Dr. Armen Kroyan Profile

Dr. Armen Kroyan

Senior Engineer

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Author

Publications (19)

Proceedings Article | 17 December 2003 Paper

A new concept of image imbalance correction for phase-shift mask lithography at 65 nm

Vishnu Kamat, Armen Kroyan

Proceedings Volume 5256, (2003) https://doi.org/10.1117/12.518165

KEYWORDS: Photomasks, Phase shifts, Manufacturing, Lithography, Semiconducting wafers, 3D image processing, Image quality, Image resolution, Binary data, Scattering

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Proceedings Article | 17 December 2003 Paper

Implementing AAPSM in 90-nm product with practical image imbalance correction

Benjamin Lin, Shu-hao Hsu, I. H. Huang, Kunyuan Chen, Frank Hsieh, Tony Hsu, Hua-Yu Liu, Armen Kroyan, Freeman Hsu, Jason Huang

Proceedings Volume 5256, (2003) https://doi.org/10.1117/12.518029

KEYWORDS: Photomasks, Semiconducting wafers, Quartz, Optical proximity correction, Binary data, Phase shifts, Reticles, Neodymium, Optical lithography, Manufacturing

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Each new technology node tests the limits of optical lithography. As exposure wavelength is reduced, new imaging techniques are needed to maximize resolution capabilities. The phase shift mask (PSM) is one such technique that is utilized to push the limits of optical lithography. Altering the optical phase of the light that transmits through a photo mask can increase the resolution of a lithographic image significantly. There are several types of phase shift mask and each has a general charateristic in which some transparent area of the mask are given 180° shift in optical phase relative to other nearby transparent areas. The interaction of the aerial images between two features with a relative phase difference of 180° create interference regions that can be used to printed images much closer together and with an increased depth of focus than that of a standard chrome-on-glass mask. An AAPSM is fabricated using a subtractive process in which the quartz substrate is etched to a given depth to produce the desired phase shift. However, intensity imbalances between the etched and non-etched regions due to sidewall scattering can cause resolution, phase and placement errors on the wafer. One method to balance the transmission is 40 nm undercut with 16 nm shifter width bias. Based on our previous study, 40 nm undercut with 16 nm shifter width bias showed an improved balance of intensities between the etched and non-etched regions. The object of this experiment is to implement the AAPSM with 40 nm undercut and 16 nm shifter width bias in SRAM product and the exposure wavelength is 193 nm. The main purpose is to proof the technology of AAPSM with 40 nm undercut and 16 nm shifter width bias in real product. Also verifying all issue of AAPSM in production. In this study, the image imbalance has been corrected via 40 nm undercut and 16 nm shifter width bias, and the DOF of AAPSM for wafer print performance is larger than binary mask. The DOF of AAPSM is about 0.5 μm and the conventional binary mask is 0.3μm.

Proceedings Article | 28 August 2003 Paper

Practical approach for AAPSM image imbalance correction for sub-100-nm lithography

Hung Lin Cho, Shu Yi Lin, Frank Hsieh, Armen Kroyan, Hua-Yu Liu, Jason Huang, Shu-Hao Hsu, I-Hsiung Huang, Benjamin Lin, Kuei-Chun Hung

Proceedings Volume 5130, (2003) https://doi.org/10.1117/12.504393

KEYWORDS: Photomasks, Chromium, Critical dimension metrology, Manufacturing, Lithography, Semiconducting wafers, Reticles, Scanning electron microscopy, Optical proximity correction, Image resolution

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Proceedings Article | 10 July 2003 Paper

Resolution enhancement technology requirements for 65-nm node

Armen Kroyan, Hua-Yu Liu

Proceedings Volume 5042, (2003) https://doi.org/10.1117/12.485486

KEYWORDS: Photomasks, Resolution enhancement technologies, Nanoimprint lithography, Cadmium, Optical proximity correction, 193nm lithography, Critical dimension metrology, Electroluminescence, Image quality, Lithography

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Proceedings Article | 26 June 2003 Paper

Image-blur tolerances for 65-nm and 45-nm node IC manufacturing

Ivan Lalovic, Armen Kroyan, Jongwook Kye, Hua-Yu Liu, Harry Levinson

Proceedings Volume 5040, (2003) https://doi.org/10.1117/12.485510

KEYWORDS: Semiconducting wafers, Critical dimension metrology, Reticles, Image processing, Lithography, Manufacturing, Tolerancing, Nanoimprint lithography, Image quality, Control systems

