Film bulk acoustic resonator and manufacturing method thereof

Abstract

The invention relates to a film bulk acoustic resonator and a manufacturing method thereof; the film bulk acoustic resonator comprises a first substrate and a support layer arranged on the first substrate, wherein the support layer is provided with a first cavity; a piezoelectric laminated structure, which covers the first cavity, and comprises a first electrode, a piezoelectric layer and a second electrode which are laminated in sequence; a first groove that is formed in the piezoelectric laminated structure and penetrates through the first electrode and the piezoelectric layer, and the first groove is communicated with the first cavity; a second groove that is formed in the piezoelectric laminated structure and penetrates through the second electrode and the piezoelectric layer, wherein an area enclosed by the first groove and the second groove is an effective resonance area of the resonator; and a dielectric layer arranged in the first groove and / or the second groove. According to the invention, the dielectric layer is filled in the groove to form a support with the electrode in the area where the groove is located, so that the firmness of the device structure is enhanced, the resonator structure is prevented from being damaged; in addition, acoustic impedance mismatch is formed to prevent sound wave leakage.

Description

technical field [0001] The invention relates to the field of semiconductor device manufacturing, in particular to a thin-film bulk acoustic wave resonator and a manufacturing method thereof. Background technique [0002] Since the development of analog RF communication technology in the early 1990s, RF front-end modules have gradually become the core components of communication equipment. Among all RF front-end modules, filters have become the components with the strongest growth momentum and the greatest development prospects. With the rapid development of wireless communication technology and the maturity of 5G communication protocols, the market has also put forward stricter standards for the performance of RF filters in all aspects. The performance of a filter is determined by the resonator units that make up the filter. Among the existing filters, the film bulk acoustic resonator (FBAR) has the characteristics of small size, low insertion loss, large out-of-band suppr...

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Problems solved by technology

[0004] However, in the thin film bulk acoustic resonator produced at present, after the piezoelectric layer is dug, the entire device structure is supported by a layer of piezoelectric film, and the structure is easily broken during the process, resulting in low yield and quality factors. Bad problems, and its quality factor (Q) cannot be further improved, so it cannot meet the needs of high-performance radio frequency systems

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