Mr. Peter Buck Profile

Peter Buck

Retired at Siemens EDA

SPIE Involvement:

Track Chair | Author | Editor

Area of Expertise:

Photomasks , OPC , Lithography Simulation

Websites:

Company Website

Publications (85)

Proceedings Article | 1 November 2022 Paper

Curvilinear mask process correction: status quo and outlook

Ingo Bork, Peter Buck, Kushlendra Mishra, Rachit Sharma, Mary Zuo

Proceedings Volume 12472, 124720S (2022) https://doi.org/10.1117/12.2640001

KEYWORDS: Photomasks, Calibration, SRAF, Manufacturing, Optical proximity correction, Scanning electron microscopy, Process modeling, Scattering

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Proceedings Article | 16 September 2022 Paper

Status of curvilinear data format working group

Jin Choi, Soo Ryu, Sukho Lee, Minah Kim, Sanghee Lee, Peter Buck, Bhardwaj Durvasula, Sayalee Gharat, Vlad Liubich

Proceedings Volume 12325, 1232508 (2022) https://doi.org/10.1117/12.2641557

KEYWORDS: Photomasks, Optical proximity correction, Extreme ultraviolet, Optical lithography, Mask making

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SPIE Journal Paper | 1 November 2021 Open Access

Study on various curvilinear data representations and their impact on mask and wafer manufacturing

Jin Choi, Soo Ryu, Sukho Lee, Minah Kim, JoonSoo Park, Peter Buck, Ingo Bork, Bhardwaj Durvasula, Sayalee Gharat, Nageswara Rao, Ravi Pai, Sandeep Koranne, Alexander Tritchkov

JM3, Vol. 20, Issue 04, 041403, (November 2021) https://doi.org/10.1117/12.10.1117/1.JMM.20.4.041403

KEYWORDS: Photomasks, Tolerancing, Optical proximity correction, Semiconducting wafers, Manufacturing, Extreme ultraviolet, Vestigial sideband modulation, Extreme ultraviolet lithography, Scanning electron microscopy, Lithography

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Proceedings Article | 22 October 2021 Presentation + Paper

Curvature based fragmentation for curvilinear mask process correction

Ingo Bork, Peter Buck, Bhardwaj Durvasula, Vlad Liubich, Nageswara Rao, Rachit Sharma, Mary Zuo

Proceedings Volume 11855, 118550R (2021) https://doi.org/10.1117/12.2601032

KEYWORDS: Photomasks, SRAF, Optical proximity correction, Semiconducting wafers, Solids, Image segmentation, Data corrections, Data processing, Tolerancing, Lithography

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Proceedings Article | 12 October 2021 Presentation + Paper

Sensitivity analysis based SEM measurement down-sampling approach for mask process modeling applications

Kushlendra Mishra, Rachit Sharma, Ingo Bork, Peter Buck, Dongeun Cha, Seungheon Na, Jaekwang Kim, Kiwook Park, Inpyo Kim

Proceedings Volume 11855, 118550Z (2021) https://doi.org/10.1117/12.2600926

KEYWORDS: Data modeling, Calibration, Photomasks, Process modeling, Statistical modeling, Scanning electron microscopy, Metrology, Critical dimension metrology, Error analysis

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Proceedings Article | 12 October 2021 Presentation + Paper

Using curvature-based pre-bias to reduce number of iterations in curvilinear mask process correction

Zhiheng (Mary) Zuo, Malavika Sharma, Ingo Bork, Bhardwaj Durvasula, Peter Buck

Proceedings Volume 11855, 118550Q (2021) https://doi.org/10.1117/12.2600959

KEYWORDS: Computational lithography, Photomasks, Optical proximity correction, Process modeling, Model-based design, Manufacturing

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Proceedings Article | 22 February 2021 Presentation + Paper

A study on various curvilinear data representations and their impact on mask manufacturing flow

Sayalee Gharat, Bhardwaj Durvasula, Ravi Pai, Peter Buck, Sandeep Koranne, Alexander Tritchkov

Proceedings Volume 11613, 116130B (2021) https://doi.org/10.1117/12.2588374

KEYWORDS: Photomasks, Manufacturing, Semiconducting wafers, Mask making, Optics manufacturing, Extreme ultraviolet lithography, EUV optics

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Proceedings Article | 22 February 2021 Presentation + Paper

Curvilinear data format working group for MBMW era

Jin Choi, Soo Ryu, Sukho Lee, Minah Kim, JoonSoo Park, Buck Peter, Ingo Bork, Bhardwaj Durvasula, Sayalee Gharat, Nageswara Rao

Proceedings Volume 11610, 116100S (2021) https://doi.org/10.1117/12.2587109

KEYWORDS: Optical proximity correction, Mask making, Electronic design automation

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Proceedings Article | 13 October 2020 Presentation + Paper

Automatic classification of patterned mask defects for requalification at wafer fabs in absence of layout data

Samir Bhamidipati, Prakash Deep, Mark Pereira, Sankaranarayanan Paninjath, Peter Buck, Keitaro Katabuchi, Takenori Kato, Frank Wu, Chin Kuei Chang, Chain Ping Chen

Proceedings Volume 11518, 115180K (2020) https://doi.org/10.1117/12.2573122

KEYWORDS: Photomasks, Semiconducting wafers, Inspection, Image classification, Wafer inspection, Contamination, Air contamination, Image processing, Printing, Yield improvement

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Patterned masks require requalification at wafer fabrication plants. Periodic inspections are done at the wafer fab to identify any new defects, such as haze and contamination, which develop or get added on the mask due to their usage and the way they are handled. These defects, if not monitored over time, may result in mask defects that print on the wafer. It is thus mandatory to identify and fix them in their early stages. Repeated inspections, coupled with higher sensitivity inspections employed at wafer fabs, result in a large number of defects reported, which includes many small and faint defects. However, some of these small and faint defects need detailed operator review time, due to their potential to grow and have a larger impact later. Efficiency of classification includes both speed and accuracy. For a manual review, accuracy is primarily affected by consistency, arising due to the bulk and monotonous nature of classification task affected by human fatigue. The requirement for higher accuracy however, necessitates increased operator review and analysis time. Increased operator review time translates to the amount of time a mask in not used for printing wafers, i.e. productivity loss. Calibre® DefectClassify™ tool enables automatic classification of defects by employing stable algorithms to ensure consistency and accuracy, while algorithm efficiency ensures adequate speed. The tool thus aids in improving the throughput and yield at wafer fabs. The tool reads defect images, analyzes image properties to extract potential defect regions, processes the regions to identify actual defects and classifies them. This paper mainly focuses on the challenges faced in characterization and classification of defects from images reported by the inspection machine. The primary difference between analyzing inspections at wafer fab and mask shop is the availability of layout data. Unavailability of layout data complicates the tasks of identifying different pattern regions on the mask, especially assist features. With advanced technology nodes, the number of assist features present is higher while the features themselves get smaller in size. These features, if not identified correctly, may be mistaken as defects. Other than that, single die defects are a category that gets affected due to lack of layout information. Without a reference to compare with, these defects require separate sets of rules to be applied to images for their identification and classification. In particular, identification of defects on pattern edges and corners from single die images is challenging without a reference image.

