Although I have read the Small Hole Reliability study by the IPC, I feel that it is very outdated (1988?). In those days, board fabricators were on a learning curve for small holes. Many process improvements have been put in place since then, including vibrators in the deposition baths to remove entrapped air bubbles. I stand by my earlier staement that removal of non-functional pads is much preferred by board houses. As layers increase, the amount of copper drilled through can be as much as .016" - .018"! It is time for the IPC to do another study instead of relying on a seemingly outdated document. Tom Coyle Field Services Engineer HADCO Corporation [log in to unmask]