11 ms·

foundry is a capital intensives business. the processing steps that is involved is like 300+. that's why you hear the term "yield" in the semis foundry busines

• hinkley 5y ago
  The more times you have to fiddle with something, the more opportunities you have to break it. It's compound interest essentially, and that can add up real fast. If you have 300 steps and by some freak coincidence, each step had exactly the same error rate, so that you lose N% at each step, then here are the overall yields: 1% loss: 4.9% yield 0.5% loss: 22.2% yield 0.1% loss: 74% yield 0.01% loss: 97% yield You have to have an error rate in the range of X failures per thousand per step to get above 50% yield, and X/10000 for a really good yield. And all of these things are so small that a spec of dust causes failures.