Dr. Mohamed Al-Imam Profile

Dr. Mohamed Al-Imam

Engineer at Siemens EDA

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Author

Publications (22)

Proceedings Article | 16 March 2016 Paper

A random approach of test macro generation for early detection of hotspots

Jong-hyun Lee, Chin Kim, Minsoo Kang, Sungwook Hwang, Jae-seok Yang, Mohammed Harb, Mohamed Al-Imam, Kareem Madkour, Wael ElManhawy, Joe Kwan

Proceedings Volume 9781, 97810J (2016) https://doi.org/10.1117/12.2218806

KEYWORDS: Defect detection, New and emerging technologies, Process modeling, Design for manufacturing, Silicon, Design for manufacturability, Particles, Visualization, Lithography

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Proceedings Article | 15 March 2012 Paper

Thickness-aware LFD for the hotspot detection induced by topology

Jae-Hyun Kang, Naya Ha, Joo-Hyun Park, Byung-Moo Kim, Seung Weon Paek, Hungbok Choi, Kee Sup Kim, Ahmed Mohy, Shady Abdelwahed, Mohamed Imam

Proceedings Volume 8327, 83270P (2012) https://doi.org/10.1117/12.917998

KEYWORDS: Semiconducting wafers, Metals, Process modeling, Image processing, Design for manufacturing, Chemical mechanical planarization, Optical proximity correction, 3D modeling, Photovoltaics, Scanning electron microscopy

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Proceedings Article | 14 October 2011 Paper

Dynamic feedback controller for optical proximity correction

Ahmed Omran, Jochen Schacht, Jully Pan, Junjiang Lei, Le Hong, Mohamed Al-Imam, Nick Cobb, Regina Shen, Ryan Chou

Proceedings Volume 8166, 81663I (2011) https://doi.org/10.1117/12.896677

KEYWORDS: Optical proximity correction, Feedback control, Photomasks, Logic, Visualization, Semiconducting wafers, Diffraction, Lithography, Detection and tracking algorithms, Critical dimension metrology

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Proceedings Article | 4 March 2010 Paper

Automation of sample plan creation for process model calibration

James Oberschmidt, Amr Abdo, Tamer Desouky, Mohamed Al-Imam, Azalia Krasnoperova, Ramya Viswanathan

Proceedings Volume 7640, 76401G (2010) https://doi.org/10.1117/12.846276

KEYWORDS: Calibration, Process modeling, Statistical modeling, Data modeling, Photoresist processing, Lithography, Computer simulations, Image processing, Metrology, Optical proximity correction

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Proceedings Article | 16 March 2009 Paper

Design driven test patterns for OPC models calibration

Mohamed Al-Imam

Proceedings Volume 7274, 727427 (2009) https://doi.org/10.1117/12.813975

KEYWORDS: Calibration, Optical proximity correction, Process modeling, Databases, Data modeling, Geometrical optics, Resolution enhancement technologies, Silicon, Lithography, Photomasks

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Proceedings Article | 13 March 2009 Paper

Implementing a framework to generate a unified OPC database from different EDA vendors for 45nm and beyond

Shady Abdelwahed, Mohamed Al-Iman, Rami Fathy, Nader Hindawy, Jochen Schacht, Regina Shen, Chia Wei Huang, Pei Ru Tsai, Te Hung Wu, Chuen Huei Yang

Proceedings Volume 7275, 72751O (2009) https://doi.org/10.1117/12.816281

KEYWORDS: Optical proximity correction, Electronic design automation, Photomasks, Semiconducting wafers, Data modeling, SRAF, Visualization, Wafer-level optics, Databases, Lithography

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Proceedings Article | 17 October 2008 Paper

Toward faster OPC convergence: advanced analysis for OPC iterations and simulation environment

Mohamed Bahnas, Mohamed Al-Imam, Tamer Tawfik

Proceedings Volume 7122, 712248 (2008) https://doi.org/10.1117/12.801878

KEYWORDS: Optical proximity correction, Photomasks, Optical simulations, Semiconducting wafers, Computer simulations, Silicon, SRAF, Signal attenuation, Manufacturing, Image processing

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Proceedings Article | 7 March 2008 Paper

OPC model calibration considerations for data variance

Mohamed Bahnas, Mohamed Al-Imam

Proceedings Volume 6924, 69243U (2008) https://doi.org/10.1117/12.776896

KEYWORDS: Data modeling, Calibration, Process modeling, Systems modeling, Optical proximity correction, Semiconducting wafers, Statistical modeling, Computer simulations, Mathematical modeling, Image processing

