Acoustic streaming effects in megasonic cleaning of EUV photomasks

A continuum model

Vivek Kapila, Pierre A Deymier, Hrishikesh Shende, Viraj Pandit, Srini Raghavan, Florence O. Eschbach

Research output: Chapter in Book/Report/Conference proceedingConference contribution

15 Citations (Scopus)

Abstract

Removal of nano-scale contaminant particles from the photomasks is of critical importance to the implementation of EUV lithography for 32nm node. Megasonic cleaning has traditionally been used for photomask cleaning and extensions to sub 50nm participates removal is being considered as a pattern damage free cleaning approach. Several mechanisms for removal are believed to be active in megasonic cleaning systems, e.g., cavitation, and acoustic streaming (Eckart, Schlichting, and microstreaming). It is often difficult to separate the effects of these individual mechanisms on contamination removal in a conventional experimental setup. Therefore, a theoretical approach is undertaken in this work with a focus on determining the contribution of acoustic streaming in cleaning process. A continuum model is used to describe the interaction between megasonic waves and a substrate (fused silica) immersed in a fluid (water). The model accounts for the viscous nature of the fluid. We calculate the acoustic vibrational modes of the system. These in turn are used to determine the acoustic streaming forces that lead to Schlichting streaming in a narrow acoustic boundary layer at the substrate/fluid interface. These forces are subsequently used to estimate the streaming velocities that may in turn apply a pressure and drag force on the contaminant particles adhering to the substrate. These effects are calculated as a function of angle of incidence, frequency and intensity of the megasonic wave. The relevance of this study is then discussed in the context of the cleaning efficiency and pattern damage in competing megasonic cleaning technologies, such as immersion, and nozzle-based systems.

Original languageEnglish (US)
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
EditorsJ. Tracy Weed, P.M. Martin
Volume5992
Edition2
DOIs
StatePublished - 2005
Event25th Annual BACUS Symposium on Photomask Technology - Monterey, CA, United States
Duration: Oct 4 2005Oct 7 2005

Other

Other25th Annual BACUS Symposium on Photomask Technology
CountryUnited States
CityMonterey, CA
Period10/4/0510/7/05

Fingerprint

Photomasks
photomasks
cleaning
Cleaning
Acoustics
continuums
acoustics
contaminants
Fluids
fluids
Substrates
Impurities
damage
Extreme ultraviolet lithography
Fused silica
cavitation flow
Cavitation
submerging
nozzles
drag

Keywords

  • Acoustic streaming
  • Euv lithography
  • Megasonic cleaning

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics

Cite this

Kapila, V., Deymier, P. A., Shende, H., Pandit, V., Raghavan, S., & Eschbach, F. O. (2005). Acoustic streaming effects in megasonic cleaning of EUV photomasks: A continuum model. In J. Tracy Weed, & P. M. Martin (Eds.), Proceedings of SPIE - The International Society for Optical Engineering (2 ed., Vol. 5992). [59923X] https://doi.org/10.1117/12.633378

Acoustic streaming effects in megasonic cleaning of EUV photomasks : A continuum model. / Kapila, Vivek; Deymier, Pierre A; Shende, Hrishikesh; Pandit, Viraj; Raghavan, Srini; Eschbach, Florence O.

Proceedings of SPIE - The International Society for Optical Engineering. ed. / J. Tracy Weed; P.M. Martin. Vol. 5992 2. ed. 2005. 59923X.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Kapila, V, Deymier, PA, Shende, H, Pandit, V, Raghavan, S & Eschbach, FO 2005, Acoustic streaming effects in megasonic cleaning of EUV photomasks: A continuum model. in J Tracy Weed & PM Martin (eds), Proceedings of SPIE - The International Society for Optical Engineering. 2 edn, vol. 5992, 59923X, 25th Annual BACUS Symposium on Photomask Technology, Monterey, CA, United States, 10/4/05. https://doi.org/10.1117/12.633378
Kapila V, Deymier PA, Shende H, Pandit V, Raghavan S, Eschbach FO. Acoustic streaming effects in megasonic cleaning of EUV photomasks: A continuum model. In Tracy Weed J, Martin PM, editors, Proceedings of SPIE - The International Society for Optical Engineering. 2 ed. Vol. 5992. 2005. 59923X https://doi.org/10.1117/12.633378
Kapila, Vivek ; Deymier, Pierre A ; Shende, Hrishikesh ; Pandit, Viraj ; Raghavan, Srini ; Eschbach, Florence O. / Acoustic streaming effects in megasonic cleaning of EUV photomasks : A continuum model. Proceedings of SPIE - The International Society for Optical Engineering. editor / J. Tracy Weed ; P.M. Martin. Vol. 5992 2. ed. 2005.
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