Mr. Wonil Cho Profile

Wonil Cho

Applications Manager at Lasertec USA Inc

SPIE Involvement:

Author

Publications (25)

Proceedings Article | 21 November 2023 Presentation + Paper

Presentation + Paper

Die-to-database inspections of optical patterned masks

Christopher Wieland, Kristy Kormondy, Annelise Beck, Britain Smith, Firoz Ghadiali, Jun Kim, Frank Abboud, Tetsuya Sendoda, Naonari Kondo, Tomohiro Imahoko, Jeoung Kim, Chikato Kaga, Arosha Goonesekera, Wonil Cho, Sankaranarayanan Paninjath, Saikiran Madhusudhan, Prakash Deep, Shivam Nln, Sasidhara Reddy, Ranganadh Peesapati

Proceedings Volume 12751, 1275105 (2023) https://doi.org/10.1117/12.2688267

KEYWORDS: Inspection, Defect inspection, Photomasks, Optical inspection, Semiconducting wafers, Printing, Image processing, Detection and tracking algorithms, Defect detection

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Proceedings Article | 3 October 2018 Paper

Paper

Improving mask yield by implementing an advanced mask blank inspection system

Gregg Inderhees, Bill Kalsbeck, Alexander Tan, Paul Chung, JiUk Hur, Eric Kwon, Min Choo, Wonil Cho, Chan-Uk Jeon, IlYong Jang, In-Yong Kang, JeongHun Seo, Suein Son

Proceedings Volume 10810, 1081017 (2018) https://doi.org/10.1117/12.2511160

KEYWORDS: Inspection, Extreme ultraviolet, Photomasks, Reticles, Yield improvement, Coating, Optical lithography, Extreme ultraviolet lithography

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Proceedings Article | 26 October 2017 Paper

Paper

Classification and printability of EUV mask defects from SEM images

Wonil Cho, Daniel Price, Paul Morgan, Daniel Rost, Masaki Satake, Vikram Tolani

Proceedings Volume 10450, 1045006 (2017) https://doi.org/10.1117/12.2280837

KEYWORDS: Scanning electron microscopy, Photomasks, Extreme ultraviolet, Inspection, Extreme ultraviolet lithography, Defect detection, Line edge roughness

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Classification and Printability of EUV Mask Defects from SEM images EUV lithography is starting to show more promise for patterning some critical layers at 5nm technology node and beyond. However, there still are many key technical obstacles to overcome before bringing EUV Lithography into high volume manufacturing (HVM). One of the greatest obstacles is manufacturing defect-free masks. For pattern defect inspections in the mask-shop, cutting-edge 193nm optical inspection tools have been used so far due to lacking any e-beam mask inspection (EBMI) or EUV actinic pattern inspection (API) tools. The main issue with current 193nm inspection tools is the limited resolution for mask dimensions targeted for EUV patterning. The theoretical resolution limit for 193nm mask inspection tools is about 60nm HP on masks, which means that main feature sizes on EUV masks will be well beyond the practical resolution of 193nm inspection tools. Nevertheless, 193nm inspection tools with various illumination conditions that maximize defect sensitivity and/or main-pattern modulation are being explored for initial EUV defect detection. Due to the generally low signal-to-noise in the 193nm inspection imaging at EUV patterning dimensions, these inspections often result in hundreds and thousands of defects which then need to be accurately reviewed and dispositioned. Manually reviewing each defect is difficult due to poor resolution. In addition, the lack of a reliable aerial dispositioning system makes it very challenging to disposition for printability. In this paper, we present the use of SEM images of EUV masks for higher resolution review and disposition of defects. In this approach, most of the defects detected by the 193nm inspection tools are first imaged on a mask SEM tool. These images together with the corresponding post-OPC design clips are provided to KLA-Tencor’s Reticle Decision Center (RDC) platform which provides ADC (Automated Defect Classification) and S2A (SEM-to-Aerial printability) analysis of every defect. First, a defect-free or reference mask SEM is rendered from the post-OPC design, and the defective signature is detected from the defect-reference difference image. These signatures help assess the true nature of the defect as evident in e-beam imaging; for example, excess or missing absorber, line-edge roughness, contamination, etc. Next, defect and reference contours are extracted from the grayscale SEM images and fed into the simulation engine with an EUV scanner model to generate corresponding EUV defect and reference aerial images. These are then analyzed for printability and dispositioned using an Aerial Image Analyzer (AIA) application to automatically measure and determine the amount of CD errors. Thus by integrating EUV ADC and S2A applications together, every defect detection is characterized for its type and printability which is essential for not only determining which defects to repair, but also in monitoring the performance of EUV mask process tools. The accuracy of the S2A print modeling has been verified with other commercially-available simulators, and will also be verified with actual wafer print results. With EUV lithography progressing towards volume manufacturing at 5nm technology, and the likelihood of EBMI inspectors approaching the horizon, the EUV ADC-S2A system will continue serving an essential role of dispositioning defects off e-beam imaging.

