Method for manufacturing surface acoustic wave element, as well as surface acoustic wave element manufactured by the same method

A method for manufacturing a surface acoustic wave element, comprising the steps of:

• forming a conductive film on a surface of a piezoelectric substrate;
• forming a photoresist film on the conductive film;
• printing a pattern by exposing and developing the pattern, which is originally provided on a photomask, onto the photoresist film by reduced projection;
• forming an electrode of a surface acoustic wave element by etching the conductive film using the patterned photoresist film as a mask;
• measuring a resonant frequency of the surface acoustic wave element formed on the piezoelectric substrate;
• calculating an anodic oxidation voltage based on an amount of anodic oxidation of the electrode that is calculated in advance from the measured resonant frequency and a preset target resonant frequency;
• and
• performing anodic oxidation based on the anodic oxidation voltage calculated in the voltage calculation step and finishing anodic oxidation after detecting an end-point of oxidation reaction of the electrode,
• wherein the measured resonant frequency of the piezoelectric substrate is an average of resonant frequencies that are measured for the individual surface acoustic wave elements formed at a plurality of preset positions on the piezoelectric substrate.