Dr. Andrew R. Eckert Profile

Dr. Andrew R. Eckert

Research Staff Member at Tekscend Photomask Round Rock Inc

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Publications (9)

Proceedings Article | 14 May 2004 Paper

E-beam proximity effect parameters for sub-100nm features

Keith Mountfield, Andrew Eckert, XiaoMin Yang, Earl Johns

Proceedings Volume 5376, (2004) https://doi.org/10.1117/12.535766

KEYWORDS: Neck, Magnetism, Scattering, Semiconducting wafers, Head, Electrons, Tantalum, Computer aided design, Compact discs, Glasses

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Proceedings Article | 14 May 2004 Paper

Resist formulation effects on contrast and top-loss as measured by 3D-SEM metrology

Andrew Eckert, Carl Seiler, Robert Brainard

Proceedings Volume 5374, (2004) https://doi.org/10.1117/12.535723

KEYWORDS: Critical dimension metrology, Metrology, Data modeling, 3D metrology, Semiconducting wafers, 3D modeling, Systems modeling, Lithography, Photoresist processing, Data storage

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Proceedings Article | 16 June 2003 Paper

Three-dimensional imaging of isolated lines of negative e-beam resist

Andrew Eckert, Harold Gentile, Keith Mountfield, Carl Seiler, XiaoMin Yang, Earl Johns

Proceedings Volume 5037, (2003) https://doi.org/10.1117/12.482323

KEYWORDS: 3D metrology, Critical dimension metrology, Neck, 3D image processing, Stereoscopy, Semiconducting wafers, Metrology, Electron beam lithography, Scanning electron microscopy, Lithography

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We have implemented traditional CD-SEM metrology complimented with the 3D imaging capability of the VERASEM 3D CD-SEM from Applied Materials. 3D imaging is performed by tilting the SEM beam to capture images at two unique angles. Reconstruction of these images allows for the determination of resist thickness and sidewall angle at the same point the critical dimension, CD, is measured. These three output parameters provide the user with automated multi-metric lithographic process control. We have used these techniques to characterize e-beam lithography of isolated lines in ~0.6μm of negative resist at CDs between ~50 and ~100 nm. The flexibility of our e-beam lithography system allows us to expose an array of identical features with 30 distinct dose values over a small area of a wafer. We have characterized the resist CD and thickness as a function of small incremental decreases in dose. As the dose decreases so does the CD of the isolated resist line at a rate of ~1 nm per 1μC/cm² of area exposure. At a nominally high dose where the isolated line CD is ~100 nm the resist is measured by 3D imaging to be close to full thickness. The main observation is that the resist thickness erodes at a rate of ~5 nm in height per every 1nm decrease in CD down to the resolution limit of 50-60 nm. As the dose is further lowered the resist is then completely washed away. This subtle but significant loss in resist etch mask integrity could not have been observed by traditional top-down CD-SEM metrology alone. This also demonstrates the tilt capability of the VERASEM 3D to measure very thin resist films of ~100 nm. Additionally, we have successfully used this methodology to characterize this effect as a function of isolated line length from ~0.5-2.0μm, and resist thickness from ~0.25-0.6 μm. The CD is strongly correlated with the total isolated line length due to the e-beam proximity effect, while the resist erosion rate remains fairly constant. The resist erosion rate is also similar for the resist films regardless of initial thickness. However, we also confirm the trend that identical area doses produce larger CDs for thicker resist films with some subtle effects for the thinner films.

Proceedings Article | 16 June 2003 Paper

Electron-beam lithography method for sub-50-nm isolated trench with high aspect ratio

XiaoMin Yang, Andrew Eckert, Keith Mountfield, Harold Gentile, Carl Seiler, Stanko Brankovic, Robert Harris, Earl Johns

Proceedings Volume 5037, (2003) https://doi.org/10.1117/12.482343

KEYWORDS: Photoresist processing, Scanning electron microscopy, Magnetism, Plating, Real-time computing, Semiconducting wafers, Electron beam lithography, Thin films, Lithography, Atomic force microscopy

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Proceedings Article | 1 July 2002 Paper

Electron-beam lithography of isolated trenches with chemically amplified positive resist

Andrew Eckert, Richard Bojko, Harold Gentile, Robert Harris, Jay Jayashankar, Earl Johns, Kevin Minor, Keith Mountfield, Carl Seiler, XiaoMin Yang

