Abstract

Magnesium fluoride (MgF2) films deposited by resistive heating evaporation with oblique-angle deposition have been investigated in details. The optical and micro-structural properties of single-layer MgF2 films were characterized by UV-VIS and FTIR spectrophotometers, scanning electron microscope (SEM), atomic force microscope (AFM), and x-ray diffraction (XRD), respectively. The dependences of the optical and micro-structural parameters of the thin films on the deposition angle were analyzed. It was found that the MgF2 film in a columnar microstructure was negatively inhomogeneous of refractive index and polycrystalline. As the deposition angle increased, the optical loss, extinction coefficient, root-mean-square (rms) roughness, dislocation density and columnar angle of the MgF2 films increased, while the refractive index, packing density and grain size decreased. Furthermore, IR absorption of the MgF2 films depended on the columnar structured growth.

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  1. M. C. Liu, C. C. Lee, M. Kaneko, K. Nakahira, and Y. Takano, “Microstructure of magnesium fluoride films deposited by boat evaporation at 193 nm,” Appl. Opt.45(28), 7319–7324 (2006).
    [CrossRef] [PubMed]
  2. K. Iwahori, M. Furuta, Y. Taki, T. Yamamura, and A. Tanaka, “Optical properties of fluoride thin films deposited by RF magnetron sputtering,” Appl. Opt.45(19), 4598–4602 (2006).
    [CrossRef] [PubMed]
  3. M. Bischoff, M. Sode, D. Gäbler, H. Bernitzki, C. Zaczek, N. Kaiser, and A. Tünnermann, “Metal fluoride coatings prepared by ion-assisted deposition,” Proc. SPIE7101, 71010L, 71010L-10 (2008).
    [CrossRef]
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    [CrossRef] [PubMed]
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    [CrossRef]
  6. P. Kelkar, B. Tirri, R. Wilklow, and D. Peterson, “Deposition and characterization of challenging DUV coatings,” Proc. SPIE7067, 706708, 706708-8 (2008).
    [CrossRef]
  7. C. Zaczek, S. Müllender, H. Enkisch, and F. Bijkerk, “Coatings for next generation lithography,” Proc. SPIE7101, 71010X, 71010X-10 (2008).
    [CrossRef]
  8. C. Zaczek, A. Pazidis, and H. Feldermann, “High-performance optical coating for VUV lithography application,” in Optical Interference Coatings Topic meeting 2007-OSA Technical Digest Series (Optical Society of America, 2007), paper FA1.
  9. C. C. Jaing, M. C. Liu, C. C. Lee, W. H. Cho, W. T. Shen, C. J. Tang, and B. H. Liao, “Residual stress in obliquely deposited MgF2 thin films,” Appl. Opt.47(13), C266–C270 (2008).
    [CrossRef] [PubMed]
  10. J. Wang, R. Maier, P. G. Dewa, H. Schreiber, R. A. Bellman, and D. D. Elli, “Nanoporous structure of a GdF(3) thin film evaluated by variable angle spectroscopic ellipsometry,” Appl. Opt.46(16), 3221–3226 (2007).
    [CrossRef] [PubMed]
  11. C. Guo, M. Kong, W. Gao, and B. Li, “Simultaneous determination of optical constants, thickness, and surface roughness of thin film from spectrophotometric measurements,” Opt. Lett. (to be published).
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    [CrossRef] [PubMed]
  13. C. K. Carniglia and D. G. Jensen, “Single-layer model for surface roughness,” Appl. Opt.41(16), 3167–3171 (2002).
    [CrossRef] [PubMed]
  14. E. D. Palik, Handbook of optical constants of solids II, (Academic Press, Boston, 1991).
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    [CrossRef]
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    [CrossRef] [PubMed]
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    [CrossRef]
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    [CrossRef] [PubMed]
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    [CrossRef]

2008 (4)

M. Bischoff, M. Sode, D. Gäbler, H. Bernitzki, C. Zaczek, N. Kaiser, and A. Tünnermann, “Metal fluoride coatings prepared by ion-assisted deposition,” Proc. SPIE7101, 71010L, 71010L-10 (2008).
[CrossRef]

P. Kelkar, B. Tirri, R. Wilklow, and D. Peterson, “Deposition and characterization of challenging DUV coatings,” Proc. SPIE7067, 706708, 706708-8 (2008).
[CrossRef]

