Scanning probe lithography on calixarene towards single-digit nanometer fabrication

Cost effective patterning based on scanning probe nanolithography(SPL)has the potential for electronic and optical nano-device manufacturing and other nanotechnological applications.One of the fundamental advantages of SPL is its capability for patterning and imaging employing the same probe.This is achieved with self-sensing and self-actuating cantilevers,also known as‘active'cantilevers.Here we used active cantilevers to demonstrate a novel path towards single digit nanoscale patterning by employing a low energy(<100 eV)electron exposure to thin films of molecular resist.By tuning the electron energies to the lithographically relevant chemical resist transformations,the interaction volumes can be highly localized.This method allows for greater control over spatially confined lithography and enhances sensitivity.We found that at low electron energies,the exposure in ambient conditions required approximately 10 electrons per single calixarene molecule to induce a crosslinking event.The sensitivity was 80-times greater than a classical electron beam exposure at 30 keV.By operating the electro-exposure process in ambient conditions a novel lithographic reaction scheme based on a direct ablation of resist material(positive tone)is presented.

Heterodyne Standing-Wave Interferometer with Improved Phase Stability

This paper describes a standing-wave interferometer with two laser sources of different wavelengths,diametrically opposed and emitting towards each other.The resulting standing wave has an intensity profile which is moving with a constant velocity,and is directly detected inside the laser beam by two thin and transparent photo sensors.The first sensor is at a fixed position,serving as a phase reference for the second one which is moved along the optical axis,resulting in a frequency shift,proportional to the velocity.The phase difference between both sensors is evaluated for the purpose of interferometric length measurements.

Tip-and Laser-based 3D Nanofabrication in Extended Macroscopic Working Areas

The field of optical lithography is subject to intense research and has gained enormous improvement.However,the effort necessary for creating structures at the size of 20 nm and below is considerable using conventional technologies.This effort and the resulting financial requirements can only be tackled by few global companies and thus a paradigm change for the semiconductor industry is conceivable:custom design and solutions for specific applications will dominate future development(Fritze in:Panning EM,Liddle JA(eds)Novel patterning technologies.International society for optics and photonics.SPIE,Bellingham,2021.https://doi.org/10.1117/12.2593229).For this reason,new aspects arise for future lithography,which is why enormous effort has been directed to the development of alternative fabrication technologies.Yet,the technologies emerging from this process,which are promising for coping with the current resolution and accuracy challenges,are only demonstrated as a proof-of-concept on a lab scale of several square micrometers.Such scale is not adequate for the requirements of modern lithography;therefore,there is the need for new and alternative cross-scale solutions to further advance the possibilities of unconventional nanotechnologies.Similar challenges arise because of the technical progress in various other fields,realizing new and unique functionalities based on nanoscale effects,e.g.,in nanophotonics,quantum computing,energy harvesting,and life sciences.Experimental platforms for basic research in the field of scale-spanning nanomeasuring and nanofabrication are necessary for these tasks,which are available at the Technische Universitiit Ilmenau in the form of nanopositioning and nanomeasuring(NPM)machines.With this equipment,the limits of technical structurability are explored for high-performance tip-based and laser-based processes for enabling real 3D nanofabrication with the highest precision in an adequate working range of several thousand cubic millimeters.