Proceedings Article | 1 October 2013 Paper

Paper

Improving inspectability of sub-2x-nm node masks with complex SRAF

In Yong Kang, Gisung Yoon, Jonghee Lee, Donghoon Paul Chung, Byung-Gook Kim, Chan-Uk Jeon, Gregg Inderhees, Trent Hutchinson, Wonil Cho, Jiuk Hur

Proceedings Volume 8886, 88860O (2013) https://doi.org/10.1117/12.2030976

KEYWORDS: Inspection, Photomasks, SRAF, Printing, Source mask optimization, Calibration, Model-based design, Scanners, Lithography, Image processing

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Proceedings Article | 1 October 2013 Paper

Paper

A novel design-based global CDU metrology for 1X nm node logic devices

Young-Keun Yoon, Dong Chung, Min-Ho Kim, Jung-Uk Seo, Byung-Gook Kim, Chan-Uk Jeon, JiUk Hur, Wonil Cho, Tetsuya Yamamoto

Proceedings Volume 8880, 88801A (2013) https://doi.org/10.1117/12.2025694

KEYWORDS: Critical dimension metrology, Logic, Photomasks, Inspection, Cadmium, Metrology, Computer aided design, Logic devices, Semiconducting wafers, Wafer-level optics

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As dimension of device shrinks to 1X nm node, an extreme control of critical dimension uniformity (CDU) of masks becomes one of key techniques for mask and wafer fabrication. For memory devices, a large number of optical techniques have been studied and applied to mask production so far. The advantages of these methods are to eliminate the sampling dependency due to their high throughput, to minimize the local CD errors due to their large field of view (FOV) and to improve the correlation with wafer infield uniformity if they have scanner-like optics. For logic devices, however, CD-SEM has been a single solution to characterize CD performance of logic masks for a long time and simple monitoring patterns, instead of the cell patterns, have been measured to monitor the CD quality of masks. Therefore a global CDU of the mask tends to show its ambiguity because of the limited number of measurement sites and large local CD errors. An application of optical metrology for logic mask is a challenging task because patterns are more complex and random in shape and because there is no guarantee of finding patterns for CDU everywhere on the mask. CDU map still consists of the results from the indirect measurements and the traditional definition of uniformity, a statistical deviation of a typical pattern, seems to be unsuitable for logic CDU. A new definition of CDU is required in order to maximize the coverage area on a mask. In this study, we have focused of the possibility of measuring cell patterns and of using an inspection tool with data base handling capability, KLA Teron617, to find the areas and positions where the repeating patterns exist and the patterns which satisfy a certain set of condition and we have devised a new definition of CDU, which can handle multiple target CDs. Then we have checked the feasibility and validity of our new methodology through evaluation its fundamental performance such as accuracy, repeatability, and correlation with other CD metrology tools with a set of logic masks.

