"Real smart move - ain't it ? Guys do have brains and they crack it well ! "

There are a lot more possibilities of how to protect semiconductors from tampering. Usually used in smart cards and ATM encryption cards and/or devices.

Like wires embedded in the casing of the device that disable the device when broken.
Special Radiation sensors if the device is irradiated by an point beam (to break certain paths so you can prevent wiping of the data in the device).
Light sensors is also one.
Strange layout of the chip making it difficult to reverse engineer (making it more costly and time consuming.
And covering the die with Teflon or some other acid resistant material that doesnt dissolve equally (by varying the thickness and local composition).

Combine these in one or more devices, makes it quite hard. Or too lengthy so they keys would have expired long time ago.