Interesting: “It is by no means uncommon” for modern IC integration design engineers to assume the fast obsolescence of the end product, and therefore IC environmental protections are not incorporated. Such devices will therefore have short lifetimes by design, and while that’s not a problem in market due to fast obsolescence, it means that you’re SOL if you want to keep such a device for an extended period of time.
It reminds me of the story of Henry Ford, who perused junk yards for his cars. He asked the proprietors which parts lasted longest, and then instructed his engineers to make those parts more cheaply because, by his reasoning, they were overbuilt.
Anyways, here’s the relevant quote:
The traditional functions of a semiconductor device package are to protect the die from degradation by the atmosphere and fan-out the electrical interconnects to the next level. Because of the benign environment in which most modern semiconductors are used coupled with short expected life through product obsolescence, the need for the package to provide environmental protection has virtually disappeared. It is by no means uncommon to see essentially package-less chips attached to circuit boards, with just a polymer covering over the exposed bond pads.