Method for manufacturing ultrasonic fingerprint sensor by using nanorod structure

A method for manufacturing an ultrasonic fingerprint sensor by using a nanorod structure, the method comprising:

• a conductive mold generating step of generating a plurality of rod generation holes spaced apart at predetermined intervals by etching a conductive substrate;
• a nanorod generating step of generating nanorods by filling the plurality of rod generation holes with a nano-piezoelectric material;
• a conductive mold etching step of generating nanorods and side electrodes by performing primary etching on the conductive mold except for the nanorods, the side electrodes, and a conductive substrate base connecting the nanorods and the side electrodes;
• an insulating material filling step of filling portions etched at the conductive mold etching step with an insulating material;
• a lower electrode forming step of etching the insulating material so that first end portions of the nanorods and side electrodes surrounded with the insulating material are exposed and forming lower electrodes on the exposed first end portions of the nanorods and the side electrodes;
• a dummy substrate bonding step of bonding a dummy substrate to a surface of the conductive mold on which the lower electrodes are formed;
• and
• an upper electrode forming step of removing the conductive substrate base connecting the nanorod and the side electrodes and forming upper electrodes on exposed remaining end portions of the nanorods and the side electrodes.