Fluorine—an enabler in advanced photolithography

Rothschild, M.; Bloomstein, Theodore M.; Fedynyshyn, Theodore H.; Liberman, Vladimir; Mowers, William A.; Sinta, R.; Switkes, M.; Grenville, Andrew; Orvek, Kevin J.

doi:10.1016/s0022-1139(03)00074-5

Cited by 17 publications

(20 citation statements)

References 18 publications

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“…1, 2 In specific applications such as photomasks for lithography at 157 nm and materials for vuv sources, silicalike structural features are unique in assuring low thermal expansion coefficient and good workability. 3 For these reasons, modifications of silica optical properties through specific synthesis or doping processes are currently being investigated to extend its operational window into the vuv. Fluorine modified silica-based materials are promising candidates for these applications, since the silica absorption edge shifts toward high energy after fluorine doping.…”

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confidence: 99%

High-energy shift of the Urbach ultraviolet absorption from attenuated dynamical disorder in fluorine modified sol-gel silica

Палеари

Meinardi

Lauria

et al. 2007

Applied Physics Letters

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Fluorine modified amorphous silica has been synthetized via sol-gel route and studied through analysis of the temperature dependence of the Urbach absorption tail in the vacuum-ultraviolet region. The modified glass has a steep absorption edge above 8 eV, with the absorption coefficient ␣ ϰ exp͓E / E U ͑T͔͒ showing Urbach energy values E U ͑T͒ ranging between 50 and 66 meV. The comparison of E U ͑T͒ with pure silica data indicates a structural softening caused by the reduction of dynamical disorder, and suggests that the F-modified sol-gel synthesis is an appropriate route for achieving high energy shifts of the absorption edge. © 2007 American Institute of Physics. ͓DOI: 10.1063/1.2794429͔ Several technological areas are looking for new material compositions and synthetic routes for the production of optical materials with transmission window extending into the vacuum ultraviolet ͑vuv͒ region and with improved radiation hardness and thermal stability. 1,2 In specific applications such as photomasks for lithography at 157 nm and materials for vuv sources, silicalike structural features are unique in assuring low thermal expansion coefficient and good workability. 3 For these reasons, modifications of silica optical properties through specific synthesis or doping processes are currently being investigated to extend its operational window into the vuv. Fluorine modified silica-based materials are promising candidates for these applications, since the silica absorption edge shifts toward high energy after fluorine doping. [4][5][6][7][8] The structural origin of this effect was analyzed in F-modified glasses from chemical vapor deposition ͑CVD͒ methods, identifying different roles of fluorine, mainly in the modification of the mean bond energy and the structural disorder of the amorphous matrix. 5,[9][10][11] In this scenario, fabrication of F-modified silica from sol-gel synthesis 12 should, in principle, be an interesting target because of the relatively lowcost and sustainable features of the process, and for the expected improvement in radiation hardness with respect to other types of silica. 13,14 However, only few studies on F-doped sol-gel silica have been reported regarding preforms for low-index optical fibers, 15 and no vuv data have been published on fluorinated silica from sol-gel synthesis. In fact, sol-gel silica usually contains a large number of OH groups that are responsible for a broad absorption band at 8 eV, 16 which is strongly detrimental for vuv applications. In the present work, we disclose a method for the fabrication of optical grade bulk samples of F-doped dry silica by means of a modified sol-gel method. Our results show that the achievable reduction of dynamical disorder and -OH content opens the way to the utilization of sol-gel materials in vuv applications.Bulk samples, about 0.5 mm thick, of fluorine-modified silica were prepared by the sol-gel technique, cogelling tetraethoxysilane and trimethoxyfluorosilane, with concentration ratio 1:9. After gelation and drying, the xerogel samp...

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mentioning

confidence: 99%

High-energy shift of the Urbach ultraviolet absorption from attenuated dynamical disorder in fluorine modified sol-gel silica

Палеари

Meinardi

Lauria

et al. 2007

Applied Physics Letters

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“…The next step, then in preparation, was down to 157 nm (F 2 laser) [13]. The next step, then in preparation, was down to 157 nm (F 2 laser) [13].…”

Section: Polymers and Lubricants 253mentioning

confidence: 99%

Halofluorocarbons, Hydrofluorocarbons, and Related Compounds

2013

Modern Fluoroorganic Chemistry

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“…The characteristic of polymers developed for 157 nm lithography is the high fluorine content, which considerably increases the transparency at the exposure wavelength [55][56][57][58][59][60][61][62][63]. Usually, these polymers are co,-ter-, or tetra-polymers, containing monomers that bring specific properties to the material.…”

Section: Polymers For 157 Nm Optical Lithographymentioning

confidence: 99%