Seminar Schedule – Spring 2018

Tuesday, April 24, 2018
Time: 3:30pm – 5:00pm
Place: WRW 102

Engineering Mechanics Challenges in Micro and Nanomanufacturing Applications

Michael A. Cullinan, University of Texas at Austin

The Nanoscale Design and Manufacturing Laboratory (NDML) at the University of Texas at Austin focuses on the design and development of novel processes and equipment for the manufacturing of micro and nanoscale devices and structures. This presentation will focus on two current projects in the NDML with significant engineering mechanics problems: (1) The mechanical testing of nanoscale additively manufactured structures and (2) The exfoliation of silicon wafers for flexible electronics manufacturing. The mechanical properties of nanoscale additively produced materials are highly dependent on the process parameters used to make these materials. However, there are significant challenges in measuring these properties because of the difficulties in handling and directly straining flexible nanoscale structures. In order to overcome these challenges, we have developed a MEMS-based tensile tester that can be directly integrated into the two photon polymerization (TPP) process. This allows the nanoscale structures to be directly printed onto the MEMS devices thus avoiding the need for post process handling and allowing us to get a direct measurement of the mechanical properties of the materials printed. The second half of this presentation will focus on a new method we have developed to precisely exfoliate thin sheets of silicon from bulk silicon wafers. This processes uses a compressive nickel film to create a stress concentration below the top surface of the wafer and polymer film with controlled tension to propagate a crack along this stress concentration. The advantage of this process is that it allows us to cheaply take electronics that have be fabricated using traditional manufacturing processes on bulk silicon wafers and turn them into flexible electronics using just one additional processing step. Many of the engineering mechanics challenges in precisely controlling the thickness of the exfoliated silicon sheets will be discussed in this presentation.

For further information, please contact Dr. Kenneth Liechti at kml@mail.utexas.edu or (512) 471-4164.