An optimization of conditions for excitation of xenon laser plasma in a source of extreme ultraviolet radiation for nanolithography in order to increase its efficiency

Publication in Journal of Optical Technology

For Russian citation (Opticheskii Zhurnal):

Буторин П.С., Калмыков С.Г. Оптимизация условий возбуждения ксеноновой лазерной плазмы в источнике экстремального ультрафиолетового излучения для нанолитографии с целью повышения его эффективности // Оптический журнал. 2024. Т. 91. № 5. С. 95–104. http://doi.org/10.17586/1023-5086-2024-91-05-95-104

Butorin P.S., Kalmykov S.G. An optimization of conditions for excitation of xenon laser plasma in a source of extreme ultraviolet radiation for nanolithography in order to increase its efficiency [in Russian] // Opticheskii Zhurnal. 2024. V. 91. № 5. P. 95–104. http://doi.org/10.17586/1023-5086-2024-91-05-95-104

For citation (Journal of Optical Technology):

Abstract:

Subject of study. Laser plasma excited by the xenon gas jet of a target. Goal of the work. Increasing the output of extreme ultraviolet radiation from such a plasma, used as a source of working radiation in a new branch of lithography with a wavelength near 11.2 nm, to a level that meets the requirements of industrial production. Method. The main method used was to change the diameter of the laser beam by moving Xe of the gas-jet target along its axis, which led to a change in the size of the area of interaction of the beam with the target and, accordingly, to a change in the size of the laser spark. The intensity of plasma radiation with wavelengths of 11.2 and 13.5 nm was measured using a surfacebarrier Si photosensor and a Bragg mirror, and the laser radiation energy absorbed by the plasma was also measured. Main results. When the diameter of the laser beam illuminating the target increases from 46 to 344 μm, the energy emitted in the extreme ultraviolet range increases approximately
5 times. In the found irradiation mode, the efficiency of conversion of laser radiation into radiation with a wavelength of 11.2 nm was 3.9%. Recent measurements of the plasma lifetime have shown that it depends on the size of the plasma and in a number of experiments turns out to be significantly shorter than the laser pulse, which makes it possible to use this parameter (plasma lifetime) as an optimization parameter when choosing the laser pulse duration. Practical significance. The results obtained demonstrate a record efficiency for laser-plasma radiation sources with a gas target for the conversion of laser pulse energy into the energy of extreme ultraviolet radiation, which opens up the prospect of using such a source in the industrial production of microcircuits.

Keywords:

laser plasma, extreme ultraviolet, conversion factor, nanolithography, laser breakdown

Acknowledgements:

this work was carried out in accordance with the State Assignment of Ioffe Institute (№ 0040-2019-0001)

OCIS codes: 140.3440, 350.5400, 260.7200

References:

1. Bakshi V. EUV sources for lithography. SPIE Press, 2005. 1057 p.
2. Andreev A.A., Nikolaev V.G., Platonov, K.Y., et. al. Key methods for intensifying soft X-ray emission from a laser plasma for lithography // Tech. Phys. 2007. V. 52. P.739–746. https://doi.org/10.1134/S1063784207060102
3. Schupp R., Behnke L., Bouza Z., et. al. Characterization of angularly resolved EUV emission from 2-μmwavelength laser-driven Sn plasmas using preformed liquid disk targets // J. Phys. D: Appl. Phys. 2021. V. 54. P. 365103. https://iopscience.iop.org/article/10.1088/1361-6463/ac0b70
4. Fomenkov I. EUV Source for Lithography: Readiness for HVM and Outlook for Increase in Power and Availability. 2018 Source Workshop. Report. [Electronic resource]. Access mode: https://www.euvlitho.com/2018/S1.pdf/, free. in English (accessed 28/09/2023).
5. Fomenkov I. EUV Source for Lithography in HVM: Performance and prospects. Report #S1 on 2019 Source Workshop, Report. [Electronic resource]. Access mode: https://www.euvlitho.com/2019/S1.pdf/, free. in English (accessed 28/09/2023).
6. Chkhalo N., Salashchenko N. Next generation nanolithography based on Ru/Be and Rh/Sr multilayer optics // AIP Adv. 2013. V. 3. P. 082130. https://doi.org/10.1063/1.4820354
7. Gusev S., Nechay A., Pariev D., et. al. High-reflection Mo/Be/Si multilayers for EUV lithography // Opt. Lett. 2017. V. 42. № 24. P. 5070–5073. https://doi.org/10.1364/OL.42.005070
8. Garbaruk A.V., Gritskevich M.S., Kalmykov S.G., et. al. Prepulse-induced shock waves in the gas jet target of a laser plasma EUV radiation source // J. Phys. D: Appl. Phys. 2022. V. 55. P. 025201. https://doi.org/10.1088/1361-6463/50/2/025201
9. de Bruijn R., Koshelev K., Bijkerk F. Enhancement of laser plasma EUV emission by shockwave-plasma interaction // J. Phys. D: Appl. Phys. 2003. V. 36. P. 88–91. https://iopscience.iop.org/article/10.1088/0022-3727/36/18/L03
10. de Bruijn R., Koshelev K., Zakharov S., et. al. Enhancement of laser plasma extreme ultraviolet emission by shockwave-laser interaction // Phys. Plasm. 2005. V. 12. P. 042701. https://doi.org/10.1063/1.1857914
11. Butorin, P.S., Kalmykov, S.G., Sasin, M.E. A New method of suppressing peripheral absorption in a laserplasma short-wave radiation source with a Xe gas-jet target // Tech. Phys. Lett. 2018. V. 44. P. 1100–1103. https://doi.org/10.1134/S1063785018120209
12. Kalmykov S., Butorin P., Sasin M. Xe laser-plasma EUV radiation source with a wavelength near 11 nm — Optimization and conversion efficiency // J. Appl. Phys. 2019. V. 126. P. 103301. https://doi.org/10.1063/1.5115785
13. Kalmykov S.G., Butorin P.S., Sasin M.E., et. al. Absorption of laser radiation in a laser-produced plasma of Xe: Hydrodynamic effects and nonequilibrium ionization // J. Phys. D: Appl. Phys. 2022. V. 55. P. 105203. https://iopscience.iop.org/article/10.1088/ 1361-6463/ac368c
14. Zabrodskii V.V., Belik V.P., Aruev P.N., et. al. Quantum yield of a silicon avalanche photodiode in the wavelength range of 120–170 nm // Tech. Phys. 2020. V. 65. P. 1333–1339. https://doi.org/10.1134/S1063784220080022
15. Levashov V.E., Mednikov K.N., Pirozhkov A.S., et. al. Optimisation of a laser-plasma soft X-ray source excited in a pulsed xenon jet // Quantum Electronics. 2006. V. 36. № 6. P. 549–552. https://doi.org/10.1070/QE2006v036n06ABEH013163
16. Chkhalo N.I., Garakhin S.A., Lopatin A.Ya., et. al. Conversion efficiency of a laser-plasma source based on a Xe jet in the vicinity of a wavelength of 11 nm // AIP Adv. 2018. V. 8. P. 105003. https://doi.org/10.1063/1.5048288