Semiconductors get old, and eventually die. It’s getting worse.

How do semiconductor companies plan for aging? There has never been a truly efficient solution, and according to this article, problems are getting worse. For example, electronics in cars continue to get more complex (and more safety critical). But cars are used in very different ways after being sold, and in very different climates.

Electromigration

Electromigration is one form of aging. Credit:  JoupYoup – Own work, CC BY-SA 4.0, 

When a device is used constantly in a heavy load model for aging, particular stress patterns exaggerate things. An Uber-like vehicle, whether fully automated or not, has a completely different use model than the standard family car that actually stays parked in a particular state a lot of the time, even though the electronics are always somewhat alive. There’s a completely different aging model and you can’t guard-band both cases correctly.

Aging is dealt with by heuristics, which typically add a “safety margin” to designs. But it’s not accurate, and leaves money (chip area = $ per chip) on the table.

Moreover, margin typically isn’t just one thing. It’s actually a stack.“The foundry, with the models that they give us, includes a little bit of padding to cover themselves,” said ANSYS’ Geada. “And then the library vendor adds a little bit of padding and nobody talks about what that is, but everybody adds up this stack of margin along the way. “

Source: Circuit Aging Becoming A Critical Consideration 

But of course, the semicon industry has been dealing with emerging challenges like this for its entire existence. Each new problem starts at a low stage of knowledge, beginning with Stage 0 (nobody knows the problem exists) and usually ending at about Stage 6.

Intel-AMD case

The lawsuit between Intel and AMD was settled a few weeks ago, five years after it was first filed by AMD. This was a private civil lawsuit; various government investigations are still going. According to reports, Intel agreed to pay $1,250,000,000, and to extend various license agreements with AMD. ($1.25 billion)

I was an expert witness on the case, which was an interesting experience to say the least. As an academic, I wish there were a way to use the data from civil lawsuits  cases for academic research. Of course, the confidential data itself has to be kept secret, but in principle it should often be possible to find ways to provide high-level analysis without revealing anything private.  As far as I know, though, this is never done. Certainly the standard agreements for using the data don’t allow it, and in practice it would probably take an agreement by both sides. The companies don’t seem to have much incentive to allow this. (I’m not speaking of AMD or Intel  or anything about this case in particular.)

There’s one  situation where some of the data does come out, namely if the case actually goes to trial. An example was the US vs Microsoft case in the late 1990s. But this is very rare – most cases settle before trial, and even when they don’t I gather that agreements to seal the data are standard.