METHOD FOR MANUFACTURING PIEZOELECTRIC ELEMENT

摘要

Disclosed is a method for manufacturing a piezoelectric element having an appropriately shaped ferroelectric film processed by plasma etching. A metal mask formed of a thin metal film that is not easily etched by oxygen gas is placed on an object to be processed including a lower electrode layer and a ferroelectric film laminated in this order on a substrate. An etching gas including a mixture of oxygen gas and a reactive gas that contains fluorine in the chemical structure is transformed into plasma, and is brought into contact with the metal mask and the object to be processed. An AC voltage is applied to an electrode disposed below the object to be processed so that ions in the plasma enter the object. With this, anisotropic etching is performed on the ferroelectric film. This allows long-time etching, and results in a piezoelectric element having an appropriately shaped ferroelectric film without etching products adhering to the etched side.