Testing microBGA solderability with local fiducials

How do you verify that your microBGA will actually solder well?

By measuring. And sometimes by creating little works of art. To assess the solderability of this BGA, the engineer designed test structures. Not to look pretty — but to make sure soldering won't bring any surprises.

In the detail photo you can see an important design detail:

The BGA contour is included in the solder mask. Not just in the silkscreen. Why?

• Silkscreen has limited accuracy
• Silkscreen height can interfere with the stencil

A mask outline stays visible, is more accurate and helps with quick visual alignment checks.

And for the Pick & Place machine we add local fiducials. Global reference is often not enough for fine-pitch.

Local fiducials increase placement accuracy and reduce the risk of marginal solder joints.

PCBAProtoLabLearnings PCBdesign MicroBGA Fiducials DFM HappyEngineering