Round Robin Measurements of Mechanical Properties of MEMS
Abstract
A new method for tensile testing of thin films has been developed. The method employs AFM or STM acquired surface topologies of deforming specimens to determine (fields of) strains. An electrostatic grip apparatus was designed and implemented to measure the elastic and failure properties (Young's modulus, Poisson's ratio, tensile strength) of surface micromachined polysilicon specimens. The tensile specimens were "dog-bone" shaped ending in a large paddle' for electrostatic gripping. The deformation of a part of the test section is monitored by an Atomic Force Microscope (AFM). The topographic records of the specimen surface, obtained during the deformation, via Digital Image Correlation (DIC) method provide fields of strain. The natural surface features serve as distributed markers that depict the displacement field. An alternative operation mode, which employs tour thin gold markers to define a square area, as the base length of "micro-gages". In this mode the AFM determines the length changes between the markers. The effect of other parameters on property measurements, such as surface roughness, has been examined computationally. Results of elastic modulus values and fracture strength of small specimens are reported and compared to the results obtained by other researchers.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1999
- Accession Number
- ADA359725
Entities
People
- Ioannis Chasiotis
- Wolfgang G. Knauss
Organizations
- California Institute of Technology