Proceedings Article | 16 October 2019 Presentation + Paper

Creating nonideality: enabling cross-platform process matching solutions with MPC (and a lot of hard work)

Charles Whiting, Ingo Bork, Peter Buck, Robin Chia, Bharadwaj Durvasula, Daniel Hill, Gazi Huda, Ken Jantzen, Matthew Leuthold, Jianliang Li, Joerg Mellmann, Kushlendra Mishra, Jed Rankin, Nageswara Rao, Malavika Sharma, Rachit Sharma, Adam Smith, Michaela Wentz

Proceedings Volume 11148, 1114805 (2019) https://doi.org/10.1117/12.2538347

KEYWORDS: Photomasks, Data modeling, Optical proximity correction, Critical dimension metrology, Calibration, Lithography, Semiconducting wafers, Manufacturing, Opacity, Etching

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Proceedings Article | 3 October 2019 Paper

Machine learning guided curvilinear MPC

Malavika Sharma, Bhardwaj Durvasula, Nageswara Rao, Ingo Bork, Rachit Sharma, Kushlendra Mishra, Peter Buck

Proceedings Volume 11148, 111480Q (2019) https://doi.org/10.1117/12.2538646

KEYWORDS: Photomasks, Machine learning, Optical proximity correction, Computational lithography, Data modeling, Lithography, Neural networks, Waveguides, Vestigial sideband modulation, Data processing

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Proceedings Article | 26 September 2019 Paper

Resist-slope aware modeling for mask process correction applications

Rachit Sharma, Ingo Bork, Kushlendra Mishra, ShiZhi Lyu, Linna Cong, Mingjing Tian, Malavika Sharma, Bhardwaj Durvasula, Nageswara Rao, Peter Buck

Proceedings Volume 11148, 111480G (2019) https://doi.org/10.1117/12.2536529

KEYWORDS: Process modeling, Photomasks, Etching, Critical dimension metrology, Calibration, Semiconductor manufacturing, Control systems, Model-based design, Scattering, Photoresist processing

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Proceedings Article | 29 August 2019 Paper

MPC strategies for multi-beam mask writers

Ingo Bork, Peter Buck

Proceedings Volume 11177, 1117707 (2019) https://doi.org/10.1117/12.2535375

KEYWORDS: Electron beam lithography, Mask making, Photomasks

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The benefit of complex and curvilinear mask shapes as well as the demand for fast mask production cycles has been driving the development of Multi-Beam Mask Writers (MBMW) for several years. Meanwhile, those writers have reached a quality level where they can be integrated into mask production flows at various nodes and even be used for writing imprint lithography templates at wafer scale. 50 keV e-beam writers whether Multi-Beam or Variable Shaped Beam (VSB), are affected by scattering effects at various length scales and require significant corrections in order to print mask features on target. Correction methods for long-range effects such as PEC (Proximity Effect Correction) and FEC (Fogging Effect Correction) have been developed for VSB machines and can be applied to MBMWs in the same way. Similarly, long-range mask process effects like loading (LEC) can be corrected using the same methods as developed for VSB machines. Besides long-range scattering and etch effects, critical masks for the 14 nm technology node and below are affected by short-range scattering and etch effects like e-beam forward scattering and etch micro-loading. Those effects increase at length scales below several 100 nm and change printed CDs significantly at minimum feature sizes on DUV and EUV masks where SRAFs are targeted around 60 nm and 30 nm, respectively. Figure 1 (left) shows an example of a typical mask CD error signature where the range of CD errors from small, isolated features to large nested features can easily cover 15 nm or more. Those short range distortions are generally corrected using so called Mask-Process-Correction (MPC) tools which compensate mask errors by moving edges of the input design and optionally adjust the dose of printed features locally. Simulated mask contours before and after MPC are shown in Figure 1 (center, right) demonstrating the large effect of MPC on SRAFs but also the non-negligible effect on main feature CDs, especially on line-ends and narrow lines.

Proceedings Article | 12 November 2018 Presentation + Paper

Mask process correction validation for multi-beam mask lithography

Ingo Bork, Peter Buck, Christian Bürgel, Bhardwaj Durvasula, Stefan Eder-Kapl, Peter Hudek, Michal Jurkovic, Jan Klikovits, Elmar Platzgummer, Jed Rankin, Rao Nageswara, Murali Reddy, Christoph Spengler

Proceedings Volume 10810, 108100K (2018) https://doi.org/10.1117/12.2503284

KEYWORDS: Photomasks, SRAF, Calibration, Cadmium, Lithography, Double patterning technology, Data modeling, Etching, Vestigial sideband modulation, Scanning electron microscopy

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Proceedings Article | 3 October 2018 Presentation + Paper

Advanced jog handling techniques in MPC for better QoR

Bhardwaj Durvasula, Ingo Bork, Peter Buck, Archana Rajagopalan, Nageswara Rao, Murali Reddy, Steffen Schulze

Proceedings Volume 10810, 108100M (2018) https://doi.org/10.1117/12.2503550

KEYWORDS: Optical proximity correction, Metals, Error analysis, Vestigial sideband modulation, Visualization, Data corrections, Beam shaping, Process modeling, Image quality, Computer simulations

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Proceedings Article | 3 October 2018 Presentation + Paper

Extending mask data preparation to scale to thousands of CPUs and beyond

Archana Rajagopalan, Amanda Bowhill, Peter Buck, Bhardwaj Durvasula, Pascal Gilgenkrantz, Stephen Kim, Minyoung Park, Nageswara Rao, Steffen Schulze

Proceedings Volume 10810, 108100L (2018) https://doi.org/10.1117/12.2503551

KEYWORDS: Distributed computing, Data processing, Data storage servers, Data communications, Computing systems, Optical proximity correction

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Proceedings Article | 31 October 2017 Presentation + Paper

CLMPC: curvilinear MPC in a mask data preparation flow

Ingo Bork, Murali Reddy, Bhardwaj Durvasula, Nageswara Rao, Malavika Sharma, Peter Buck

Proceedings Volume 10451, 1045109 (2017) https://doi.org/10.1117/12.2282502

KEYWORDS: Photomasks, Optical proximity correction, Model-based design, Semiconducting wafers, Data modeling, Lithography, Calibration, Electron beam lithography, Mask making

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Proceedings Article | 16 October 2017 Paper

Mask process correction method comparison and study: CD-SEM box versus standard correction method

Mingjing Tian, Shizhi Lyu, Eric Guo, Ingo Bork, Peter Buck, Yifan Li, Delin Mo, Cong Lu, Kushlendra Mishra, Anil Parchuri

Proceedings Volume 10451, 104511T (2017) https://doi.org/10.1117/12.2280280

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Proceedings Article | 28 September 2017 Paper

The role of model-based MPC in advanced mask manufacturing

Ingo Bork, Peter Buck

Proceedings Volume 10446, 104460B (2017) https://doi.org/10.1117/12.2281894

KEYWORDS: Photomasks, Optical proximity correction, Manufacturing, Model-based design, Extreme ultraviolet, SRAF, Lithography, Calibration, Optical calibration

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Proceedings Article | 25 October 2016 Paper

Software-based data path for raster-scanned multi-beam mask lithography

Archana Rajagopalan, Ankita Agarwal, Peter Buck, Paul Geller, H. Christopher Hamaker, Nagswara Rao

Proceedings Volume 9985, 998519 (2016) https://doi.org/10.1117/12.2243035

KEYWORDS: Photomasks, Lithography, Electronic design automation, Computing systems, Data processing, Printing, Data conversion, Raster graphics, Germanium, Distributed computing

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According to the 2013 SEMATECH Mask Industry Survey,i roughly half of all photomasks are produced using laser mask pattern generator (“LMPG”) lithography. LMPG lithography can be used for all layers at mature technology nodes, and for many non-critical and semi-critical masks at advanced nodes. The extensive use of multi-patterning at the 14-nm node significantly increases the number of critical mask layers, and the transition in wafer lithography from positive tone resist to negative tone resist at the 14-nm design node enables the switch from advanced binary masks back to attenuated phase shifting masks that require second level writes to remove unwanted chrome. LMPG lithography is typically used for second level writes due to its high productivity, absence of charging effects, and versatile non-actinic alignment capability. As multi-patterning use expands from double to triple patterning and beyond, the number of LMPG second level writes increases correspondingly. The desire to reserve the limited capacity of advanced electron beam writers for use when essential is another factor driving the demand for LMPG capacity. The increasing demand for cost-effective productivity has kept most of the laser mask writers ever manufactured running in production, sometimes long past their projected lifespan, and new writers continue to be built based on hardware developed some years ago.ii The data path is a case in point. While state-ofthe- art when first introduced, hardware-based data path systems are difficult to modify or add new features to meet the changing requirements of the market. As data volumes increase, design styles change, and new uses are found for laser writers, it is useful to consider a replacement for this critical subsystem. The availability of low-cost, high-performance, distributed computer systems combined with highly scalable EDA software lends itself well to creating an advanced data path system. EDA software, in routine production today, scales well to hundreds or even thousands of CPU-cores, offering the potential for virtually unlimited capacity. Features available in EDA software such as sizing, scaling, tone reversal, OPC, MPC, rasterization, and others are easily adapted to the requirements of a data path system. This paper presents the motivation, requirements, design and performance of an advanced, scalable software data path system suitable to support multi-beam laser mask lithography.

