High-Speed PCIe Digitizers for Scanning Acoustic Microscopy and Semiconductor Package Inspection
Scanning acoustic microscopy (SAM) uses ultrasonic echoes to reveal internal interfaces and anomalies in semiconductor packages. The acquisition subsystem must reliably capture the receiver waveform at many scan positions and enable accurate timing and amplitude analysis.
Application overview
A pulser excites a focused ultrasound transducer. Echoes return from package interfaces, are converted to electrical signals and pass through a receiver. The digitizer captures each A-scan waveform while scanning motion and acquisition timing are coordinated. Software applies depth gating, time-of-flight and amplitude analysis to form acoustic images.
Challenges faced by equipment developers
High-frequency echoes: Some acoustic microscopes operate with transducers at hundreds of MHz; electrical receiver bandwidth must be matched to the digitizer input.
Closely spaced reflections: Echo timing and waveform shape require adequate bandwidth, trigger repeatability and suitable processing.
Inspection speed: Acquiring many scan points can strain trigger throughput, acquisition dead time, buffering and PCIe transfer.
Weak defect signatures: Analog gain, noise, input range, effective resolution and coupling influence detectability.
Where the PCIe digitizer fits
Typical waveforms and acquisition behavior
Digitizer selection checklist
| Selection factor | Engineering consideration |
|---|---|
| Received frequency | Choose based on the full electrical echo spectrum rather than transducer center frequency alone. |
| Timing | Confirm trigger-to-sample behavior, minimum re-arm time and synchronization to stage coordinates. |
| Resolution / SNR | Evaluate weak reflections and high-amplitude echoes across realistic input conditions. |
| Throughput | Estimate scan-point count × waveform length × bytes/sample; assess onboard feature extraction only if truly supported. |
Example engineering calculation
A 1,000 × 1,000-position scan capturing 4,096 samples per position at 2 bytes/sample produces 8.192 GB of raw waveforms (decimal GB), before metadata. Selective depth-window capture or validated feature extraction can reduce storage requirements.
Product integration opportunities
PCIe digitizer suitability must be checked against the selected model’s analog bandwidth, resolution, channel configuration, trigger design, memory and sustained host throughput. Confirm required functions and available configurations for your application.
Potential applications include:
- Semiconductor package delamination and void detection
- Advanced packaging and electronic component NDT
- High-frequency acoustic microscopy
- Materials and bonded-interface characterization
Frequently asked questions
What rate is suitable for SAM?
Choose it from receiver signal bandwidth, timing requirements and waveform-processing needs; there is no universal rate.
Will 10 GS/s always improve C-scan results?
No. The acoustic transducer, receiver SNR, focus, synchronization and processing can be limiting.
Can the card connect to an automated inspection system?
It can be evaluated as the acquisition component when host software, trigger and sustained throughput satisfy the design.
Application references
Discuss your application
Provide transducer frequency, receiver bandwidth, scan resolution, waveform window and repetition rate to evaluate a PCIe digitizer.