Ultrahigh-frequency piezoelectric resonator and preparation method thereof

Abstract

The invention belongs to the field of resonators, provides an ultrahigh-frequency piezoelectric resonator and a preparation method thereof, and solves the problem that the performance of a device is influenced by uneven etching surface, uneven etching thickness and stress concentration due to the fact that a cavity is formed on a substrate by the ultrahigh-frequency piezoelectric resonator in a back etching mode. The method comprises the following steps: etching a groove on the upper surface of a substrate; depositing a first isolation layer on the surface of the groove, wherein the thicknessof the first isolation layer is less than the depth of the groove; filling the whole groove with a sacrificial layer, wherein the upper surface of the sacrificial layer is flush with the upper surfaceof the substrate layer; depositing a second isolation layer on the upper surface of the substrate filled with the sacrificial layer; forming a piezoelectric layer on the upper surface of the second isolation layer; forming an electrode layer on the upper surface of the piezoelectric layer; forming a release port above the groove, and removing the sacrificial layer through the release port to forma cavity. According to the invention, the sacrificial layer in the groove is surrounded by the two isolation layers, so the problem of uneven etching surface when the sacrificial layer is removed canbe avoided.

Description

technical field [0001] The invention relates to the field of resonators, in particular to an ultra-high frequency piezoelectric resonator and a preparation method thereof. Background technique [0002] With the rapid development of wireless communication, the frequency band becomes more and more crowded. In order to meet the needs of the increasingly large market, the frequency band gradually develops to high frequency and ultra high frequency. Electronic equipment with high frequency band, large bandwidth, and high stability has become an urgently needed product in the market. Among them, the filter is an indispensable device in wireless electronic communication; and the resonator, one of the components of the filter, also needs to be constantly updated to meet the market demand. Nowadays, the structure of ultra-high frequency resonators is gradually proposed at home and abroad. The new generation of ultra-high frequency resonators has large bandwidth, ultra-high frequency...

AI Technical Summary

Problems solved by technology

[0004] The technical problem solved by the present invention is to provide an ultra-high-frequency piezoelectric resonator and its preparation method, which solves the problem that the ultra-high-frequency piezoelectric resonator adopts back etching to form a cavity on the substrate and cause the etching surface to be uneven , uneven etching thickness and stress concentration and other problems that affect the performance of the device

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