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The deployment of 157nm lithography for manufacturing of integrated circuits is faced with many challenges. The 65 and 45nm ITRS nodes, in particular, require that the lithographic imaging technology be pursued to its theoretical limits with full use of the strongest resolution enhancement techniques. Stringent demands are therefore placed on the quality of the imaging optics to attain the optimal image fidelity for all critical IC device structures. Besides aberrations and light scatter in projection optics, image quality is also strongly influenced by the dynamics of the wafer and reticle stage. The tradeoffs involved in increasing scan speeds and exposure slit-widths, to achieve the ever-important productivity improvements as well as aberration, distortion, and pulse-energy averaging, must be carefully gauged against the image quality impacts of scan-induced errors. In this work, we present a simulation methodology, based on incoherent image superposition, for treatment of the general aerial image effects of transverse image-blur in two dimensions. Initial simulations and experimental results from state-of-the-art 193nm scanner exposures are discussed. The requirements for the transverse image stability during a step-and-scan exposure are defined in the context of 193nm and 157nm lithography, based on generalized image contrast and process window criteria. Furthermore, careful consideration of actual mask layout (post resolution enhancement and optical proximity correction) is necessary in order to understand the implications on CD control. Additionally, we discuss the contributors to transverse image blur in scan-and-repeat lithography, and show that the fading requirements for 65nm and 45nm node imaging notably differ from predicted exposure set-up and process contributions in manufacturing. The total fading budget, or tolerance, for the 65nm node is 15nm, and less than 10nm for the 45nm node given the present imaging strategy assumptions. This work concludes that image-blur contributors must be well controlled, and as such are enablers of 65nm and 45nm lithographic imaging.

SPIE Journal Paper | 1 April 2003

Understanding chromatic aberration impacts on lithographic imaging

Kafai Lai, Ivan Lalovic, Robert Fair, Armen Kroyan, Christopher Progler, Nigel Farrar, Dennis Ames, Khurshid Ahmed

JM3, Vol. 2, Issue 02, (April 2003) https://doi.org/10.1117/12.10.1117/1.1562929

KEYWORDS: Chromatic aberrations, Image enhancement, Lithography, Excimer lasers, Image processing, Electroluminescence, Optical simulations, Lithographic illumination, Monochromatic aberrations, Deep ultraviolet

Proceedings Article | 27 December 2002 Paper

Fast full-chip MEEF simulations for mask and wafer metrology

Chi-Ming Tsai, Hua-Yu Liu, Armen Kroyan, Ning-Chuan Shen, Yao-Ting Wang

Proceedings Volume 4889, (2002) https://doi.org/10.1117/12.467851

KEYWORDS: Photomasks, Semiconducting wafers, Metrology, Computer simulations, Critical dimension metrology, Optical proximity correction, Model-based design, Binary data, Databases, Manufacturing

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Proceedings Article | 27 December 2002 Paper

Effects of alternating aperture PSM design on image imbalance for 65-nm technology

Armen Kroyan, Hua-Yu Liu

Proceedings Volume 4889, (2002) https://doi.org/10.1117/12.467852

KEYWORDS: Chromium, Photomasks, Critical dimension metrology, Cadmium, 193nm lithography, Image enhancement, Optical proximity correction, Phase shifts, Light scattering, Panoramic photography

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Proceedings Article | 11 March 2002 Paper

Illumination spectral width impacts on mask error enhancement factor and iso-dense bias in 0.6-NA KrF imaging

Ivan Lalovic, Armen Kroyan, Paolo Zambon, Christopher Silsby, Nigel Farrar

Proceedings Volume 4562, (2002) https://doi.org/10.1117/12.458263

KEYWORDS: Photoresist materials, Photomasks, Lithography, Critical dimension metrology, Semiconducting wafers, Excimer lasers, Manufacturing, Optical proximity correction, Scanning electron microscopy, Reticles

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Proceedings Article | 11 March 2002 Paper

Contribution of polychromatic illumination to optical proximity effects in the context of deep-UV lithography

Armen Kroyan, Ivan Lalovic, Nigel Farrar

Proceedings Volume 4562, (2002) https://doi.org/10.1117/12.458276

KEYWORDS: Optical proximity correction, Lithographic illumination, Lithography, Critical dimension metrology, Excimer lasers, Computer simulations, Chromatic aberrations, Photomasks, Deep ultraviolet, Laser optics

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Proceedings Article | 14 September 2001 Paper

Effects of 95% integral vs. FWHM bandwidth specifications on lithographic imaging

Armen Kroyan, Ivan Lalovic, Nigel Farrar

Proceedings Volume 4346, (2001) https://doi.org/10.1117/12.435661

KEYWORDS: Lithography, Metrology, Critical dimension metrology, Computer simulations, Chromatic aberrations, Lithographic illumination, Projection systems, Signal to noise ratio, Cadmium, Nanoimprint lithography

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Proceedings Article | 14 September 2001 Paper

Investigation of cross-field wavefront aberrations of KrF lithography exposure systems as a function of excimer laser bandwidth

Ivan Lalovic, Armen Kroyan, Nigel Farrar, Dennis Taitano, Paolo Zambon, Adlai Smith

Proceedings Volume 4346, (2001) https://doi.org/10.1117/12.435655

KEYWORDS: Monochromatic aberrations, Photoresist materials, Wavefronts, Lithography, Excimer lasers, Scanners, Diagnostics, Interferometers, Wavefront aberrations, Control systems

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Proceedings Article | 5 July 2000 Paper

Modeling the effects of excimer laser bandwidths on lithographic performance

Armen Kroyan, Joseph Bendik, Olivier Semprez, Nigel Farrar, Christopher Rowan, Chris Mack

