It's all about burn-in test. The silion wafer has some defects when produced, each element has to pass a final inspection. Therefore they have a so called burn-in chamber for test (don't know for the existance of freeze-in, probably not needed) where different temperatures are set, acording to the market destination. In consumer, most of ICs survive also if there is a defect. In industrial those with large defective wafer will fail, in military burning room, those with just small defect will fail. So if you are lucky, you can get a consumer part that is good as military. I forgot to mention- the test is usally destructive for defectous parts.

It's all about burn-in testing. The silicon wafer has some defects when produced, and each element has to pass a final inspection. Therefore they have a so-called burn-in chamber for testing (I don't know for the existence of freeze-in, probably not needed) where different temperatures are set, according to the market destination. 

In consumer, most of ICs survive also if there is a defect. In industrial, those with a large defective wafer will fail, in military burning room, those with just a small defect will fail.

So if you are lucky, you can get a consumer part that is good as military. I forgot to mention- the test is usually destructive for defective parts.