Key test factors are grounded in geometry, pitch, and interconnect density – variables that directly affect probing, access, and test coverage. Known-good everything: The economic imperativeHigh-value AI accelerator companies change test strategies and test insertion steps based on economic drivers. This includes mechanical scale, current delivery, power dissipation, contact integrity, probe force, and thermo-mechanical warpage stability at probe. At this stage, electrical access is typically limited to C4 bump interfaces, requiring test to be performed before substrate attach using probe-based methods rather than traditional package test. As a result, test access must be brought physically closer to the device under test, thus minimizing parasitics and maintaining signal fidelity.