Patent ID: 6778038
Filing Date: 2004-08-17
Classification: H01L,H03H,Y10T

Abstract:
A method of manufacturing a piezoelectric resonant filter including a thin-film piezoelectric resonator, the thin-film piezoelectric resonator having a piezoelectric thin film with a piezoelectric property and two exciting electrodes disposed on both surfaces of the piezoelectric thin film to apply an exciting voltage to the piezoelectric thin film, the piezoelectric resonant filter comprising a chip having the thin-film piezoelectric resonator, and a mounting substrate on which the chip is mounted, wherein the chip has: a plurality of chip-side conductors made of a metal, the chip-side conductors being connected to the exciting electrodes or constituting the exciting electrodes: a plurality of bumps provided on the chip-side conductors; and a conductor layer disposed between each of the chip-side conductors and each of the bumps, the conductor layer being made of a metal different from the respective metals of which the bumps and the conductors are made, and the mounting substrate has a plurality of substrate-side conductors that are made of a metal and to be electrically connected to the chip-side conductors, the method of manufacturing the piezoelectric resonant filter comprising the steps of:fabricating the chip; fabricating the mounting; and mounting the chip on the mounting substrate by flip chip bonding such that the chip-side conductors and the substrate-side conductors are electrically and mechanically connected to each other via the bumps, wherein in the step of mounting, the bumps are bonded to the substrate-side conductors by interdiffusion between atoms of the respective metals of which the bumps and the conductors are made, without involving melting of the respective metals of which the bumps and the conductors are made.