Mr. Cheng-Tsung Lee Profile

Cheng-Tsung Lee

RET Design Engineer at Intel Corp

SPIE Involvement:

Author

Area of Expertise:

lithography , OPC , photoresist materials

Publications (11)

Proceedings Article | 1 April 2009 Paper

Understanding pattern collapse in high-resolution lithography: impact of feature width on critical stress

David Noga, Richard Lawson, Cheng-Tsung Lee, Laren Tolbert, Clifford Henderson

Proceedings Volume 7273, 727334 (2009) https://doi.org/10.1117/12.829142

KEYWORDS: Photoresist materials, Liquids, Lithography, Capillaries, Photoresist processing, Optical lithography, Head-mounted displays, Distortion, Scanning electron microscopy, Polymer thin films

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Proceedings Article | 15 April 2008 Paper

Effect of PAG and matrix structure on PAG acid generation behavior under UV and high-energy radiation exposure

Cheng-Tsung Lee, Mingxing Wang, Kenneth Gonsalves, Wang Yueh, Jeanette Roberts, Todd Younkin, Clifford Henderson

Proceedings Volume 6923, 69232F (2008) https://doi.org/10.1117/12.782634

KEYWORDS: Polymers, Polymer thin films, Ionization, Picosecond phenomena, Deep ultraviolet, Absorption, Photoresist materials, Molecules, Matrices, Photolysis

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Chemically amplified resists (CAR) have successfully facilitated the development of deep ultra-violet (DUV) and 193 nm lithography techniques for more than two decades due to their acid-catalyzed deprotection scheme that enhances their photospeed. This acid-catalyzed mechanism provides a method for amplifying the initial chemical reactions caused by interaction of radiation with the resist film, thus making each interaction event between radiation and resist more productive. However, when switching from low energy photolysis to high energy radiolysis, changes in the manner in which the radiation interacts with the resist material can alter the acid generation efficiency and mechanism of PAG excitation. In high energy radiation cases where the radiation energy exceeds the ionization potential of the PAG and the polymer resin, the radiation absorption in the resist film becomes non-selective. The ratio of PAG excited by direct excitation as compared to polymer or matrix sensitization pathways can shift heavily in favor of matrix sensitization in such high energy exposure cases. Such sensitization pathways may become a potential method for enhancing resist sensitivity under high energy radiation through careful selection of matrix and PAG materials. A better understanding and study the efficiency of acid generation through direct and indirect PAG excitation pathways and the effect of PAG and matrix structure on these pathways would be extremely valuable for the design of future high sensitivity resist materials. In this work, the acid generation of typical ionic (onium salt) and non-ionic PAGs under DUV (248 nm) and electron-beam exposure in polymer film have been studied. The effect of PAG type and structure on its acid generation under photolysis and radiolysis has been determined. The effect of polymer resin structure on PAG photoacid generation under photolysis and radiolysis has also been investigated. Concepts for PAG and polymer design for producing enhanced sensitivity resists for excitational and ionizational exposure is discussed.

Proceedings Article | 27 March 2008 Paper

Single molecule chemically amplified resists based on ionic and non-ionic PAGs

Richard Lawson, Cheng-Tsung Lee, Wang Yueh, Laren Tolbert, Clifford Henderson

Proceedings Volume 6923, 69230K (2008) https://doi.org/10.1117/12.773570

KEYWORDS: Molecules, Line edge roughness, Glasses, Diffusion, Image resolution, Deep ultraviolet, Polymers, Extreme ultraviolet lithography, Etching, Chemically amplified resists

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Proceedings Article | 26 March 2008 Paper

A new technique for studying photo-acid generator chemistry and physics in polymer films using on-wafer ellipsometry and acid-sensitive dyes

Cheng-Tsung Lee, Wang Yueh, Jeanette Roberts, Todd Younkin, Clifford Henderson

Proceedings Volume 6923, 692316 (2008) https://doi.org/10.1117/12.773393

KEYWORDS: Polymers, Polymer thin films, Polymethylmethacrylate, Absorbance, Ellipsometry, Lithography, Deep ultraviolet, Photolysis, Absorption, Chemistry

