Calculating Layer Registration Drift Budgets for High Layer Count Multilayers
Layer registration drift budgets require RSS vector stacking of material shrink, tooling clearance, and drill wander to protect inner layer annular rings.
Vector Stacking
Memory Allocation
The process of combining and loading multiple test vectors into the high-speed local memory of automatic test equipment allows sequential execution without pause. This practice, called vector stacking, prevents the tester from having to reload the memory from the main workstation during a run. It maximizes the efficiency of digital functional testing by keeping the test hardware running at full speed.
This technique is especially important for complex boards that require millions of patterns to verify operation. It minimizes the time spent in non-testing cycles and helps optimize test hardware utilization.
Test Compression
Memory capacity on testing pins is limited and expensive, forcing engineers to compress and structure the pattern sequence. By stacking the vectors, the compiler eliminates redundant cycles and optimizes the sequence. This compression ensures the entire suite fits within the physical constraints of the test channel cards.
It prevents the need for multiple slow load cycles.
Throughput Impact
Eliminating load pauses reduces the test time per board, which directly increases the throughput of the manufacturing line. High-speed testing is critical for high-volume consumer electronics where every second of machine time is calculated in the cost. Stacking vectors allows a continuous flow of boards through the test station.
This process reduces the overall cost of ownership of the test system.