Packaging method and packaging structure of bulk acoustic wave resonator

Abstract

According to a packaging method and a packaging structure of a bulk acoustic wave resonator provided by the invention, a resonator cover body is manufactured by forming an elastic bonding material layer with a second cavity on a second substrate, then the resonator cover body can be directly bonded with a resonant cavity main body structure through the elastic bonding material layer on the resonator cover body, the elastic bonding material layer loses elasticity, after that, a through hole and a conductive interconnection layer covering the inner surface of the through hole can be formed on the resonator cover body. The process has the characteristics of low cost, simple process and high compatibility with a resonant cavity main body structure process, does not cause the pollution problemof a gold-gold bonding process, and can reduce the influence on a first cavity to the maximum extent; and the elasticity of the elastic bonding material layer can be utilized to tolerate a certain step height difference of the bulk acoustic wave resonance structure in the peripheral area of the first cavity in the bonding process, so that the bonding reliability and stability can be ensured.

Description

technical field [0001] The invention relates to the technical field of packaging of radio frequency products, in particular to a packaging method and a packaging structure of a bulk acoustic wave resonator. Background technique [0002] A bulk acoustic resonator (FBAR) includes electrodes typically disposed above and / or below a piezoelectric layer. The piezoelectric layer can oscillate in response to a high frequency signal applied to the electrodes. FBAR can be used in a wireless signal transmission system to realize wireless data input and / or output. For example, FBARs may be used in wireless communication devices, wireless power transmitters, filters for wireless sensors, transmitters, receivers, duplexers, and the like. [0003] Please refer to figure 1 , the current conventional BAW resonator packaging process usually includes the following steps: [0004] (1) A silicon dioxide layer 200 is grown on a carrier wafer (not shown) by a thermal oxidation process or a che...

AI Technical Summary

Problems solved by technology

[0009] In the packaging process of the above-mentioned bulk acoustic wave resonator, since it is necessary to deposit and etch a silicon dioxide layer on the carrier wafer, and a gold-gold bonding process is required to bond the first cavity 1011 and the second cavity 2001 together , and the carrier wafer needs to be removed after bonding, so the process is complicated and the equipment cost is high

And because the gold-gold bonding process introduces gold elements, there are problems of high material costs and element pollution to the production line

In addition, the passivation layer 205 in the above process is usually formed by depositing a thin layer of commonly used passivation layer materials such as silicon oxide or silicon nitride, which will cause gaps at the hole 203, so that the second cavity 2001 The sidewall is thinner, which leads to insufficient mechanical strength of the upper chamber cover, which will lead to device reliability risks

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