Proceedings Article | 20 October 2016 Paper

Enhancing EUV mask blanks usability through smart shift and blank-design pairing optimization

Rakesh Kumar Soni, Sankaranarayanan Paninjath, Mark Pereira, Peter Buck, Peter Thwaite

Proceedings Volume 10032, 100320G (2016) https://doi.org/10.1117/12.2250106

KEYWORDS: Photomasks, Extreme ultraviolet, Extreme ultraviolet lithography, Manufacturing, SRAF, Databases, Inspection, Visualization, Defect inspection, Fabrication

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EUV Defect avoidance techniques will play a vital role in extreme ultraviolet lithography (EUVL) photomask fabrication with the anticipation that defect free mask blanks won’t be available and that cost effective techniques will not be available for defect repairing. In addition, mask shops may not have a large inventory of expensive EUV mask blanks. Given these facts, defect avoidance can be used as cost effective technique to optimize the mask blank and design data (mask data) pair selection across mask blank manufacturers and mask shops so that overall mask blank utilization can be enhanced.

In previous work, it was determined that the pattern shift based solution increases the chance that a defective mask blank can be used that would otherwise be discarded [1]. In pattern shift, design data is shifted such that defects are either moved to isolated regions or hidden under the patterns that are written. However pattern shifts techniques don’t perform well with masks with higher defect counts. Pattern shift techniques in this form assume all defects to be equally critical. In addition, a defect is critical or important only if it lands on the main pattern. A defect landing on fill, sub-resolution assist feature (SRAF) or fiducial areas may not be critical. In this paper we assess the performance of pattern shift techniques assuming defects that are not critical based upon size or type, as well as defects landing in non-critical areas (smart shift) can be ignored.

In a production mask manufacturing environment it is necessary to co-optimize and prioritize blank-design pairing for multiple mask layouts in the queue with the available blanks. A blank-design pairing tool maximizes the utilization of blanks by finding the best pairing between blanks and design data so that the maximum number of mask blanks can be used. In this paper we also propose a novel process which would optimize the usage of costly EUV mask blanks across mask blank manufacturers and mask shops which write masks.

Proceedings Article | 3 October 2016 Paper

Comparing curvilinear vs Manhattan ILT shape efficacy on EPE and process window

Dan Zhang, Peter Buck, Alexander Tritchkov, Saikiran Madhusudhan, James Word

Proceedings Volume 9985, 99850V (2016) https://doi.org/10.1117/12.2243030

KEYWORDS: Optical proximity correction, Photomasks, Lithography, Data processing, Semiconducting wafers, Manufacturing, Metals, Process control, Image processing, Cadmium sulfide

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Proceedings Article | 10 May 2016 Paper

ILT based defect simulation of inspection images accurately predicts mask defect printability on wafer

Prakash Deep, Sankaranarayanan Paninjath, Mark Pereira, Peter Buck

Proceedings Volume 9984, 99840C (2016) https://doi.org/10.1117/12.2240117

KEYWORDS: Photomasks, Inspection, Defect inspection, Semiconducting wafers, Critical dimension metrology, Image resolution, Wafer-level optics, Image processing, Scanners, Resolution enhancement technologies

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At advanced technology nodes mask complexity has been increased because of large-scale use of resolution enhancement technologies (RET) which includes Optical Proximity Correction (OPC), Inverse Lithography Technology (ILT) and Source Mask Optimization (SMO). The number of defects detected during inspection of such mask increased drastically and differentiation of critical and non-critical defects are more challenging, complex and time consuming. Because of significant defectivity of EUVL masks and non-availability of actinic inspection, it is important and also challenging to predict the criticality of defects for printability on wafer. This is one of the significant barriers for the adoption of EUVL for semiconductor manufacturing. Techniques to decide criticality of defects from images captured using non actinic inspection images is desired till actinic inspection is not available. High resolution inspection of photomask images detects many defects which are used for process and mask qualification. Repairing all defects is not practical and probably not required, however it’s imperative to know which defects are severe enough to impact wafer before repair. Additionally, wafer printability check is always desired after repairing a defect. AIMS^TM review is the industry standard for this, however doing AIMSTM review for all defects is expensive and very time consuming. Fast, accurate and an economical mechanism is desired which can predict defect printability on wafer accurately and quickly from images captured using high resolution inspection machine. Predicting defect printability from such images is challenging due to the fact that the high resolution images do not correlate with actual mask contours. The challenge is increased due to use of different optical condition during inspection other than actual scanner condition, and defects found in such images do not have correlation with actual impact on wafer. Our automated defect simulation tool predicts printability of defects at wafer level and automates the process of defect dispositioning from images captured using high resolution inspection machine. It first eliminates false defects due to registration, focus errors, image capture errors and random noise caused during inspection. For the remaining real defects, actual mask-like contours are generated using the Calibre® ILT solution [1][2], which is enhanced to predict the actual mask contours from high resolution defect images. It enables accurate prediction of defect contours, which is not possible from images captured using inspection machine because some information is already lost due to optical effects. Calibre’s simulation engine is used to generate images at wafer level using scanner optical conditions and mask-like contours as input. The tool then analyses simulated images and predicts defect printability. It automatically calculates maximum CD variation and decides which defects are severe to affect patterns on wafer. In this paper, we assess the printability of defects for the mask of advanced technology nodes. In particular, we will compare the recovered mask contours with contours extracted from SEM image of the mask and compare simulation results with AIMS^TM for a variety of defects and patterns. The results of printability assessment and the accuracy of comparison are presented in this paper. We also suggest how this method can be extended to predict printability of defects identified on EUV photomasks.

SPIE Journal Paper | 27 April 2016

Accurate mask model implementation in optical proximity correction model for 14-nm nodes and beyond

Nacer Zine El Abidine, Frank Sundermann, Emek Yesilada, Vincent Farys, Frederic Huguennet, Ana-Maria Armeanu, Ingo Bork, Michael Chomat, Peter Buck, Isabelle Schanen

JM3, Vol. 15, Issue 02, 021011, (April 2016) https://doi.org/10.1117/12.10.1117/1.JMM.15.2.021011

KEYWORDS: Photomasks, Calibration, Optical proximity correction, Critical dimension metrology, Electroluminescence, Wafer-level optics, Semiconducting wafers, Data modeling, 3D modeling, Scanning electron microscopy

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Proceedings Article | 23 October 2015 Paper

Accurate mask model implementation in OPC model for 14nm nodes and beyond

Nacer Zine El Abidine, Frank Sundermann, Emek Yesilada, Vincent Farys, Frederic Huguennet, Ana-Maria Armeanu, Ingo Bork, Michael Chomat, Peter Buck, Isabelle Schanen

Proceedings Volume 9635, 96350W (2015) https://doi.org/10.1117/12.2203267

KEYWORDS: Photomasks, Calibration, Critical dimension metrology, Semiconducting wafers, Optical proximity correction, Wafer-level optics, Process modeling, Data modeling, Photoresist processing, Neck

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Proceedings Article | 23 October 2015 Paper

A fully model-based MPC solution including VSB shot dose assignment and shape correction

Ingo Bork, Peter Buck, Murali Reddy, Bhardwaj Durvasula

Proceedings Volume 9635, 96350U (2015) https://doi.org/10.1117/12.2199157

KEYWORDS: Model-based design, Modulation, Backscatter, SRAF, Photomask technology, Optimization (mathematics), Calibration, Photomasks, Diffusion, Visualization

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Proceedings Article | 9 July 2015 Paper

Automatic classification and accurate size measurement of blank mask defects

Samir Bhamidipati, Sankaranarayanan Paninjath, Mark Pereira, Peter Buck

Proceedings Volume 9658, 96580X (2015) https://doi.org/10.1117/12.2198001

KEYWORDS: Inspection, Photomasks, Coating, Particles, Image processing, Defect detection, Optical lithography, Photoresist processing, Visualization, Photoresist materials

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A blank mask and its preparation stages, such as cleaning or resist coating, play an important role in the eventual yield obtained by using it. Blank mask defects’ impact analysis directly depends on the amount of available information such as the number of defects observed, their accurate locations and sizes. Mask usability qualification at the start of the preparation process, is crudely based on number of defects. Similarly, defect information such as size is sought to estimate eventual defect printability on the wafer. Tracking of defect characteristics, specifically size and shape, across multiple stages, can further be indicative of process related information such as cleaning or coating process efficiencies. At the first level, inspection machines address the requirement of defect characterization by detecting and reporting relevant defect information. The analysis of this information though is still largely a manual process. With advancing technology nodes and reducing half-pitch sizes, a large number of defects are observed; and the detailed knowledge associated, make manual defect review process an arduous task, in addition to adding sensitivity to human errors. Cases where defect information reported by inspection machine is not sufficient, mask shops rely on other tools. Use of CDSEM tools is one such option. However, these additional steps translate into increased costs. Calibre NxDAT based MDPAutoClassify tool provides an automated software alternative to the manual defect review process. Working on defect images generated by inspection machines, the tool extracts and reports additional information such as defect location, useful for defect avoidance^[4][5]; defect size, useful in estimating defect printability; and, defect nature e.g. particle, scratch, resist void, etc., useful for process monitoring. The tool makes use of smart and elaborate post-processing algorithms to achieve this. Their elaborateness is a consequence of the variety and complexity of defects encountered. The variety arises due to factors such as defect nature, size, shape and composition; and the optical phenomena occurring around the defect. This paper focuses on preliminary characterization results, in terms of classification and size estimation, obtained by Calibre MDPAutoClassify tool on a variety of mask blank defects. It primarily highlights the challenges faced in achieving the results with reference to the variety of defects observed on blank mask substrates and the underlying complexities which make accurate defect size measurement an important and challenging task.

