Dr. Tim E. Dallas Profile

Dr. Tim E. Dallas

Professor at Texas Tech Univ

SPIE Involvement:

Author

Area of Expertise:

Microelectromechanical Systems , Wireless Medical Sensors , MEMS , Nanocoatings

Dr. Tim Dallas is an Associate Professor of Electrical and Computer Engineering at Texas Tech University. He has an established research program in Microelectromechanical Systems (MEMS), nanocoatings, and wireless medical sensor systems. His MEMS group develops and tests various microactuators for micro/nano positioning applications, as well as systems for MEMS education. He is President and CTO of Class on a Chip, a company that commercializes MEMS education products. Dr. Dallas is part of a team of researchers, medical clinicians, and companies developing geriatric fall detection and prevention systems utilizing wireless MEMS sensor systems.

Proceedings Article | 15 February 2012 Paper

Characterization of flourocarbon SAM coated MEMS tribogauge

Ashwin Vijayasai, Gautham Ramachandran, Ganapathy Sivakumar, Charlie Anderson, Richard Gale, Tim Dallas

Proceedings Volume 8250, 82500B (2012) https://doi.org/10.1117/12.909301

KEYWORDS: Microelectromechanical systems, Capacitance, Actuators, Computer aided design, Particles, Scanning electron microscopy, Plasma, Humidity, Adhesives, LabVIEW

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Proceedings Article | 15 February 2012 Paper

Characterization of a nanocoating using a MEMS tribogauge

Ashwin Vijayasai, Gautham Ramachandran, Ganapathy Sivakumar, Charlie Anderson, Richard Gale, Tim Dallas

Proceedings Volume 8250, 82500C (2012) https://doi.org/10.1117/12.909335

KEYWORDS: Microelectromechanical systems, Coating, Nano coatings, Capacitance, Silicon, Actuators, Liquids, Reliability, Adhesives, Plasma

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Proceedings Article | 15 February 2012 Paper

Usage induced changes to surface topography and material properties in polysilicon MEMS electrothermal structures

Sahil Oak, Gautham Ramachandran, Tim Dallas

Proceedings Volume 8250, 825005 (2012) https://doi.org/10.1117/12.909180

KEYWORDS: Actuators, Microelectromechanical systems, Resistance, Oxides, Finite element methods, Atomic force microscopy, Annealing, Silica, Reliability, Coating

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Proceedings Article | 18 February 2010 Paper

Pseudo-analog electrostatic piston micromirror

Hao Gu, Ganapathy Sivakumar, Tim Dallas

Proceedings Volume 7595, 75950P (2010) https://doi.org/10.1117/12.842437

KEYWORDS: Mirrors, Electrodes, Micromirrors, Binary data, Computer aided design, Analog electronics, Control systems, Computer simulations, Digital micromirror devices, Performance modeling

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Proceedings Article | 18 February 2010 Paper

Mesoscale to microscale controlled manipulation of microscale objects using MEMS based microgripper and haptic interface

Ashwin Vijayasai, Ganapathy Sivakumar, Matthew Mulsow, Shelby Lacouture, Alex Holness, Tim Dallas

Proceedings Volume 7593, 75930J (2010) https://doi.org/10.1117/12.842298

KEYWORDS: Haptic technology, Microelectromechanical systems, LabVIEW, Control systems, Sensors, Actuators, Calibration, Liquids, Motion models, Capacitance

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Proceedings Article | 18 February 2010 Paper

MEMS-based sensing and algorithm development for fall detection and gait analysis

Piyush Gupta, Gabriel Ramirez, Donald Y. C. Lie, Tim Dallas, Ron Banister, Andrew Dentino

Proceedings Volume 7593, 75930U (2010) https://doi.org/10.1117/12.841963

KEYWORDS: Algorithm development, Gait analysis, Sensors, Detection and tracking algorithms, Microelectromechanical systems, Detector development, Wavelet transforms, Transform theory, Injuries, System integration

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Proceedings Article | 17 February 2010 Paper

Development and testing of a multi-level chevron actuator based positioning system

Sandesh Rawool, Ganapathy Sivakumar, Johan Hendriske, Daniel Buscarello, Immanuel Purushothaman, Tim Dallas

Proceedings Volume 7592, 75920Q (2010) https://doi.org/10.1117/12.842270

KEYWORDS: Actuators, Teeth, 3D modeling, Microelectromechanical systems, LabVIEW, Optical fabrication equipment, Motion models, Optical fabrication, Computing systems, Multilayers

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Proceedings Article | 17 February 2010 Paper

A 2-DOF MEMS positioning system

Ganapathy Sivakumar, James Mathews, Tim Dallas

Proceedings Volume 7592, 75920S (2010) https://doi.org/10.1117/12.842435

KEYWORDS: Computer aided design, Actuators, Microelectromechanical systems, Optical fabrication, Custom fabrication, LabVIEW, Digital cameras, Silicon, Electrodes, 3D modeling

