SGER: Feasibility Study of Novel Instrumentation With nN Force Resolution

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

Feasibility Study of Novel Instrumentation with nN Force Resolution NSF SGER Proposal submitted to Dr. Jorn Larsen-Basse By Andreas A. Polycarpou, Department of Mechanical and Industrial Engineering, UIUC The performance and durability of many devices that experience contact, especially micro/ nanodevices is heavily influenced by the surface properties and interfacial phenomena like adhesion,friction and wear. Research in the areas of friction, adhesion and nanomechanical properties of advanced engineering systems and miniature systems, such as the Head Disk Interface (HDI) in magnetic storage and microelectromechanical systems (MEMS), have advanced considerably. As the size scale of miniature systems shrinks further, finer tolerances are required, surfaces become smoother, thin-films become thinner and phenomena like strong intermolecular adhesion forces, high stiction and catastrophic failures at the interfaces may occur. Even though many of these problems have been alleviated or resolved, a major issue that remains and will be tackled in this research is the direct force measurement with extremely low resolution. The proposed one year exploratory research deals with the co-development and purchase of novel instrumentation capable for direct force measurements with very high resolution of 1 nN. Current state of the art direct force instruments are capable of 0.5 nN - 1 nN force resolution. The 3 orders of magnitude improvement in the force resolution will be accomplish by: (a) Significantly reducing the mass of the current systems from over 200 mg to 20 mg (using a combination of integrated circuit-IC and MEMS technologies). (b) Incorporating active vibration cancellation inside the force transducer. (c) Improving the drive electronics of the force transducer and actuator to minimize thermal drift. The proposed instrumentation will then be integrated with an existing multi-mode Atomic Force Microscope (AFM) and will be used to perform preliminary interfacial nanoscale experiments to demonstrate the nN force resolution capabilities. Specifically, two types of experiments will be performed: (a) iasub nanoindentationl-A experiments for extracting material properties of sub 10 nm ultra thin layers and (b) adhesion and pull-off force experiments using isidealln surfaces and actual surfaces from microsystems, e.g., low flying head-disk interfaces from magnetic storage. The significance of this research is that it will enable the feasibility of novel direct force measurement instrumentation capable of nN and possibly sub nN resolution and the capability of performing qualitative nanoindentation and adhesion experiments at small scales that were not possible before. The proposed research is exploratory and high risk due to the novel prototype low mass direct force transducers. The success of this research will have a great impact on the future of nanoscale testing and nanotribology. The PI's background in macrotribology and his approach of applying micro/nano techniques to explain phenomena at multiple length scales, his strong instrumentation background and his strong relation with novel sensor manufacturers, and industrial companies place him in a unique position to develop novel instrumentation capable of nN force resolution and investigate interfacial phenomena and mechanical properties of sub-nm thick layers.