If you eliminated vulnerabilities due to evil doping, you can use a free electron laser to holographically capture the 3 dimensional structure inside, and then

If you eliminated vulnerabilities due to evil doping, you can use a free electron laser to holographically capture the 3 dimensional structure inside, and then you can compare the enlarged+scanned/digitally-captured patterns with those that you expect from simulating the holographic imaging. In certain settings this should work non-destructively, but that might require something like lapped (grinding the backside after fabrication to thin out the substrate) non-stacked >=22 nm chips.