METHOD FOR FORMING BUMP ON ELECTRODE PAD WITH USE OF DOUBLE-LAYERED FILM

摘要

A method for forming a bump on an electrode pad characterized in that at least the following steps (a)-(d) are conducted on a wiring substrate which is composed of a base and a plurality of electrode pads: (a) a step wherein a double-layered film composed of a lower layer made of an alkali-soluble, radiation-nonsensitive resin composition and an upper layer made of a negative, radiation-sensitive resin composition is formed on the wiring substrate, and then an aperture pattern is formed in a corresponding position of the electrode pad; (b) a step wherein a low-melting metal is introduced into the aperture pattern; (c) a step wherein the low-melting metal is reflowed by conducting a press or a heat treatment so as to from a bump, and (d) a step wherein the double-layered film is removed from the substrate. By using the double-layered film having different characteristics, the high-resolution property and the easy-release property become compatible.