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OPC models have been improving their accuracy over the years by modeling more error sources in the lithographic systems, but model calibration techniques are improving at a slower pace. One area of modeling calibration that has garnered little interest is the statistical variance of the calibration data set. OPC models are very susceptible to parameter divergence with statistical variance, but modest caution is given to the data variance once the calibration sequence has started. Not only should the calibration data be a good representation of the design intent, but measure redundancy is required to take into consideration the process and metrology variance. Considering it takes five to nine redundant measurements to generate a good statistical distribution for averaging and it takes tens of thousands of measurements to mimic the design intent, the data volume requirements become overwhelming. Typically, the data redundancy is reduced due to this data explosion, so some level of variance will creep into the model-tuning process. This is a feasibility study for treatment of data variance during model calibration. This approach was developed to improve the model fitness for primary out-of-specification features present in the calibration test pattern by performing small manipulations of the measured data combined with data weighting during the model calibration process. This data manipulation is executed in image-parameter groups (Imin, Imax, slope and curvature) to control model convergence. These critical-CD perturbations are typically fractions of nanometers, which is consistent with the residual variance of the statically valid data set. With this datamanipulation approach the critical features are pulled into specification without diverging other feature types. This paper will detail this model calibration technique and the use of imaging parameters and weights to converge the model for key feature types. It will also demonstrate its effectiveness on realistic applications.

Proceedings Article | 1 November 2007 Paper

Automatic OPC repair flow: optimized implementation of the repair recipe

Mohamed Bahnas, Mohamed Al-Imam, James Word

Proceedings Volume 6730, 67303S (2007) https://doi.org/10.1117/12.746950

KEYWORDS: Optical proximity correction, Neodymium, Photomasks, Printing, Resolution enhancement technologies, Manufacturing, Semiconducting wafers, Lithography, Feedback loops, Visualization

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Virtual manufacturing that is enabled by rapid, accurate, full-chip simulation is a main pillar in achieving successful mask tape-out in the cutting-edge low-k1 lithography. It facilitates detecting printing failures before a costly and time-consuming mask tape-out and wafer print occur. The OPC verification step role is critical at the early production phases of a new process development, since various layout patterns will be suspected that they might to fail or cause performance degradation, and in turn need to be accurately flagged to be fed back to the OPC Engineer for further learning and enhancing in the OPC recipe. At the advanced phases of the process development, there is much less probability of detecting failures but still the OPC Verification step act as the last-line-of-defense for the whole RET implemented work. In recent publication the optimum approach of responding to these detected failures was addressed, and a solution was proposed to repair these defects in an automated methodology and fully integrated and compatible with the main RET/OPC flow. In this paper the authors will present further work and optimizations of this Repair flow. An automated analysis methodology for root causes of the defects and classification of them to cover all possible causes will be discussed. This automated analysis approach will include all the learning experience of the previously highlighted causes and include any new discoveries. Next, according to the automated pre-classification of the defects, application of the appropriate approach of OPC repair (i.e. OPC knob) on each classified defect location can be easily selected, instead of applying all approaches on all locations. This will help in cutting down the runtime of the OPC repair processing and reduce the needed number of iterations to reach the status of zero defects. An output report for existing causes of defects and how the tool handled them will be generated. The report will with help further learning and facilitate the enhancement of the main OPC recipe. Accordingly, the main OPC recipe can be more robust, converging faster and probably in a fewer number of iterations. This knowledge feedback loop is one of the fruitful benefits of the Automatic OPC Repair flow.

Proceedings Article | 31 October 2007 Paper

Safe interpolation distance for VT5 resist model

Walid Tawfic, Mohamed Al-Imam, George Bailey

Proceedings Volume 6730, 673054 (2007) https://doi.org/10.1117/12.746613

KEYWORDS: Process modeling, Data modeling, Calibration, Image processing, Optical proximity correction, Lithography, Semiconducting wafers, Geometrical optics, Printing, Integrated circuits

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Proceedings Article | 30 October 2007 Paper

Optimization of OPC runtime using efficient optical simulation

Mohamed Al-Imam, Walid Tawfic

Proceedings Volume 6730, 67302T (2007) https://doi.org/10.1117/12.746608

KEYWORDS: Computer simulations, Optical simulations, Optical proximity correction, Resolution enhancement technologies, Printing, Photomasks, Semiconducting wafers, Control systems, Visualization, Model-based design