C. Zaczek, S. Müllender, H. Enkisch, and F. Bijkerk, “Coatings for next generation lithography,” Proc. SPIE7101, 71010X, 71010X-10 (2008).
[CrossRef]

C. C. Jaing, M. C. Liu, C. C. Lee, W. H. Cho, W. T. Shen, C. J. Tang, and B. H. Liao, “Residual stress in obliquely deposited MgF2 thin films,” Appl. Opt.47(13), C266–C270 (2008).
[CrossRef] [PubMed]

2007 (1)

2006 (4)

2004 (2)

T. Murata, H. Isgizawa, I. Motoyama, and A. Tanaka, “Investigations of MgF2 optical thin films prepared from autoclaved sol,” J. Sol-Gel Sci. Technol.32(1-3), 161–165 (2004).
[CrossRef]

M. Vijayakumar, S. Selvasekarapandian, T. Gnanasekaran, S. Fujihara, and S. Koji, “Structural and impedance studies on LaF3 thin films prepared by vacuum evaporation,” J. Fluor. Chem.125(7), 1119–1125 (2004).
[CrossRef]

2002 (2)

1998 (1)

1997 (1)

L. Abelmann and C. Lodder, “Oblique evaporation and surface diffusion,” Thin Solid Films305(1-2), 1–21 (1997).
[CrossRef]

1993 (1)

R. N. Tait, T. Smy, and M. J. Brett, “Modeling and characterization of columnar growth in evaporated films,” Thin Solid Films226(2), 196–201 (1993).
[CrossRef]

Abelmann, L.

L. Abelmann and C. Lodder, “Oblique evaporation and surface diffusion,” Thin Solid Films305(1-2), 1–21 (1997).
[CrossRef]

Al-Kuhaili, M. F.

Bellman, R. A.

Bernitzki, H.

M. Bischoff, M. Sode, D. Gäbler, H. Bernitzki, C. Zaczek, N. Kaiser, and A. Tünnermann, “Metal fluoride coatings prepared by ion-assisted deposition,” Proc. SPIE7101, 71010L, 71010L-10 (2008).
[CrossRef]

Bijkerk, F.

C. Zaczek, S. Müllender, H. Enkisch, and F. Bijkerk, “Coatings for next generation lithography,” Proc. SPIE7101, 71010X, 71010X-10 (2008).
[CrossRef]

Bischoff, M.

M. Bischoff, M. Sode, D. Gäbler, H. Bernitzki, C. Zaczek, N. Kaiser, and A. Tünnermann, “Metal fluoride coatings prepared by ion-assisted deposition,” Proc. SPIE7101, 71010L, 71010L-10 (2008).
[CrossRef]

Brett, M. J.

R. N. Tait, T. Smy, and M. J. Brett, “Modeling and characterization of columnar growth in evaporated films,” Thin Solid Films226(2), 196–201 (1993).
[CrossRef]

Carniglia, C. K.

Cho, W. H.

Dewa, P. G.

Durrani, S. M. A.

Elli, D. D.

Enkisch, H.

C. Zaczek, S. Müllender, H. Enkisch, and F. Bijkerk, “Coatings for next generation lithography,” Proc. SPIE7101, 71010X, 71010X-10 (2008).
[CrossRef]

Etoh, K.

Fujihara, S.

M. Vijayakumar, S. Selvasekarapandian, T. Gnanasekaran, S. Fujihara, and S. Koji, “Structural and impedance studies on LaF3 thin films prepared by vacuum evaporation,” J. Fluor. Chem.125(7), 1119–1125 (2004).
[CrossRef]

Furuta, M.

Gäbler, D.

M. Bischoff, M. Sode, D. Gäbler, H. Bernitzki, C. Zaczek, N. Kaiser, and A. Tünnermann, “Metal fluoride coatings prepared by ion-assisted deposition,” Proc. SPIE7101, 71010L, 71010L-10 (2008).
[CrossRef]

Gao, W.

C. Guo, M. Kong, W. Gao, and B. Li, “Simultaneous determination of optical constants, thickness, and surface roughness of thin film from spectrophotometric measurements,” Opt. Lett. (to be published).

Gnanasekaran, T.

M. Vijayakumar, S. Selvasekarapandian, T. Gnanasekaran, S. Fujihara, and S. Koji, “Structural and impedance studies on LaF3 thin films prepared by vacuum evaporation,” J. Fluor. Chem.125(7), 1119–1125 (2004).
[CrossRef]

Guo, C.

