Piezoelectric component and manufacturing method thereof

A piezoelectric component manufacturing method comprising the steps of:

• preparing a piezoelectric substrate having comb-teeth electrodes and wiring electrodes formed on a principal surface thereof, and forming a protective film on the principal surface;
• removing, by means of photolithography and dry etching, said protective film on the surface of said comb-teeth electrodes and said wiring electrode sections thereby exposing them;
• forming a seed layer on the surface of said wiring electrode sections by means of photolithography;
• applying Cu and Sn electrolytic plating on said seed layer;
• laminating a cover film on an entire surface, on which said electrolytic plating has been applied;
• grinding a back surface of said piezoelectric substrate by a predetermined amount, and after thinning the thickness thereof, further applying sandblasting on the back surface;
• forming partial through holes in the back surface of said piezoelectric substrate by means of photolithography and sandblasting;
• forming further complete through holes by any one of or a combination of wet etching, sandblasting, excimer laser, and dry etching;
• removing the photoresist remaining on the back surface of said piezoelectric substrate, and then forming a seed layer on said wiring electrodes;
• forming cavities for forming wiring electrodes, electrode terminals, and through electrodes, by means of photolithography, and applying electrolytic Cu plating to the cavities, thereby forming said wiring electrodes, said electrode terminals, and said through electrodes;
• removing the photoresist, and removing said seed layer by means of etching;
• laminating at least two of the piezoelectric substrates that have been processed in said respective previous steps, while the piezoelectric element formation surfaces thereof are made to face each other, and bonding them on another piezoelectric substrate that has already been patterned;
• sequentially affixing a heat resistant tape and a dicing film on a bottom surface of said bonded piezoelectric substrate, and then dividing only said bonded piezoelectric substrate into individual pieces by means of dicing;
• removing said dicing film, and then laminating and thereby resin-sealing with a resin film, the piezoelectric substrate that has been divided into individual pieces;
• and dividing the resin-sealed piezoelectric substrate into individual piezoelectric components by means of dicing.