alt Hacker NewsKind of.
There's a mysterious fab entity known as "the Recipe" - the product of long iterative dialing in of the fab's operating parameters. Of which there are a great many. A modern fab performs hundreds of manufacturing steps, with thousands of tweakable parameters, and they may interact in non-obvious ways to affect the outcomes. This is what's discovered and adjusted as the fab runs.
The difference between having the Recipe and not having the Recipe is the difference between 96% yield and 12% yield.
Changing the process (i.e. 4nm to 2nm) is the most sure way to lose the Recipe. The fab knowledge you spent months and years of engineering work discovering will no longer apply. But you can also lose the Recipe by replacing fab hardware, by changing the suppliers, by an act of god, and more.
Can a recipe be acquired and reproduced to perform correctly from the start? Say one line is performing well, can its parameters be copied over to a new one and start producing?
My head annoyingly refuses to accept the non-deterministic outcomes when applied to electronics. In other disciplines, let's say bow or musical instrument making, you need to harvest the wood, age it, dry it, pray to a deity, work with its natural im/perfections etc, but this is "just" bits.