C. Guo, M. Kong, W. Gao, and B. Li, “Simultaneous determination of optical constants, thickness, and surface roughness of thin film from spectrophotometric measurements,” Opt. Lett. (to be published).

Hazel, J.

Hodgkinson, I.

Isgizawa, H.

T. Murata, H. Isgizawa, I. Motoyama, and A. Tanaka, “Investigations of MgF2 optical thin films prepared from autoclaved sol,” J. Sol-Gel Sci. Technol.32(1-3), 161–165 (2004).
[CrossRef]

Iwahori, K.

Jaing, C. C.

Jensen, D. G.

Kaiser, N.

M. Bischoff, M. Sode, D. Gäbler, H. Bernitzki, C. Zaczek, N. Kaiser, and A. Tünnermann, “Metal fluoride coatings prepared by ion-assisted deposition,” Proc. SPIE7101, 71010L, 71010L-10 (2008).
[CrossRef]

N. Kaiser, “Review of the fundamentals of thin-film growth,” Appl. Opt.41(16), 3053–3060 (2002).
[CrossRef] [PubMed]

Kaneko, M.

Kelkar, P.

P. Kelkar, B. Tirri, R. Wilklow, and D. Peterson, “Deposition and characterization of challenging DUV coatings,” Proc. SPIE7067, 706708, 706708-8 (2008).
[CrossRef]

Khawaja, E. E.

Koji, S.

M. Vijayakumar, S. Selvasekarapandian, T. Gnanasekaran, S. Fujihara, and S. Koji, “Structural and impedance studies on LaF3 thin films prepared by vacuum evaporation,” J. Fluor. Chem.125(7), 1119–1125 (2004).
[CrossRef]

Kong, M.

C. Guo, M. Kong, W. Gao, and B. Li, “Simultaneous determination of optical constants, thickness, and surface roughness of thin film from spectrophotometric measurements,” Opt. Lett. (to be published).

Lee, C. C.

Li, B.

C. Guo, M. Kong, W. Gao, and B. Li, “Simultaneous determination of optical constants, thickness, and surface roughness of thin film from spectrophotometric measurements,” Opt. Lett. (to be published).

Liao, B. H.

Liu, M. C.

Lodder, C.

L. Abelmann and C. Lodder, “Oblique evaporation and surface diffusion,” Thin Solid Films305(1-2), 1–21 (1997).
[CrossRef]

Maier, R.

Motoyama, I.

T. Murata, H. Isgizawa, I. Motoyama, and A. Tanaka, “Investigations of MgF2 optical thin films prepared from autoclaved sol,” J. Sol-Gel Sci. Technol.32(1-3), 161–165 (2004).
[CrossRef]

Müllender, S.

C. Zaczek, S. Müllender, H. Enkisch, and F. Bijkerk, “Coatings for next generation lithography,” Proc. SPIE7101, 71010X, 71010X-10 (2008).
[CrossRef]

Murata, T.

T. Murata, H. Isgizawa, I. Motoyama, and A. Tanaka, “Investigations of MgF2 optical thin films prepared from autoclaved sol,” J. Sol-Gel Sci. Technol.32(1-3), 161–165 (2004).
[CrossRef]

Nakahira, K.

Nishimoto, K.

Peterson, D.

P. Kelkar, B. Tirri, R. Wilklow, and D. Peterson, “Deposition and characterization of challenging DUV coatings,” Proc. SPIE7067, 706708, 706708-8 (2008).
[CrossRef]

Schreiber, H.

Sekine, K.

Selvasekarapandian, S.

M. Vijayakumar, S. Selvasekarapandian, T. Gnanasekaran, S. Fujihara, and S. Koji, “Structural and impedance studies on LaF3 thin films prepared by vacuum evaporation,” J. Fluor. Chem.125(7), 1119–1125 (2004).
[CrossRef]

Shen, W. T.

Smy, T.

R. N. Tait, T. Smy, and M. J. Brett, “Modeling and characterization of columnar growth in evaporated films,” Thin Solid Films226(2), 196–201 (1993).
[CrossRef]

Sode, M.

M. Bischoff, M. Sode, D. Gäbler, H. Bernitzki, C. Zaczek, N. Kaiser, and A. Tünnermann, “Metal fluoride coatings prepared by ion-assisted deposition,” Proc. SPIE7101, 71010L, 71010L-10 (2008).
[CrossRef]

Tait, R. N.