Proceedings Article | 17 October 2014 Paper

14-nm photomask simulation sensitivity

John Sturtevant, Peter Buck, Steffen Schulze, David Fryer, Edita Tejnil, Kostas Adam, Michael Lam, Chris Clifford, Mike Oliver, Ana Armeanu, Franklin Kalk, Kent Nakagawa, Guoxiang Ning, Paul Ackmann, Fritz Gans, Christian Buergel

Proceedings Volume 9231, 92310I (2014) https://doi.org/10.1117/12.2066483

KEYWORDS: Photomasks, 3D modeling, Semiconducting wafers, Optical proximity correction, Data modeling, Calibration, Manufacturing, Photoresist materials, Metrology, Refractive index

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Proceedings Article | 17 October 2014 Paper

Using rule-based shot dose assignment in model-based MPC applications

Ingo Bork, Peter Buck, Lin Wang, Uwe Müller

Proceedings Volume 9235, 92351T (2014) https://doi.org/10.1117/12.2069677

KEYWORDS: Critical dimension metrology, Vestigial sideband modulation, Model-based design, SRAF, Visualization, Cadmium, Distance measurement, Backscatter, Optical proximity correction

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Shrinking feature sizes and the need for tighter CD (Critical Dimension) control require the introduction of new technologies in mask making processes. One of those methods is the dose assignment of individual shots on VSB (Variable Shaped Beam) mask writers to compensate CD non-linearity effects and improve dose edge slope. Using increased dose levels only for most critical features, generally only for the smallest CDs on a mask, the change in mask write time is minimal while the increase in image quality can be significant. This paper describes a method combining rule-based shot dose assignment with model-based shot size correction. This combination proves to be very efficient in correcting mask linearity errors while also improving dose edge slope of small features. Shot dose assignment is based on tables assigning certain dose levels to a range of feature sizes. The dose to feature size assignment is derived from mask measurements in such a way that shape corrections are kept to a minimum. For example, if a 50nm drawn line on mask results in a 45nm chrome line using nominal dose, a dose level is chosen which is closest to getting the line back on target. Since CD non-linearity is different for lines, line-ends and contacts, different tables are generated for the different shape categories. The actual dose assignment is done via DRC rules in a pre-processing step before executing the shape correction in the MPC engine. Dose assignment to line ends can be restricted to critical line/space dimensions since it might not be required for all line ends. In addition, adding dose assignment to a wide range of line ends might increase shot count which is undesirable. The dose assignment algorithm is very flexible and can be adjusted based on the type of layer and the best balance between accuracy and shot count. These methods can be optimized for the number of dose levels available for specific mask writers. The MPC engine now needs to be able to handle different dose levels and requires a model which accurately predicts mask shapes at all dose levels used. The calibration of such a model is described in a separate paper [1]. In summary this paper presents an efficient method for combining rule-based VSB shot dose assignment with modelbased shape corrections in MPC. This method expands the printability of small features sizes without the need for increasing the base dose of the e-beam writer which reduces backscattering and increases the lifetime of the electron gun of the writer.

Proceedings Article | 17 October 2014 Paper

Automatic classification of blank substrate defects

Tom Boettiger, Peter Buck, Sankaranarayanan Paninjath, Mark Pereira, Rob Ronald, Dan Rost, Bhamidipati Samir

Proceedings Volume 9235, 92351J (2014) https://doi.org/10.1117/12.2069678

KEYWORDS: Inspection, Photomasks, Defect inspection, Image classification, Particles, Defect detection, Image processing, Manufacturing, Semiconducting wafers, Liquids

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Mask preparation stages are crucial in mask manufacturing, since this mask is to later act as a template for considerable number of dies on wafer. Defects on the initial blank substrate, and subsequent cleaned and coated substrates, can have a profound impact on the usability of the finished mask. This emphasizes the need for early and accurate identification of blank substrate defects and the risk they pose to the patterned reticle. While Automatic Defect Classification (ADC) is a well-developed technology for inspection and analysis of defects on patterned wafers and masks in the semiconductors industry, ADC for mask blanks is still in the early stages of adoption and development. Calibre ADC is a powerful analysis tool for fast, accurate, consistent and automatic classification of defects on mask blanks. Accurate, automated classification of mask blanks leads to better usability of blanks by enabling defect avoidance technologies during mask writing. Detailed information on blank defects can help to select appropriate job-decks to be written on the mask by defect avoidance tools [1][4][5]. Smart algorithms separate critical defects from the potentially large number of non-critical defects or false defects detected at various stages during mask blank preparation. Mechanisms used by Calibre ADC to identify and characterize defects include defect location and size, signal polarity (dark, bright) in both transmitted and reflected review images, distinguishing defect signals from background noise in defect images. The Calibre ADC engine then uses a decision tree to translate this information into a defect classification code. Using this automated process improves classification accuracy, repeatability and speed, while avoiding the subjectivity of human judgment compared to the alternative of manual defect classification by trained personnel [2]. This paper focuses on the results from the evaluation of Automatic Defect Classification (ADC) product at MP Mask Technology Center (MPMask). The Calibre ADC tool was qualified on production mask blanks against the manual classification. The classification accuracy of ADC is greater than 95% for critical defects with an overall accuracy of 90%. The sensitivity to weak defect signals and locating the defect in the images is a challenge we are resolving. The performance of the tool has been demonstrated on multiple mask types and is ready for deployment in full volume mask manufacturing production flow. Implementation of Calibre ADC is estimated to reduce the misclassification of critical defects by 60-80%.

Proceedings Article | 8 October 2014 Paper

Mask model calibration for MPC applications utilizing shot dose assignment

Ingo Bork, Peter Buck, Sankaranarayanan Paninjath, Kushlendra Mishra, Christian Bürgel, Keith Standiford, Gek Soon Chua

Proceedings Volume 9235, 92350A (2014) https://doi.org/10.1117/12.2069617

KEYWORDS: Calibration, Critical dimension metrology, Scanning electron microscopy, Cadmium, Etching, Error analysis, Visualization, Photomasks, Vestigial sideband modulation, Statistical modeling

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Shrinking feature sizes and the need for tighter CD (Critical Dimension) control require the introduction of new technologies in mask making processes. One of those methods is the dose assignment of individual shots on VSB (Variable Shaped Beam) mask writers to compensate CD non-linearity effects and improve dose edge slope. Using increased dose levels only for most critical features, generally only for the smallest CDs on a mask, the change in mask write time is minimal while the increase in image quality can be significant. However, this technology requires accurate modeling of the mask effects, especially the CD/dose dependencies. This paper describes a mask model calibration flow for Mask Process Correction (MPC) applications with shot dose assignment. The first step in the calibration flow is the selection of appropriate test structures. For this work, a combination of linespace patterns as well as a series of contact patterns are used for calibration. Features sizes vary from 34 nm up to several micrometers in order to capture a wide range of CDs and pattern densities. After mask measurements are completed the results are carefully analyzed and measurements very close to the process window limitation and outliers are removed from the data set. One key finding in this study is that by including patterns exposed at various dose levels the simulated contours of the calibrated model very well match the SEM contours even if the calibration was based entirely on gauge based CD values. In the calibration example shown in this paper, only 1D line and space measurements as well as 1D contact measurements are used for calibration. However, those measurements include patterns exposed at dose levels between 75% and 150% of the nominal dose. The best model achieved in this study uses 2 e-beam kernels and 4 kernels for the simulation of development and etch effects. The model error RMS on a large range of CD down to 34 nm line CD is 0.71 nm. The calibrated model is then used to generate 2D contours for line ends, space ends and contacts and those contours are compared to SEM images. For all patterns, including those very close to the resolution limit, very good contour overlay is achieved. It appears that by including the various dose levels in the calibration a very good separation of the e-beam model components from the etch components is possible and that this also results in very accurate 2D model quality. In conclusion, very accurate mask model calibration is achieved for mask processes using shot dose assignment. Standard test patterns can be used for calibration if they include the dose variations intended for correction.

