EUV scanners have been adopted worldwide for High-Volume Manufacturing (HVM) of 10-20 nm lithographic structures. Last year, the next generation of EUV scanners has started shipping, extending the resolution to feature sizes of below 10 nm.
Work has started on extending the resolution limits further by increasing the NA – and possibly even further by reducing the wavelength below 13.5...
For advancements in EUV lithography, the behaviour of thin film materials during EUV exposure in various background gas conditions is key to find the optimal material properties. Therefore, we investigated the EUV- and radical-driven degradation mechanisms of chromium oxide ($CrO_x$) cap layers (3-5 nm) on $SiN_k$ free-standing windows in a vacuum, hydrogen and water background. In this...
The authors present their recent work on the identification and characterization of latent images in EUV photoresists using a small-scale EUV reflectometry and scatterometry setup at RWTH Aachen University. Optical metrology methods like scatterometry can identify latent images, if the photochemical changes in the resist lead to an optically detectable change of the material or a variation in...
Extreme ultraviolet (EUV) and soft X-ray radiation can be efficiently utilized for non-destructive characterization of nanostructures with nanometer accuracy. Conventional scatterometry enables structural characterization of periodic structures [1] while diffuse scatter measurements allow to characterize surface and interface roughness [2]. In this work we demonstrate results of the first time...
The degradation and Carbon contamination of X-ray optics is a well-known problem in X-ray beamlines that has been detrimental to beamline performance for several decades. This is particularly problematic, as such optics are usually highly specialized and coated with various materials. Consequences of such contamination include loss of flux, distortion of the wavefront, and reduction in...
Norbert Böwering(1) and Christian Meier(1)
Bowering@physik.uni-bielefeld.de
(1) Bielefeld University, Universitätsstraße, 33615 Bielefeld, Germany
Considerable tin-splash contamination can occur on multilayer-coated optics when used with tin-based plasma light sources in EUV lithography applications. Generally, thick tin deposits cannot be removed sufficiently fast by plasma etching;...
For the measurement of the spectral distribution in a broadband wavelength range, spectrographs are typically used. Depending on the target application, the spectrograph can be designed for reflection or transmission mode. Although reflective spectrographs generally offer a higher resolution due to the possibility of applying aberration corrections and focusing options, the main advantages of...
With the rapid growth of data-intensive applications such as autonomous driving and artificial intelligence, the performance requirements of semiconductor devices have significantly escalated. In parallel, the critical dimensions of circuit patterns have been reduced to the nanoscale, necessitating the adoption of extreme ultraviolet (EUV) lithography to overcome the resolution limits of...
The WDSX-300 spectrometer, developed at the Institute for Applied Photonics (IAP) in cooperation with Nano Optics Berlin (NOB), has been designed for wavelength dispersive X-ray fluorescence analysis with a scanning electron microscope (SEM-WDX) in the EUV and soft X-ray range. With the currently installed setup, an energy range from 30 eV to 400 eV can be covered, including K fluorescence...
This work investigates the potential benefits of employing combined s- and p-polarized extreme ultraviolet (EUV) reflectometry for the accurate and efficient determination of thin film optical constants and geometrical parameters. EUV reflectometry (EUVR) is a powerful non-destructive technique for characterizing thin films, which is crucial for advancements in fields such as lithography and...
Fused silica (amorphous SiO₂) and quartz crystal both feature ultra-low thermal expansion and exceptional transparency from the visible to the deep-ultraviolet. Quartz additionally offers strong piezoelectricity and pronounced birefringence, making both materials cornerstones of modern optics. Yet their optical properties in the extreme- and vacuum-ultraviolet (35–140 nm) remain largely...
We design a wavelength dispersive spectrometer for the extreme ultraviolet, based on a collimating polycapillary lens (PCL) and an array of reflection zone plates (RZPs). The two-channel instrument is optimized for narrow-band fluorescence or inverse photoelectron spectroscopy around 15 eV and 36 eV, respectively. The halved PCL is composed of $\sim 10^{6}$ tapered borosilicate glass tubes...
Angle-resolved X-ray fluorescence is a powerful tool for elemental depth distribution characterization of thin films. This technique is based on the formation of an X-ray standing wave (XSW), which is strictly dependent on the coherence length of the propagating wave. In grazing incidence geometry finite coherence length leads to a wave modulation which reduces interference fringes contrast...
The continuously shrinking dimensions of the features in the semiconductor industry as well as their increasing complexity require innovative metrology solutions. Non-destructive methods with high throughput that are able to assess complex 3D structures are of major importance. Measurement techniques based on light-structure interaction allow fast and non-destructive inspection of structured...
Scatterometry provides a fast and indirect method for nano-optical shape reconstruction from measured light intensities. The shape parameters are determined by solving an inverse problem, that is based on the forward model. Bayesian inversion is a powerful tool for solving inverse problems but limited by the complexity of the forward model. As nanotechnology advances and structures become...
The development of compact radiation sources has enabled a multitude of lab-size applications, especially in the field of metrology [1]. A broadband spectral characterization of the source emission is of utmost importance for the investigation of photon-induced processes and metrology [2].
