Method of manufacturing a piezoelectric actuator

1. A method of manufacturing a piezoelectric actuator, comprising the steps of:

forming a lower electrode film on an insulating substrate;

forming a piezoelectric film on the lower electrode film;

forming a slit on the piezoelectric film to expose a portion of the lower electrode film through an upper surface side of the piezoelectric film;

forming an insulating layer which covers a portion of the piezoelectric film;

forming an upper electrode film so as to span the insulating layer and the piezoelectric film;

forming, on the piezoelectric film, a lower wire in connection with the portion of the lower electrode film exposed through the slit;

depositing a first metal film on the lower wire and thereby making a film thickness of the lower wire greater than a film thickness of the lower electrode film; and

depositing a second metal film on a portion of the upper electrode film on the insulating layer and thereby making a film thickness of the portion of the upper electrode film on the insulating layer greater than a film thickness of a portion of the upper electrode film that has been deposited directly on the piezoelectric film.

2. The method as defined in claim 1 , wherein the first and second metal films are simultaneously deposited by carrying out electrolytic plating on the lower wire and the portion of the upper electrode film on the insulating layer.

3. The method as defined in claim 1 , further comprising the step of forming a third metal film which covers the piezoelectric film in which the slit has been formed, and is in connection with the portion of the lower electrode film exposed through the slit, wherein:

in the upper electrode film forming step, the upper electrode film is formed by patterning the third metal film to separate a portion of the third metal film from the portion of the lower electrode film exposed through the slit; and

in the lower wire forming step, the lower wire is formed by patterning the third metal film.