Proceedings Article | 28 July 2014 Paper

Accurate mask model for advanced nodes

Nacer Zine El Abidine, Frank Sundermann, Emek Yesilada, El Hadji Omar Ndiaye, Kushlendra Mishra, Sankaranarayanan Paninjath, Ingo Bork, Peter Buck, Olivier Toublan, Isabelle Schanen

Proceedings Volume 9256, 925603 (2014) https://doi.org/10.1117/12.2069977

KEYWORDS: Photomasks, Calibration, Data modeling, Optical proximity correction, Etching, Error analysis, Printing, Electron beam lithography, Scanning electron microscopy, Semiconducting wafers

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SPIE Journal Paper | 2 December 2013

Impact of 14-nm photomask uncertainties on computational lithography solutions

John Sturtevant, Edita Tejnil, Timothy Lin, Steffen Schulze, Peter Buck, Franklin Kalk, Kent Nakagawa, GuoXiang Ning, Paul Ackmann, Fritz Gans, Christian Buergel

JM3, Vol. 13, Issue 01, 011004, (December 2013) https://doi.org/10.1117/12.10.1117/1.JMM.13.1.011004

KEYWORDS: Photomasks, Semiconducting wafers, 3D modeling, Optical proximity correction, Critical dimension metrology, Calibration, Photoresist materials, Computational lithography, Data modeling, Mathematical modeling

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Proceedings Article | 10 September 2013 Paper

The impact of 14nm photomask variability and uncertainty on computational lithography solutions

John Sturtevant, Edita Tejnil, Peter Buck, Steffen Schulze, Franklin Kalk, Kent Nakagawa, Guoxiang Ning, Paul Ackmann, Fritz Gans, Christian Buergel

Proceedings Volume 8880, 88800F (2013) https://doi.org/10.1117/12.2030733

KEYWORDS: Photomasks, Semiconducting wafers, 3D modeling, Optical proximity correction, Calibration, Photoresist materials, Critical dimension metrology, Manufacturing, Data modeling, Mathematical modeling

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Proceedings Article | 12 April 2013 Paper

The impact of 14-nm photomask uncertainties on computational lithography solutions

John Sturtevant, Edita Tejnil, Tim Lin, Steffen Schultze, Peter Buck, Franklin Kalk, Kent Nakagawa, Guoxiang Ning, Paul Ackmann, Fritz Gans, Christian Buergel

Proceedings Volume 8683, 868307 (2013) https://doi.org/10.1117/12.2013748

KEYWORDS: Photomasks, Semiconducting wafers, Optical proximity correction, 3D modeling, Calibration, Critical dimension metrology, Manufacturing, Process modeling, Data modeling, Computational lithography

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Proceedings Article | 8 November 2012 Paper

Mask design automation: an integrated approach

Richard Gladhill, Peter Buck, Al Wong

Proceedings Volume 8522, 85220U (2012) https://doi.org/10.1117/12.979350

KEYWORDS: Photomasks, Electronic design automation, Semiconducting wafers, Manufacturing, Optical proximity correction, Process control, Lithography, Wafer-level optics, Image processing, Data processing

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Proceedings Article | 15 February 2012 Paper

Programmed resist sidewall profiles using subresolution binary grayscale masks for Si-photonics applications

Ofir Gan, Paul Allen, Assia Barkai, Peter Buck, Brid Connolly, Harel Frish, Massimiliano Pindo

Proceedings Volume 8249, 82490W (2012) https://doi.org/10.1117/12.907275

KEYWORDS: Photomasks, Calibration, Lithography, Photoresist materials, Transmittance, Semiconducting wafers, Etching, Manufacturing, Data modeling, Silicon

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Proceedings Article | 4 April 2011 Paper

Extending analog design scaling to sub-wavelength lithography: co-optimization of RET and photomasks

Ashesh Parikh, Siew Dorris, Tom Smelko, Walter Walbrick, Pushpa Mahalingam, John Arch, Kent Green, Vishal Garg, Peter Buck, Craig West

Proceedings Volume 7974, 79740N (2011) https://doi.org/10.1117/12.877487

KEYWORDS: Photomasks, Reticles, Deep ultraviolet, Analog electronics, Silicon, Optical proximity correction, Critical dimension metrology, Lithography, Resolution enhancement technologies, CMOS technology

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Proceedings Article | 27 May 2009 Paper

Mask contribution on CD and OVL errors budgets for double patterning lithography

I. Servin, C. Lapeyre, S. Barnola, B. Connolly, R. Ploss, K. Nakagawa, P. Buck, M. McCallum

Proceedings Volume 7470, 747009 (2009) https://doi.org/10.1117/12.835171

KEYWORDS: Photomasks, Semiconducting wafers, Critical dimension metrology, Reticles, Double patterning technology, Pellicles, Lithography, Image registration, Optical alignment, Scanners

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Proceedings Article | 30 October 2007 Paper

Mask manufacturability improvement by MRC

A. Balasinski, D. Coburn, P. Buck

Proceedings Volume 6730, 67303J (2007) https://doi.org/10.1117/12.746188

KEYWORDS: Photomasks, Inspection, Computer aided design, Manufacturing, Error analysis, Optical proximity correction, Databases, Metrology, Semiconducting wafers, Control systems

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Proceedings Article | 27 March 2007 Paper

Golden curve method for OPC signature stability control in high MEEF applications

Katja Geidel, Torsten Franke, Stefan Roling, Peter Buck, Martin Sczyrba, Engelbert Mittermeier, Russell Cinque

Proceedings Volume 6520, 652040 (2007) https://doi.org/10.1117/12.712867

KEYWORDS: Photomasks, Optical proximity correction, Critical dimension metrology, Semiconducting wafers, Metrology, Lithography, Manufacturing, Control systems, Image processing, Etching

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Proceedings Article | 21 March 2007 Paper

Mask manufacturing rules checking (MRC) as a DFM strategy

Peter Buck, Richard Gladhill, Joseph Straub

Proceedings Volume 6521, 65211V (2007) https://doi.org/10.1117/12.712373

KEYWORDS: Photomasks, Manufacturing, Inspection, Design for manufacturing, Lithography, Lawrencium, Metals, Chemical mechanical planarization, Semiconducting wafers, Design for manufacturability

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Proceedings Article | 20 October 2006 Paper

Advanced manufacturing rules check (MRC) for fully automated assessment of complex reticle designs: Part II

J. Straub, D. Aguilar, P. Buck, D. Dawkins, R. Gladhill, S. Nolke, J. Riddick

Proceedings Volume 6349, 63493W (2006) https://doi.org/10.1117/12.686134

KEYWORDS: Inspection, Photomasks, Manufacturing, Defect inspection, Reticles, Electronic design automation, Lithography, Optical proximity correction, Design for manufacturing, Visualization

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Proceedings Article | 20 October 2006 Paper

Metrics to assess fracture quality for variable shaped beam lithography

M. Bloecker, R. Gladhill, P. Buck, M. Kempf, D. Aguilar, R. Cinque

Proceedings Volume 6349, 63490Z (2006) https://doi.org/10.1117/12.686713

KEYWORDS: Photomasks, Critical dimension metrology, Lithography, Beam shaping, Vestigial sideband modulation, Manufacturing, Electronic design automation, Optical proximity correction, Control systems, Electron beam lithography

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Proceedings Article | 21 June 2006 Paper

Mask data volume: historical perspective and future requirements

Chris Spence, Scott Goad, Peter Buck, Richard Gladhill, Russell Cinque, Jürgen Preuninger, Üwe Griesinger, Martin Blöcker

Proceedings Volume 6281, 62810H (2006) https://doi.org/10.1117/12.692639

KEYWORDS: Optical proximity correction, Photomasks, Vestigial sideband modulation, Logic, SRAF, Reticles, Resolution enhancement technologies, Manufacturing, Metals, Data storage

