Abstract

To address the requirements of multi-level semiconductors, we propose a new technique for overcoming the height limitation of direct laser lithography. In the proposed system, an original source beam is fed into an interference generator that divides the input beam by 50: 50 into two output beams. After going through an imaging lens, these two beams make two focusing spots, which are slightly separated in the axial direction. In the overlapped region, these two spots generate a small interferogram that shortens the depth of focus. By using this phenomenon, we are able to overcome the height limitation of direct laser lithography. The governing equations are also derived in this manuscript by using the Gaussian beam model.

© 2011 OSA

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  1. M. Haruna, M. Takahashi, K. Wakahayashi, and H. Nishihara, “Laser beam lithographed micro-Fresnel lenses,” Appl. Opt. 29(34), 5120–5126 (1990).
    [CrossRef] [PubMed]
  2. M. T. Gale, M. Rossi, J. Pedersen, and H. Schutz, “Fabrication of continuous-relief micro-optical elements by direct laser writing in photoresists,” Opt. Eng. 33(11), 3556–3566 (1994).
    [CrossRef]
  3. A. G. Poleshchuk, E. G. Churin, V. P. Koronkevich, V. P. Korolkov, A. A. Kharissov, V. V. Cherkashin, V. P. Kiryanov, A. V. Kiryanov, S. A. Kokarev, and A. G. Verhoglyad, “Polar coordinate laser pattern generator for fabrication of diffractive optical elements with arbitrary structure,” Appl. Opt. 38(8), 1295–1301 (1999).
    [CrossRef] [PubMed]
  4. J.-M. Asfour and A. G. Poleshchuk, “Asphere testing with a Fizeau interferometer based on a combined computer-generated hologram,” J. Opt. Soc. Am. A 23(1), 172–178 (2006).
    [CrossRef] [PubMed]
  5. J. H. Burge, “Fabrication of large circular diffractive optics,” in Diffractive Optics and Micro-Optics, OSA Tech. Dig. 10 (1998).
  6. H.-G. Rhee and Y.-W. Lee, “Improvement of linewidth in laser beam lithographed computer generated hologram,” Opt. Express 18(2), 1734–1740 (2010).
    [CrossRef] [PubMed]
  7. J. Jin, J. W. Kim, C.-S. Kang, J.-A. Kim, and T. B. Eom, “Thickness and refractive index measurement of a silicon wafer based on an optical comb,” Opt. Express 18(17), 18339–18346 (2010).
    [CrossRef] [PubMed]
  8. J. W. Goodman, “Analog optical information processing,” in Introduction to Fourier Optics, 2nd ed., (McGraw-Hill, Singapore, 1996), Chap. 4.
  9. V. Westphal, C. M. Blanca, M. Dyba, L. Kastrup, and S. W. Hell, “Laser-diode-stimulated emission depletion microscopy,” Appl. Phys. Lett. 82(18), 3125–3127 (2003).
    [CrossRef]
  10. B. E. A. Saleh and M. C. Teich, “Beam optics,” in Fundamentals of Photonics (John Wiley & Sons, Inc., New York, 1991), Chap. 3.
  11. D.-I. Kim, H.-G. Rhee, J.-B. Song, and Y.-W. Lee, “Laser output power stabilization for direct laser writing system by using an acousto-optic modulator,” Rev. Sci. Instrum. 78(10), 103110 (2007).
    [CrossRef] [PubMed]
  12. D. K. Cohen, W. H. Gee, M. Ludeke, and J. Lewkowicz, “Automatic focus control: the astigmatic lens approach,” Appl. Opt. 23(4), 565–570 (1984).
    [CrossRef] [PubMed]
  13. H.-G. Rhee, D.-I. Kim, and Y.-W. Lee, “Realization and performance evaluation of high speed autofocusing for direct laser lithography,” Rev. Sci. Instrum. 80(7), 073103 (2009).
    [CrossRef] [PubMed]
  14. L. Deck and P. de Groot, “High-speed noncontact profiler based on scanning white-light interferometry,” Appl. Opt. 33(31), 7334–7338 (1994).
    [CrossRef] [PubMed]
  15. A. Harasaki, J. Schmit, and J. C. Wyant, “Improved vertical-scanning interferometry,” Appl. Opt. 39(13), 2107–2115 (2000).
    [CrossRef] [PubMed]
  16. G. Binnig, C. F. Quate, and C. Gerber, “Atomic force microscope,” Phys. Rev. Lett. 56(9), 930–933 (1986).
    [CrossRef] [PubMed]
  17. T. Doi, T. V. Vorburger, and P. J. Sullivan, “Effects of defocus and algorithm on optical step height calibration,” Precis. Eng. 23(3), 135–143 (1999).
    [CrossRef]

