Method for manufacturing niobate-system ferroelectric thin-film device

A method for manufacturing a niobate-system ferroelectric thin film device comprising:

• a lower electrode film formation step of forming a lower electrode film on a substrate;
• a ferroelectric thin film formation step of forming a niobate-system ferroelectric thin film on the lower electrode film;
• an etch mask pattern formation step of forming an etch mask in a desired pattern on the niobate-system ferroelectric thin film;
• and
• a ferroelectric thin film etching step of shaping the niobate-system ferroelectric thin film into a desired fine pattern by wet etching using an etchant comprising:
• a predetermined chelating agent comprising at least one selected from ethylenediamine tetra(methylene phosphonic acid), nitrilotris(methylene phosphonic acid), cyclohexane diamine tetraacetic acid, 1-hydroxyethane-1,1-diphosphonic acid(etidronic acid), glycine-N,N-bis(methylene phosphonic acid), diethylenetriamine penta(methylene phosphonic acid), and citric acid;
• an aqueous alkaline solution comprising an aqueous ammonia solution;
• and
• an aqueous hydrogen peroxide solution.