EXCIMER-LASER PROCESSING OF BK7-GLASS AND BGG31-GLASS

Large-area excimer laser processing of BK7 and BGG31 glasses was inves tigated for laser etching and laser-assisted metallization. Laser etch ing experiments were performed at wavelengths of 193, 248 and 308 nm a nd energy densities up to 5 J/cm2 in various inert and reactive gases. The investigations revealed a good applicability of ArF excimer laser s for nondestructive laser etching of glass. The laser etching behavio r is characterized by a characteristic threshold energy density of the order of 1 J/cm2. Below this threshold laser etching is achieved only in reactive gases and is typically of the order of 0.1 nm/pulse. Abov e this specific threshold energy density the etch rate rapidly increas es and is practically independent of the gas nature but depends more s trongly on the gas pressure. In this ablation region the etch rate is of the order of 0.1 mum/pulse. A qualitative thermal model describing laser etching of glass in the ablation region is discussed. Laser-assi sted metallization of glass surfaces has been achieved upon excimer la ser irradiation of thin organometallic films on the glass surface and post-processing by electroless plating. Metallic nickel deposits showe d a good adhesion and structures of a size between several 10 mum and a few millimeters were produced.