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In our high-tech world, it’s easy to overlook the importance of the humble printed circuit board (PCB).
Buried in each electronic gadget or appliance there’s always at least one PCB and each one has to be perfect. There’s quite simply no latitude – a PCB fault will kill the device it’s part of.
Although they are largely passive platforms for surface mounted and leaded components, PCBs are by no means simple in design or easy to manufacture. Many of the fabrication processes have to be precisely controlled in case they destroy the board under construction or cause faults which will surface on the assembly line or in the field.
Now, to add to the challenges faced by PCB manufacturers, today’s already tiny PCBs are getting smaller and increasingly complex. The tolerances they have to work with are measured in microns and the faults they have to guard against are, quite literally, microscopic and buried deep within the layers of the board.
To check each layer as it’s completed, automatic optical inspection (AOI) and flying probe tests verify copper pattern quality and the integrity of pad, trace and via connections. Those tests are relatively straightforward, but checking the completed board, where the interior layers are entombed and the faults being checked for are microscopic and probably latent, is far more difficult.


KeyWords Tag：electronic printed circuit board