Ultrasonic inspection is one of the most powerful methods in the field of non-destructive defect localization. It allows imaging through optically opaque materials for detecting local delaminations and voids with lateral resolutions in the range down to below 1 μm, depending on the applied frequency and the sample under investigation. Together with PVA TePla Analytical Systems GmbH, Fraunhofer CAM has developed an acoustic microscope set-up that covers the frequency range from 100 MHz up to 2 GHz. The system has been supplemented with an extended signal acquisition unit in order to increase signal sensitivity and image resolution but also to enable parametric imaging.
The acoustic microscope set-up provides a scan area of up to 2 mm and a defocus range of 7 mm to allow for shear- and Rayleigh wave excitation. Acoustic microscopy inspection is performed in pulse-echo mode. The application of highly focused large N.A. lenses provides a superior surface- and near-surface sensitivity for the detection of defects and voids down to 500 nm.
Key Features of the GHz-SAM:
- Acoustic frequency 100 MHz – 2 GHz
- Lateral resolution down to 0.7 μm
- Excitation of shear- and surface wave modes provided
- Combined time-resolved- and analog pre-processed data acquisition
- Extremely fast high-resolution scanner with 50 nm scan resolution
- Superior surface- and subsurface sensitivity