Laser Microembossing of Thin Copper and Silver Foils with an Ultraviolet (UV) Excimer Laser
M. Ehrhardt, P. Lorenz and K. Zimmer
Laser microembossing is a micromanufacturing technique which enables the direct fabrication of three-dimensional microstructures in metal foils by replication. In the present study a simplified arrangement of pulsed laser microembossing is introduced which allows a more flexible fabrication process with laser microembossing using a laser scanning scheme. To demonstrate the capability of the manufacturing process microstructures were successfully transferred from high quality silica micromoulds into silver and copper foils by using ultraviolet (UV) excimer laser pulses. The replicated micropatterns had a high accuracy regarding the shape and the spatial resolution. An almost linear correlation between the laser fluence and the height of the embossed microstructures was observed. Surface analytical investigations of the embossed surface areas reveal an increase of the reflectivity due to the significant reduction of the surface roughness down to 3 nm root-mean-square (RMS). This smoothing effect appears both at the microstructures as well as at extended flat surface areas.
Keywords: Laser embossing, laser microembossing microforming, plastic deformation, planning, metal foil