Sensitive polysulfone based chain scissioning resists for 193 nm lithography

Chain scissioning resists do not require addition of photoacid generators to function. Previously reported chain scissioning polysulfone resists were able to achieve enhanced sensitivity by incorporation of absorbing repeat units, but these groups also inhibited the depolymerization reaction, which could further enhance sensitivity. Here we report the development of sensitive polysulfone chain scissioning resists for 193 nm that are able to undergo depolymerization. The effect of depolymerization of LER is also discussed. These polymers underwent CD shrinkage upon overdose, which may be useful for double patterning processes

X ray microscope assembly and alignment support and advanced x ray microscope design and analysis

Considerable efforts have been devoted recently to the design, analysis, fabrication, and testing of spherical Schwarzschild microscopes for soft x ray application in microscopy and projection lithography. The spherical Schwarzschild microscope consists of two concentric spherical mirrors configured such that the third order spherical aberration and coma are zero. Since multilayers are used on the mirror substrates for x ray applications, it is desirable to have only two reflecting surfaces in a microscope. In order to reduce microscope aberrations and increase the field of view, generalized mirror surface profiles have been considered in this investigation. Based on incoherent and sine wave modulation transfer function (MTF) calculations, the object plane resolution of a microscope has been analyzed as a function of the object height and numerical aperture (NA) of the primary for several spherical Schwarzschild, conic, and aspherical head reflecting two mirror microscope configurations

X ray imaging microscope for cancer research

The NASA technology employed during the Stanford MSFC LLNL Rocket X Ray Spectroheliograph flight established that doubly reflecting, normal incidence multilayer optics can be designed, fabricated, and used for high resolution x ray imaging of the Sun. Technology developed as part of the MSFC X Ray Microscope program, showed that high quality, high resolution multilayer x ray imaging microscopes are feasible. Using technology developed at Stanford University and at the DOE Lawrence Livermore National Laboratory (LLNL), Troy W. Barbee, Jr. has fabricated multilayer coatings with near theoretical reflectivities and perfect bandpass matching for a new rocket borne solar observatory, the Multi-Spectral Solar Telescope Array (MSSTA). Advanced Flow Polishing has provided multilayer mirror substrates with sub-angstrom (rms) smoothnesss for the astronomical x ray telescopes and x ray microscopes. The combination of these important technological advancements has paved the way for the development of a Water Window Imaging X Ray Microscope for cancer research

Recent Advances in Positive Photoresists: Mechanisms and Fabrication

Photoresists are fundamental materials in photolithography and are crucial for precise patterning in microelectronic devices, MEMS, and nanostructures. This paper provides an in-depth review of recent advancements in positive photoresist research and development, focusing on discussion regarding the underlying mechanisms governing their behavior, exploring innovative fabrication techniques, and highlighting the advantages of the photoresist classes discussed. The paper begins by discussing the need for the development of new photoresist technologies, highlighting issues associated with adopting extreme ultraviolet photolithography and addressing these challenges through the development of advanced positive-tone resist materials with improved patterning features, resolution, and sensitivity. Subsequently, it discusses the working mechanisms and synthesis methods of different types and subtypes of photoresists, starting from non-chemically amplified, organic, and inorganic–organic hybrid photoresists and progressing to dry film resists, with an emphasis on the upsides of each. The paper concludes by discussing how future research in the field of lithography—prioritizing concerns related to environmental impacts, improved photoresist material and properties, and utilization of advanced quantum technology—can assist with revolutionizing lithography techniques.publishedVersio

Spectroscopic investigations of photon-induced reactions in tin-oxo cage photoresists

Molecular compounds such as tin-oxo cages are promising photoresists for Extreme UltraViolet (EUV) photolithography, which is the latest nano-patterning technology for high-end computer chips. Solubility switching of the resist is the key for pattern transfer to the semiconductor substrate. In this thesis, different spectroscopic techniques were used to gain insight into the photochemistry upon exposure, which is crucial for optimizing the resist performance. In one research line, we developed a laser-based high harmonic generation setup as the exposure source in the soft-X-ray (XUV) region to perform broadband absorption spectroscopy on tin-oxo cage samples. Resist-coated thin films were exposed to light with energies of 21 – 70 eV, and the induced changes in the transmission as a function of exposure dose were used to quantify the photoconversion of the resist. The results were compared with those obtained with EUV (92 eV). The resist properties were further investigated using X-ray photoelectron spectroscopy and Total Electron Yield techniques. A synchrotron beamline was used as the exposure source (5-150 eV) to study the low-energy emitted electrons from the resist. Outgassing measurements (residual gas analysis) and ellipsometry techniques were used to investigate the resist’s photoconversion under 92 eV exposure. Outgassing species from the resist were determined to be mainly organic carbon-containing products. The outgassing rate was measured for a few selected masses and the induced resist’s thickness change at different exposure doses was related to the outgassing rate of the resist. The fundamental insight obtained in our studies can help to design improved EUV photoresists