Method for manufacturing capacitive electromechanical transducer

A method for manufacturing a capacitive electromechanical transducer that converts between mechanical energy and electrical energy by means of a displacement of a vibrating membrane, the method comprising the steps of:

• forming a first electrode on a substrate;
• forming a sacrificial layer on the first electrode;
• forming a vibrating membrane on the sacrificial layer, the vibrating membrane being provided with a second electrode;
• forming an opening that communicates the sacrificial layer with the outside;
• and
• forming a cavity by electrolytically etching the sacrificial layer in an electrolyte solution by applying an electric field between the first electrode and a third electrode provided outside,
• wherein the sacrificial layer is composed of an electrically conductive material having a smaller dissolution potential than the dissolution potential of the first electrode, and
• an electric potential applied between the first electrode and the third electrode in the step of forming the cavity is larger than the dissolution potential of the sacrificial layer and is smaller than the dissolution potential of the first electrode.