In this study, the authors present a unique setup and corresponding measurement results for the...
X-Ray Reflectivity (XRR) is a well-established metrology method for multilayer characterization. With XRR, we determine the structural parameters describing the optical structure of a given sample (i.e., layer thickness, intermixing/roughness and optical density); we do so by solving the related inverse problem. To do so, one uses a model which calculates the reflectivity given a set of...
In recent years, the Institut für Nanophotonik Göttingen e.V. (formerly Laser-Laboratorium Göttingen) has successfully developed several Hartmann wavefront sensors in collaboration with DESY. These sensors have been designed for the precise focus characterization and optics alignment of the FEL FLASH in the soft X-ray spectral range, with a wavelength of approximately 5 - 40 nm. Even when...
Zeiss is a leading manufacturer of high-quality holographic diffraction gratings, with an emphasis on beamlines in synchrotrons and linear accelerators as well. These gratings exhibit exceptional properties, including low stray light, high diffraction efficiency, and the absence of regular addressing errors in grating line distribution. Additionally, Zeiss has the capability to produce both...
The beamline BEAR was open to users from 2003 till July 2025, and it is expected to reopen in 2028 after the upgrade to Elettra 2.0. BEAR is a IOM-CNR bending magnet beamline, working in the spectral region 2.8-1600 eV (443-0.775 nm) [1].
Elettra is the Italian synchrotron radiation facility and it is currently upgrading to Elettra 2.0, a new light source with a significant enhancement of the...
The broadband plasma patterned wafer defect inspection systems enable wafer-level discovery of yield-critical defects and inline monitoring for advanced logic and leading-edge memory design nodes. We will address the application of optical wafer inspection and its image capture methodology, including difference image generation, sub-resolution sensitivity and speed. We will introduce the...
Transition metals are key constituents of EUV optical elements. Most transition metals have high melting points and are compatible with Ion Beam Deposition (IBD) alongside magnetron sputtering techniques. These techniques allow coating dense, very smooth and pure thin films. Metals are used as main coatings and also as secondary layers such as capping layers and interdiffusion barriers. The...
Extending ellipsometry to the vacuum-ultraviolet spectral region, i.e., photon energies larger than 6.5 eV, is not only demanding in terms of the instrumentation but also with regard to the mathematical modelling of the measured data in order to obtain a physical interpretation in terms of the dielectric function or the optical constants of a material. In particular the extreme surface...
EUV-Optics with NA=0.33 are fully industrialized and are a key ingredient to the state-of-the-art semiconductor devices. We will shortly comment on the relevant performance indices.
We will also describe the outstanding performance of the high-NA optics with NA=0.55 currently being introduced into the market. Finally, we will comment on the challenges that would come with either higher NA...
Norbert Böwering(1) and Christian Meier(1)
Bowering@physik.uni-bielefeld.de
(1) Bielefeld University, Universitätsstraße, 33615 Bielefeld, Germany
Conventional EUV lasers in pinched capillary-discharge configurations for neon-like argon ions at 46.9 nm have mostly employed fairly inefficient excitation schemes using very high supply voltages (≥100 kV) and very large stored energies...
High harmonic generation (HHG) sources [1] provide fully coherent laser-like radiation in the Extreme-Ultraviolet (EUV/XUV) and soft X-ray spectral range with femto- or attosecond pulse duration. These sources are ideal metrology tools in scientific or industrial applications: The short wavelength allows very high spatial resolution in scattering or imaging of nanostructures created by...
n 2009, the ESA microsatellite PROBA2 was launched, carrying a radiometer in its scientific payload designed to monitor solar emissions across four broadband channels in the UV-VUV spectrum. This instrument, named LYRA, was developed under the lead of the Royal Observatory of Belgium and featured pioneering wide-bandgap photodetectors made from diamond, which were particularly well-suited for...
Astronomical spectroscopy is an indispensable tool for probing the physical and chemical
properties of celestial objects. When moving from the infrared and the detection of molecular
vibrations and rotations towards the visible spectral range and the observation of characteristic
gas absorption lines, the increased energy at even shorter wavelengths in the extreme ultraviolet
(EUV)...
State-of-the-art x-ray beamlines are equipped with x-ray mirrors according to their applications such as surface and materials science, chemical dynamics, photo emission spectroscopy, protein crystallography, x-ray microscopy [1]. In the case of free-electron lasers (FEL) and synchrotron radiation sources, total-reflection mirrors are an important optical element to guide and shape the beam....
Interferometric position sensors play a vital role in semiconductor fabrication, nanotechnology, and advanced scientific applications requiring sub-nanometer accuracy in position monitoring and control. The core operating principle of these sensors relies on the quadrature detection scheme, which enables the extraction of the interferometric phase from two phase-shifted sinusoidal signals....
Reflection zone plates (RZPs), an innovative class of 2-D varied line space gratings that combine dispersion, one- or two-dimensional focusing and reflection in one element [1], are good candidates to provide optimized efficiency at high energy resolution. Conventional RZPs on planar substrates suffer from a narrow energy range in parallel spectra registration, limiting the applications of...
