Fabrication of optical microstructures through fractional Talbot imaging

Suleski, Thomas J.; Chuang, Yi-Chen; Deguzman, Panfilo C.; Barton, Robert A.

doi:10.1117/12.599125

Cited by 5 publications

(6 citation statements)

References 9 publications

(11 reference statements)

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“…The exposure wavelength is denoted by λ . As mentioned above, the geometry of the mask aligner aperture is rapidly scaled down and obeys the relation (2) where f is given by the focal length of the mask aligner Fourier lens. Typical values for the aperture scaling are in the range between 2000 and 50000.…”

Section: Basic Resultsmentioning

confidence: 99%

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Half-tone proximity lithography

et al. 2010

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The half-tone lithography using pixilated chromium masks in a projection stepper is an established technology in microoptics fabrication. However, the projection lithography tool is comparably expensive and the achievable lateral resolution is typically limited. By using pixel diffraction effects, binary and continuous profile lithography with submicron resolution can be installed on a conventional mask aligner. To achieve this goal the control of both, the angular spectrum of the illumination and the mask features is essential. We used a novel micro-optics based illumination system referred as "MO Exposure Optics System" in a SUSS MicroTec MA6 mask aligner for the dedicated shaping of the angular illumination distribution. In combination with an adapted lithography mask the formation of a desired intensity distribution in the resist layer is possible. A general mathematic model describes the relation between the angular spectrum of the mask illumination, pixel size and pitch in the mask, proximity distance and propagated field, which also includes special cases like Talbot imaging. We show that a wide range of different micro-optical structures can be optimized by controlling the light diffraction in proximity lithography. Parameter settings were found for submicron binary pattern up to continuous profile structures with extensions up to several tens of microns. An additional interesting application of this approach is the combination of binary and continuous profiles in single elements, e.g. micro lenses with diffractive correction or AR structures. Experimental results achieved for blazed gratings with a period of 2 microns are presented.

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Section: Basic Resultsmentioning

confidence: 99%

“…For periodic mask pattern discrete proximity gaps were interesting, where a self-imaging of the mask pattern due to the Talbot effect occurs. This has been successfully used for copying gratings or for period reduction [2]. Figure 2.…”

Section: Introductionmentioning

confidence: 99%

Half-tone proximity lithography

et al. 2010

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“…This assumption is driven by the common sense that fractional Talbot images of amplitude grating with small opening slits have an integer multiple of the frequency of the mask [8,9,[12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

“…There are different approaches for Talbot lithography. "One shot" techniques can be used for duplicating periodic nanopatterns without an EUV-imaging system [7] or for synthesizing new phase gratings [8]. "Multipatterning" techniques [9][10][11] are mainly used for writing diffraction gratings with continuous surface relief structures.…”

Section: Introductionmentioning

confidence: 99%

Quantitative analysis of imperfect frequency multiplying in fractional Talbot planes and its effect on high-frequency-grating lithography

2014

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Fractional Talbot images of amplitude line gratings, with small opening slits compared to the period, are characterized by an integer multiple of the gratings' spatial frequency. We investigate the formation of fractional Talbot images analytically within a scalar framework and give a comprehensible insight into the paraxial limits involved. Particular attention is paid to nonparaxial effects on the intensity distribution at fractional Talbot planes and their lateral periodicities. We present a comparison between the measured intensity distributions and a numerical implementation of our analytical method. Both ways reveal the paraxial limits of frequency multiplication on fractional Talbot images. The use of fractional Talbot images for lithography results in ghost diffraction orders. We roughly estimate the ghost orders quantitatively with a simple numerical model for monochromatic and polychromatic illumination.

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“…In comparison to alternative laser based lithographic techniques, the Talbot lithography allows to combine advantages of both, serial and parallel processes, so that also micro-optical structures can be realized in a single exposure step [9]. The utilization of two-photon effects in Talbot lithography allows the manufacturing of well-defined three-dimensional (3D) nanostructures [10].…”

Section: Introductionmentioning

confidence: 99%

Effective and flexible modeling approach to investigate various 3D Talbot carpets from a spatial finite mask

Maaß

Sandfuchs

Thomae

et al. 2013

J. Eur. Opt. Soc.-Rapid Publ.

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We present an effective modeling approach for a fast calculation of the Talbot carpet from an initially 2-dimensional mask pattern. The introduced numerical algorithm is based on a modified angular-spectrum method, in which it is possible to consider the border effects of the Talbot region from a mask with a finite aperture. The Bluestein's fast Fourier transform (FFT) algorithm is applied to speed up the calculation. This approach allows as well to decouple the sampling points in the real space and the spatial frequency domain so that both parameters can be chosen independently. As a result an extended three-dimensional Talbot-carpet can be calculated with a minimized number of numerical steps and computation time, but still with high accuracy. The algorithm was applied to various 2-dimensional mask patterns and illumination setups. The influence of specific mask patterns to the resulting field intensity distribution is discussed.

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Fabrication of optical microstructures through fractional Talbot imaging

Cited by 5 publications

References 9 publications

Half-tone proximity lithography

Half-tone proximity lithography

Quantitative analysis of imperfect frequency multiplying in fractional Talbot planes and its effect on high-frequency-grating lithography

Effective and flexible modeling approach to investigate various 3D Talbot carpets from a spatial finite mask

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