Mr. Ron A. Synowicki Profile

Ron A. Synowicki

Applications Engineer at JA Woollam

SPIE Involvement:

Author | Instructor

Proceedings Article | 27 April 2023 Presentation + Paper

Alignment and overlay through opaque metal layers

V. Blanco Carballo, E. Canga, C. Jehoul, A. Moussa, A. Tamaddon, C. Tabery, G. Gunjala, B. Menchtchikov, V. Zacca, S. Lalbahadoersing, A. den Boef, R. Synowicki

Proceedings Volume 12496, 124960I (2023) https://doi.org/10.1117/12.2658084

KEYWORDS: Ruthenium, Optical alignment, Semiconducting wafers, Overlay metrology, Oxides, Silicon, Metals, Etching, Scanners, Copper

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Proceedings Article | 17 October 2008 Paper

Spectroscopic ellipsometry applications in photomask technology

Ron Synowicki, James Hilfiker

Proceedings Volume 7122, 712231 (2008) https://doi.org/10.1117/12.801861

KEYWORDS: Photomasks, Silica, Refractive index, Ellipsometry, Pellicles, Data acquisition, Data modeling, Polarization, Spectroscopic ellipsometry, Surface roughness

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Development and manufacture of advanced photomasks requires understanding the optical properties of mask materials and the ability to carefully monitor and control the film thickness, refractive index, and absorption of each film layer. Spectroscopic Ellipsometry (SE), a nondestructive optical analysis technique for determination of film thickness, refractive index, absorption, and film microstructure has been applied to many applications in current and emerging areas of photomask technology. This work surveys a variety of applications including analysis of fused silica mask blanks, imprint lithography templates, free-standing pellicles, deposited films of chromium, chromium oxide, MoSi, and multiple layers of these materials. For fused silica substrates we determine the optical properties (n & k) versus wavelength as well as the surface roughness. The near-surface index and surface roughness are used as indicators of surface polishing quality, which is an issue in the use of photomask substrates as template stamps in imprint lithography. Pellicles are free-standing films stretched over a metal frame. Because these thin pellicles are much thinner than the light coherence length, spectroscopic ellipsometry can determine the thickness, refractive index, and absorbance of the pellicle versus wavelength via interference between light reflecting from the upper and lower surfaces of the film. It is also possible to measure pellicles suspended over an underlying mask. The optical constants (n & k) of MoSi films vary widely with deposition conditions due to both composition and microstructure. Films optimized for 248 nm and 193 nm wavelengths have been analyzed. Spectroscopic ellipsometry shows good sensitivity to surface roughness and index gradients through the MoSi films. Multilayer masks such as NTAR have multiple absorbing layers such as chromium and chrome oxide. It is possible to simultaneously analyze multiple data sets acquired from the front side, from the back side through the substrate, and transmitted data through the stack. This increases the information content in the data, allowing more details from the multilayer to be determined. It is also possible to measure the birefringence in mask substrates and coated masks by using ellipsometry in transmission mode. By establishing a known polarization state incident on the mask it is possible to analyze the polarization after transmission to determine the phase difference, which is used to measure the birefringence of the sample. For patterned structures such as gratings it is possible to measure polarization-dependent diffraction effects versus angle. Measurement can be made in either reflection or transmission mode. It is possible to independently measure both s- and p-polarization components and compare to theory. As photomasks become more complex, with increasing numbers of layers (such as multilayer mirrors for EUV masks) in-situ ellipsometry shows great promise, providing the ultimate characterization of each film by allowing measurement in real-time as each layer is added to the mask structure.

