Packaging method and packaging structure of bulk acoustic wave resonator

Abstract

The invention provides a packaging method and a packaging structure of a bulk acoustic wave resonator. A resonator cover body is manufactured by forming an elastic bonding material layer with a secondcavity and an initial opening 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 theresonator cover body, then the resonator cover body can penetrate through the resonator cover body and is communicated with the initial opening to form a through hole, and a conductive interconnectionlayer is formed on the inner surface of the through hole and a part of the surface of the second substrate. Because the initial opening is firstly formed, and then the second substrate is penetratedto be communicated with the initial opening so as to obtain the complete through hole, the difficulty of forming the through hole can be reduced, the adverse effect on the performance of the resonatorcaused by the process of forming the through hole and the conductive interconnection layer can be avoided, the reliability of the resonator is improved, and meanwhile, the performance of the formed through hole and the conductive interconnection layer is ensured.

Description

technical field [0001] The present invention relates to the technical field of packaging of radio frequency products, in particular to a packaging method and 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. FBARs can be used in wireless signal transmission systems to enable 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 substrate (not shown) by a thermal oxidation process...

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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 substrate, and a gold-gold bonding process is required to bond the first cavity 1011 and the second cavity 2001 together , and the carrier substrate 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 cost 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 in 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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