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Proceedings Article | 28 March 2007 Paper

Feedback flow to improve model-based OPC calibration test patterns

Walid Tawfic, Mohamed Al-Imam, Karim Madkour, Rami Fathy, Ir Kusnadi, George Bailey

Proceedings Volume 6521, 65211J (2007) https://doi.org/10.1117/12.712843

KEYWORDS: Calibration, Data modeling, Image processing, Process modeling, Scanning electron microscopy, Optical proximity correction, Photoresist processing, Feature extraction, Optical lithography, Printing

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Proceedings Article | 26 March 2007 Paper

SEM based data extraction for model calibration

Mohamed Al-Imam, H. Y. Liao, Jochen Schacht, George Bailey, Te Hung Wu, Chia Wei Huang, Sheng Yuan Huang, Pei Ru Tsai, Chuen Huei Yang

Proceedings Volume 6520, 65203B (2007) https://doi.org/10.1117/12.707353

KEYWORDS: Data modeling, Scanning electron microscopy, Calibration, Process modeling, Image processing, Optical proximity correction, Semiconducting wafers, Metrology, Resolution enhancement technologies, Feature extraction

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The model calibration process, in a resolution enhancement technique (RET) flow, is one of the most critical steps towards building an accurate OPC recipe. RET simulation platforms use models for predicting latent images in the wafer due to exposure of different design layouts. Accurate models can precisely capture the proximity effects for the lithographic process and help RET engineers build the proper recipes to obtain high yield. To calibrate OPC models, test geometries are created and exposed through the lithography environment that we want to model, and metrology data are collected for these geometries. This data is then used to tune or calibrate the model parameters. Metrology tools usually provide critical dimension (CD) data and not edge placement error (EPE - the displacement between the polygon and resist edge) data however model calibration requires EPE data for simulation. To work around this problem, only symmetrical geometries are used since, having this constraint, EPE can be easily extracted from CD measurements. In real designs, it is more likely to encounter asymmetrical structures as well as complex 2D structures that cannot easily be made symmetrical, especially when we talk about technology nodes for 65nm and beyond. The absence of 2D and asymmetric test structures in the calibration process would require models to interpolate or extrapolate the EPE's for these structures in a real design. In this paper we present an approach to extract the EPE information from both SEM images and contours extracted by the metrology tools for structures on test wafers, and directly use them in the calibration of a 55nm poly process. These new EPE structures would now mimic the complexity of real 2D designs. Each of these structures can be individually weighed according to the data variance. Model accuracy is then compared to the conventional method of calibration using symmetrical data only. The paper also illustrates the ability of the new flow to extract more accurate measurement out of wafer data that are more immune to errors compared to the conventional method.

Proceedings Article | 21 March 2007 Paper

Litho aware method for circuit timing/power analysis through process

R. Fathy, M. Al-Imam, H. Diab, M. Fakhry, J. A. Torres, B. Graupp, J. M. Brunet, M. Bahnas

Proceedings Volume 6521, 65210O (2007) https://doi.org/10.1117/12.711723

KEYWORDS: Lithography, Oscillators, Semiconducting wafers, Transistors, Visualization, Design for manufacturing, Integrated circuit design, Silicon, Process modeling, Etching

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Proceedings Article | 21 March 2007 Paper

A systematic approach for capturing interconnects hot spots

Mohamed Al-Imam, H. Y. Liao, Jochen Schacht, Te Hung Wu, Chia Wei Huang, Shen Yuan Huang, Pei Ru Tsai, Chuen Huei Yang

Proceedings Volume 6521, 65211C (2007) https://doi.org/10.1117/12.713521

KEYWORDS: Semiconducting wafers, Photomasks, Image processing, Overlay metrology, Integrated circuits, Lithography, Resistance, Classification systems, Integrated circuit design, Transistors

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Proceedings Article | 21 March 2007 Paper

Real-time VT5 model coverage calculations during OPC simulations

Ioana Graur, Scott Mansfield, Moahmed Gheith, Mohamed Al-Imam

Proceedings Volume 6521, 65211R (2007) https://doi.org/10.1117/12.712394

KEYWORDS: Data modeling, Calibration, Optical proximity correction, Computer simulations, Semiconducting wafers, Quantization, Process modeling, Mathematical modeling, Scanning electron microscopy, Image processing

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Proceedings Article | 20 October 2006 Paper

