Distribution of Fraunhofer IISB Lithography Simulation Software

The Fraunhofer IISB lithography simulation software will be distributed as the Dr.LiTHO [1, 2] software package. Dr.LiTHO was formerly used as the internal development and research lithography simulator of Fraunhofer IISB and can now be purchased from this institute. This direct approach to market replaces the collaboration with SIGMA-C. Following the acquisition of SIGMA-C by Synopsys, Synopsys and Fraunhofer IISB could not reach a new agreement on the terms for continuing the cooperation.

The Munich-based software house SIGMA-C has been the sales partner for the simulation algorithms developed by Fraunhofer. As frequently published during this long-lasting cooperation between Fraunhofer IISB and SIGMA-C, important kernel algorithms of the established lithography simulators SOLID-C, SOLID-EUV, and SOLID-E were developed at Fraunhofer IISB. This, among others, includes FDTD [3] and the Waveguide Method [4] for the rigorous simulation of light diffraction from optical masks and extensions thereof for the modeling of EUV masks [3], for lithographic exposures over topography [5], and decomposition techniques for the fast rigorous simulation of larger mask areas [6].

The Fraunhofer software Dr.LiTHO includes revised and optimized versions of the Waveguide Method for the rigorous simulation of mask diffraction effects, mesoscopic models for the description of line edge roughness (LER), and several interfaces for the coupling of lithography simulation flows with external academic or commercial simulators, in addition to standard simulation models which were also included in SOLID-E.

Dr.LiTHO employs a user concept based on the modern programming language Python. This approach offers wide portability, various methods for parallelization, easy-to-use visualization components, and much more [1, 2]. Dr.LiTHO can be easily adapted to the modeling of alternative lithography techniques such as interference exposures, near field lithography, and/or contact and proximity printing. Optionally, Dr.LiTHO can be combined with the advanced optimization tools of Fraunhofer IISB [1]. Additional capabilities and interfaces will be added to Dr.LiTHO through future research and development.

In the future, the advanced lithography simulation algorithms of Fraunhofer IISB will also be combined and commercialized in combination with various simulation and metrology tools of academic research groups and commercial suppliers. New developments in the distribution of the IISB simulation software, including strategic alliances, will be published on our web site [1]

and on appropriate occasions elsewhere.

A user group will be established to support the industrial application and further development of Dr.LiTHO. Fraunhofer IISB will support members of this user group to adapt the simulation algorithms of Dr.LiTHO to their specific purpose. The requirements as defined by the user group will have a strong impact on the further development of Dr.LiTHO, both for “traditional applications” of lithography simulation in projection printing for semiconductor fabrication and for alternative lithographic technologies and areas of application.

The Fraunhofer IISB lithography simulation group has a long-standing history in lithography simulation. Almost 20 years ago Wolfgang Henke, at that time at Fraunhofer IMT, started to develop algorithms for the simulation of lithographic projection printing processes [7]. Today, the lithography simulation group of Fraunhofer IISB led by Andreas Erdmann employs 8 scientists and PhD students with various backgrounds in physics/optics, electrical engineering, and computer science.

[1] www.drlitho.com.
[2] T. Fühner, T. Schnattinger, G. Ardelean, and A. Erdmann: “Dr.LiTHO – a development and research lithography simulator”, Proc. SPIE 6520 (2007) 65203F-1
[3] A. Vial, A. Erdmann, T. Schmöller, and C.K. Kalus: “Modification of boundaries conditions in the FDTD algorithm for EUV masks modelling”, Proc. SPIE 4754 (2002) 890
[4] A. Erdmann and P. Evanschitzky: “Rigorous mask modeling using waveguide and FDTD methods”, SIGMA-C User Workshop Japan, 21. April, 2006
P. Evanschitzky and A. Erdmann: “Fast near field simulation of optical and EUV masks using the Waveguide Method”, Proc. of SPIE 6533 (2007) 65530Y
[5] A. Erdmann, C.K. Kalus, T. Schmöller, Y. Klyonova, T. Sato, A. Endo, T. Shibata, and Y. Kobayashi: “Rigorous simulation of exposure over nonplanar wafers”, Proc. SPIE 5040 (2003) 101
[6] A. Erdmann, C.K. Kalus, T. Schmöller, and A. Wolter: “Efficient simulation of light diffraction from 3-dimensional EUV-masks using field decomposition techniques”, Proc. SPIE 5037 (2003) 482

[7] W. Henke, R. Schwalm, M. Weiss, and J. Pelka: “Diffraction effects in submicron contact/proximity printing”, Microelectronic Engineering 10 (1989)

Fraunhofer Institute of
Integrated Systems and
Device Technology (IISB)
Lithography Simulation
Dr. Andreas Erdmann
Phone +49 (0) 9131 761-258
Fax +49 (0) 9131 761-212
dr.litho@iisb.fraunhofer.de