Test Quantification
Quality assurance programs utilize a structured repository of test points and simulated failure modes to measure the effectiveness of board diagnostic routines. This data structure, known as a fault coverage matrix, maps each potential electrical defect to the specific test step designed to detect it. Without this mapping, untested regions of the circuit can escape inspection and fail after assembly.
Boundary Development
Software simulators generate digital test vectors to evaluate the physical faults each test sequence can identify. Developing a fault coverage matrix involves running fault simulations on a circuit netlist, where each node is forced to a stuck-at high or low state. This systematic evaluation defines the boundaries of test coverage.
Board Yield
Production yield suffers when unmapped trace bridges slip through the screening process. Using the fault coverage matrix, factory engineers can identify unmonitored traces and revise the test program to add coverage for those areas. This revision ensures that solder bridges under fine-pitch packages are discovered before final packaging.
High-volume manufacturing relies on this matrix to guarantee escape rates remain below specified thresholds. An optimized test plan balances vector execution time with the percentage of tested components to optimize the overall cycle time.
