There are three things I know mathematically about PCB yields: Defects that produce low yields may be systemic and repeatable, while others may be random (but you can test for this); you can predict yields if you take the time to collect the data; and yields are such wonderful things, so we should write about them more.
Yields are the dividing phenomena that often decide whether we make a profit. They certainly control our efficiency and throughput. Most customers acknowledge high yields with competence, control, and capability for the fabricator. So, why don’t you read more about them? I think it’s because we have been very poorly schooled in statistics. Not boring statistics like the kind I had in college with endless equations and proofs, where only the professor seemed to care about the endless stream of numbers. I’m talking about statistics that are fun and revealing, and a tool that every engineer must embrace. These kinds of statistics allow the numbers (yields) to reveal certain truths.
To read this entire article, which appeared in the November 2024 issue of PCB007 Magazine, click here.