Crack Detection in Full Size Cz-Silicon Wafers Using Lamb Wave Air Coupled Ultrasonic Testing (LAC-UT)

2011 ◽  
Vol 31 (1) ◽  
pp. 46-55 ◽  
Author(s):  
Sunil Kishore Chakrapani ◽  
M. Janardhan Padiyar ◽  
Krishnan Balasubramaniam
2006 ◽  
Vol 88 (11) ◽  
pp. 111907 ◽  
Author(s):  
A. Belyaev ◽  
O. Polupan ◽  
W. Dallas ◽  
S. Ostapenko ◽  
D. Hess ◽  
...  

2005 ◽  
Vol 108-109 ◽  
pp. 509-514 ◽  
Author(s):  
A.E. Belyaev ◽  
O. Polupan ◽  
W. Dallas ◽  
Sergei S. Ostapenko ◽  
D. Hess ◽  
...  

An experimental approach for fast crack detection and length determination in fullsize solar-grade crystalline silicon wafers using a Resonance Ultrasonic Vibrations (RUV) technique is presented. The RUV method is based on excitation of the longitudinal ultrasonic vibrations in full-size wafers. Using an external piezoelectric transducer combined with a high sensitivity ultrasonic probe and computer controlled data acquisition system, real-time frequency response analysis can be accomplished. On a set of identical crystalline Si wafers with artificially introduced periphery cracks, it was demonstrated that the crack results in a frequency shift in a selected RUV peak to a lower frequency and increases the resonance peak band width. Both characteristics were found to increase with the length of the crack. The frequency shift and bandwidth serve as reliable indicators of the crack appearance in silicon wafers and are suitable for mechanical quality control and fast wafer inspection.


2006 ◽  
Vol 21 (3) ◽  
pp. 254-260 ◽  
Author(s):  
A Belyaev ◽  
O Polupan ◽  
S Ostapenko ◽  
D Hess ◽  
J P Kalejs

Author(s):  
Junzhen Wang ◽  
Yanfeng Shen

Abstract This paper presents a numerical study on nonlinear Lamb wave time reversing for fatigue crack detection. An analytical framework is initially presented, modeling Lamb wave generation, propagation, wave crack linear and nonlinear interaction, and reception. Subsequently, a 3D transient dynamic coupled-field finite element model is constructed to simulate the pitch-catch procedure in an aluminum plate using the commercial finite element software (ANSYS). The excitation frequency is carefully selected, where only single Lamb wave mode will be generated by the Piezoelectric Wafer Active Sensor (PWAS). The fatigue cracks are modelled nucleating from both sides of a rivet hole. In addition, contact dynamics are considered to capture the nonlinear interactions between guided waves and the fatigue cracks, which would induce Contact Acoustic Nonlinearity (CAN) into the guided waves. Then the conventional and virtual time reversal methods are realized by finite element simulation. Advanced signal processing techniques are used to extract the distinctive nonlinear features. Via the Fast Fourier Transform (FFT) and time-frequency spectral analysis, nonlinear superharmonic components are observed. The reconstructed signals attained from the conventional and virtual time reversal methods are compared and analyzed. Finally, various Damage Indices (DIs), based on the difference between the reconstructed signal and the excitation waveform as well as the amplitude ratio between the superharmonic and the fundamental frequency components are adopted to evaluate the fatigue crack severity. The DIs could provide quantitative diagnostic information for fatigue crack detection. This paper finishes with summary, concluding remarks, and suggestions for future work.


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