R. N. Tait, T. Smy, and M. J. Brett, “Modeling and characterization of columnar growth in evaporated films,” Thin Solid Films226(2), 196–201 (1993).
[CrossRef]

Takano, Y.

Taki, Y.

Tanaka, A.

K. Iwahori, M. Furuta, Y. Taki, T. Yamamura, and A. Tanaka, “Optical properties of fluoride thin films deposited by RF magnetron sputtering,” Appl. Opt.45(19), 4598–4602 (2006).
[CrossRef] [PubMed]

T. Murata, H. Isgizawa, I. Motoyama, and A. Tanaka, “Investigations of MgF2 optical thin films prepared from autoclaved sol,” J. Sol-Gel Sci. Technol.32(1-3), 161–165 (2004).
[CrossRef]

Tang, C. J.

Tirri, B.

P. Kelkar, B. Tirri, R. Wilklow, and D. Peterson, “Deposition and characterization of challenging DUV coatings,” Proc. SPIE7067, 706708, 706708-8 (2008).
[CrossRef]

Tünnermann, A.

M. Bischoff, M. Sode, D. Gäbler, H. Bernitzki, C. Zaczek, N. Kaiser, and A. Tünnermann, “Metal fluoride coatings prepared by ion-assisted deposition,” Proc. SPIE7101, 71010L, 71010L-10 (2008).
[CrossRef]

Vijayakumar, M.

M. Vijayakumar, S. Selvasekarapandian, T. Gnanasekaran, S. Fujihara, and S. Koji, “Structural and impedance studies on LaF3 thin films prepared by vacuum evaporation,” J. Fluor. Chem.125(7), 1119–1125 (2004).
[CrossRef]

Wang, J.

Wilklow, R.

P. Kelkar, B. Tirri, R. Wilklow, and D. Peterson, “Deposition and characterization of challenging DUV coatings,” Proc. SPIE7067, 706708, 706708-8 (2008).
[CrossRef]

Wu, Q. H.

Yamamura, T.

Yoshida, T.

Zaczek, C.

M. Bischoff, M. Sode, D. Gäbler, H. Bernitzki, C. Zaczek, N. Kaiser, and A. Tünnermann, “Metal fluoride coatings prepared by ion-assisted deposition,” Proc. SPIE7101, 71010L, 71010L-10 (2008).
[CrossRef]

C. Zaczek, S. Müllender, H. Enkisch, and F. Bijkerk, “Coatings for next generation lithography,” Proc. SPIE7101, 71010X, 71010X-10 (2008).
[CrossRef]

Appl. Opt. (9)

I. Hodgkinson, Q. H. Wu, and J. Hazel, “Empirical equations for the principal refractive indices and column angle of obliquely deposited films of tantalum oxide, titanium oxide, and zirconium oxide,” Appl. Opt.37(13), 2653–2659 (1998).
[CrossRef] [PubMed]

C. K. Carniglia and D. G. Jensen, “Single-layer model for surface roughness,” Appl. Opt.41(16), 3167–3171 (2002).
[CrossRef] [PubMed]

N. Kaiser, “Review of the fundamentals of thin-film growth,” Appl. Opt.41(16), 3053–3060 (2002).
[CrossRef] [PubMed]

T. Yoshida, K. Nishimoto, K. Sekine, and K. Etoh, “Fluoride antireflection coatings for deep ultraviolet optics deposited by ion-beam sputtering,” Appl. Opt.45(7), 1375–1379 (2006).
[CrossRef] [PubMed]

M. F. Al-Kuhaili, E. E. Khawaja, and S. M. A. Durrani, “Determination of the optical constants (n and k) of inhomogeneous thin films with linear index profiles,” Appl. Opt.45(19), 4591–4597 (2006).
[CrossRef] [PubMed]

K. Iwahori, M. Furuta, Y. Taki, T. Yamamura, and A. Tanaka, “Optical properties of fluoride thin films deposited by RF magnetron sputtering,” Appl. Opt.45(19), 4598–4602 (2006).
[CrossRef] [PubMed]

M. C. Liu, C. C. Lee, M. Kaneko, K. Nakahira, and Y. Takano, “Microstructure of magnesium fluoride films deposited by boat evaporation at 193 nm,” Appl. Opt.45(28), 7319–7324 (2006).
[CrossRef] [PubMed]

