Preparation method of bulk acoustic wave resonator

Abstract

The embodiment of the invention discloses a preparation method of a bulk acoustic wave resonator. The method comprises the steps of providing a piezoelectric substrate, and carrying out ion implantation on the piezoelectric substrate to form a first substrate and a second substrate with defect layer connection; forming a metal electrode on the first substrate, and patterning the metal electrode toform bottom electrodes; bonding one surface of the piezoelectric substrate with bottom electrodes to a support substrate with a preset cavity, wherein the bottom electrodes are located in the cavity;stripping the second substrate of the piezoelectric substrate; thinning the first substrate to a required thickness; and forming a top electrode on one surface, far away from the bottom electrodes, of the first substrate. The problem that adverse effects are generated on the resonator structure in the bottom cavity forming process in a conventional process and the problem that metal and the support substrate are difficult to bond in the conventional process are solved. The process fault tolerance degree is reduced. The process steps and the process cost are reduced, and the working characteristics of the device are ensured.

Description

technical field [0001] The embodiments of the present invention relate to the technical field of resonators, and in particular to a method for preparing a bulk acoustic wave resonator. Background technique [0002] At present, the piezoelectric film of the bulk acoustic wave filter on the market mainly adopts the aluminum nitride film material prepared by the vacuum sputtering method. However, the electromechanical coupling coefficient and Q value of aluminum nitride materials are low, which cannot meet the requirements of high frequency, large bandwidth, and low loss of 5G bandpass filters. Related material and technical problems still need to be solved urgently. Theoretical studies have shown that the electromechanical coupling coefficient of lithium niobate thin films is relatively high. For example, the coupling coefficient of the X-tangential lithium niobate film can reach up to 45%, much higher than the 8% of the aluminum nitride film. Correspondingly, the relative b...

AI Technical Summary

Problems solved by technology

[0004] The embodiment of the present invention provides a method for preparing a bulk acoustic wave resonator, which overcomes the difficulty in bonding the metal to the support substrate in the conventional process and the adverse effects on the structure of the resonator during the formation of the bottom cavity in the conventional process. Reduce process tolerance, reduce process steps and process costs, and ensure device operating characteristics

Images