Vasiliki Kosma
Cornell University
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Publication
Featured researches published by Vasiliki Kosma.
Proceedings of SPIE | 2017
Kazuki Kasahara; Hong Xu; Vasiliki Kosma; Jérémy Odent; Emmanuel P. Giannelis; Christopher K. Ober
EUV (extreme ultraviolet) lithography is one of the most promising candidates for next generation lithography. The main challenge for EUV resists is to simultaneously satisfy resolution, LWR (line-width roughness) and sensitivity requirements according to the ITRS roadmap. Though polymer type CAR (chemically amplified resist) is the currently standard photoresist, entirely new resist platforms are required due to the performance targets of smaller process nodes. In this paper, recent progress in nanoparticle photoresists which Cornell University has intensely studied is discussed. Lithography performance, especially scum elimination, improvement studies with the dissolution rate acceleration concept and new metal core applications are described.
Proceedings of SPIE | 2016
Kazuki Kasahara; Vasiliki Kosma; Jérémy Odent; Hong Xu; Mufei Yu; Emmanuel P. Giannelis; Christopher K. Ober
Extreme ultraviolet (EUV) lithography is a promising candidate for next generation lithography. For high volume manufacturing of semiconductor devices, significant improvement of resolution and sensitivity is required for successful implementation of EUV resists. Performance requirements for such resists demand the development of entirely new resist platforms. Cornell University has intensely studied metal oxide nanoparticle photoresists with high sensitivity for EUV lithography applications. Zirconium oxide nanoparticles with PAG enabling sub 30nm line negative tone patterns at an EUV dose below 5 mJ/cm2 show one of the best EUV sensitivity results ever reported. In this paper, recent progress in metal oxide nanoparticle photoresist research will be discussed. Several studies regarding composition investigation and new metal element study are reported.
Polymer-plastics Technology and Engineering | 2018
Eleni Kollia; George Mastrotheodoros; Vasiliki Kosma; K. Beltsios
ABSTRACT Water-glass, a low-cost silica precursor solution, is used to produce mostly skinned, polymer–silicate composite membranes with a porous bulk. We explore primarily Nylon 6-10/formic acid dopes where the polymer solvent is an acid, and polysulfone/DMF dope as an example of a polymer dope based on a non-acidic water-miscible solvent. Elemental distribution of silicon in cross sections suggests compositional uniformity of the formed membranes with in some cases 20 wt. % of silicate load. Membranes formed can be used either as separation media or as precursors for compact polymers reinforced with silicate particles. Graphical Abstract
Extreme Ultraviolet (EUV) Lithography IX | 2018
Christopher K. Ober; Hong Xu; Vasiliki Kosma; Kazunori Sakai; Emmanuel P. Giannelis
With the rapid development of semiconductors, todays optical lithography is approaching its physical limits, and thus alternative patterning technology is urgently desired. Extreme ultra-violet (EUV) lithography, using a wavelength of 13.5 nm, is considered one of the most prominent candidates for next generation lithography. The main challenge for EUV resists is to simultaneously satisfy resolution, LWR (line-width roughness) and sensitivity requirements following the ITRS roadmap. Though polymer-based CAR (chemically amplified resist) is the current standard photoresist, entirely new resist platforms are required due to the performance targets of smaller process nodes. In this paper, our recent progress in metal oxide nanoparticle photoresist research will be discussed. Brief discussion of a number of important structure and property issues pertaining to key characteristics affecting resist performance is also included.
Extreme Ultraviolet (EUV) Lithography IX | 2018
Kazuki Kasahara; Vasiliki Kosma; Kazunori Sakai; Emmanuel P. Giannelis; Christopher K. Ober; Kou Yang; Hong Xu
Extreme ultraviolet (EUV) lithography, using 13.5 nm radiation, is considered one of the most prominent candidates for next generation lithography. The main challenge for EUV resists is to simultaneously satisfy resolution, LWR (line-width roughness) and sensitivity requirements according to the ITRS roadmap1. Over the past few years, our main effort has been to focus on ZrO2 and HfO2 nanoparticle-based photoresists. However, both Zr and Hf are relatively low EUV absorbing metals2, and integration of high EUV absorption elements is considered to be a more promising route to further improve lithographic performance under EUV radiation. Here, we demonstrate novel zinc oxide-based nanoparticle photoresists, possessing small particle size, good solubility in spin-coating solvents, good film-forming abilitie and patterning by incorporating a photo-acid generator or photo-radical generator.
Extreme Ultraviolet (EUV) Lithography IX | 2018
Vasiliki Kosma; Kazuki Kasahara; Hong Xu; Kazunori Sakai; Christopher K. Ober; Emmanuel P. Giannelis
EUV lithography is nowadays considered as one of the most feasible choices for high volume manufacturing. In this work, we wish to report a series of studies aiming at shedding more light on the development mechanism of metal based EUV hybrid photoresists. We have studied zirconium (Zr) and hafnium (Hf) based hybrid resists which have shown high sensitivity, they suffer though from scumming issues. On the other hand, our clusters based on zinc (Zn) which absorbs strongly in EUV seem to be free of scumming but still Zr and Hf outperform in terms of sensitivity. In an effort to understand better what controls sensitivity and scumming phenomena we have employed a combination of analytical techniques (Electrospray ionization mass spectrometry ESI-MS, X-ray photoelectron spectroscopy XPS, and Fouriertransform infrared spectroscopy FT-IR) to study the patterning mechanism in detail, in order to be able to optimize the development process and develop systems with optimal features.
Journal of Micro-nanolithography Mems and Moems | 2017
Vasiliki Kosma; Kazuki Kasahara; Hong Xu; Jérémy Odent; Christopher K. Ober
Abstract. We report a series of studies aimed at shedding more light on the development mechanism of zirconium (Zr)-based extreme-UV hybrid photoresists. In earlier works, our group demonstrated that Zr-based hybrid resists are capable of resolving 30-nm half-pitch features with a very high sensitivity in the range of 1 to 20 mJ/cm2, which renders these materials potential candidates in the area of nonchemically amplified inorganic resists. While attractive because of its high sensitivity, Zr-methacrylic acid suffers from scumming problems. In an effort to better understand what controls sensitivity and scumming phenomena, we employed a combination of analytical techniques (electrospray ionization mass spectrometry, x-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy) to study the patterning mechanism in detail, to be able to optimize the development process and develop systems with optimal features.
Polymer Journal | 2018
Hong Xu; Vasiliki Kosma; Emmanuel P. Giannelis; Christopher K. Ober
Journal of Photopolymer Science and Technology | 2016
Mufei Yu; Hong Xu; Vasiliki Kosma; Jérémy Odent; Kazuki Kasahara; Emmanuel P. Giannelis; Christopher K. Ober
Journal of Photopolymer Science and Technology | 2018
Christopher K. Ober; Vasiliki Kosma; Hong Xu; Kazunori Sakai; Emmanuel P. Giannelis