METHOD FOR FABRICATING FBAR BAND PASS FILTER, CONCERNED WITH MOVING ONLY ABSOLUTE VALUE OF FREQUENCY BAND BY ETCHING SILICON NITRIDE LAYER OR DEPOSITING ALUMINUM NITRIDE BEFORE OR AFTER PACKAGING PROCESS

摘要

PURPOSE: A method for fabricating an FBAR(Film Bulk Acoustic Resonator) band pass filter is provided to obtain a desired frequency band by etching a silicon nitride layer or depositing an aluminum nitride on an upper part or a lower part of a substrate before or after a packaging process. CONSTITUTION: A band pass filter having an FBAR is formed by depositing a silicon nitride layer, a lower electrode(17), a piezoelectric material, and an upper electrode(18) on a substrate. The substrate is partially removed. A frequency band of the band pass filter is measured. The frequency band is accurately controlled by etching the silicon nitride layer or depositing an aluminum nitride on an upper part or a lower part of the substrate when the measured frequency band is different from a designed frequency band.