Contrast properties of spatial light modulators for microlithography

Heber, Joerg; Kunze, Detlef; Dürr, Peter; Rudloff, D.; Wagner, Michael; Björnängen, Peter; Luberek, Jarek; Berzinsh, U.; Sandstrom, Tor; Karlin, Tord

doi:10.1117/12.747015

Cited by 7 publications

(9 citation statements)

References 17 publications

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“…However, as a central result of the studies performed earlier, only a single spatial frequency component of the surface corrugation determines the contrast limit. Here, this spatial frequency component is represented by the surface parameter 1 , corresponding to the peak-to-valley amplitude of the surface corrugations at the mirror pitch frequency and yielding for the surface scatter-limited contrast ratio [16]:…”

Section: Resultsmentioning

confidence: 99%

“…The unprecedentedly high contrast ratios prompted us to check the consistency of our measurement results. To this end, we estimated the expected contrast ratios based on the micromirror surface roughness, which is known to be a determining factor for the MMA contrast [16]. In general, surface corrugations induce an upper contrast limit, which scales quadratically with the wavelength because of the underlying process of surface scattering [9].…”

Section: Resultsmentioning

confidence: 99%

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Spatially resolved contrast measurement of diffractive micromirror arrays

et al. 2015

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Diffractive micromirror arrays (MMA) are a special class of optical MEMS, serving as spatial light modulators (SLM) that control the phase of reflected light. Since the surface profile is the determining factor for an accurate phase modulation, high-precision topographic characterization techniques are essential to reach highest optical performance. While optical profiling techniques such as white-light interferometry are still considered to be most suitable to this task, the practical limits of interferometric techniques start to become apparent with the current state of optical MEMS technology. Light scatter from structured surfaces carries information about their topography, making scatter techniques a promising alternative. Therefore, a spatially resolved scatter measurement technique, which takes advantage of the MMA’s diffractive principle, has been implemented experimentally. Spectral measurements show very high contrast ratios (up to 10 000 in selected samples), which are consistent with calculations from micromirror roughness parameters obtained by white-light interferometry, and demonstrate a high sensitivity to changes in the surface topography. The technique thus seems promising for the fast and highly sensitive characterization of diffractive MMAs

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Spatially resolved contrast measurement of diffractive micromirror arrays

et al. 2015

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“…In order to demonstrate the optical performance of the MMAs in the visible region, a characterization setup according to [10] has been used to record MMA images with a CCD-camera. The setup used a 532 nm laser and the optics enables to resolve individual pixels of the MMA.…”

Section: Optical Testmentioning

confidence: 99%

Technology development of diffractive micromirror arrays for the deep ultraviolet to the near infrared spectral range

et al. 2010

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A new generation of micromirror arrays (MMAs) with torsional actuators is being developed within the European research project MEMI in order to extend the usable spectral range of diffractive MMAs from deep ultraviolet into the visible and near infrared. The MMAs have 256 x 256 pixels reaching deflections above 350 nm at a frame rate of 1 kHz, which enables an operation in the target wavelength range between 240 nm and 800 nm. Customized driver electronics facilitates computer controlled operation and simple integration of the MMA into various optical setups. Tests in the visible wavelength range demonstrate the functionality and the high application potential of first MMA test samples

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“…As example, Figure 4 sketches a setup of optical components to realize the transformation of MMA phase information into intensity patterns for zero order operation. The relation between image intensity I, mirror deflection d and laser illumination wavelength λ determines the simple formula [8], [9]:…”

Section: Analog Micromirror Arrays and Their Application As Programma...mentioning

confidence: 99%

Calibration of diffractive micromirror arrays for microscopy applications

Berndt

Heber

Sinning

et al. 2011

International Symposium on Photoelectronic Detection and Imaging 2011: Sensor and Micromachined Optical Device Technologies

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We report on our investigation to precisely actuate diffractive micromirror arrays (MMA) with an accuracy of /100. The test samples consist of analog, torsional MEMS arrays with 65 536 (256x256) mirror elements. These light modulators were developed for structured illumination purposes to be applied as programmable mask for life science and semiconductor microscopy application. Main part of the work relies on the well known characterization of MEMS mirrors with profilometry to automatically measure and approximate the MMA actuation state with high resolution. Examples illustrate the potential of this strategy to control the tilt state of many thousand micromirrors within the accuracy range of the characterization tool. In a dynamic range between 0 and >250 nm the MMA deflection has been precisely adjusted for final MMA application in the deep-UV - VIS - NIR spectral range. The optical properties of calibrated MMAs are tested in a laser measurement setup. After MMA calib ration an increased homogeneity and improved image contrast are demonstrated for various illumination patterns

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Contrast properties of spatial light modulators for microlithography

Cited by 7 publications

References 17 publications

Spatially resolved contrast measurement of diffractive micromirror arrays

Spatially resolved contrast measurement of diffractive micromirror arrays

Technology development of diffractive micromirror arrays for the deep ultraviolet to the near infrared spectral range

Calibration of diffractive micromirror arrays for microscopy applications

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