Metallic Micropatterns on Anodic Alumina: Laser-Assisted Exposure of Trapped Seeds for Metallization

Abstract

Microscale metallic patterns are fabricated on the anodic alumina by demonstrating a novel technique. The porous anodic alumina was colored in organic dye solution containing small amounts of palladium acetate and then hydro-thermally sealed. Such coloring and pore-sealing of porous anodic alumina enhanced the absorption of laser beam by the film, facilitating the laser ablation on the film surface. The palladium ions, impregnated during coloring, were trapped underneath the crystalline hydroxide layer that had formed during the hydrothermal treatment. Removing the surface layer with the help of laser beam exposed the palladium on the surface, which acts as seeds for the subsequent electroless plating. Various metallic micro-patterns with thickness of about 2µm were fabricated on the anodic alumina. The metallic patterns were free from cracks or defects, and can be fabricate with high precision.