2010

2009

H.-G. Rhee, D.-I. Kim, and Y.-W. Lee, “Realization and performance evaluation of high speed autofocusing for direct laser lithography,” Rev. Sci. Instrum. 80(7), 073103 (2009).
[CrossRef] [PubMed]

2007

D.-I. Kim, H.-G. Rhee, J.-B. Song, and Y.-W. Lee, “Laser output power stabilization for direct laser writing system by using an acousto-optic modulator,” Rev. Sci. Instrum. 78(10), 103110 (2007).
[CrossRef] [PubMed]

2006

2003

V. Westphal, C. M. Blanca, M. Dyba, L. Kastrup, and S. W. Hell, “Laser-diode-stimulated emission depletion microscopy,” Appl. Phys. Lett. 82(18), 3125–3127 (2003).
[CrossRef]

2000

1999

1994

M. T. Gale, M. Rossi, J. Pedersen, and H. Schutz, “Fabrication of continuous-relief micro-optical elements by direct laser writing in photoresists,” Opt. Eng. 33(11), 3556–3566 (1994).
[CrossRef]

L. Deck and P. de Groot, “High-speed noncontact profiler based on scanning white-light interferometry,” Appl. Opt. 33(31), 7334–7338 (1994).
[CrossRef] [PubMed]

1990

1986

G. Binnig, C. F. Quate, and C. Gerber, “Atomic force microscope,” Phys. Rev. Lett. 56(9), 930–933 (1986).
[CrossRef] [PubMed]

1984

Asfour, J.-M.

Binnig, G.

G. Binnig, C. F. Quate, and C. Gerber, “Atomic force microscope,” Phys. Rev. Lett. 56(9), 930–933 (1986).
[CrossRef] [PubMed]

Blanca, C. M.

V. Westphal, C. M. Blanca, M. Dyba, L. Kastrup, and S. W. Hell, “Laser-diode-stimulated emission depletion microscopy,” Appl. Phys. Lett. 82(18), 3125–3127 (2003).
[CrossRef]

Cherkashin, V. V.

Churin, E. G.

Cohen, D. K.

de Groot, P.

Deck, L.

Doi, T.

T. Doi, T. V. Vorburger, and P. J. Sullivan, “Effects of defocus and algorithm on optical step height calibration,” Precis. Eng. 23(3), 135–143 (1999).
[CrossRef]

Dyba, M.

V. Westphal, C. M. Blanca, M. Dyba, L. Kastrup, and S. W. Hell, “Laser-diode-stimulated emission depletion microscopy,” Appl. Phys. Lett. 82(18), 3125–3127 (2003).
[CrossRef]

Eom, T. B.

Gale, M. T.

M. T. Gale, M. Rossi, J. Pedersen, and H. Schutz, “Fabrication of continuous-relief micro-optical elements by direct laser writing in photoresists,” Opt. Eng. 33(11), 3556–3566 (1994).
[CrossRef]

Gee, W. H.

Gerber, C.

G. Binnig, C. F. Quate, and C. Gerber, “Atomic force microscope,” Phys. Rev. Lett. 56(9), 930–933 (1986).
[CrossRef] [PubMed]

Harasaki, A.

Haruna, M.

Hell, S. W.

V. Westphal, C. M. Blanca, M. Dyba, L. Kastrup, and S. W. Hell, “Laser-diode-stimulated emission depletion microscopy,” Appl. Phys. Lett. 82(18), 3125–3127 (2003).
[CrossRef]

Jin, J.

Kang, C.-S.

Kastrup, L.

V. Westphal, C. M. Blanca, M. Dyba, L. Kastrup, and S. W. Hell, “Laser-diode-stimulated emission depletion microscopy,” Appl. Phys. Lett. 82(18), 3125–3127 (2003).
[CrossRef]

Kharissov, A. A.

Kim, D.-I.

H.-G. Rhee, D.-I. Kim, and Y.-W. Lee, “Realization and performance evaluation of high speed autofocusing for direct laser lithography,” Rev. Sci. Instrum. 80(7), 073103 (2009).
[CrossRef] [PubMed]

D.-I. Kim, H.-G. Rhee, J.-B. Song, and Y.-W. Lee, “Laser output power stabilization for direct laser writing system by using an acousto-optic modulator,” Rev. Sci. Instrum. 78(10), 103110 (2007).
[CrossRef] [PubMed]

Kim, J. W.

Kim, J.-A.

Kiryanov, A. V.

Kiryanov, V. P.

Kokarev, S. A.

Korolkov, V. P.

Koronkevich, V. P.

Lee, Y.-W.

