| 摘要 |
A method and apparatus for in-line mechanical quality control of wafers, the method allows for fast detection of cracks including the determination of their size and position on a wafer. The method comprises steps of coupling the wafer and an actuator and exciting a superposition of ultrasonic vibrations in the wafer by sweeping the frequency of the actuator simultaneously around at least two predetermined resonance peaks, recording the resonance frequency, amplitude and bandwidth of resonant frequency curves and comparing that with the resonance frequency, amplitude and bandwidth of reference frequency curves recorded for a mechanically sound crack- free standard wafer. Based on the comparison a reject- accept command is generated using a statistical rejection algorithm.
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