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Proceedings Article | 20 May 2006 Paper

Experimental characterization of constituent errors in electron-beam lithography

Russell Cinque, Peter Buck, Kyungsoo Yeo, Tadashi Komagata, Yasutoshi Nakagawa

Proceedings Volume 6283, 62831M (2006) https://doi.org/10.1117/12.681748

KEYWORDS: Photomasks, Critical dimension metrology, Lithography, Error analysis, Metrology, Vestigial sideband modulation, Composites, Beam shaping, Calibration, Standards development

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Proceedings Article | 5 November 2005 Paper

A mask manufacturer’s perspective on maskless lithography

Peter Buck, Charles Biechler, Franklin Kalk

Proceedings Volume 5992, 599225 (2005) https://doi.org/10.1117/12.629774

KEYWORDS: Photomasks, Lithography, Manufacturing, Semiconducting wafers, Prototyping, Maskless lithography, Electron beam lithography, Metals, Data modeling, Reticles

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Maskless Lithography (ML2) is again being considered for use in mainstream CMOS IC manufacturing. Sessions at technical conferences are being devoted to ML2. A multitude of new companies have been formed in the last several years to apply new concepts to breaking the throughput barrier that has in the past prevented ML2 from achieving the cost and cycle time performance necessary to become economically viable, except in rare cases. Has Maskless Lithography's (we used to call it "Direct Write Lithography") time really come? If so, what is the expected impact on the mask manufacturer and does it matter? The lithography tools used today in mask manufacturing are similar in concept to ML2 except for scale, both in throughput and feature size. These mask tools produce highly accurate lithographic images directly from electronic pattern files, perform multi-layer overlay, and mix-n-match across multiple tools, tool types and sites. Mask manufacturers are already accustomed to the ultimate low volume - one substrate per design layer. In order to achieve the economically required throughput, proposed ML2 systems eliminate or greatly reduce some of the functions that are the source of the mask writer's accuracy. Can these ML2 systems meet the demanding lithographic requirements without these functions? ML2 may eliminate the reticle but many of the processes and procedures performed today by the mask manufacturer are still required. Examples include the increasingly complex mask data preparation step and the verification performed to ensure that the pattern on the reticle is accurately representing the design intent. The error sources that are fixed on a reticle are variable with time on an ML2 system. It has been proposed that if ML2 is successful it will become uneconomical to be in the mask business - that ML2, by taking the high profit masks will take all profitability out of mask manufacturing and thereby endanger the entire semiconductor industry. Others suggest that a successful ML2 system solves the mask cost issue and thereby reduces the need and attractiveness of ML2. Are these concerns valid? In this paper we will present a perspective on maskless lithography from the considerable "direct write" experience of a mask manufacturer. We will examine the various business models proposed for ML2 insertion as well as the key technical challenges to achieving simultaneously the throughput and the lithographic quality necessary to become economically viable. We will consider the question of the economic viability of the mask industry in a post-ML2 world and will propose possible models where the mask industry can meaningfully participate.

Proceedings Article | 5 November 2005 Paper

Mask data volume: explosion or damp squib?

Chris Spence, Scott Goad, Peter Buck, Richard Gladhill, Russell Cinque

Proceedings Volume 5992, 599211 (2005) https://doi.org/10.1117/12.629369

KEYWORDS: Photomasks, Optical proximity correction, Vestigial sideband modulation, Resolution enhancement technologies, SRAF, Metals, Manufacturing, Logic, Reticles, Data storage

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Proceedings Article | 5 November 2005 Paper

Pattern fidelity performance from next-generation DUV laser lithography on 65nm masks and wafers

Robert Kiefer, Peter Buck, Vishal Garg, Jason Hickethier, Curt Jackson, John Manfredo, Cris Morgante, Paul Allen, Michael White

Proceedings Volume 5992, 59920U (2005) https://doi.org/10.1117/12.632227

KEYWORDS: Photomasks, Deep ultraviolet, Artificial intelligence, Printing, Metals, Lithography, Semiconducting wafers, Bragg cells, Evolutionary algorithms, Optical alignment

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Proceedings Article | 4 November 2005 Paper

Advanced manufacturing rules check (MRC) for fully-automated assessment of complex reticle designs

R. Gladhill, D. Aguilar, P. Buck, D. Dawkins, S. Nolke, J. Riddick, J. Straub

Proceedings Volume 5992, 59920A (2005) https://doi.org/10.1117/12.632743

KEYWORDS: Inspection, Photomasks, Manufacturing, Lithography, Electronic design automation, Optical proximity correction, Yield improvement, Reticles, Software development, Computed tomography

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Proceedings Article | 28 June 2005 Paper

Print characterization of photomasks from next-generation deep-ultra-violet laser pattern generator

Curt Jackson, Robert Kiefer, Peter Buck, David Mellenthin, John Manfredo, Vishal Garg, Jason Hickethier, Sarah Cohen, Cris Morgante, Paul Allen, Eric Christenson, Michael White

Proceedings Volume 5853, (2005) https://doi.org/10.1117/12.617524

KEYWORDS: Photomasks, Deep ultraviolet, Semiconducting wafers, Printing, Objectives, Diffractive optical elements, Bragg cells, Vestigial sideband modulation, Image enhancement, Optical proximity correction

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Proceedings Article | 12 May 2005 Paper

A novel mask-based approach to improve low-k1 corner and angle definition in alternating-aperture phase-shift mask structures

Kent Nakagawa, David Siefers, Susan MacDonald, Peter Buck

Proceedings Volume 5754, (2005) https://doi.org/10.1117/12.597617

KEYWORDS: Photomasks, Semiconducting wafers, Magnetism, Neck, Manufacturing, Scanning electron microscopy, Phase shifts, Optical proximity correction, Quartz, Distortion

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Proceedings Article | 12 May 2005 Paper

Enhancement of the image fidelity and pattern accuracy of a DUV laser generated photomask through next-generation hardware

Robert Kiefer, Curt Jackson, Vishal Garg, David Mellenthin, John Manfredo, Peter Buck, Sarah Cohen, Cris Morgante, Paul Allen, Michael White

Proceedings Volume 5754, (2005) https://doi.org/10.1117/12.600368

KEYWORDS: Photomasks, Deep ultraviolet, Image enhancement, Objectives, Diffractive optical elements, Bragg cells, Optical proximity correction, Metals, Optical lithography, Control systems

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Proceedings Article | 20 August 2004 Paper

Imaging properties of a leading-edge DUV laser generated photomask

Curt Jackson, Peter Buck, Sarah Cohen, Vishal Garg, Jason Hickethier, Charles Howard, Robert Kiefer, Matt Lamantia, John Manfredo, James Tsou

Proceedings Volume 5446, (2004) https://doi.org/10.1117/12.557720

KEYWORDS: Deep ultraviolet, Photomasks, Lithography, Semiconducting wafers, Manufacturing, Lithographic illumination, Electron beam lithography, Solids, Tolerancing, Vestigial sideband modulation

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Proceedings Article | 2 June 2004 Paper

OASIS: progress on implementing the new stream format for containing data size explosion

Steffen Schulze, Kent Nakagawa, Peter Buck

Proceedings Volume 5504, (2004) https://doi.org/10.1117/12.568027

KEYWORDS: Optical proximity correction, Information operations, Manufacturing, Integrated circuits, Data conversion, Data processing, Seaborgium, Photomasks, Databases, Beam shaping

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Proceedings Article | 28 May 2004 Paper

Conversion from 50 KeV to DUV mask writer for 90-nm technology critical layers

Dongsung Hong, Prakash Krishnan, Dianna Coburn, Mary Zawadzki, Yonghong Yang, Kent Green, Peter Buck, Curt Jackson, Larry Martinez

Proceedings Volume 5377, (2004) https://doi.org/10.1117/12.535882

KEYWORDS: Photomasks, Deep ultraviolet, Semiconducting wafers, Optical proximity correction, Lithography, Electron beam lithography, Error control coding, Metals, Laser systems engineering, Binary data

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One of Cypress’ primary goals for 90-nm generation mask strategy is to control mask costs while not compromising on performance. One key objective is to replace the use of 50-ke V electron beam pattern generation with DUV laser mask lithography where possible. The higher productivity of the DUV laser systems compared to the 50Ke V e-beam platforms offers a unique opportunity for mask cost reduction. Compared to previous i-line generations of laser lithography systems, the DUV laser systems provide significantly improved resolution and pattern fidelity that more closely approaches that of ebeam lithography. We have previously published experimental results demonstrating that the difference in fidelity on the mask between the laser and EB platforms does not always translate to a measurable difference in wafer litho performance or even more importantly to a measurable difference in electrical performance. Through this work, Cypress was able to eliminate the use of 50Ke V ebeam writers for all of their 130nm technology node layers. In some cases the improved performance of the DUV tools was sufficient to replace i-line produced masks where wafer performance was marginal without having to resort to EB lithography. This study addresses the conversion of 50Ke V ebeam layers to DUV laser platform specifically for the critical layers of the Cypress’ 90nm Technology node. EB lithography was originally specified for these layers as a conservative approach in part due to the timing of 90-nm technology development relative to the maturation of the DUV laser mask lithography process. In this study, the electrical performance and wafer yield are evaluated for equivalency in order to take advantage of the lower cost and faster cycletime that use of a ALTA DUV system provides over the 50Ke V VSB systems. In addition, the wafer OPC is not changed between the two mask writing systems in order to allow interchangeable use of the two writing systems if the experimental results indicated no difference in wafer performance.

