This guy has a laser engraver manufacturing business, and he's nixed the notion of using a laser to remove the Cu from the Cu-clad. Apparently not enough of the energy would stay on the Cu long enough to do the work, and where it goes from there is a hazard.

If that were to work properly, one could etch in the same way those LPKF mills do it, and drill the holes in the process too. You could drill really fine holes that way! Another advantage might be that less copper has to be removed, and, of course, you could create those 2-mil tracks on 4-mil centers that way, too, without much risk of "overetching" or "underetching".

RE