An intermittent failure in a next-generation pacemaker raised alarms in the implantable device industry. After months of operation, the main processor randomly lost connection. The 3D inspection pipeline, using VGSTUDIO MAX for volumetric analysis of high-energy X-rays, revealed the cause: a cold solder joint in a BGA on the circuit. Ultrasonic vibration during assembly had fractured the joint without visibly breaking it.
3D X-ray inspection and correlation with Allegro 🔬
The process began with a micro-CT scan of the control board. VGSTUDIO MAX allowed segmenting each solder sphere of the BGA and measuring its density and porosity. One of them showed a barely perceptible discontinuity in 2D, but clear in the three-dimensional reconstruction. By correlating the defect's position with the original design in Cadence Allegro, it was identified that this ball corresponded to the main power line of the processor. GOM Inspect was used to verify the mechanical deformation of the board, confirming that the stress induced by ultrasonic vibration had been the trigger for the failure.
Lessons for reliability in medical devices ⚕️
This case demonstrates that micro-soldering is not just a manufacturing problem, but a critical reliability point in devices that operate inside the human body. A cold solder joint can pass all initial electrical tests and fail months later. The combination of 3D X-ray inspection and analysis software like VGSTUDIO MAX becomes a non-negotiable requirement to ensure the lifespan of pacemakers and other active implants.
Since the cold solder joint in these pacemakers was detected through 3D X-ray computed tomography, what additive microfabrication or 3D assembly techniques could be implemented to prevent this type of intermittent failure in future implantable devices?
(PS: simulating a 200mm wafer is like making a pizza: everyone wants a slice)