A PCB quality inspection enables faults to be detected as soon after the manufacturing process as possible. As such the PCB inspection process is an essential element of any PCB manufacturing process.

Looking to qualify a new process, or check up on one that has been turning out questionable products? Concerned that a subcontractor may have made a change in their materials, reflow process, or any of a countless number of variables that might spell disaster for your product reliability?

A PCB quality inspection and audit can help uncover these sorts of issues and bring you peace of mind – or, in the worst case, leverage with which to implement corrective action.

Fundamentals

A PCB quality inspection can be limited only to non-destructive analysis. An optical inspection may reveal process indicators, as those specified by IPC-A-600 and IPC-A-610, which may be sufficient to determine whether a product has been produced to acceptable standards. Such an inspection can identify a wide range of defects and anomalies that could potentially be reliability pitfalls, such as incomplete solder mask coverage or via and thru-hole misregistration.

This inspection can be augmented by elemental analysis techniques like energy dispersive spectroscopy (EDS) or x-ray fluorescence (XRF) to characterize whether a change in materials has been made (for example, if a lead-free solder has been substituted for leaded solder). X-ray imaging can also identify issues internal to the board – misaligned blind vias, cracked traces, and so on.

Should non-destructive testing be insufficient, destructive physical analysis provides additional data for consideration. A cross-section can reveal information on plating thicknesses, the integrity of the board lamination, and more; other techniques like dye penetrant testing can reveal information about solder integrity.

Sample types

PCBs or PCAs of any size, unpopulated or populated, can be inspected for quality control. Some tests are only applicable to certain types of devices; spirit will advise you of our recommended methodology at the time of quotation.

Applications

• Continuous monitoring of an established process
• Qualification of a new device or process
• Comparative analysis of product produced by multiple subcontractors