Proceedings Article | 14 October 2011 Paper

Paper

EUVL mask inspection using 193nm wavelength for 30nm node and beyond

Jihoon Na, Wonil Cho, Tae-Geun Kim, In-Yong Kang, Byungcheol Cha, Inkyun Shin, Han-Ku Cho

Proceedings Volume 8166, 81661H (2011) https://doi.org/10.1117/12.898896

KEYWORDS: Photomasks, Inspection, Semiconducting wafers, Extreme ultraviolet lithography, Modulation, Defect detection, Scanning electron microscopy, Scanners, Reflectivity, Wafer-level optics

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Proceedings Article | 2 April 2011 Paper

Paper

Current status of EUV mask inspection using 193nm optical inspection system in 30nm node and beyond

Sang Hoon Han, Jihoon Na, Wonil Cho, Dong Hoon Chung, Chan-Uk Jeon, HanKu Cho, Dana Bernstein, Eun Young Park, Anoop Sreenath, Shmoolik Mangan

Proceedings Volume 7985, 79850V (2011) https://doi.org/10.1117/12.895209

KEYWORDS: Photomasks, Inspection, Extreme ultraviolet, Extreme ultraviolet lithography, Signal to noise ratio, Optical inspection, Lithography, Scanners, Manufacturing, Semiconducting wafers

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Proceedings Article | 25 September 2010 Paper

Paper

An analysis of correlation between scanning direction and defect detection at ultra high resolution

Kwon Lim, SungPil Choi, Wonil Cho, Dong Hoon Chung, Chan-Uk Jeon, HanKu Cho

Proceedings Volume 7823, 782334 (2010) https://doi.org/10.1117/12.866017

KEYWORDS: Inspection, Photomasks, Sensors, Extreme ultraviolet lithography, Image processing, Defect detection, Image quality, Image sensors, Extreme ultraviolet, Semiconducting wafers

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Proceedings Article | 23 September 2009 Paper

Paper

Inspection of complex OPC patterns for 4x node and beyond

Sang Hoon Han, Wonil Cho, Won-Sun Kim, Dong Hoon Chung, Chan-Uk Jeon, HanKu Cho

Proceedings Volume 7488, 74882S (2009) https://doi.org/10.1117/12.830032

KEYWORDS: Inspection, SRAF, Optical proximity correction, Artificial intelligence, Defect detection, Semiconducting wafers, Photomasks, Reticles, Model-based design, Image resolution

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Proceedings Article | 23 March 2009 Paper

Paper

Requirements of the inspection for double patterning technology reticles

Wonil Cho, Won-Sun Kim, Sung-Joon Sohn, Sunpyo Lee, Jihyeon Choi, Yonghoon Kim, HanKu Cho

Proceedings Volume 7272, 72721T (2009) https://doi.org/10.1117/12.814101

KEYWORDS: Inspection, Reticles, Double patterning technology, Defect detection, Critical dimension metrology, Ear, Semiconducting wafers, Photomasks, Defect inspection, Radon

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Proceedings Article | 2 May 2008 Paper

Paper

EUV blank inspection

J. Peters, C. Tonk, D. Spriegel, Hak-Seung Han, Wonil Cho, Stefan Wurm

Proceedings Volume 6792, 67920F (2008) https://doi.org/10.1117/12.798594

KEYWORDS: Inspection, Extreme ultraviolet, Photomasks, Printing, Defect detection, Particles, Quartz, Signal detection, Data centers, Defect inspection

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Proceedings Article | 21 March 2008 Paper

Paper

Determining the critical size of EUV mask substrate defects

Hakseung Han, Wonil Cho, Kenneth Goldberg, Eric Gullikson, Chan-Uk Jeon, Stefan Wurm

Proceedings Volume 6921, 69211Y (2008) https://doi.org/10.1117/12.772590

KEYWORDS: Photomasks, Critical dimension metrology, Extreme ultraviolet lithography, Extreme ultraviolet, Semiconducting wafers, Charge-coupled devices, Inspection, Lithography, Scanners, Line width roughness