Proceedings Volume 4688, (2002) https://doi.org/10.1117/12.472361

KEYWORDS: Semiconducting wafers, Plating, Critical dimension metrology, Lithography, Electron beam lithography, Scanning electron microscopy, Computer aided design, Thin film coatings, Scattering, Chemically amplified resists

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Proceedings Article | 29 June 1998 Paper

Polymer-bound sensitizer in i-line resist formulations

Premlatha Jagannathan, Charlotte DeWan, Andrew Eckert, Rebecca Mih, Kathleen Martinek, Charles Richwine, Leo Linehan, Wayne Moreau, Randolph Smith

Proceedings Volume 3333, (1998) https://doi.org/10.1117/12.312385

KEYWORDS: Polymers, Photoresist materials, Energy transfer, Lithography, Deep ultraviolet, Ultraviolet radiation, Absorbance, Microelectronics, Chemically amplified resists, Resistance

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Proceedings Article | 7 July 1997 Paper

Fluorescence detection of photoacid in chemically amplified resists

Andrew Eckert, Wayne Moreau

Proceedings Volume 3049, (1997) https://doi.org/10.1117/12.275890

KEYWORDS: Chemically amplified resists, Fluorescence spectroscopy, Quantum efficiency, Chemical analysis, Absorption spectroscopy

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Proceedings Article | 7 July 1997 Paper

Acid diffusion through polymer films

Ping Zhang, Andrew Eckert, C. Grant Willson, Stephen Webber, Jeff Byers

Proceedings Volume 3049, (1997) https://doi.org/10.1117/12.275903

KEYWORDS: Diffusion, Polymer thin films, Polymers, Luminescence, Sensors, Quartz, Photoresist materials, Critical dimension metrology, In situ metrology, Data analysis

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In order to perform 0.2 micrometer processes, one needs to study the diffusion of photoacid generators within the photoresist system, since diffusion during post exposure bake time has an influence on the critical dimension (CD). We have developed a new method to study the diffusion of photoacid generators within a polymer film. This new method is based on monitoring the change of the fluorescence intensity of a pH- sensitive fluorescent dye caused by the reaction with photoacid. A simplified version of this experiment has been conducted by introducing acid vapor to quench the fluorescence intensity of this pH sensor. A thin polymer film is spin cast onto the sensor to create a barrier to the acid diffusion process. During the acid diffusion process, the fluorescence intensity of this pH sensor is measured in situ, using excitation and emission wavelengths at 466 nm and 516 nm, respectively. Fluoresceinamine, the pH sensitive fluorescent dye, is covalently bonded onto the treated quartz substrate to form a single dye layer. Poly(hydroxystyrene) (M_n equals 13k, T_g equals 180 degrees Celsius) in PGMEA (5% - 18% by weight) is spin cast onto this quartz substrate to form films with varying thickness. The soft bake time is 60 seconds at 90 degrees Celsius and a typical film has a thickness of 1.4 micrometers. Trifluoroacetic acid is introduced into a small chamber while the fluorescence from this quartz window is observed. Our study focuses on finding the diffusion constant of the vaporized acid (trifluoroacetic acid) in the poly(hydroxystyrene) polymer film. By applying the Fick's second law, (I_t - I_o)/(I_(infinity ) - I_o) equals erfc [L/(Dt)^1/2] is obtained. The change of fluorescence intensity with respect to the diffusion time is monitored. The above equation is used for the data analysis, where L represents the film thickness and t represents the average time for the acid to diffuse through the film. The diffusion constant is calculated to be at the order of 10^-10 cm²/s to 10^-12 cm²/s. All the experiments are conducted at room temperature and are valid only for acid vapor. With different film thickness, it was found that the acid diffuses through the film with a similar diffusion constant. The diffusion is faster with increased solvent residue in the film (controlled by spin coating speed). The theoretical computer modeling of the local acid concentration with respect to acid diffusion is also performed.

Proceedings Article | 14 June 1996 Paper

Removable organic antireflection coating

John Sturtevant, Linda Insalaco, Tony Flaim, Vandana Krishnamurthy, James Meador, John Petersen, Andrew Eckert

Proceedings Volume 2724, (1996) https://doi.org/10.1117/12.241872

KEYWORDS: Etching, Semiconducting wafers, Absorption, Antireflective coatings, Photoresist materials, Plasma etching, Deep ultraviolet, Ultraviolet radiation, Plasma, Photoresist processing

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Showing 5 of 9 publications

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