Patent ID: 9620704
Date: 2017-04-11
CPC Classifications: H01L

Claim:
1. A method for manufacturing a piezoelectric element, comprising: a lower electrode forming step of forming a lower electrode on a substrate; a piezoelectric film forming step of forming a piezoelectric film on the lower electrode; a metal film forming step of forming a metal film having a thickness of 20 nm to 300 nm on the piezoelectric film; a resist film forming step of forming a resist film on the metal film and patterning the resist film; a metal film etching step of etching the metal film with a first etchant by using the resist film as a mask material; a piezoelectric film etching step of etching the piezoelectric film with a second etchant by using the metal film after the metal film etching step as a mask material; a resist film removing step of removing the resist film after the piezoelectric film etching step; a metal film removing step of removing the metal film after the resist film removing step; and an upper electrode forming step of forming an upper electrode on the piezoelectric film from which the metal film has been removed in the metal film removing step, wherein: the metal film is made of a material containing one of Fe, Cr, NiCr, SUS, Al, Cu, and Au; as the first etchant, an etchant to which the piezoelectric film has etching resistance is used, and the first etchant contains one of ferric chloride, sulfuric acid, ammonium persulfate, a mixed liquid of iodine and alkali iodide, ceric ammonium nitrate, a mixed liquid of hydrogen peroxide solution and phosphoric acid, nitric acid, and potassium hydroxide; and as the second etchant, an etchant to which the metal film has etching resistance is used.