Etching lasers generate too much heat for most ICs. Remember the IC itself is a tiny wafer of silicon (about the size of a typed dot (period). The connections are made in the epitaxial plastic from the wafer to the IC pins using ultra-thin conductors. If you heat the IC up too much, the wire or the bond to the wafer may be compromised or damage to the chip itself. Try old-fashioned engraving or milling.