20 layer board that is 200 micron thick. That is 10 micron per layer. Only hope that guys are not pulling a fast one !!

Very frankly I never even knew that 20 layer PCBs existed- I was under the (foolish) impression that 6 layers is the limit. Wonder what kind of circuit complexity will call for 20 layers - or is it one of those "if it can be done , it will be done " stuff ?

Raghu