J. Wang, R. Maier, P. G. Dewa, H. Schreiber, R. A. Bellman, and D. D. Elli, “Nanoporous structure of a GdF(3) thin film evaluated by variable angle spectroscopic ellipsometry,” Appl. Opt.46(16), 3221–3226 (2007).
[CrossRef] [PubMed]

C. C. Jaing, M. C. Liu, C. C. Lee, W. H. Cho, W. T. Shen, C. J. Tang, and B. H. Liao, “Residual stress in obliquely deposited MgF2 thin films,” Appl. Opt.47(13), C266–C270 (2008).
[CrossRef] [PubMed]

J. Fluor. Chem. (1)

M. Vijayakumar, S. Selvasekarapandian, T. Gnanasekaran, S. Fujihara, and S. Koji, “Structural and impedance studies on LaF3 thin films prepared by vacuum evaporation,” J. Fluor. Chem.125(7), 1119–1125 (2004).
[CrossRef]

J. Sol-Gel Sci. Technol. (1)

T. Murata, H. Isgizawa, I. Motoyama, and A. Tanaka, “Investigations of MgF2 optical thin films prepared from autoclaved sol,” J. Sol-Gel Sci. Technol.32(1-3), 161–165 (2004).
[CrossRef]

Opt. Lett. (1)

C. Guo, M. Kong, W. Gao, and B. Li, “Simultaneous determination of optical constants, thickness, and surface roughness of thin film from spectrophotometric measurements,” Opt. Lett. (to be published).

Proc. SPIE (3)

P. Kelkar, B. Tirri, R. Wilklow, and D. Peterson, “Deposition and characterization of challenging DUV coatings,” Proc. SPIE7067, 706708, 706708-8 (2008).
[CrossRef]

C. Zaczek, S. Müllender, H. Enkisch, and F. Bijkerk, “Coatings for next generation lithography,” Proc. SPIE7101, 71010X, 71010X-10 (2008).
[CrossRef]

M. Bischoff, M. Sode, D. Gäbler, H. Bernitzki, C. Zaczek, N. Kaiser, and A. Tünnermann, “Metal fluoride coatings prepared by ion-assisted deposition,” Proc. SPIE7101, 71010L, 71010L-10 (2008).
[CrossRef]

Thin Solid Films (2)

L. Abelmann and C. Lodder, “Oblique evaporation and surface diffusion,” Thin Solid Films305(1-2), 1–21 (1997).
[CrossRef]

R. N. Tait, T. Smy, and M. J. Brett, “Modeling and characterization of columnar growth in evaporated films,” Thin Solid Films226(2), 196–201 (1993).
[CrossRef]

Other (2)

E. D. Palik, Handbook of optical constants of solids II, (Academic Press, Boston, 1991).

C. Zaczek, A. Pazidis, and H. Feldermann, “High-performance optical coating for VUV lithography application,” in Optical Interference Coatings Topic meeting 2007-OSA Technical Digest Series (Optical Society of America, 2007), paper FA1.

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Figures (6)

Fig. 1
Fig. 1

Transmittance spectra of fused silica substrate and of the MgF2 films prepared with different deposition angles. (a)The measured spectra; (b) the corresponding calculated spectra with an assumed film thickness of 300 nm.

Fig. 2
Fig. 2

Cross-sectional SEM micrographs of the MgF2 films prepared with different deposition angles: (a) 0°; (b) 30°; (c) 40°; (d) 50°; (e) 60°; (f) 70°.

Fig. 3
Fig. 3

The measured dependence of tangent of columnar angle φ on tangent of deposition angle ϕ and the corresponding best fit with the Tangent rule [18].

Fig. 4
Fig. 4

AFM surface morphologies of MgF2 films prepared at different deposition angles. (a) 0°, (b) 30°, (c) 40°, (d) 50°,(e) 60°, and (f) 70°.

Fig. 5
Fig. 5

X-ray diffraction patterns of MgF2 films prepared with different deposition angles.

Fig. 6
Fig. 6

IR spectra of MgF2 films prepared at different deposition angles.

Tables (1)

Tables Icon

Table 1 Parameters of MgF2 films obtained from optical and microstructure characterization at193nm

Equations (3)

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L=1TR
D= 0.94λ βcosθ
δ= 1 D 2

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