H.-G. Rhee and Y.-W. Lee, “Improvement of linewidth in laser beam lithographed computer generated hologram,” Opt. Express 18(2), 1734–1740 (2010).
[CrossRef] [PubMed]

H.-G. Rhee, D.-I. Kim, and Y.-W. Lee, “Realization and performance evaluation of high speed autofocusing for direct laser lithography,” Rev. Sci. Instrum. 80(7), 073103 (2009).
[CrossRef] [PubMed]

D.-I. Kim, H.-G. Rhee, J.-B. Song, and Y.-W. Lee, “Laser output power stabilization for direct laser writing system by using an acousto-optic modulator,” Rev. Sci. Instrum. 78(10), 103110 (2007).
[CrossRef] [PubMed]

Lewkowicz, J.

Ludeke, M.

Nishihara, H.

Pedersen, J.

M. T. Gale, M. Rossi, J. Pedersen, and H. Schutz, “Fabrication of continuous-relief micro-optical elements by direct laser writing in photoresists,” Opt. Eng. 33(11), 3556–3566 (1994).
[CrossRef]

Poleshchuk, A. G.

Quate, C. F.

G. Binnig, C. F. Quate, and C. Gerber, “Atomic force microscope,” Phys. Rev. Lett. 56(9), 930–933 (1986).
[CrossRef] [PubMed]

Rhee, H.-G.

H.-G. Rhee and Y.-W. Lee, “Improvement of linewidth in laser beam lithographed computer generated hologram,” Opt. Express 18(2), 1734–1740 (2010).
[CrossRef] [PubMed]

H.-G. Rhee, D.-I. Kim, and Y.-W. Lee, “Realization and performance evaluation of high speed autofocusing for direct laser lithography,” Rev. Sci. Instrum. 80(7), 073103 (2009).
[CrossRef] [PubMed]

D.-I. Kim, H.-G. Rhee, J.-B. Song, and Y.-W. Lee, “Laser output power stabilization for direct laser writing system by using an acousto-optic modulator,” Rev. Sci. Instrum. 78(10), 103110 (2007).
[CrossRef] [PubMed]

Rossi, M.

M. T. Gale, M. Rossi, J. Pedersen, and H. Schutz, “Fabrication of continuous-relief micro-optical elements by direct laser writing in photoresists,” Opt. Eng. 33(11), 3556–3566 (1994).
[CrossRef]

Schmit, J.

Schutz, H.

M. T. Gale, M. Rossi, J. Pedersen, and H. Schutz, “Fabrication of continuous-relief micro-optical elements by direct laser writing in photoresists,” Opt. Eng. 33(11), 3556–3566 (1994).
[CrossRef]

Song, J.-B.

D.-I. Kim, H.-G. Rhee, J.-B. Song, and Y.-W. Lee, “Laser output power stabilization for direct laser writing system by using an acousto-optic modulator,” Rev. Sci. Instrum. 78(10), 103110 (2007).
[CrossRef] [PubMed]

Sullivan, P. J.

T. Doi, T. V. Vorburger, and P. J. Sullivan, “Effects of defocus and algorithm on optical step height calibration,” Precis. Eng. 23(3), 135–143 (1999).
[CrossRef]

Takahashi, M.

Verhoglyad, A. G.

Vorburger, T. V.

T. Doi, T. V. Vorburger, and P. J. Sullivan, “Effects of defocus and algorithm on optical step height calibration,” Precis. Eng. 23(3), 135–143 (1999).
[CrossRef]

Wakahayashi, K.

Westphal, V.

V. Westphal, C. M. Blanca, M. Dyba, L. Kastrup, and S. W. Hell, “Laser-diode-stimulated emission depletion microscopy,” Appl. Phys. Lett. 82(18), 3125–3127 (2003).
[CrossRef]

Wyant, J. C.

Appl. Opt.

Appl. Phys. Lett.

V. Westphal, C. M. Blanca, M. Dyba, L. Kastrup, and S. W. Hell, “Laser-diode-stimulated emission depletion microscopy,” Appl. Phys. Lett. 82(18), 3125–3127 (2003).
[CrossRef]

J. Opt. Soc. Am. A

Opt. Eng.

M. T. Gale, M. Rossi, J. Pedersen, and H. Schutz, “Fabrication of continuous-relief micro-optical elements by direct laser writing in photoresists,” Opt. Eng. 33(11), 3556–3566 (1994).
[CrossRef]

Opt. Express

Phys. Rev. Lett.

G. Binnig, C. F. Quate, and C. Gerber, “Atomic force microscope,” Phys. Rev. Lett. 56(9), 930–933 (1986).
[CrossRef] [PubMed]

Precis. Eng.

T. Doi, T. V. Vorburger, and P. J. Sullivan, “Effects of defocus and algorithm on optical step height calibration,” Precis. Eng. 23(3), 135–143 (1999).
[CrossRef]

Rev. Sci. Instrum.

