An acoustic set up for the vibration analysis of silicon wafers

S. Mitterhofer, J. D. Pühringer, V. Schlosser,

Faculty of Physics, University of Vienna, Vienna, Austria

ABSTRACT -Two simple experimental set-ups for acoustic mode analysis of silicon wafers were established. Audible vibratory mode data of single- and multi-crystalline silicon wafers with different thicknesses were investigated. Natural frequency data were found to correlate linearly with the wafer thickness. The observed dependence is theoretically explained by the Kirchhoff plate model. Deviations from the linear variation are attributed to inhomogeneities and mechanical damage of the wafer. Mechanical defects are the reason for an increased fracture probability.

Keywords-silicon wafer; vibrations; diagnostics;