Patent ID: 9406867
Filing Date: 2016-08-02
CPC Classification: H01L,Y10T

Claim Text:
1. A method for manufacturing a piezoelectric film wafer, said method comprising: an etching for carrying out a dry etching on a piezoelectric film formed on a substrate by using a gas, the piezoelectric film comprising an alkali niobate-based perovskite structure expressed in a composition formula (K changing a rate of the dry etching by detecting a change in an emission peak intensity of Na in emitted ion plasma, wherein the gas comprises a mixed gas of Ar and a fluorine-based reactive gas, wherein the piezoelectric film is formed on a Pt bottom electrode layer, wherein the dry etching is stopped at a value of an attenuated state in which the emission peak intensity of Na is deteriorated to about 50% to 60% of a steady-state value of the emission peak intensity of Na, the steady-state value being an average value of emission peak intensities of NA in a range from ¼ hours to ¾ hours before the emission peak intensity of Na begins to fall more rapidly than drops of the emission peak intensity of Na within the range from ¼ hours to ¾ hours, and wherein said stopping the dry etching comprises detecting an attenuation change in an emission peak intensity of a Na emission spectrum within a range from 586 nm to 588.5 nm in the ion plasma.