D.-I. Kim, H.-G. Rhee, J.-B. Song, and Y.-W. Lee, “Laser output power stabilization for direct laser writing system by using an acousto-optic modulator,” Rev. Sci. Instrum. 78(10), 103110 (2007).
[CrossRef] [PubMed]

H.-G. Rhee, D.-I. Kim, and Y.-W. Lee, “Realization and performance evaluation of high speed autofocusing for direct laser lithography,” Rev. Sci. Instrum. 80(7), 073103 (2009).
[CrossRef] [PubMed]

Other

J. H. Burge, “Fabrication of large circular diffractive optics,” in Diffractive Optics and Micro-Optics, OSA Tech. Dig. 10 (1998).

J. W. Goodman, “Analog optical information processing,” in Introduction to Fourier Optics, 2nd ed., (McGraw-Hill, Singapore, 1996), Chap. 4.

B. E. A. Saleh and M. C. Teich, “Beam optics,” in Fundamentals of Photonics (John Wiley & Sons, Inc., New York, 1991), Chap. 3.

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Figures (9)

Fig. 1
Fig. 1

(a) Fabrication of a pattern in multiple layers, and (b) after etching process. Undesired defects commonly occurred when the depth of focus (DOF) of the lithographic system was larger than the thickness of the layer.

Fig. 2
Fig. 2

Schematic configuration of the proposed lithographic system: AOM, acousto-optic modulator; BS, beam splitter; PD, photodetector; IG, interference generator; QD, quadrant detector; LD, laser diode.

Fig. 3
Fig. 3

Interference generator: PBS, polarized beam splitter; QWP: quarter wave plate. A Haidinger fringe is observed when we put a screen at plane A.

Fig. 4
Fig. 4

(a) Axially separated two focused beam. (b) Intensity profile without and (c) with the interference. The parameter zo is known as the Rayleigh range [10].

Fig. 5
Fig. 5

(a) Τhe phase retardation ζ(z) along with the optical axis, and (b) contour plot of the intensity distribution at focal plane (z = 0).

Fig. 6
Fig. 6

(a) Intensity profiles with various α, and (b) comparison between the previous and the proposed method (α=0.82z0). EDOF means the effective depth of focus with the interference generator.

Fig. 7
Fig. 7

Fabricated result on the photoresist film (a) without and (b) with the interference generator.

Fig. 8
Fig. 8

AFM readings. The pattern was fabricated (a) without and (b) with the interference generator.

Fig. 9
Fig. 9

Fabricated result on the multi-level layer. (a) Test flan, (b) after the photoresist film etching, and (c) then after the chromium etching. The 3D profiles shown in (b) and (c) were obtained by the white-light scanning interferometer.

Tables (1)

Tables Icon

Table 1 Averaged height values calculated from 10 different samples. To calculate the step heights, we used a modification of a two sided algorithm [17].

Equations (9)

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heightlimitation depth of focus (DOF)= 2π W 0 2 λ ,
W 0 centralwidthofthe Airypattern=1.22 λ NA ,
U(x,y,z)=A(x,y,z)exp[jkz],
( 2 x 2 + 2 y 2 )A(x,y,z)j2k z A(x,y,z)=0.
A(x,y,z)= A 1 q(z) exp[jk x 2 + y 2 2q(z) ], where 1 q(z) = 1 z+j z 0 = 1 z+ z 0 2 z j 1 λ z 0 +λ z 2 z 0 = 1 R(z) j 1 π W 2 (z) .
U(x,y,z)= A 1 j z 0 W 0 W(z) exp[ x 2 + y 2 W 2 (z) ]exp[jkzjk x 2 + y 2 2R(z) +jς(z)], wherethephaseretardation of Gaussian beamς(z)= tan 1 z z 0 .(seeFig.5(a))
I(x,y,z)= | U(x,y,z) | 2 = | A 1 j z 0 | 2 ( W 0 W(z) ) 2 exp[2 x 2 + y 2 W 2 (z) ]
U 1 (x,y,z)= A 0 W 0 W(z+α) exp[ x 2 + y 2 W 2 (z+α) ]exp[jk(z+α)jk x 2 + y 2 2R(z+α) +jς(z+α)],and U 2 (x,y,z)= A 0 W 0 W(zα) exp[ x 2 + y 2 W 2 (zα) ]exp[jk(zα)jk x 2 + y 2 2R(zα) +jς(zα)].
I new (x,y,z)= | U 1 + U 2 | 2 =I(x,y,z+α)+I(x,y,zα)+2 I(x,y,z+α)I(x,y,zα) cos[ φ 1 φ 2 ]. where φ 1 φ 2 =k2αk x 2 + y 2 2 [ 1 R(z+α) 1 R(zα) ]+ς(z+α)ς(zα).

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