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Chemically amplified resists (CARs) are likely to continue to be the main resist materials platform for next generation lithography using shorter wavelength and higher energy radiation sources, such as extreme ultra-violet (EUV) and electron-beam (EB) lithography, to pattern features at and below the 32 nm technology node. As the cost of generating and manipulating high energy radiation in these techniques increases dramatically, photoacid generators (PAGs) with high sensitivities to these exposure sources are required to efficiently utilize such radiation and maintain high lithography tool throughputs. On the other hand, the high energy radiation used in current and next generation lithography tools can increasingly interact non-selectively with the PAG and polymer resin. Photoacid generation from PAG sensitization pathways involving the photoresist resin (e.g. polymer) becomes another potential route for boosting the photospeed of CARs if the PAG and matrix resin chemistry is selected properly. In this work, a fast, convenient, and material saving method which can measure the acid generation rate and yield under photolysis and radiolysis, as well as determine the efficiency of acid generation through direct PAG excitation and indirect PAG sensitization pathways has been developed. This method utilizes on-wafer ellipsometry to determine the absorption of protonated Courmarin 6 (C6) dye, which is incorporated into the polymer resin as a proton indicator. In this work, triphenylsulfonium triflate PAG is used in two different matrix resins, poly(methyl methacrylate) and poly(hydroxystyrene), to illustrate this point that matrix sensitization of the PAG can be important and can be studied using the method developed in this work. This study serves as the starting point for building the structure property relationships needed for intelligent PAG and matrix design to optimize exposure energy utilization in CARs. The validity of this new analytical method is verified by comparing our results in selected PAG-polymer combinations with results obtained from previous studies using different techniques. The potential measurement errors possible when using dye as the proton indicator in a solid-state medium, such as the probability of proton-dye contact and acid generation through dye radiation absorption and sensitization of the PAG, are also analyzed and discussed in this paper.

Proceedings Article | 26 March 2008 Paper

Water-developable negative-tone single-molecule resists: high-sensitivity nonchemically amplified resists

Richard Lawson, Cheng-Tsung Lee, Wang Yueh, Laren Tolbert, Clifford Henderson

Proceedings Volume 6923, 69231I (2008) https://doi.org/10.1117/12.773188

KEYWORDS: Molecules, Image resolution, Imaging systems, Line edge roughness, Electron beam lithography, Deep ultraviolet, Chemically amplified resists, Image processing, Switching, Diffusion

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Proceedings Article | 26 March 2008 Paper

Mesoscale simulation of molecular glass photoresists: effect of PAG loading and acid diffusion coefficient

Richard Lawson, Cheng-Tsung Lee, Wang Yueh, Laren Tolbert, Clifford Henderson

Proceedings Volume 6923, 69230Q (2008) https://doi.org/10.1117/12.774619

KEYWORDS: Line edge roughness, Diffusion, Molecules, Glasses, Critical dimension metrology, Polymers, Photoresist materials, Chemically amplified resists, Lithography, Solid modeling

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Proceedings Article | 26 March 2008 Paper

Synthesis and properties of new anionic photoacid generators bound polymer resists for e-beam and EUV lithography

Mingxing Wang, Cheng-Tsung Lee, Clifford Henderson, Wang Yueh, Jeanette Roberts, Kenneth Gonsalves

Proceedings Volume 6923, 692312 (2008) https://doi.org/10.1117/12.769004

KEYWORDS: Polymers, Absorption, Extreme ultraviolet lithography, Deep ultraviolet, Lithography, Line edge roughness, Polymer thin films, NOx, Silicon, Scanning electron microscopy

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Proceedings Article | 23 March 2007 Paper

Photosensitivity and line-edge roughness of novel polymer-bound PAG photoresists

Cheng-Tsung Lee, Mingxing Wang, Nathan Jarnagin, Kenneth Gonsalves, Jeanette Roberts, Wang Yueh, Clifford Henderson