Proceedings Article | 28 May 2004 Paper

DUV laser lithography for photomask fabrication

Curt Jackson, Peter Buck, Sarah Cohen, Vishal Garg, Charles Howard, Robert Kiefer, John Manfredo, James Tsou

Proceedings Volume 5377, (2004) https://doi.org/10.1117/12.534575

KEYWORDS: Deep ultraviolet, Photomasks, Lithography, Manufacturing, Thin film coatings, Vestigial sideband modulation, Critical dimension metrology, Photoresist processing, Image enhancement, Printing

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Proceedings Article | 28 May 2004 Paper

Through pitch intensity balancing and phase error analysis of 193-nm alternating phase shift masks

Kent Nakagawa, Gregory Hughes, Keuntaek Park, Peter Buck

Proceedings Volume 5377, (2004) https://doi.org/10.1117/12.535956

KEYWORDS: Photomasks, Etching, Phase shifts, Wet etching, Error analysis, Manufacturing, Mask making, Lithography, Quartz, 193nm lithography

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Proceedings Article | 17 December 2003 Paper

DUV laser lithography for photomask fabrication

Curt Jackson, Peter Buck, Sarah Cohen, Vishal Garg, Charles Howard, Robert Kiefer, John Manfredo, James Tsou

Proceedings Volume 5256, (2003) https://doi.org/10.1117/12.518269

KEYWORDS: Deep ultraviolet, Photomasks, Lithography, Manufacturing, Thin film coatings, Vestigial sideband modulation, Photoresist processing, Critical dimension metrology, Inspection, Printing

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Proceedings Article | 17 December 2003 Paper

DUV mask writer for BEOL 90-nm technology layers

Dongsung Hong, Prakash Krishnan, Dianna Coburn, Nazneen Jeewakhan, Shengqi Xie, Joshua Broussard, Bradley Ferguson, Kent Green, Peter Buck, Curt Jackson, Larry Martinez

Proceedings Volume 5256, (2003) https://doi.org/10.1117/12.518051

KEYWORDS: Photomasks, Deep ultraviolet, Semiconducting wafers, Metals, Vestigial sideband modulation, Reticles, Optical proximity correction, Back end of line, Critical dimension metrology, Cadmium

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Proceedings Article | 27 December 2002 Paper

Comparison of DUV wafer and reticle lithography: What is the resolution limit?

Chris Spence, Cyrus Tabery, Gerald Cantrell, Leslie Dahl, Peter Buck, William Wilkinson

Proceedings Volume 4889, (2002) https://doi.org/10.1117/12.468094

KEYWORDS: Semiconducting wafers, Photomasks, Reticles, Image processing, Lithography, Etching, Photoresist processing, Absorption, Reflectivity, Optical proximity correction

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Proceedings Article | 27 December 2002 Paper

Advanced write tool effects on 100-nm node OPC

Peter Buck, Kent Green, Kent Ibsen, Kent Nakagawa, Dongsung Hong, Prakash Krishnan, Dianna Coburn

Proceedings Volume 4889, (2002) https://doi.org/10.1117/12.467761

KEYWORDS: Photomasks, Semiconducting wafers, Optical proximity correction, Lithography, Deep ultraviolet, Image processing, Electron beam lithography, Printing, Scanning electron microscopy, Manufacturing

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Proceedings Article | 27 December 2002 Paper

GDS-based mask data preparation flow: data volume containment by hierarchical data processing

Steffen Schulze, Pat LaCour, Peter Buck

Proceedings Volume 4889, (2002) https://doi.org/10.1117/12.468273

KEYWORDS: Photomasks, Manufacturing, Data processing, Resolution enhancement technologies, Lithography, Process control, Data conversion, Data storage, Optical proximity correction, Data communications

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As the industry enters the development of the 65nm node the pressure on the data path and tapeout flow is growing. Design complexity and increased deployment of resolution enhancement techniques (RET) result in rapidly growing file sizes, which turns what used to be the relatively simple task of mask data preparation into a real bottleneck. This discussion introduces the data preparation scheme in the mask house and analyzes its evolution. Mask data preparation (MDP) has evolved from a flow that only needed to support a single mask lithography tool data format (MEBES) with minimal data alteration steps to one which requires the support of many mask lithography tool data formats and at the same time requires significant data alteration to support the increased precision necessary for today’s advanced masks.. However, the MDP flow developed around the MEBES format and it’s derivatives still exists. The design community has migrated towards the use of hierarchical data formats and processes to control file size and processing time. MDP, which from a file size and process complexity point of view is beginning to look more and more like the advanced RET operations performed on the data prior to mask manufacturing, is still standardized on a flat data format that is poorly optimized for a growing number of mask lithography tools. Based on examples it will be shown how this complicates the data handling further. An alternate data preparation flow accommodating the larger files and re-gaining flexibility for turnaround time (TAT) and throughput management is suggested. This flow utilizes the hierarchical GDS-II format as the exchange format for mask data preparation. It complements the existing flow for the most complex designs. The introduction of a hierarchical exchange format enables the transfer of a number of necessary data preparation steps into the hierarchical domain. Data processing strategies are discussed. The paper illustrates the benefit of hierarchical processing based on GDS-II files with experimental data on file size reduction and TAT improvement for direct format conversions vs. re-fracturing as well as other processing steps. The implications for the established data preparation approaches and potential alternatives for the communication between the mask manufacturer and the customer will be discussed. The potential for further enhancements by converting to a hierarchical format that has a more efficient data representation than the commonly used GDS-II format will be discussed and illustrated.

Proceedings Article | 1 August 2002 Paper

Adjustment of optical proximity correction (OPC) software for mask process correction (MPC): Module 2. Lithography simulation based on optical mask writing tool simulation

Alexandra Barberet, Peter Buck, Gilles Fanget, Olivier Toublan, Jean-Charles Richoilley, Michel Tissier

Proceedings Volume 4754, (2002) https://doi.org/10.1117/12.476988

KEYWORDS: Photomasks, Optical proximity correction, Scanning electron microscopy, Semiconducting wafers, Databases, Data modeling, Lithography, Process modeling, Optical simulations, Manufacturing

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Proceedings Article | 12 July 2002 Paper

Role of mask acuity in advanced lithographic process design

Peter Buck

Proceedings Volume 4692, (2002) https://doi.org/10.1117/12.475682

KEYWORDS: Photomasks, Lithography, Semiconducting wafers, Optical proximity correction, Image processing, Vestigial sideband modulation, Convolution, Reticles, Solid state lighting, Standards development

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Proceedings Article | 11 March 2002 Paper

Adjustment of optical proximity correction (OPC) software for mask process correction (MPC). Module 1: Optical mask writing tool simulation

Alexandra Barberet, Gilles Fanget, Peter Buck, Olivier Toublan, Jean-Charles Richoilley, Michel Tissier

Proceedings Volume 4562, (2002) https://doi.org/10.1117/12.458328

KEYWORDS: Photomasks, Data modeling, Databases, Silicon, Lithography, Process modeling, Optical simulations, Semiconducting wafers, 193nm lithography, Optical proximity correction

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Proceedings Article | 22 January 2001 Paper

