Direct metallization of gold patterns on polyimide substrate by microcontact printing and selective surface modification

Patterned gold microstructures were fabricated on a polymer substrate by a novel method involving selective electroless plating and microcontact printing. The micro-sized gold patterns were made by the site-selective chemical modification of polyimide substrate films using aqueous potassium hydroxide solution and microcontact printing with a pitch size in the range of 20-200 μm. The base-treated area of the polyimide film became hydrophilic in the regions where the ion-exchange reactions took place for the subsequent metallization. The hydrophilic patterns were sensitized by placing the film in a solution of PdCl₂ and, subsequently, the activated substrate was immersed in an electroless plating solution of Ni and Au to provide well-developed gold patterns on polyimide substrate films.