Scanning Acoustic Microscopy
Scanning Acoustic Microscopy
Acoustic microscopy offers the unique advantage of examining the internal structure of a material non-destructively — such as ingots in the production of wafers and MEMS devices, which are opaque to infrared or X-ray methods. By measuring variations in acoustic impedance within the specimen, this technique generates clear contrasts that reveal hidden features. One notable property is the complete reflection of sound waves at air inclusions, producing bright signals and phase shifts. As a result, acoustic microscopy is highly effective in identifying material defects such as microcracks, inclusions, gas bubbles, and delamination, supporting quality assurance and advanced materials analysis.
Execution of non-destructive analyses
Scan modes of ultrasonic microscopy
Scanning modes - also known as imaging modes - can perform non-destructive analyses of the internal structure of components under the acoustic microscope. In particular, these imaging modes help to explain the individual layers and structures of components for delamination and crack detection. To get detailed insights, different imaging or scanning modes are used.
Overview of Scan Modes
The A-scan provides local time of flight from the sample — a time-dependent ultrasonic wave reflected by the component. This information digitizes the selected sample range by means of a previously selected data gate. This data gate for the quantitative time-distance measurement (echo time) is used to set electronic time windows in the depth. Appropriately selected ranges are then incorporated into the C-scan. A digital oscilloscope on the screen represents the incoming echo. If more than one time window is placed (X- or G-scans), multiple images are displayed on the monitor.
In principle, the B-scan involves stringing together A-scans. They produce a depth-resolved cross-section image of the component in the X direction. The gate is set for the entire time range, but can be configured by the user. With the help of the SAMnalysis software, additional options for the B-scan analysis are provided.
In this case, the gate is set at a specific depth and width (controlled in WINSAM). Scanning the component in the X and Y directions generates a stratified image of the component, whose width corresponds to that of the set data gate. In the event of delaminated surfaces, this area can be marked red immediately (display of phase inversion).
In the X-scan, more than 100 C-scan images of varying depth ranges can be generated simultaneously and displayed in real time during one scanning operation.
The Z-scan mode acquires three-dimensional data records (tomographic information) and enables off-line reconstructions of B-, C-, D-, P-, X-, A-, and 3D-scans as well as runtime measurements of the images with user-selectable gates. These can then be processed by the SAMnalysis and WINSAM software.
A transducer positioned above the sample emits an ultrasound signal, which is detected by a second transducer below the sample. This scanning mode provides the user with information about the structure of the sample. In this process, both transducers analyze the sample simultaneously.
Relevant industries
Energy
Scanning acoustic microscopy enables reliable, non-destructive inspection of power electronics and semiconductor components for the energy industry, ensuring quality and safety for critical applications. This technology detects internal defects such as delaminations, voids, cracks, and bonding issues in modules like IGBT, heat sinks, thin film layers, and advanced semiconductor devices.
Automotive
Non-destructive, comprehensive testing is essential for safety-critical automotive assemblies and components. As electric mobility advances, new technologies and power electronics in cars, ICEs, and trains must meet stringent quality standards. Our systems check compound materials, power electronics, sensors, control devices, seals, and welded, soldered, and sintered connections.
Semiconductor
Our systems provide non-destructive structural mapping to detect defects and connection errors in semiconductor production, supporting applications from frontend to backend. Typical checks include wafers, SiC and Si ingots, MEMS, die structures, microprocessors, LEDs, flip chips, power electronics, bonded interfaces, CMOS sensors, molded and passive components, and packaging.
Medical
Non-destructive acoustic microscopy reveals subsurface structures in medical samples without pretreatment, enabling reliable, high-quality analysis of implants, bones, tissue, cells, thrombus formation, and teeth. Ongoing collaboration with leading research institutes ensures continuous technological advancement for medical applications.
Interested in scanning acoustic microscopy?