Mike,
Sorry I should have explained my thinking better.
My little CO2 laser operates at a wavelength which sees copper as the best possible reflector so there is no chance of even slightly etching the surface.
The fibre lasers, operating at a different wavelength, are good with metals but are relatively new technology and carry a commercial price tag. Home construction is doubtful at present because of the lack of availability of materials.
I have a YAG which cuts holes in aluminium in a single burst but I doubt it will touch copper - something for me to try one day perhaps.
I am guessing here but a laser to etch away copper is going to cost upwards of $20,000.
Tweakie.