Patent ID: 7524432

Claim:
A method of forming a metal pattern, the method comprising: forming a metal film with a lower and upper layer, with the lower layer and upper layer each made of a metal, the upper layer made from a metal different than the lower layer; forming a resist film on the upper layer according to a predetermined pattern; and forming a patterned metal film, the process of forming the patterned metal film, comprising: etching the upper layer using a first etchant and the resist film as a mask; immersing the resist film and the upper layer in a pretreatment liquid containing a nonionic surfactant following etching the upper layer using the first etchant, the nonionic surfactant in the pretreatment liquid forming a nonionic surfactant film over the upper layer and the resist film; immersing the metal film, resist film, and nonionic surfactant film in a second etchant; and etching the lower layer using a second etchant and the resist film as a mask, wherein the nonionic surfactant film formed over the upper layer and the resist film prevents the second etchant from etching the upper layer.