Resonance ultrasonic vibration diagnostics of elastic stress in full-size silicon wafers

Abstract

A resonance vibration approach is developed to measure residual stress non-destructively in full-size multicrystalline silicon wafers used in solar cell manufacturing. This method is based on excitation of longitudinal resonance ultrasonic vibrations in the material using an external piezoelectric transducer combined with high-sensitive ultrasonic probe and data acquisition of the frequency response to make the method suitable for in-line diagnostics during wafer and cell manufacturing. Theoretical and experimental analysis of the vibration mode in single-crystal and multicrystalline silicon wafers is used to provide a benchmark reference analysis and validation of the approach.