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Proceedings Article | 16 November 2007 Paper

Paper

Detectability and printability of EUVL mask blank defects for the 32-nm HP node

Wonil Cho, Hak-Seung Han, Kenneth Goldberg, Patrick Kearney, Chan-Uk Jeon

Proceedings Volume 6730, 673013 (2007) https://doi.org/10.1117/12.746698

KEYWORDS: Photomasks, Inspection, Extreme ultraviolet lithography, Semiconducting wafers, Defect detection, Critical dimension metrology, Extreme ultraviolet, Reflectivity, Manufacturing, Line width roughness

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Proceedings Article | 30 October 2007 Paper

Paper

The effect of size and shape of sub-50 nm defects on their detectability

Abbas Rastegar, Wonil Cho, Eric Gullikson, Sean Eichenlaub

Proceedings Volume 6730, 67305F (2007) https://doi.org/10.1117/12.746816

KEYWORDS: Particles, Gold, Inspection, Quartz, Silica, Photomasks, Optical spheres, Defect detection, Extreme ultraviolet, Atomic force microscopy

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Proceedings Article | 15 May 2007 Paper

Paper

EUV mask blank defect inspection strategies for 32-nm half-pitch and beyond

Stefan Wurm, Hakseung Han, Patrick Kearney, Wonil Cho, Chan-Uk Jeon, Eric Gullikson

Proceedings Volume 6607, 66073A (2007) https://doi.org/10.1117/12.729029

KEYWORDS: Inspection, Photomasks, Defect inspection, Extreme ultraviolet, Extreme ultraviolet lithography, Visible radiation, Printing, Wafer inspection, Mask making, Manufacturing

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Proceedings Article | 3 May 2007 Paper

Paper

EUV mask infrastructure challenges

Stefan Wurm, Phil Seidel, Chris Van Peski, Long He, Hakseung Han, Pat Kearney, Wonil Cho

Proceedings Volume 6533, 65330Z (2007) https://doi.org/10.1117/12.737154

KEYWORDS: Photomasks, Extreme ultraviolet, Inspection, Reticles, Defect inspection, Extreme ultraviolet lithography, Manufacturing, Semiconducting wafers, Standards development, Printing

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Proceedings Article | 13 March 2007 Paper

Paper

Inspection with the Lasertec M7360 at the SEMATECH Mask Blank Development Center

Wonil Cho, Patrick Kearney, Eric Gullikson, Anwei Jia, Tomoya Tamura, Atsushi Tajima, Hal Kusunose, Chan-Uk Jeon

Proceedings Volume 6517, 65170D (2007) https://doi.org/10.1117/12.712990

KEYWORDS: Inspection, Photomasks, Extreme ultraviolet lithography, Defect detection, Extreme ultraviolet, Reflectivity, Multilayers, Defect inspection, Atomic force microscopy, Optical spheres

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Proceedings Article | 4 November 2005 Paper

Paper

The detectability of Qz phase defects and its application for 65nm node CPL mask manufacturing

Won Il Cho, Jin Hyung Park, Dong Hoon Chung, Sung Woon Choi, Woo Sung Han

Proceedings Volume 5992, 599205 (2005) https://doi.org/10.1117/12.632335

KEYWORDS: Inspection, Photomasks, Defect detection, Deep ultraviolet, Manufacturing, Semiconducting wafers, Resolution enhancement technologies, Optics manufacturing, Lithography, Defect inspection

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Proceedings Article | 4 November 2005 Paper

Paper

Implementation of reflected light die-to-die inspection and ReviewSmart to improve 65nm DRAM mask fabrication

Do Young Kim, Won Il Cho, Jin Hyung Park, Dong Hoon Chung, Byung Chul Cha, Seong Woon Choi, Woo Sung Han, Ki Hun Park, Nam Wook Kim, Carl Hess, Weimin Ma, David Kim

