AVS 51st International Symposium
    MEMS and NEMS Monday Sessions
       Session MN-MoM

Paper MN-MoM11
Microfabrication and Nanomechanical Characterization of Polymer MEMS for Biological Applications

Monday, November 15, 2004, 11:40 am, Room 213C

Session: Processing and Characterization for MEMS and NEMS
Presenter: G. Wei, The Ohio State University
Authors: G. Wei, The Ohio State University
B. Bhushan, The Ohio State University
N. Ferrell, The Ohio State University
D. Hansford, The Ohio State University
Correspondent: Click to Email
Polymer Microelectromechanical System (MEMS) devices are promising for biological applications such as development of biosensors and biomechanical devices. The relatively low stiffness and improved biological interface between cells and polymeric materials make polymer cantilever and beam structures attractive as highly sensitive force sensors for measuring cellular and biomolecular nanomechanics. In order to develop polymer Bio-MEMS, novel polymer microfabrication techniques are required, and the nanomechanics studies including measurement of the mechanical properties of the polymer materials in the nano scale must be carried out. This paper presents the development of soft lithography based polymer Bio-MEMS microfabrication techniques and systematic studies on the nanomechanical characterization of the polymer materials, polymer beams and polymer cantilevers. Poly (methyl methacrylate) (PMMA) and poly (propyl methacrylate) (PPMA) are used to make the polymer beams and cantilevers, which are 5 µm wide, 10-30 µm long and 200 nm-5 µm thick, for MEMS integration. The hardness, creep behavior and scratch resistance of the PMMA and PPMA microstructures were measured using nanoindentation/nanoscratch technique with a Nano Indenter II system, and the nanomechanical properties are compared with the bulk values. The elastic modulus of the polymer beam was obtained from the bending tests performed by nanoindentation, and the nano scale fatigue of the polymer cantilever was measured using the nanoindentation Continuous Stiffness Measurement (CSM) technique. To simulate the working environment of the polymer Bio-MEMS, PMMA and PPMA beams and cantilevers were also placed in an aqueous solution (saline, DI water, etc.), and nanoindentation experiments were performed on such samples. The results are discussed along with the dry condition values.