Integration of the Micronic Omega6500 into the mask manufacturing environment

Peter Buck, Mans Bjuggren, Hartmut Buenning, Vishal Garg, Johan Larsson, Tomas Vikholm

Proceedings Volume 4186, (2001) https://doi.org/10.1117/12.410726

KEYWORDS: Photomasks, Lithography, Manufacturing, Photoresist processing, Laser systems engineering, Etching, Printing, Metrology, Optical proximity correction, Diffractive optical elements

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Proceedings Article | 22 January 2001 Paper

Characterization of an acetal-based chemically amplified resist for 257-nm laser mask fabrication

Benjamen Rathsack, Cyrus Tabery, Jeff Albelo, Peter Buck, C. Grant Willson

Proceedings Volume 4186, (2001) https://doi.org/10.1117/12.410739

KEYWORDS: Photomasks, Chromium, Reflectivity, Oxides, Absorption, Refraction, Chemically amplified resists, Lithography, Photoresist processing, Mask making

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Proceedings Article | 11 June 1999 Paper

Optical lithography simulation and photoresist optimization for photomask fabrication

Benjamen Rathsack, Cyrus Tabery, Steven Scheer, Mike Pochkowski, Cecilia Philbin, Franklin Kalk, Clifford Henderson, Peter Buck, C. Grant Willson

Proceedings Volume 3678, (1999) https://doi.org/10.1117/12.350173

KEYWORDS: Photomasks, Refraction, Lithography, Picture Archiving and Communication System, Data modeling, Photoresist materials, Device simulation, Chromium, Photoresist processing, Optical simulations

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Proceedings Article | 1 September 1998 Paper

Performance of the ALTA 3500 scanned-laser mask lithography system

Peter Buck, Alex Buxbaum, Thomas Coleman, Long Tran

Proceedings Volume 3412, (1998) https://doi.org/10.1117/12.328807

KEYWORDS: Etching, Photomasks, Lithography, Critical dimension metrology, Photoresist processing, Calibration, Dry etching, Anisotropic etching, Wet etching, Plasma etching

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Proceedings Article | 28 July 1997 Paper

Post apply bake optimization for 6025 masks

Peter Buck, Robert Holmstrom

Proceedings Volume 3096, (1997) https://doi.org/10.1117/12.277273

KEYWORDS: Photomasks, Temperature metrology, Critical dimension metrology, Sensors, Lithography, Error analysis, Sensor calibration, Calibration, Etching, Aluminum

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Proceedings Article | 12 February 1997 Paper

Performance of a new high-NA scanned-laser mask lithography system

Henry Chris Hamaker, Peter Buck

Proceedings Volume 3236, (1997) https://doi.org/10.1117/12.301205

KEYWORDS: Composites, Photomasks, Critical dimension metrology, Error analysis, Etching, Image processing, Lithography, Reticles, Photoresist materials, Metrology

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Proceedings Article | 27 December 1996 Paper

Plasma etching of Cr films in the fabrication of photomasks: II. a comparison of etch technologies and a first look at defects

Thomas Coleman, Peter Buck, David Johnson

Proceedings Volume 2884, (1996) https://doi.org/10.1117/12.262796

KEYWORDS: Etching, Plasma etching, Plasma, Dry etching, Reactive ion etching, Critical dimension metrology, Chromium, Oxygen, Photomasks, Wet etching

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Proceedings Article | 8 December 1995 Paper

Plasma etching of chromium films in the fabrication of photomasks

Thomas Coleman, Peter Buck

Proceedings Volume 2621, (1995) https://doi.org/10.1117/12.228216

KEYWORDS: Etching, Oxygen, Dry etching, Plasma etching, Line edge roughness, Critical dimension metrology, Chromium, Wet etching, Photomasks, Photoresist processing

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Proceedings Article | 8 December 1995 Paper

Optimizing the use of multipass printing to minimize printing errors in advanced laser reticle-writing systems

Henry Chris Hamaker, Gary Burns, Peter Buck

Proceedings Volume 2621, (1995) https://doi.org/10.1117/12.228185

KEYWORDS: Printing, Reticles, Composites, Laser systems engineering, Critical dimension metrology, Performance modeling, Statistical analysis, Yield improvement, Photomasks, System identification

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Proceedings Article | 7 December 1994 Paper

Technical performance of the ALTA-3000 laser writer

Brian Grenon, D. Defibaugh, Donna Sprout, Henry Chris Hamaker, Peter Buck

Proceedings Volume 2322, (1994) https://doi.org/10.1117/12.195845

KEYWORDS: Photomasks, Printing, Lithography, Critical dimension metrology, Composites, Inspection, Manufacturing, Photomask technology, Bragg cells, Overlay metrology

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Proceedings Article | 7 December 1994 Paper

Investigation of a negative i-line resist with the CORE-2564 laser writer

Brian Grenon, Donna Sprout, William Aaskov, Peter Buck

Proceedings Volume 2322, (1994) https://doi.org/10.1117/12.195810

KEYWORDS: Photoresist processing, Photomasks, Etching, Temperature metrology, Lithography, Wet etching, Photomask technology, Chemistry, Dry etching, Critical dimension metrology

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Proceedings Article | 17 May 1994 Paper

Techniques for improving overlay on multilayer phase-shift masks

Henry Chris Hamaker, Michael Bohan, Peter Buck, Claudia Geller, Takashi Makiyama, Francis Mathew, William Neeland

Proceedings Volume 2197, (1994) https://doi.org/10.1117/12.175411

KEYWORDS: Optical alignment, Overlay metrology, Printing, Photomasks, Metrology, CCD cameras, Cameras, Etching, Error analysis, Tolerancing

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Proceedings Article | 15 February 1994 Paper

Comparison of wet and dry chrome etching with the CORE-2564

Peter Buck, Brian Grenon

Proceedings Volume 2087, (1994) https://doi.org/10.1117/12.167247

KEYWORDS: Etching, Dry etching, Critical dimension metrology, Wet etching, Photoresist processing, Photomask technology, Picture Archiving and Communication System, Reactive ion etching, Contamination, Edge roughness

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Proceedings Article | 26 March 1993 Paper

Understanding CD error sources in optical mask processing

Peter Buck

Proceedings Volume 1809, (1993) https://doi.org/10.1117/12.142151

KEYWORDS: Etching, Photomasks, Critical dimension metrology, Photoresist processing, Picture Archiving and Communication System, Lithography, Cadmium, Reflectivity, Metrology, Electron beam lithography

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Proceedings Article | 1 June 1992 Paper

Lithographic alternatives to PSM repair

Michael Rieger, Peter Buck, Mark Shaw

Proceedings Volume 1674, (1992) https://doi.org/10.1117/12.130356

KEYWORDS: Photomasks, Semiconducting wafers, Phase shifts, Lithography, Optical lithography, Critical dimension metrology, Printing, Photomicroscopy, Wafer-level optics, Submicron lithography

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Proceedings Article | 1 January 1992 Paper

Specifying phase-shift mask image quality parameters

Peter Buck, Michael Rieger

Proceedings Volume 1604, (1992) https://doi.org/10.1117/12.56954

KEYWORDS: Etching, Photomasks, Phase shifts, Semiconducting wafers, Quartz, Coating, Image quality, Thin film coatings, Control systems, Lithography

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Proceedings Article | 1 July 1991 Paper

Phase-shift mask applications

Peter Buck, Michael Rieger

Proceedings Volume 1463, (1991) https://doi.org/10.1117/12.44806

KEYWORDS: Photomasks, Phase shifts, Manufacturing, Coating, Lithography, Semiconducting wafers, Printing, Phase shifting, Etching, Optical alignment

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Proceedings Article | 1 June 1990 Paper

0.5-um optical mask process for 364-nm scanned laser lithography

Peter Buck

Proceedings Volume 1264, (1990) https://doi.org/10.1117/12.20186

KEYWORDS: Photomasks, Lithography, Etching, Chromium, Electron beam lithography, Optics manufacturing, Oxides, Optical lithography, Critical dimension metrology, Wet etching

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Proceedings Article | 1 June 1990 Paper

Resolution performance of a 0.60-NA, 364-nm laser direct writer

Paul Allen, Peter Buck

Proceedings Volume 1264, (1990) https://doi.org/10.1117/12.20200

KEYWORDS: Printing, Optical lithography, Semiconducting wafers, Sensors, Gaussian beams, Photoresist materials, Photomasks, Optical alignment, Mirrors, Calibration

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