optiXfab Custom 13.5 nm EUV Schwarzschild Objective

Overview

The optiXfab Custom 13.5 nm EUV Schwarzschild Objective is a high-precision, all-reflective imaging optical system engineered for extreme ultraviolet (EUV) radiation at the industry-standard wavelength of 13.5 nm. Based on the classical Schwarzschild configuration—comprising two concentric, coaxial spherical mirrors—the objective eliminates chromatic aberration and delivers diffraction-limited performance in the EUV spectral region where conventional refractive optics are nonfunctional. Its design leverages Mo/Si multilayer interference coatings developed from Fraunhofer Institute patents and commercially matured since 2012, ensuring high reflectivity (>65% per surface at 13.5 nm, incidence angle ~5°), low thermal drift, and long-term stability under vacuum-compatible operation. The objective is optimized for use with compact EUV sources including laser-driven plasma (LDP) and high-harmonic generation (HHG) systems, supporting both laboratory-scale metrology and pre-commercial lithography R&D.

Key Features

• Two custom-configurable variants: 20× (NA = 0.44, EFL = 26.95 mm) and 10× (NA = 0.2, EFL = 53.06 mm), each tailored to specific source brightness and detector pixel pitch requirements.
• Stress-free optical mounting using monolithic solid-hinge kinematic supports, minimizing thermo-mechanical distortion and enabling sub-microradian mirror alignment repeatability.
• Full-sphere Mo/Si multilayer coating deposited via magnetron sputtering under ultra-high vacuum (UHV) conditions; layer count >60, thickness control <0.1 nm RMS, interface roughness <0.3 nm.
• Integrated in-situ mirror adjustment mechanism permitting tip/tilt correction during operation without breaking vacuum—critical for maintaining wavefront fidelity in dynamic EUV beamlines.
• Primary and secondary mirrors fabricated from low-expansion ULE® or Zerodur® substrates, polished to ≤0.15 nm RMS surface roughness and figure error <λ/20 @ 633 nm (equivalent to <3.4 nm PV at 13.5 nm).

Sample Compatibility & Compliance

The optiXfab 13.5 nm Schwarzschild Objective is compatible with standard 100 mm × 100 mm × 25 mm UHV-compatible flange mounts (CF-63 or CF-100), and operates under base pressures ≤1×10⁻⁷ mbar. It meets mechanical and thermal specifications outlined in ISO 10110-7 (surface imperfections) and ISO 10110-8 (coating homogeneity). While not a medical or industrial safety-certified device, its design conforms to EUV optical handling protocols referenced in SEMI F57 (EUV Source Interface Standards) and supports compliance with GLP-aligned experimental documentation when integrated into traceable metrology workflows.

Software & Data Management

As a passive optical component, the Schwarzschild objective does not include embedded firmware or digital interfaces. However, it is fully compatible with third-party alignment and wavefront characterization platforms—including Zygo Verifire™ Interferometers (with EUV-compatible null optics), Physik Instrumente (PI) nanopositioning controllers, and MATLAB-based ray-tracing models (e.g., Code V EUV module). OptiXfab provides full Zemax OpticStudio-compatible .ZAR files and measured interferometric wavefront maps (in .DAT format) for each delivered unit, enabling rigorous system-level modeling and uncertainty propagation in accordance with ISO/IEC 17025 calibration traceability frameworks.

Applications

• High-resolution EUV microscopy of nanostructured samples, including mask defect inspection, nanowire morphology analysis, and thin-film interfacial dynamics.
• Coherent diffractive imaging (CDI) and ptychography experiments requiring high NA and minimal phase distortion.
• Source metrology for HHG and LDP systems—used as collection optics in EUV power and spatial profile diagnostics.
• Development and validation of next-generation EUV projection optics, serving as a reference-grade testbed for coating durability, contamination resistance, and thermal load response.
• Time-resolved pump-probe studies in attosecond science, where mechanical stability and alignment retention over extended acquisition windows (>24 h) are essential.

FAQ

Is this objective suitable for ambient or atmospheric operation?
No. The Mo/Si multilayer coating degrades rapidly in air or moisture-rich environments. Operation requires high-vacuum or UHV conditions (≤1×10⁻⁷ mbar) with inert gas purging during venting cycles.
Can the objective be re-coated after extended use?
Yes. OptiXfab offers recoating services under controlled cleanroom conditions (ISO Class 5), including substrate re-polishing and multilayer re-deposition, with full interferometric verification prior to delivery.
What vacuum feedthroughs or motion stages are recommended for alignment?
We recommend six-axis UHV-compatible nanopositioning stages (e.g., PI P-563 series) with closed-loop capacitive sensing and ≤5 nm resolution, mounted on kinematic bases compliant with ISO 2768-mK tolerances.
Do you provide wavefront error data for individual units?
Yes. Each objective ships with a calibrated interferogram acquired at 633 nm using a transmission sphere, plus modeled EUV wavefront predictions at 13.5 nm derived from coating stack metrology and surface topography.
Is there a standard warranty or calibration certificate included?
All units include a 24-month limited warranty covering material and workmanship defects. A manufacturer’s Certificate of Conformance (CoC) is provided; NIST-traceable calibration is available as an optional service.