Sure you can get to 100 DPPM in deep submicron, but it'll cost ya

The sub-100 DPPM numbers in deep submicron is being built, but the tolls is fairly steep. Traditional methods using simple fault models and pass/fail testing have to be abandoned in favor of probabilistic and statistical approaches. Tests generated for simple fault models detect numerous types of real defects. The cost is increased tester time, though this can be mitigated somewhat by the application of relatively new on-chip pattern compression schemes.