A5048601537- Advancements in Photolithography Techniques
- Electron and X-Ray Spectroscopy Techniques
- Integrated Circuits and Semiconductor Failure Analysis
- Advanced X-ray Imaging Techniques
- Welding Techniques and Residual Stresses
- Silicon and Solar Cell Technologies
- Optical Coatings and Gratings
- Calibration and Measurement Techniques
Fraunhofer Institute for Integrated Systems and Device Technology
2018-2024
Schott (Germany)
2020
Carl Zeiss (Germany)
2018
Friedrich-Alexander-Universität Erlangen-Nürnberg
2018
Next-generation extreme ultraviolet (EUV) systems with numerical apertures of 0.55 have the potential to provide sub-8-nm half-pitch resolution. The increased importance stochastic effects at smaller feature sizes places further demands on scanner and mask high contrast images. We use rigorous diffraction imaging simulation understand impact EUV absorber identify most appropriate optical parameters for NA imaging. Simulations various cases material options indicate two main types solutions:...
Background: The successful introduction of extreme ultraviolet (EUV) lithography to high volume manufacturing has increased the interest push this technology its ultimate limits. This will require photoresist materials, which enable a better tradeoff between resolution, linewidth roughness and sensitivity, adaptation optical resolution enhancements that were originally developed for deep (DUV) lithography. Aim: We review published research on attenuated phase shift masks (attPSM) EUV with...
Novel mask absorber designs are catching the attention of EUVL community due to their ability mitigate 3D effects. Material selection is part such an optimization. We propose several candidates as novel EUV lithography absorbers, namely TaTeN, Ru–Ta, and Pt–Mo alloys. The choice these materials based on theoretical performance evaluated by imaging simulation complex refractive index N ( λ ) = n + ik , where optical constants k relate phase velocity absorption electromagnetic radiation with a...
The understanding, characterization, and mitigation of three-dimensional (3-D) mask effects including telecentricity errors, contrast fading, best focus shifts become increasingly important for the performance optimization future extreme ultraviolet (EUV) projection systems designs. We explore potential attenuated phase shift (attPSM) to mitigate 3-D exploit them EUV imaging. scattering light at absorber edges results in significant deformations, which impact effective lithographic attPSM...
The understanding, characterization and mitigation of 3D mask effects including telecentricity errors, contrast fading best focus shifts becomes increasingly important for the performance optimization future extreme ultraviolet (EUV) projection systems designs. scattering light at absorber edges results in significant phase deformations, which impact effective lithographic attenuated shift (attPSM) EUV. We employ rigorous imaging simulations combination with multi-objective techniques to...
Background: Explaining imaging phenomena in EUV lithography requires more than a single point of view. Traditionally, the diffraction characteristics masks are analyzed terms amplitude and phase orders that generated by absorber pattern. Aim: We propose complementary perspective to view mask openings as waveguides. Approach: Comparisons between RCWA simulations analytical solutions waveguide equations performed prove absorbers behave waveguide. Results: This can explain left unexplained...
Mitigation of 3D-mask effects is a requirement for pushing high-NA (0.55) EUV lithography to its limits. Both the absorber and reflective multilayer parts mask contribute effects. This paper focuses on investigation optimization multilayer. The impact different parameters imaging performance investigated used explain outcome. Multilayer yields better lithographic by including metrics in merit function instead reflectivity data only. Different geometrical representations are optimized their...
Today's EUV masks are optimized for maximum reflectivity at 6o angle of incidence to support imaging on the 0.33NA scanners. The High-NA scanner will have an NA 0.55 and anamorphic optics, as right balance between productivity keeping angles mask level compatible with current masks. However, selected use-cases increased Mask-3D effects observed. enlarged angular spread vertical L/S may cause, amongst others, non-telecentricity variation across slit compared 0.33NA, potentially leading...
BackgroundThe lithographic imaging performance of extreme ultraviolet (EUV) lithography is limited by the efficiency light diffraction and contrast fading caused 3D mask effects. The dual monopole concept has been proposed Joern-Holger Franke to mitigate for line-space (L/S) patterns.AimWe employ various modeling techniques investigate extendibility or split pupil exposures (SPs) dense arrays contacts on dark field masks using different absorber options.ApproachFirst, a semi-analytic model...
Novel mask absorber designs are calling attention of the EUVL community due to their ability mitigate 3D effects. Material selection is part such optimization [1]. In this paper we propose several candidates as novel EUV lithography absorbers, namely TaTeN, Ru-Ta and Pt-Mo alloys. The choice these materials based on theoretical performance evaluated by imaging simulation complex refractive index N(λ) = n(λ) +ik(λ), where optical constants n k relate phase velocity absorption an...
State-of-the-art EUV exposure systems utilize radiation around 13.52 nm with a full band spectrum extend- ing from 13.2 to 13.8 nm. The variation of the wavelength in this range modifies diffraction angles an impact on image blur and non-telecentricity effects. Dispersion materials mirrors 3D mask introduce additional sensitivity imaging characteristics wavelength. We employed simulation models Fraunhofer IISB lithography simulator Dr.LiTHO combination measured optical material data PTB...
The impact of polarization was observed in the extreme ultraviolet (EUV) imaging simulations for high NA lithography [3] [4] [5]. It is shown that polarized illumination can improve local contrast images or NILS (normalized intensity log slope). This work investigates possibilities to polarize EUV light by optimized multilayers. characterization and simulation multilayer structures has been performed using Dr.LiTHO [10]. most efficient polarizers operate close Brewster angle, where...
We employ the hybrid mask model of Fraunhofer IISB simulator Dr.LiTHO to investigate role absorber and multilayer for observed image blur contrast loss mechanisms. Hybrid decomposes EUV into part. Both parts can be described by real 3D objects or idealized 2D objects. An is specified transmission tr phase transmitted light. mirror characterized a certain reflectivity value, an angular range bandwidth (BW) where light reflected distance Zeff from absorber. The diffraction incident absorber,...
We propose and prove an alternative view of patterns on the EUV mask absorber as waveguides. The geometrical similarities between waveguides after stripping out multilayer is shown. waveguiding effect inside demonstrated by comparing rigorous RCWA (rigorous coupled-wave analysis) to waveguide analytical solution. Our investigations near field demonstrate that effects dominate transmission light through openings in masks. This perspective not provide a model explains all phenomena imaging...
Pushing the novel anamorphic NA=0.55 EUV projection optics to k1 values below 0.4 and its ultimate resolution limit will require an alternative mask absorber stack. This paper describes application of rigorous imaging simulations in combination with multi-objective optimization access performance materials for system. Simulations various use cases material options indicate two main types solutions: high k (k>0.05, especially vertical lines/spaces) low n (n ~ 0.9) provide phase shift...
We investigate the induced best focus shifts by mask absorber. The effect of n, k, bias and target size on BF is studied. consider lines spaces with pitch = 5× size. present a correlation between Zernike phase offset fourth-order coefficient that represents defocus. When no mitigation strategies are applied, low n absorber materials can show stronger variation versus knowledge gained from this study will help to identify combinations properties (n, thickness) biasing strategies, which...
The interaction of matter and light can be described based on optical constants, shortly called δ&β. These constants provide the fundamental basis for design any system. In Extreme Ultraviolet (EUV) spectral range, however, existing data many materials or compounds is very sparse, non-existent exhibit considerable discrepancies between different sources. This further complicated since scaling effects stipulate response a thin film to differ from bulk. Oxidation, impurities interdiffusion...