High-resolution computed laminography (HRCL) for electronic components

Flat assemblies, such as electronic circuit boards, can only be examined with insufficiently good resolution due to their usually large-area sample geometry. The distance between the X-ray source and the sample is usually too large to examine small sub-areas more precisely and to detect the smallest defects, such as cracks or pores, in solder joints (BGA, QFN, QFP).

Fraunhofer IKTS offers a special X-ray tomography method for this task, which can analyze partial areas of large-area circuit carriers, such as printed circuit boards, in a high-resolution and non-destructive manner. With the so-called high-resolution computed laminography (HRCL), Fraunhofer IKTS in Dresden has a unique method for PCB examination at its disposal, in which the specimen can be examined with high resolution (up to 1.5 µm³) and with only one rotation. Extensive sample preparation for PCB inspection is no longer necessary. The HRCL can also be used for automatic X-ray inspection (AXI).

Measuring principle

Functionality of high-resolution computed laminography for the study of flat electronic assemblies.

High-resolution computed laminography is an optimization of the cone beam tomography process. Due to the changed orientation of the X-ray tube and X-ray detector, HRCL allows a flat electronic assembly to be positioned very close to the X-ray source while maintaining full rotational freedom. Due to the modified measurement setup and an optimized reconstruction algorithm, high-resolution examination of printed circuit boards is no longer a problem.

For example, control boards for automotive or power electronics as well as systems embedded in CFRP structures can be analyzed non-destructively (completeness analysis, pore analysis, void analysis, dimensional stability analysis). HRCL often offers a substitute for the preparation of metallurgical sections or, with the results, it is possible to better plan a destructive test. The electronic assemblies can be subjected to further characterization directly after the measurement.

3D visualization of a BGA ball with cracks and voids.
Crack through the interposer of a BGA.
2D view of a 100 % crack in a BGA ball.

Fields of application

  • ­Printed circuit board inspections (AXI): completeness analysis, pore analysis, void analysis, dimensional stability analysis
  • ­Inspection of systems embedded in CFRP boards

Technical details

  • ­225 kV microfocus X-ray tube
  • ­2048 x 2048 pixel area detector
  • ­Maximum real resolution: 3 µm/Voxel
  • ­Maximum sample size: < 300 mm (< 700 mm with limitations in the measuring range)
  • ­Maximum sample weight: < 6 kg

Services offered

  • ­Non-destructive, high-resolution PCB inspection and small-batch inspection without preparation effort
  • ­Fully reconstructed data sets in the desired format
  • ­Support for data viewing software
  • Individual evaluation of measurement data