Proceedings Article | 28 May 2004 Paper

Immersion fluid refractive indices using prism minimum deviation techniques

Roger French, Min Yang, Michael Lemon, Ron Synowicki, Greg Pribil, Gerald Cooney, Craig Herzinger, Steven Green, John Burnett, Simon Kaplan

Proceedings Volume 5377, (2004) https://doi.org/10.1117/12.537727

KEYWORDS: Prisms, Refractive index, Liquids, Vacuum ultraviolet, Water, Thermal optics, Refraction, Immersion lithography, Nitrogen, Environmental sensing

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Proceedings Article | 2 November 2000 Paper

Variable angle spectroscopic ellipsometry in the vacuum ultraviolet

John Woollam, James Hilfiker, Thomas Tiwald, Corey Bungay, Ron Synowicki, Duane Meyer, Craig Herzinger, Galen Pfeiffer, Gerald Cooney, Steven Green

Proceedings Volume 4099, (2000) https://doi.org/10.1117/12.405820

KEYWORDS: Vacuum ultraviolet, Spectroscopic ellipsometry, Dielectrics, Silicon carbide, Refractive index, Ellipsometry, Thin films, Lithography, Data modeling, Crystals

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Proceedings Article | 5 July 2000 Paper

Fluoropolymers for 157-nm lithography: optical properties from VUV absorbance and ellipsometry measurements

Roger French, Robert Wheland, David Jones, James Hilfiker, Ron Synowicki, Fredrick Zumsteg, Jerald Feldman, Andrew Feiring

Proceedings Volume 4000, (2000) https://doi.org/10.1117/12.388988

KEYWORDS: Absorbance, Pellicles, Vacuum ultraviolet, Polymers, Ellipsometry, Thin films, Spectroscopy, Reflectivity, Optical properties, Absorption

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With the introduction of 157 nm as the next optical lithography wavelength, the need for new pellicle and photoresist materials optimized for this wavelength has produced much activity in optical characterization of thin film materials. Here we focus on ultra transparent fluoropolymers for 157 nm pellicle applications where absorbances below 0.01/micrometers are necessary to achieve transmissions above 98 percent. Transmission-based absorbance/micrometers measurements performed using VUV spectroscopy are characterized by rapid turn-around time, and are essential during the materials design and screening phase of a new materials development program. Once suitable candidate materials families have been identified for development into 157 nm pellicles, VUV ellipsometry becomes essential to model the film structure, characterize the complex index of refraction, and to tune the pellicle's etalon design. Comparison of VUV absorbance measurements of fluoropolymer thin films on CaF₂ substrates with VUV ellipsometry measurements of the same polymers on silicon substrates demonstrates some of the artifacts in, and helps define the accuracy of transmission based absorbance measurements. Fresnel interference fringes can produce transmission oscillations that can lead to underestimation, or even negative values, of the film absorbance. Film thickness nonuniformity can serve to reduce the Fresnel interference fringes, leading to reduce variation in the apparent 157 nm absorbance for micrometers thick films. VUV ellipsometry coupled with Fresnel analysis of the thin film/substrate system formally takes into consideration all of these optical artifacts, while at the same time determining the complex index of refraction of the materials. Using VUV ellipsometry and Fresnel analysis, the absorbance values do not show the large apparent oscillations, the film thickness is directly determined in the measurement, and film microstructure is also modeled. We have identified ultra transparent fluoropolymers which have 157 nm absorbances below 0.01/micrometers . These materials have the appropriate optical properties for use as 157 nm pellicles with greater than 98 percent transmission. This is an important for the development of 157 nm lithography, since the lack of a 157nm pellicle has been identified as a critical path issue.

Proceedings Article | 2 June 2000 Paper

Optical characterization in the vacuum ultraviolet with variable angle spectroscopic ellipsometry: 157 nm and below

James Hilfiker, Bhanwar Singh, Ron Synowicki, Corey Bungay

Proceedings Volume 3998, (2000) https://doi.org/10.1117/12.386495

KEYWORDS: Refractive index, Thin films, Vacuum ultraviolet, Lithography, Silicon, Silicon films, Spectroscopic ellipsometry, Optical properties, Photoresist materials, Dielectrics

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Proceedings Article | 19 July 1999 Paper

Overview of variable-angle spectroscopic ellipsometry (VASE): I. Basic theory and typical applications

John Woollam, Blaine Johs, Craig Herzinger, James Hilfiker, Ron Synowicki, Corey Bungay

Proceedings Volume 10294, 1029402 (1999) https://doi.org/10.1117/12.351660

KEYWORDS: Spectroscopic ellipsometry

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Proceedings Article | 19 July 1999 Paper

Overview of variable-angle spectroscopic ellipsometry (VASE): II. Advanced applications

