US Patent 7524432 Metal pattern forming method

A method of forming a metal pattern comprising forming a metal film having a lower layer made of a metal and an upper layer made of a metal different from the metal of the lower layer, forming a resist film having a predetermined pattern on the upper layer, and patterning the metal film by etching the metal film using the resist film as a mask. Here, patterning the metal film comprises etching the upper layer, immersing the resist film and the upper layer in a pretreatment liquid containing a nonionic surfactant after the first etching process, and etching the lower layer after the immersing process.