Cisco Systems PCB manufacturing quality control

A Cisco PCB from circa 1997 used to illustrate the via-yield problem in multilayer board manufacture. Tom mentions student work at the New Hampshire plant.

[Tom holds up a smaller board.] A smaller one looks like this — this is from about 1997, Cisco Systems says on here. If you're trying to run the internet, this is going to go through one of these. They used to make these up at a little plant in New Hampshire. I had a student work up there, and they had lots of quality control problems, because you make something this complex — this one's not 21 thick, this is probably only 13 or 14 layers thick — but can you imagine how many tens or hundreds of thousands of dollars of electronic components are going to go on here, and every single one of these vias, every single one of these holes, has to make a connection. If it doesn't, you've got a horrendous quality control problem. How do you repair it, and you really don't want to throw it out, after you've put everything on it.