Proceedings Volume 6519, 65191E (2007) https://doi.org/10.1117/12.713369

KEYWORDS: Polymers, Line edge roughness, Lithography, Analog electronics, Diffusion, Image resolution, Polymer thin films, Silicon, Photoresist materials, Semiconducting wafers

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Substantially improved photoresist material designs, which can provide higher photosensitivity and precise critical dimension and edge roughness control, will be required to enable the application of next generation lithography technology to the production of future sub-65 nm node IC device generations. The development and characterization of novel material platforms that solve the aforementioned basic problems with chemically amplified resists (CARs) is essential and is already one of the major subjects of modern lithography research. In that regard, we have pursued development of a variety of 193 nm and EUV CARs that contain photoacid generator (PAG) units covalently bonded directly to the resin polymer backbone. However, the detailed structure-property relationships that result from this direct attachment of the PAG functional group to the polymer have previously not yet been rigorously characterized. In this work, the lithographic properties of a polymer-bound PAG CAR (GBLMA-co-EAMA-co-F4-MBS.TPS) and its blended-PAG analog resist (GBLMA-co-EAMA blend F4-IBBS.TPS) were studied and compared. The direct incorporation of PAG functionality into the resist polymer, where the resulting photoacid remains bound to the polymer, showed improved photosensitivity, resolution, and lower LER as compared with the analogous blended-PAG resist. The improved resolution and LER were expected due to the restricted photoacid diffusion and uniform PAG distribution provided by direct incorporation of the PAG into the polymer backbone to make a single-component resist material. The ability to load higher levels of PAG into the resist provided by this PAG incorporation into the polymer, as compared to the low PAG concentrations attainable by traditional blending approaches, overcomes the sensitivity loss that should result from reduction in photoacid diffusivity and concomitant smaller acid-catalytic chain lengths. In fact, the polymer-bound PAG resist achieves a faster photospeed than the blended-PAG analog material under DUV radiation in the case of the materials reported here while still providing all of the aforementioned improvements such as the improved line edge roughness.

Proceedings Article | 23 March 2007 Paper

Novel anionic photoacid generator (PAGs) and photoresist for sub-50-nm patterning by EUVL and EBL

Mingxing Wang, Cheng-Tsung Lee, Clifford Henderson, Wang Yueh, Jeanette Roberts, Kenneth Gonsalves

Proceedings Volume 6519, 65191F (2007) https://doi.org/10.1117/12.712143

KEYWORDS: Polymers, Extreme ultraviolet lithography, Line edge roughness, Extreme ultraviolet, Photoresist materials, Electron beam lithography, Lithography, Polymerization, Image processing, Optical lithography

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Proceedings Article | 21 March 2007 Paper

Molecular glass photoresists containing photoacid generator functionality: a route to a single-molecule photoresist

Richard Lawson, Cheng-Tsung Lee, Robert Whetsell, Wang Yueh, Jeanette Roberts, Laren Tolbert, Clifford Henderson

Proceedings Volume 6519, 65191N (2007) https://doi.org/10.1117/12.712928

KEYWORDS: Glasses, Line edge roughness, Etching, Polymers, Photoresist materials, Deep ultraviolet, Extreme ultraviolet lithography, Diffusion, Molecules, Reactive ion etching

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Proceedings Article | 31 March 2006 Paper

Fundamental studies of the properties of photoresists based on resins containing polymer-bound photoacid generators

Cheng-Tsung Lee, Nathan Jarnagin, Mingxing Wang, Kenneth Gonsalves, Jeanette Robert, Wang Yueh, Clifford Henderson

Proceedings Volume 6153, 61532E (2006) https://doi.org/10.1117/12.663410

KEYWORDS: Polymers, Data modeling, Diffusion, Photoresist materials, FT-IR spectroscopy, Statistical modeling, Molecules, Extreme ultraviolet lithography, Polymer thin films, Reflectivity

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Showing 5 of 11 publications

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