Radiographic Inspection
Non-destructive X-ray attenuation measurements reconstruct three-dimensional cross-sectional imagery of encapsulated electronic assemblies and sensor packages. High-resolution micro-computed tomography resolves sub-micron structural features within sealed MEMS pressure sensors and ceramic packages. Rotating a sample between an X-ray source and a flat-panel detector yields projection images across three hundred sixty degrees.
Filtered back-projection algorithms convert X-ray shadowgraphs into volumetric voxel grids representing material density gradients.
Resolution Calibration
Metrological accuracy of non-destructive volumetric measurements relies on precise voxel size calibration using traceable sphere-distance standards. Implementing micro-computed tomography for sensor dimensional verification requires calibrating rotation axis tilt and focal spot size. X-ray tube focal spot drift broadens penumbral blur, degrading spatial resolution along internal structural boundaries.
Thermal expansion of the positioning stage introduces motion artifacts, requiring drift correction algorithms during multi-hour high-resolution scans. Dimensional tolerances verified on micro-CT scans are checked against physical coordinate measuring machine data to confirm absolute geometric accuracy. Beam hardening artifacts caused by preferential absorption of low-energy photons require physical copper filtering or polychromatic correction algorithms to prevent false density gradients.
Defect Identification
Void identification in epoxy potting compounds and wire bond detachment are located non-destructively through density thresholding. Advanced micro-computed tomography inspections detect micro-cracks inside ceramic substrates down to five hundred nanometers in width. Density segmentation isolates internal leadframe copper from surrounding polymer encapsulants to calculate volumetric void ratios.
Failure analysis workflows utilize virtual cross-sectioning to inspect internal mechanical failures without introducing preparation artifacts.
Density Limit
Attenuation contrast depends on atomic number differences and material density variations within the scanned payload. Heavy metal enclosures made of tungsten or gold attenuate X-rays intensely, causing photon starvation and streak artifacts when scanning through micro-computed tomography systems. Soft biological or low-density silicone encapsulants require phase-contrast imaging enhancement to achieve sufficient contrast.
Scan speed and resolution present an operational trade-off, where higher spatial resolution demands longer exposure times and increased radiation dose.