Blaine Johs, John Woollam, Craig Herzinger, James Hilfiker, Ron Synowicki, Corey Bungay

Proceedings Volume 10294, 1029404 (1999) https://doi.org/10.1117/12.351667

KEYWORDS: Spectroscopic ellipsometry

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Proceedings Article | 8 June 1998 Paper

Refractive-index measurements of photoresist and antireflective coatings with variable angle spectroscopic ellipsometry

Ron Synowicki, James Hilfiker, Ralph Dammel, Clifford Henderson

Proceedings Volume 3332, (1998) https://doi.org/10.1117/12.308747

KEYWORDS: Refractive index, Antireflective coatings, Data modeling, Photoresist materials, Spectroscopic ellipsometry, Data acquisition, Polarization, Ultraviolet radiation, Lithography, Monochromators

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Proceedings Article | 7 July 1997 Paper

Dependence of optical constants of AZ BARLi bottom coating on bake conditions

Ralph Dammel, John Sagan, Ron Synowicki

Proceedings Volume 3049, (1997) https://doi.org/10.1117/12.275896

KEYWORDS: Coating, Thin film coatings, Spectroscopic ellipsometry, Reflectivity

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Proceedings Article | 7 July 1997 Paper

Bleaching-induced changes in the dispersion curves of DNQ photoresists

Clifford Henderson, C. Grant Willson, Ralph Dammel, Ron Synowicki

Proceedings Volume 3049, (1997) https://doi.org/10.1117/12.275861

KEYWORDS: Refractive index, Photoresist materials, Lithography, Absorption, Absorbance, Ultraviolet radiation, Data modeling, Semiconducting wafers, Dielectrics, Spectroscopic ellipsometry

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Proceedings Article | 25 October 1996 Paper

Self-calibrating modulation ellipsometer

Stephen Ducharme, Hassanayn Machlab, Paul Snyder, John Woollam, Ron Synowicki

Proceedings Volume 2839, (1996) https://doi.org/10.1117/12.255374

KEYWORDS: Modulation, Etching, Calibration, Polarization, Modulators, Ellipsometry, Optical components, Sensors, Polarizers, Data acquisition

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Proceedings Article | 4 November 1994 Paper

Degradation of thin films in low-earth-orbit and comparisons with laboratory simulation

Blaine Spady, Ron Synowicki, Jeff Hale, M. DeVries, Natale Ianno, William McGahan, John Woollam

Proceedings Volume 2253, (1994) https://doi.org/10.1117/12.192089

KEYWORDS: Adaptive optics, Silicon carbide, Thin films, Aluminum, Silicon films, Diamond, Multilayers, Silicon, Oxygen, Solar concentrators

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Showing 5 of 13 publications

Course Instructor

SC539: Spectroscopic Ellipsometry Applications in Microlithography

Variable Angle Spectroscopic Ellipsometry (VASE) is an increasingly important metrology technique in microlithography. Used for thin film measurements of photoresists, antireflective coatings, photomasks, and optical coatings for steppers, the VASE technique is now routinely used over a wide spectral range from the vacuum ultraviolet to the mid infrared. This course surveys the fundamentals of spectroscopic ellipsometry including polarized light, light interaction with materials, refractive index and optical constants (n and k), refractive index dispersion, experimental instrumentation, data acquisition, data analysis, and physical interpretation of experimental results. Specific real-world examples of important lithograpic materials are considered throughout the course.

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SC1113: Fundamentals and Applications of Spectroscopic Ellipsometry

Variable Angle Spectroscopic Ellipsometry (VASE) is an important metrology technique used for measurements of thin films and optical properties of materials. Spectroscopic ellipsometry is now routinely used over a wide spectral range from the vacuum ultraviolet to the mid infrared in a variety of settings from research to production of optical coatings, semiconductors, displays, data storage, and solar cells. This course surveys the fundamentals of spectroscopic ellipsometry including polarized light, interaction of light with materials, refractive index and optical constants (n&k), refractive index dispersion, instrumentation, data acquisition, data analysis, and physical interpretation of experimental results. Specific real-world examples are considered throughout the course.

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