Applications
Semiconductor.
Packages and solder joints.
Inspection tasks
See every solder joint.
Packages hide their connections under the die and the mould compound. X-ray and CT show voids, bridges and misalignment joint by joint, for the laboratory and for the line.
BGA and flip-chip joints
Voids, solder-ball shift, head-in-pillow defects and bridges are separated layer by layer. Planar CT does this on the full board, without cutting it.
Leads and bond wires
Lifted or bent leads, open joints and bond-wire defects show in the 3D volume, where a 2D image superimposes them.
Failure analysis
Micro-cracks, micro-voids and delamination are located before the cross-section is made, so the cut goes through the right place.
Scan examples
What the data shows.
Systems
From the bond wire to the full board.
Royma offers X-ray and CT for semiconductor packages and the boards they sit on. The RMCT2000 resolves bond wires, micro-bumps and die-attach layers with a nanofocus mode of 0.9 µm spatial resolution or better, and switches to a 225 kV microfocus mode for larger samples up to ø 300 × 250 mm. The desktop RMCT1000 gives a failure-analysis laboratory a 4 µm CT on the bench, with one-click imaging for routine samples.
For populated boards the RMX3000 tilts the microfocus source and detector by ± 70° so that a BGA or a flip-chip joint is seen from the side, in 2D or as a 3D volume, at 1.5 µm spatial resolution and in the line. The RMPCT5500 scans the complete board layer by layer with planar CT, up to 760 × 660 mm, and returns an automatic measurement and a pass or fail result per joint; the RMLVX1850 inspects assemblies in 2D at line speed with 3 µm resolution.
The systems share the same analysis: void percentage per joint, solder-ball shape and shift, head-in-pillow detection and layer spacing, written to the board record. Semiconductor and packaging manufacturers gain a joint-by-joint result without cross-sectioning, and a laboratory that finds the fault before the section is cut.
In practice
Measured per joint, stored per board.
The software segments each solder ball or bump, calculates its void fraction, diameter and offset from the pad and compares the values with the limits set for the package. Bridges and opens are flagged with their position on the board, so a rework station receives coordinates rather than a picture.
In failure analysis the CT volume shows micro-cracks, delamination and voids before the sample is prepared, so the cross-section goes through the defect at the first attempt. Royma supports the programming from the board CAD data, so inspection regions follow the layout rather than being drawn by hand.
Questions
Questions about CT for semiconductor.
- Can X-ray inspect solder joints under a BGA without cutting the board?
- Yes. The RMX3000 views the joints at an angle of up to ± 70°, and the RMPCT5500 separates them layer by layer with planar CT. Voids, bridges and head-in-pillow defects are measured per joint on the intact board.
- What resolution is available for bond wires and micro-bumps?
- The RMCT2000 offers a nanofocus mode with a spatial resolution of 0.9 µm or better; the RMX3000 reaches 1.5 µm in the line. Which one applies depends on sample size and the required scan time.
- Is inline 3D inspection of boards possible?
- Yes. The RMX3000 and the RMPCT5500 are inline systems with automatic loading, automatic measurement and a pass or fail result; the RMPCT5500 scans a field of view in 2 seconds at its fastest setting.
- How does CT help failure analysis?
- The volume locates the defect in three dimensions before any preparation, so the physical cross-section is cut at the right place and the finding is documented on the undamaged sample first.
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