Film bulk acoustic resonator and manufacturing method thereof

Abstract

The invention provides a manufacturing method of a film bulk acoustic resonator, and the method comprises the following steps: providing a substrate and forming a groove structure on the substrate, wherein the groove structure comprises a first groove and a second groove; forming a first sacrificial structure for filling the groove structure in the groove structure; forming a lower electrode on the substrate, wherein the lower electrode is located above the first groove, and at least part of the bottom surface edge area of the part, located outside the first groove, of the lower electrode falls into the opening range of the second groove; forming a piezoelectric layer covering the lower electrode on the substrate, and forming an upper electrode at the position, located above the first groove, of the piezoelectric layer; and removing the first sacrificial structure. Correspondingly, the invention also provides a film bulk acoustic resonator. According to the invention, the quality factor, the effective electromechanical coupling coefficient and the antistatic discharge capability of the film bulk acoustic resonator can be effectively improved.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a thin film bulk acoustic wave resonator and its manufacturing method. Background technique [0002] The resonator is the core component of the filter, and the performance of the resonator directly determines the performance of the filter. Among the existing resonators, the Film Bulk Acoustic Resonator (FBAR) is due to its small size, low insertion loss, large out-of-band suppression, high quality factor, high operating frequency, large power capacity and anti-static shock Good ability and other characteristics, it has a very broad application prospect in modern wireless communication technology. [0003] Typical thin-film bulk acoustic resonators mainly include air-gap bulk acoustic resonators, reverse-etched bulk acoustic resonators, and Bragg reflection bulk acoustic resonators. Please refer to Fig. 1(a), Fig. 1(b) and Fig. 1(c), 1(a), Fig. 1(b) and Fig. 1(c) are air-...

AI Technical Summary

Problems solved by technology

[0004] For the existing air-gap bulk acoustic resonator and reverse-etched bulk acoustic resonator, the edge of the lower electrode 12 is in contact with the substrate 10 and the piezoelectric layer 13. When the thin-film bulk acoustic resonator is working, the stacked Part of the sound wave in the layer structure will enter the substrate 10 and the piezoelectric layer 13 through the edge of the lower electrode 12, causing the sound wave loss of the film bulk acoustic resonator

For the existing Bragg reflection BAW resonator, the edge of the lower electrode 12 is in contact with the Bragg reflection layer 16 and the piezoelectric layer 13, so when the thin film BAW resonator is working, part of the sound waves in the laminated structure will be The edge of the lower electrode 12 enters the Bragg reflective layer 16 and the piezoelectric layer 13. Although the Bragg reflective layer 16 can reflect sound waves, there will still be a small amount of sound waves entering the substrate 10 from the Bragg reflective layer. Acoustic Loss of Acoustic Resonators

The acoustic loss of the thin film bulk acoustic resonator will reduce the quality factor, effective electromechanical coupling coefficient and anti-static discharge ability of the thin film bulk acoustic resonator.

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