Process for producing liquid ejection head

A process for producing a liquid ejection head having a piezoelectric body provided with an ejection orifice for ejecting a liquid and a pressure chamber communicating with the ejection orifice for retaining the liquid to be ejected from the ejection orifice, wherein an electrode is formed on an inner wall surface of the pressure chamber so that the pressure chamber is deformed by a piezoelectric action caused by applying a voltage to the electrode, thereby ejecting the liquid, the process comprising the steps of:

• providing the piezoelectric body in which a surface thereof on which the ejection orifice is located has a surface roughness within a range of 0.1 μm or more and 1 μm or less in terms of arithmetic mean roughness Ra,
• forming a pattern of a dry film resist on the surface of the piezoelectric body so as to expose the ejection orifice and a linear region connected to the ejection orifice, and
• forming a pattern of a metal thin film that is connected to the electrode on the inner wall surface and continuously extends from the inner wall surface to the linear region by using the pattern of the dry film resist as a mask.