Patent ID: 8470651

Claim:
A method for producing a thin film transistor, comprising the steps of: a gate electrode forming step of forming a gate electrode on an object to be processed; a gate insulating layer forming step of forming a gate insulating layer on the gate electrode; a high-resistance semiconductor layer forming step of forming a high-resistance semiconductor layer made of a semiconductor layer on the gate insulating layer; an ohmic contact layer forming step of forming an ohmic contact layer on the semiconductor layer; a metallic wiring film forming step of forming a metallic wiring film on the ohmic contact layer; and an etching step of, by patterning the ohmic contact layer and the metallic wiring film, forming a source region and a drain region from the ohmic contact layer and forming a source electrode on the source region and a drain electrode on the drain region from the metallic wiring film, wherein the metallic wiring film forming step includes an adhesion layer forming step of sputtering a target of a copper alloy containing Ca and copper in a vacuum atmosphere through introduction a gas containing a sputtering gas and an oxidizing gas and forming an adhesion layer containing copper, Ca and oxygen on the ohmic contact layer, wherein the high-resistance semiconductor layer is exposed in the etching step, and a plasma-exposed step, in which a surface of the high-resistance semiconductor layer, a surface of the source electrode and a surface of the drain electrode are exposed to a plasma containing a hydrogen gas in a state where those surfaces are exposed, is provided after the etching step.