Film bulk acoustic wave resonator, preparation method and film bulk acoustic wave filter

Abstract

The invention relates to a film bulk acoustic wave resonator, a preparation method and a film bulk acoustic wave filter. The film bulk acoustic wave resonator comprises a patterned second electrode layer, a patterned piezoelectric layer, a patterned first electrode layer and a substrate which are sequentially stacked, wherein a plurality of heat dissipation blind holes are formed in the substrate, each heat dissipation blind hole is filled with a heat conduction and dissipation material, a high-resistance material is filled above the heat conduction and dissipation material in each heat dissipation blind hole to form a total reflection structure, and the patterned first electrode layer covers openings of all the heat dissipation blind holes. According to the film bulk acoustic wave resonator, the total reflection structure is prepared on the substrate, and each heat dissipation blind hole is filled with the heat conduction and dissipation material and the high-resistance material, so that the original high Q value is maintained, the temperature influence caused by insufficient heat conduction and dissipation capability of a traditional film bulk acoustic wave resonator is solved, and the film bulk acoustic wave resonator is high in structural reliability, facilitates integration, and simple in preparation process.

Description

technical field [0001] The technical field of the thin film bulk acoustic wave resonator of the present invention, in particular relates to a thin film bulk acoustic wave resonator, a preparation method and a thin film bulk acoustic wave filter. Background technique [0002] Film Bulk Acoustic Resonator (FBAR for short) is a device based on bulk acoustic wave theory that uses acoustic resonance to achieve electrical frequency selection. The frequency is selected by resonance, and a filter structure can be formed by combining a plurality of thin film bulk acoustic resonators. [0003] Among them, thin film bulk acoustic resonators are mainly divided into two forms, namely, air cavity structure (ie FBAR resonator unit) and reflective array structure unit (ie SMR resonator unit), and related resonator devices of SMR resonator unit type are also called are solid state mounted resonator devices. specifically: [0004] 1) For the FBRA with an air cavity structure, the biggest f...

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Problems solved by technology

Compared with air-cavity FBAR devices, the multi-layer structure causes sound leakage, which affects the Q value of related devices, but the structural reliability and heat conduction and heat dissipation have been improved to a certain extent.

It should be pointed out that the preparation of the Bragg reflective grating structure requires high process precision, and the theoretical value of the thickness between reflective layers needs to be 1 / 4 wavelength. Therefore, the SMR resonant unit is higher than the FBAR resonant unit in terms of cost and process difficulty.

[0007] In addition, whether it is an FBAR resonant unit or an SMR resonant unit, its structural design is not conducive to high-density integration of components through three-dimensional stacking, and is not suitable for the current demand for chip miniaturization and integration.

[0008] In short, the main defects of the FBAR device with the air cavity structure are: poor conduction and heat dissipation, easy to be affected by temperature conditions and cause frequency shift, there are reliability risks in the structure and it is not conducive to integration; solid-state mounted SMR devices, The main defects are: complex process steps, difficult operation, high cost, lower Q value compared with air cavity FBAR devices, failure to completely solve the problem of conduction and heat dissipation, and structurally make stacking integration difficult

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