Wiring film and active matrix substrate using the same, and method for manufacturing wiring film

Abstract

An Al wiring film having a tapered shape is obtained easily and in a stable manner. An Al wiring film has a double-layer structure including a first Al alloy layer made of Al or an Al alloy, and a second Al alloy layer laid on the first Al alloy layer and having a composition different from a composition of the first Al alloy layer by containing at least one element of Ni, Pd, and Pt. The second Al alloy layer is etched by an alkaline chemical solution used in a developing process of a photoresist, and an end portion of the second Al alloy layer recedes from an end portion of the photoresist. Thereafter, by performing wet etching using the photoresist as a mask, a cross section of the Al wiring film becomes a tapered shape.

1 . A method for manufacturing a wiring film, comprising the steps of:
 forming a first layer made of Al or an Al alloy;   forming, on said first layer, a second layer made of an Al alloy containing at least one element of Ni, Pd, and Pt and having a composition different from a composition of said first layer;   coating a photoresist on said second layer and performing exposure using a photomask;   developing said photoresist after performing the exposure and etching said second layer by using an alkaline chemical solution, so that an end portion of said second layer under said photoresist after the developing recedes from an end portion of the photoresist; and   forming the wiring film including said first and second layers by etching and patterning said first and second layers simultaneously by wet etching using said photoresist after developing as a mask.   
     
     
         2 . (canceled)