Proceedings Volume 5992, 599209 (2005) https://doi.org/10.1117/12.632338

KEYWORDS: Inspection, Defect detection, Photomasks, Contamination, Binary data, Defect inspection, Nanoimprint lithography, Deep ultraviolet, Semiconducting wafers, Mask making

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Proceedings Article | 28 June 2005 Paper

Paper

Process monitoring system for instant defect detection and analysis in 65 nm node photomask fabrications

Young-Seok Cho, Jin-Hyung Park, Won-Il Cho, Jin-Hong Park, Yong-Hyun Kim, Seong-Woon Choi, Woo-Sung Han

Proceedings Volume 5853, (2005) https://doi.org/10.1117/12.617126

KEYWORDS: Inspection, Photomasks, Image processing, Etching, Defect detection, Signal processing, Particles, Signal detection, Manufacturing, Contamination

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Proceedings Article | 28 August 2003 Paper

Paper

Identification of defect source to control reticle defect density for CAR and dry etching in the photomask process

Sung-Yong Cho, Won-Suk Ahn, Won-Il Cho, Moon-Gyu Sung, Yong-Hoon Kim, Sung-Woon Choi, Hee-Sun Yoon, Jung-Min Sohn

Proceedings Volume 5130, (2003) https://doi.org/10.1117/12.504055

KEYWORDS: Particles, Inspection, Dry etching, Photomasks, Reticles, Manufacturing, Critical dimension metrology, Scanning electron microscopy, Etching, Chromium

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Proceedings Article | 27 December 2002 Paper

Paper

Identification of defect source to control reticle defect density for CAR and dry etching in the photomask process

Sung-Yong Cho, Won-Suk Ahn, Won-Il Cho, Moon-Gyu Sung, Seong-Yong Moon, Seong-Woon Choi, Hee-Sun Yoon, Jung-Min Sohn

Proceedings Volume 4889, (2002) https://doi.org/10.1117/12.468096

KEYWORDS: Particles, Inspection, Photomasks, Reticles, Dry etching, Manufacturing, Defect inspection, Scanning electron microscopy, Atomic force microscopy, Quartz

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Proceedings Article | 27 December 2002 Paper

Paper

PSM defect printability of extremely low-k1 sub-130-nm KrF lithography

Won-Il Cho, Gisung Yeo, Seong-Yong Moon, Hee-Sun Yoon, Jung-Min Sohn

Proceedings Volume 4889, (2002) https://doi.org/10.1117/12.468095

KEYWORDS: Inspection, Semiconducting wafers, Lithography, Reticles, Photomasks, Defect detection, Critical dimension metrology, Scanning electron microscopy, Lithographic illumination, Chromium

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Proceedings Article | 14 September 2001 Paper

Paper

Mask considerations for manufacturing assist features

Ji-Hyeon Choi, Won-Il Cho, Byeongsoo Kim, Seung-Hune Yang, Seong-Yong Moon, Seong-Woon Choi, Woo-Sung Han, Jung-Min Sohn

Proceedings Volume 4346, (2001) https://doi.org/10.1117/12.435681

KEYWORDS: Photomasks, Inspection, Optical proximity correction, Manufacturing, Critical dimension metrology, Semiconducting wafers, Transmittance, Defect detection, Phase shifts, Mask making

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Proceedings Article | 20 August 2001 Paper

Paper

Vacuum delay effect of CAR in mask fabrication

Chang-Hwan Kim, Chan-Uk Jeon, Sung-Jae Han, Won-Il Cho, Seong-Woon Choi, Woo-Sung Han, Jung-Min Sohn

Proceedings Volume 4343, (2001) https://doi.org/10.1117/12.436658

KEYWORDS: Critical dimension metrology, Mask making, Photoresist processing, Photomasks, Chromium, Diffusion, Optical proximity correction, Ions, Chemistry, Projection systems

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Showing 5 of 25 publications

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