Abstract

We fabricated aluminum fluoride (AlF3) thin films by pulsed DC magnetron sputtering with various CF4 flow rates and sputtering powers. Our method is distinct from the conventional deposition process in that we used inexpensive Al (99.99% purity) as the target instead of an expensive fluoride compound. The optical properties and microstructure of the thin films were examined. The optical quality of AlF3 thin films deposited at a 20  W sputtering power and injected 110   SCCM (SCCM denotes cubic centimeters per minute at standard temperature and pressure) CF4 flow at room temperature showed improvement with an extinction coefficient of less than 7×10-4 at 193  nm. The deposition of AlF3 thin films at different substrate temperatures and annealed by UV light was also investigated.

© 2008 Optical Society of America

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    [CrossRef] [PubMed]
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2006 (3)

2005 (2)

C.-C. Lee, M.-C. Liu, M. Kaneko, K. Nakahira, and Y. Takano, "Characterization of AlF3 thin films at 193 nm by thermal evaporation," Appl. Opt. 44, 7333-7338 (2005).
[CrossRef] [PubMed]

M.-C. Liu, C.-C. Lee, M. Kaneko, K. Nakahira, and Y. Takano, "Microstructure related properties of lanthanum fluoride films deposited by molybdenum boat evaporation at 193 nm," Thin Solid Films 492, 45-51 (2005).
[CrossRef]

2004 (1)

Y. Taki, "Film structure and optical constants of magnetron-sputtered fluoride films for deep ultraviolet lithography," Vacuum 74, 431-435 (2004).
[CrossRef]

2002 (1)

2001 (1)

S. Güster, D. Ristau, and S. Bosch, "Spectrophotometric determination of absorption in the DUV/VUV spectral range for MgF2 and LaF3 thin films," Proc. SPIE 4099, 299-310 (2001).

1995 (1)

A. Zuber, N. Kaiser, and J.L. Stehlé, "Variable-angle spectroscopic ellipsometry for deep UV characterization of dielectric coatings," Thin Solid Films 261, 37-43 (1995).
[CrossRef]

1985 (1)

1984 (1)

1970 (1)

W. Heitmann, "Vacuum evaporated films of aluminum fluoride," Thin Solid Films 5, 61-67 (1970).
[CrossRef]

Biro, R.

Bosch, S.

S. Güster, D. Ristau, and S. Bosch, "Spectrophotometric determination of absorption in the DUV/VUV spectral range for MgF2 and LaF3 thin films," Proc. SPIE 4099, 299-310 (2001).

Carniglia, C. K.

Craighead, H. G.

Etoh, K.

Güster, S.

S. Güster, D. Ristau, and S. Bosch, "Spectrophotometric determination of absorption in the DUV/VUV spectral range for MgF2 and LaF3 thin films," Proc. SPIE 4099, 299-310 (2001).

Hart, T. T.

Hasegawa, M.

Heitmann, W.

W. Heitmann, "Vacuum evaporated films of aluminum fluoride," Thin Solid Films 5, 61-67 (1970).
[CrossRef]

Kaiser, N.

A. Zuber, N. Kaiser, and J.L. Stehlé, "Variable-angle spectroscopic ellipsometry for deep UV characterization of dielectric coatings," Thin Solid Films 261, 37-43 (1995).
[CrossRef]

Kaneko, M.

Lee, C.-C.

Lichtenstein, T. L.

Liu, M.-C.

Lowdermilk, W. H.

Maloney, P. J.

Matsumoto, A.

Milam, D.

Nakahira, K.

Niisaka, S.

Nishimoto, K.

Otani, M.

Ouchi, C.

Rainer, F.

Ristau, D.

S. Güster, D. Ristau, and S. Bosch, "Spectrophotometric determination of absorption in the DUV/VUV spectral range for MgF2 and LaF3 thin films," Proc. SPIE 4099, 299-310 (2001).

Saito, J.

Saito, T.

Sekine, K.

Sone, K.

Stehlé, J.L.

A. Zuber, N. Kaiser, and J.L. Stehlé, "Variable-angle spectroscopic ellipsometry for deep UV characterization of dielectric coatings," Thin Solid Films 261, 37-43 (1995).
[CrossRef]

Suzuki, Y.

Sweeney, J. E.

Takano, Y.

Taki, Y.

Y. Taki, "Film structure and optical constants of magnetron-sputtered fluoride films for deep ultraviolet lithography," Vacuum 74, 431-435 (2004).
[CrossRef]

Tanaka, A.

Wood, O. R.

Yoshida, T.

Zuber, A.

A. Zuber, N. Kaiser, and J.L. Stehlé, "Variable-angle spectroscopic ellipsometry for deep UV characterization of dielectric coatings," Thin Solid Films 261, 37-43 (1995).
[CrossRef]

Appl. Opt. (7)

Proc. SPIE (1)

S. Güster, D. Ristau, and S. Bosch, "Spectrophotometric determination of absorption in the DUV/VUV spectral range for MgF2 and LaF3 thin films," Proc. SPIE 4099, 299-310 (2001).

Thin Solid Films (3)

A. Zuber, N. Kaiser, and J.L. Stehlé, "Variable-angle spectroscopic ellipsometry for deep UV characterization of dielectric coatings," Thin Solid Films 261, 37-43 (1995).
[CrossRef]

M.-C. Liu, C.-C. Lee, M. Kaneko, K. Nakahira, and Y. Takano, "Microstructure related properties of lanthanum fluoride films deposited by molybdenum boat evaporation at 193 nm," Thin Solid Films 492, 45-51 (2005).
[CrossRef]

W. Heitmann, "Vacuum evaporated films of aluminum fluoride," Thin Solid Films 5, 61-67 (1970).
[CrossRef]

Vacuum (1)

Y. Taki, "Film structure and optical constants of magnetron-sputtered fluoride films for deep ultraviolet lithography," Vacuum 74, 431-435 (2004).
[CrossRef]

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Figures (7)

Fig. 1
Fig. 1

Schematic diagram of the sputtering system.

Fig. 2
Fig. 2

Transmittance spectra of AlF 3 thin films prepared with (a) 30   W power and different CF 4 at the same sputtering time and (b) 110   SCCM CF 4 flow rate and different DC sputtering power.

Fig. 3
Fig. 3

Transmittance spectra of AlF 3 thin films prepared at different substrate temperatures.

Fig. 4
Fig. 4

(a) Refractive index and (b) extinction coefficient of AlF 3 deposition with 110 SCCM CF 4 .

Fig. 5
Fig. 5

Surface morphology of AlF3 thin films coated with different sputtering power and photographed by a SEM: (a) 15 W, (b) 20 W, (c) 25 W, (d) 30 W.

Fig. 6
Fig. 6

Cross-sectional morphology of AlF3 thin films coated with different sputtering power and photographed by a SEM: (a) 15 W, (b) 20 W, (c) 25 W, (d) 30 W.

Fig. 7
Fig. 7

Transmittance spectra of AlF3 thin films annealed by UV light.

Tables (1)

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Table 1 Surface Roughness of AlF3 Thin Films Produced with Different Sputtering Power

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