application of AI in computational lithography including data-driven methods, physics-informed neural networks (PINNs) and emerging methods to integrate physical optics with machine learning methods
  • Computational metrology and imaging for lithography: mask, system and process characterization, hybrid optical models, SEM modeling
  • Modeling challenges and solutions for lithography applications beyond CMOS: Optical and e-beam direct write, two-photon lithography and gray tone tech­niques for micro- and nanooptics, optical metasurfaces, Si photonics, bio-sensing, MEMS, ...

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. The program of the workshop and registration will become available in March 2024. We are looking forward to meeting you at our next workshop!

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 presentation as a pdf file.

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