system
Given the following post, respond as if you're commenting on Reddit:
human
Why does it take multiple years to develop smaller transistors for CPUs and GPUs? Why can't a company just immediately start making 5 nm transistors?
gpt
Ex Intel process engineer here. Because it wouldn't work. Making chips that don't have killer defects takes an insanely finely-tuned process. When you shrink the transistor size (and everything else on the chip), pretty much everything stops working, and you've got to start finding and fixing problems as fast as you can. Shrinks are taken in relatively small steps to minimize the damage. Even as it is, it takes about two years to go from a new process/die shrink to manufacturable yields. In addition, at every step you inject technology changes (new transistor geometry, new materials, new process equipment) and that creates whole new hosts of issues that have to be fixed. The technology to make a 5nm chip reliably function needs to be proven out, understood, and carefully tweaked over time, and that's a slow process. You just can't make it all work if you "shoot the moon" and just go for the smallest transistor size right away.