Method and apparatus for strain monitoring of printed circuit board assemblies

A method of testing a printed circuit board assembly for failure comprising the following steps:

• providing a printed circuit board;
• mounting at least one strain detector having a sensing portion formed of a non-ductile material on the printed circuit board;
• monitoring the sensing portion of the strain detector on the printed circuit board to determine if strain related failure has occurred;
• wherein monitoring the sensing portion of the strain detector includes determining if failure has occurred at a pre-defined location on a narrowed portion of the sensing portion of the strain detector that forms a weak link in the detector;
• wherein monitoring includes electrically inspecting the sensing portion to determine if an electrical property of the strain detector has changed
• mounting at least one integrated circuit package to the printed circuit board, the integrated circuit package having a plurality of corners;
• wherein the step of mounting at least one strain detector comprises mounting at least three strain detectors, each of the strain detectors located in proximity to a corner of the integrated circuit package, the longitudinal axis of the strain detector bisecting the adjacent corner;
• and
• wherein the step of observation is done by electronic method comprising the step of providing a strain monitoring device having a timer connected to at least one strain detector and a memory for storing results connected to the timer;
• sampling the capacitance of at least one of the strain detectors;
• and
• recording when the capacitance changes.

A printed circuit board assembly comprising:

• a circuit board substrate;
• a plurality of mounting points for receiving electrical components carried on the circuit board substrate;
• a plurality of electrically conductive pathways carried on the circuit board substrate between mounting points;
• and
• at least one strain detector mounted on the circuit board substrate, the strain detector formed of a non-ductile material;
• wherein one of the electrical components is an integrated circuit package having a plurality of corners, and further comprising:
• at least three strain detectors, each of the strain detectors located in proximity to a corner of the integrated circuit package, the longitudinal axis of the strain detector bisecting the adjacent corner;
• and
• a strain monitoring device having a timer connected to at least one strain detector and a memory for storing results connected to the timer.