Next generation of high-NA extreme ultraviolet (EUV) photolithography introduces higher power levels and faster reticle accelerations, enabling breakthrough in scanner efficiency. This results in higher temperatures and mechanical stresses on the EUV pellicles. Here we demonstrate scalable carbon nanotube (CNT) membrane mass production from a floating catalyst chemical vapor deposition (FC-CVD) reactor, using a direct dry deposition method. This direct high volume fabrication method yields highly uniform CNT networks with high strength and purity, enabling exceedingly thin CNT pellicles with high transparency at EUV. This end-to-end manufacturing process, starting from reagent gases, enables control and reproducibility over the final nanomaterial product. Control over synthesis allows tailoring of the carbon nanotube diameter and wall count (SWCNT or FWCNT), as well as control over the CNT network morphology such as the density, bundle size, and orientation of CNTs. The combination of this direct fabrication method with the exceptional mechanical and thermal properties of CNTs creates a versatile membrane platform, which can be further modified with post process steps such as purification to remove metal impurities. To enable conformal and thin coatings on CNTs, wet and dry functionalization steps are demonstrated to match the surface chemistry of CNTs to the specific deposition chemistry used in atomic layer (ALD), chemical vapor (CVD), or physical vapor (PVD) deposition processes. Thicker and denser CNT membranes with appropriate coatings are also suitable for other roles, such as filtering debris from an EUV source, blocking DUV photons and electrons, and providing a gas seal for differential pressure.
In this paper, we present the first results from an investigation performed on nanometric thin pellicles based on carbon nanotubes (CNT) of potential interest for manufacturing large area optical blocking filters to protect soft x-ray detectors in astrophysics space missions. In order to evaluate the effective capability of such materials to block UV/VIS/IR radiation, while being highly transparent in the soft x-rays and strong enough to withstand the severe launch stresses, we have performed a suite of characterization measurements. These include: UV/VIS/IR and x-ray absorption spectroscopy, x-ray photoelectron spectroscopy and scanning electron microscopy on bare and Al coated small self-standing pellicles; static mechanical tests on small freestanding samples.
Sometimes the biggest impact can be made in the smallest details. Canatu pioneers the future of semiconductor manufacturing and extreme ultraviolet (EUV) lithography with its freestanding carbon nanotube (CNT) membrane pellicles that protect photomasks from particles and defects, enhancing precision, shortening processing, and increasing production efficiency per wafer. When the already remarkable 1-dimensional intrinsic properties of virtually defect-free CNTs are expanded into a 2-dimensional network, this added degree of freedom results in a membrane with an unequaled combination of optical and mechanical properties, that may truly provide solutions for the extreme physics of EUV at increasing powers. Here, we demonstrate the extensive customizability and versatility of Canatu’s CNT synthesis and freestanding network fabrication processes. For example, the fine structure and chemistry of individual tubes, as well as the mesoscopic morphology of the network can be optimized extensively. In practice, this enables precise control over the size and type of catalyst particles, as well as the diameter of the tube and the number of walls in the carbon nanotube (Single, Double, or Multi-walled). The orientation of the CNTs in the network can also be controlled, and the CNTs can be induced to form either larger or smaller bundles, resulting in dense or sparse networks with constant optical transmittance. CNT surfaces can be further treated or coated in response to specific chemical or optical requirements. In summary, this high degree of tunability is becoming increasingly critical in applications where strict particle and impurity filtering requirements must be met with minimal optical disturbances.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.