Optimization of process window simulations for litho-friendly design framework

Mohamed Al-Imam, Andres Torres, Jean-Marie Brunet, Moutaz Fakhry, Rami Fathy

Proceedings Volume 6349, 63491C (2006) https://doi.org/10.1117/12.686313

KEYWORDS: Lithography, Image processing, Standards development, Photovoltaics, Capacitors, Visualization, Manufacturing, Silicon, Semiconducting wafers, Design for manufacturing

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Proceedings Article | 20 October 2006 Paper

Present challenges and solutions in sampling and correction for 45 nm

Ioana Graur, Mohamed Al-Imam, Pat LaCour

Proceedings Volume 6349, 63491Y (2006) https://doi.org/10.1117/12.691647

KEYWORDS: Optical proximity correction, Tolerancing, Photovoltaics, Printing, Resolution enhancement technologies, Computer simulations, Visualization, Photomasks, Manufacturing, Detection and tracking algorithms

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Proceedings Article | 20 March 2006 Paper

Process window OPC for reduced process variability and enhanced yield

Azalia Krasnoperova, James Culp, Ioana Graur, Scott Mansfield, Mohamed Al-Imam, Hesham Maaty

Proceedings Volume 6154, 61543L (2006) https://doi.org/10.1117/12.656835

KEYWORDS: Optical proximity correction, Process modeling, Lithography, Critical dimension metrology, Detection and tracking algorithms, Metals, Manufacturing, Resolution enhancement technologies, Photomasks, Yield improvement

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Proceedings Article | 17 March 2006 Paper

Implementation of adaptive site optimization in model-based OPC for minimizing ripples

M. Bahnas, M. Al-Imam, A. Seoud, P. LaCour, H. Ragai

Proceedings Volume 6156, 615615 (2006) https://doi.org/10.1117/12.660180

KEYWORDS: Optical proximity correction, Model-based design, Critical dimension metrology, Photomasks, Optimization (mathematics), Lithographic illumination, Lithography, Image processing, Printing, Visualization

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The OPC treatment of aerial mage ripples (local variations in aerial contour relative to constant target edges) is one of the growing issues with very low-k1 lithography employing hard off-axis illumination. The maxima and minima points in the aerial image, if not optimally treated within the existing model based OPC methodologies, could induce severe necking or bridging in the printed layout. The current fragmentation schemes and the subsequent site simulations are rule-based, and hence not optimized according to the aerial image profile at key points. The authors are primarily exploring more automated software methods to detect the location of the ripple peaks as well as implementing a simplified implementation strategy that is less costly. We define this to be an adaptive site placement methodology based on aerial image ripples. Recently, the phenomenon of aerial image ripples was considered within the analysis of the lithography process for cutting-edge technologies such as chromeless phase shifting masks and strong off-axis illumination approaches [3,4]. Effort is spent during the process development of conventional model-based OPC with the mere goal of locating these troublesome points. This process leads to longer development cycles and so far only partial success was reported in suppressing them (the causality of ripple occurrence has not yet fully been explored). We present here our success in the implementation of a more flexible model-based OPC solution that will dynamically locate these ripples based on the local aerial image profile nearby the features edges. This model-based dynamic tracking of ripples will cut down some time in the OPC code development phase and avoid specifying some rule-based recipes. Our implementation will include classification of the ripples bumps within one edge and the allocation of different weights in the OPC solution. This results in a new strategy of adapting site locations and OPC shifts of edge fragments to avoid any aggressive correction that may lead to increasing the ripples or propagating them to a new location. More advanced adaptation will be the ripples-aware fragmentation as a second control knob, beside the automated site placement.

Proceedings Article | 14 March 2006 Paper

Through-process modeling in a DfM environment

Scott Mansfield, Geng Han, Mohamed Al-Imam, Rami Fathy

Proceedings Volume 6156, 615603 (2006) https://doi.org/10.1117/12.658049

KEYWORDS: Optical proximity correction, Design for manufacturing, Process modeling, Data modeling, Image processing, Photomasks, Calibration, Photoresist materials, Lithography, Model-based design

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Proceedings Article | 5 November 2005 Paper

Tolerable CD variation analyzer using perturbed nominal models demonstrated on altPSM

Ioana Graur, James Culp, James Bruce, Mohamed Al-Imam, Mohamed Bahnas

Proceedings Volume 5992, 59920H (2005) https://doi.org/10.1117/12.633417

KEYWORDS: Photomasks, Tolerancing, Printing, Semiconducting wafers, Image processing, Lithography, Resolution enhancement technologies, Critical dimension metrology, Process modeling, Modulation

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Showing 5 of 22 publications

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