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Proceedings Article | 17 February 2010 Paper

Rotating out-of-plane micromirror

Sahil Oak, Greg Edmiston, Ganapathy Sivakumar, Gabriel Ramirez, Tim Dallas

Proceedings Volume 7594, 75940H (2010) https://doi.org/10.1117/12.842003

KEYWORDS: Mirrors, Micromirrors, Optical fabrication, Mirror structures, Actuators, Beam steering, Optical switching, Optical multiplexing, Light emitting diodes, Laser optics

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Proceedings Article | 17 February 2010 Paper

Lifetime estimation and reliability study of electrothermal MEMS actuators

Ganapathy Sivakumar, Stephen Johns, Jesus Nava, Tim Dallas

Proceedings Volume 7592, 75920E (2010) https://doi.org/10.1117/12.842410

KEYWORDS: Actuators, Microelectromechanical systems, Reliability, Control systems, Computer aided design, LabVIEW, Image acquisition, CCD cameras, Failure analysis, Oxidation

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Proceedings Article | 5 February 2010 Paper

Low-cost system for testing MEMS for research and educational applications

Gabriel Ramirez, Ganapathy Sivakumar, Shelby Lacouture, Tim Dallas

Proceedings Volume 7592, 75920M (2010) https://doi.org/10.1117/12.842560

KEYWORDS: Microelectromechanical systems, Control systems, Actuators, Electronics, Physics, Computer aided design, LabVIEW, Computing systems, Scanning transmission electron microscopy, Micromirrors

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Proceedings Article | 5 February 2010 Paper

Remotely accessible laboratory for MEMS testing

Ganapathy Sivakumar, Matthew Mulsow, Aaron Melinger, Shelby Lacouture, Tim Dallas

Proceedings Volume 7592, 75920K (2010) https://doi.org/10.1117/12.842465

KEYWORDS: Microelectromechanical systems, Video, Internet, Control systems, Video compression, Microscopes, Cameras, CCD cameras, Haptic technology, Computer aided design

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Proceedings Article | 5 February 2010 Paper

Reliability study of a MEMS array under varying temperature and humidity conditions

Ganapathy Sivakumar, Ranjith Ranganathan, Richard Gale, Tim Dallas

Proceedings Volume 7592, 75920C (2010) https://doi.org/10.1117/12.842384

KEYWORDS: Microelectromechanical systems, Mirrors, Humidity, Failure analysis, Coating, Reliability, Micromirrors, Molecules, Atomic force microscopy, Temperature metrology

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Proceedings Article | 30 December 1999 Paper

Characterization of a non-chemically amplified resist for photomask fabrication using a 257-nm optical pattern generator

Benjamen Rathsack, Cyrus Tabery, Timothy Stachowiak, Tim Dallas, Cheng-Bai Xu, Mike Pochkowski, C. Grant Willson

Proceedings Volume 3873, (1999) https://doi.org/10.1117/12.373362

KEYWORDS: Picture Archiving and Communication System, Photomasks, Absorption, Lithography, Absorbance, Transparency, Deep ultraviolet, Photoresist processing, Photoresist developing, Mask making

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I-line optical pattern generators using non-chemically amplified resists have become the workhorses for high throughput mask fabrication. The demand for smaller and more uniform features on photomasks has driven the development of a 257 nm optical pattern generator. A non-chemically amplified resist is being developed to maximize the performance of this new 257 nm mask tool. Resist characterization and lithography simulation are being used to formulate a non-chemically amplified resist for 257 nm optical pattern generators. Non- chemically amplified resists are advantageous for us in mask fabrication due to their storage and post-exposure stability. Chemically amplified resists may provide higher performance but they also require environmental mini-environments and a post-exposure bake equipment not commonly present in mask houses. Diazonaphthoquinone (DNQ)/novolak resists have not been used for DUV Integrated Circuit (IC) applications mainly due to the low sensitivity and the strong absorbance of the DNQ photoactive compound (PAC) at 248 nm. However, a 2,1,4 DNQ based resist has been characterized that bleaches at 257 nm and inhibits novolak. The photoproduct of the 2,1,4 DNQ PAC is much more transparent at 257 nm than 248 nm. Novolak resin is too strongly absorbing for use in formulating efficient 248 nm resists, but novolak has an absorbance minimum at 257 nm that provides transparency similar to poly (hydroxystyrene). Lithography simulation is being used to develop a non- chemically amplified resist to minimize the expensive iteration of manufacturing trials. An exposure system using a 257 nm frequency double Ar laser system has been constructed to study the resist photokinetics. Dill exposure parameters (A, B and C) have been extracted for a 2,1,4 DNQ/novolak based resist. Dissolution rate measurements have been made with a DRM developed at the University of Texas at Austin. Simulation is used to determine the optimal resist absorption, bleaching, dose and dissolution properties to maximize resolution. It is possible to formulate a high performance resist for 257 nm if care is taken in optimization of the formulation.

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