Film bulk acoustic-wave resonator and method for manufacturing the same

Abstract

Provided is a thin film piezoelectric resonator and a manufacturing method thereof, in which the electromechanical coupling coefficient kt2 and the Q value are simultaneously increased, and the film thickness control of the lower electrode is easy. The thin-film piezoelectric resonator includes: a substrate (11); a lower electrode (14), a part facing the substrate (11) is hollow and mechanically held; a piezoelectric body (15) is arranged on the lower electrode (14) , so that it contains all the lower electrodes (14) in the area occupied by itself on the plane figure; the upper electrode (16) is on the piezoelectric body (15); the relay electrode (13) is on the substrate Between (11) and the piezoelectric body (15), on the planar figure, it is located at the boundary of the occupied area of ​​the piezoelectric body (15), and is connected with the lower electrode (14) inside the occupied area; and the lower electrode wiring ( 17), extending from the boundary of the occupied area to the outside, connected to the relay electrode (13).

Description

technical field [0001] The present invention relates to a thin-film piezoelectric resonator, and more particularly to a thin-film piezoelectric resonator that utilizes longitudinal vibration in the thickness direction of a piezoelectric thin film and a method for manufacturing the same, which can be used as a high-frequency filter or a high-frequency oscillator. Background technique [0002] In recent years, the wireless center technology has been developed by leaps and bounds, especially the development for the purpose of high-speed transmission continues. With the increase in the amount of information transmitted and the further increase in frequency, the requirements for miniaturization and light weight of high-frequency communication devices are even stronger. A wireless device is generally roughly divided into an RF front-end section that processes high frequency (RF), and a baseband (BB) section that performs digital signal processing. Among them, the BB part is a par...

AI Technical Summary

Problems solved by technology

When the film thickness is beyond the optimum thickness, the resonant frequency shifts, and at the same time, the electromechanical coupling coefficient k, which is the strength index of piezoelectricity, is caused. t 2 reduction of the resonance, deterioration of the Q value indicating the sharpness of resonance, etc., so there is a limit to increasing the film thickness in order to obtain a margin for over-etching

In addition, if the corrosion rate is reduced to detect the end point, the processing time per time becomes longer, resulting in a decrease in productivity.

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