Excimer laser projection etching of copper foils in chlorine gas

Low-fluence XeCl laser etching of copper foils in a chlorine environment has been studied. The etch rate is fluence-dependent in the range 0.05–1.0 J cm^?2 and is governed by the growth characteristics of the chloride layer formed in the interpulse period. Projection etching with good pattern reproduction and resolution for high-aspect-ratio features is demonstrated.