Proceedings Volume 4000, (2000) https://doi.org/10.1117/12.389057

KEYWORDS: Chromatic aberrations, Lithography, Excimer lasers, Light sources, Optical simulations, Performance modeling, Deep ultraviolet, Chlorine, Critical dimension metrology, Optical lithography

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Proceedings Article | 26 July 1999 Paper

Effects of subresolution assist features on depth of focus and uniformity of contact windows for 193-nm lithography

Armen Kroyan, Pat Watson, Raymond Cirelli, Omkaram Nalamasu, Frank Tittel

Proceedings Volume 3679, (1999) https://doi.org/10.1117/12.354377

KEYWORDS: SRAF, Lithography, Lithographic illumination, Computer simulations, Optical proximity correction, Tolerancing, Scanning electron microscopy, Critical dimension metrology, Environmental sensing, Photomasks

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Proceedings Article | 26 July 1999 Paper

Depth of focus enhancement for 193-nm window lithography with subresolution assist features

Pat Watson, Armen Kroyan, Raymond Cirelli, H. Maynard, James Sweeney, Fred Klemens, G. Timp, Omkaram Nalamasu

Proceedings Volume 3679, (1999) https://doi.org/10.1117/12.354345

KEYWORDS: Etching, Lithography, Scanning electron microscopy, Oxides, Lithographic illumination, Critical dimension metrology, SRAF, Photoresist processing, Printing, Semiconducting wafers

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Proceedings Article | 26 July 1999 Paper

Coherent multiple imaging by means of pupil plane filtering

Miklos Erdelyi, Armen Kroyan, Karoly Osvay, Zsolt Bor, William Wilson, Michael Smayling, Frank Tittel

Proceedings Volume 3679, (1999) https://doi.org/10.1117/12.354393

KEYWORDS: Fabry–Perot interferometers, Image filtering, Coherence imaging, Optical filters, Photomasks, Resolution enhancement technologies, Spatial coherence, Image enhancement, Phase shifts, Image resolution

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Proceedings Article | 18 December 1998 Paper

Subresolution assist feature tolerences for contact windows using 193-nm lithography

Armen Kroyan, Pat Watson, Raymond Cirelli, Omkaram Nalamasu, Anthony Novembre, Frank Tittel

Proceedings Volume 3546, (1998) https://doi.org/10.1117/12.332873

KEYWORDS: SRAF, Lithography, Photoresist processing, Optical proximity correction, Critical dimension metrology, Scanning electron microscopy, Image processing, Lithographic illumination, Tolerancing, Reticles

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Combining assist features with appropriate off-axis illumination conditions can significantly improve depth of focus and uniformity of critical dimensions of contact windows. It is known that sub-resolution assist features modify the environment of isolated features in a fashion that they appear dense. In recent years the impact of assist features was mostly studied for gate-level lithography. In this paper the placement and dimension control of assist features for contact windows are examined and analyzed using 193 nm lithography in conjunction with a state-of-the-art single layer resist. Our study is primarily done for 160 nm contact windows, and it is based on experimental data obtained from critical dimension measurements with varying focus, exposure dose, and in different environments. Along with optical proximity corrections we use off-axis illumination technique which increases depth of focus of contact windows and improves the overall process latitude. Specifically for this study we have designed a test photomask with different geometries and pattern densities of contact windows with and without assist features to be used at 193 nm wavelength. To study the proximity effects, different sizes of assist features were used as well as the distances of assists from the main feature were varied. The results have shown that while increasing the process latitude for the primary feature using assist slots in combination with off-axis illumination, the resist thickness and contrast are limiting the assist feature dimensions that can be used. Assist features appear to significantly increase critical dimension uniformity of the contact windows when using both conventional and off-axis illumination techniques, and they dramatically increase the common exposure dose latitude for contact windows with densities from near-isolated to dense, decreasing the proximity effects. Assist feature technique combined with quadrupole illumination demonstrates about 0.3 micron improvement in depth of focus for every type contact window pattern used.

Proceedings Article | 29 June 1998 Paper

Present and future trends in excimer-laser-based microlithography

Frank Tittel, Miklos Erdelyi, Zoltan Horvath, Armen Kroyan, William Wilson, Michael Smayling, Zsolt Bor, Gabor Szabo

Proceedings Volume 3403, (1998) https://doi.org/10.1117/12.311947

KEYWORDS: Fabry–Perot interferometers, Objectives, Optical lithography, Wafer-level optics, Excimer lasers, Resolution enhancement technologies, Semiconducting wafers, Integrated optics, Microscopes, Mirrors

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Proceedings Article | 29 June 1998 Paper

Coping with the impact of lens aberrations in the context of wavefront engineering

Armen Kroyan, David Levenson, Frank Tittel

Proceedings Volume 3334, (1998) https://doi.org/10.1117/12.310817

KEYWORDS: Optical proximity correction, Critical dimension metrology, Photomasks, Diffractive optical elements, Projection systems, Zernike polynomials, Wavefronts, Coherence (optics), Phase shifts, Binary data

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Showing 5 of 19 publications

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