br-558.pdf (1.87 MB)
eldrs-web.pdf (431 KB)
I would say after maybe 30 years of radiation effects testing you always see surprises. We have learned through experience to not make any assumptions about how a given part will act or not act. Low-dose rate effects have changed our strategy in its details, but it has not changed our strategy from a top level, and the radiation's strategy revolves around an acceptance testing model rather than a qualification model.
And what I mean by acceptance testing is that we sample each wafer as it comes out of the fabrication line, and we take these samples and run them through the entire high-rail processing cycle, and then we do just briefly a radiation test on it, and if we encounter any rejects in that radiation test then the wafer unfortunately it has to be discarded, and so we don't build in that wafer. And that provides insight and it provides quality assurance really at the most basic level of the integrated circuit's fabrication flow.
The wafer level as you know is as far down as you can go as far as traceability is concerned. The value to the customer of getting parts that have been through the low-dose rate testing program is one of assured performance in the low-dose rate environments, and this assurance is very much the same as the one in the past which was assured performance in a high-dose rate environment.