Surface and Interface Modifications of Aluminum Thin Films on Silica Glass Substrate Using 157nm F-2 Laser for Selective Metallization

摘要

A 157 nm F-2 laser induced strong oxidation of an Al thin film surface, allowing it to show chemical resistance to KOH aqueous solution used for selective metallization on silica glass or native oxide Si substrate. The strong oxidation reactions on the surface and in the depth direction were confirmed by X-ray photoelectron spectroscopy. A high adhesion strength of 663 kgf/cm~2 between Al and silica glass was also obtained for the F-2-laser-irradiated sample, compared with that of the nonirradiated sample, 16 kgf/cm~2. The suitable thickness of Al thin films for the F-2-laser-irradiated surface and interface modifications was examined to be approximately 20 nm. The mechanism of the F-2-laser-induced interface modification was discussed regarding the dependence of substrate material and the analyses of the chemical bonding state of silica glass underneath Al thin films.