METHOD FOR QUALITY CONTROL OF CONDUCTORS OF MULTILAYER PRINTED BOARDS Russian patent published in 2023 - IPC G01N25/72 H05K13/08 

FIELD: non-destructive quality control methods.

SUBSTANCE: invention can be used to visualize hidden defects in conductors of multilayer printed circuit boards (MPC). Visualization of hidden defects in layers with the MPC conductors is achieved by the fact that the MPC conductors are divided into groups that do not have electrical connections between them. All groups of conductors, except for one, are grounded with conductive probes. An ungrounded group of conductors is heated by electromagnetic radiation (EMI). After heating, open the protective screen of the thermal imager and record the thermogram. Upon completion of the control of the first group of conductors, its grounding is restored and the next group of conductors is subjected to control, disconnecting it from the ground, heating the EMI and registering a thermogram with a thermal imager, the procedure is repeated for all groups of conductors. The MPC conductors are heated in a reverberation chamber. Inside the camera is equipped with a transmitting antenna, a swivel mechanism with metal plates and a hole for attaching a thermal imager lens with a movable protective screen. Outside the chamber, a high-frequency signal generator is placed for generating EI in the chamber and a thermal imager for recording the MPC thermograms.

EFFECT: visualization of hidden defects in layers with the MPC conductors.

1 cl, 1 dwg