US 2020/0403594 A1Published application

Method for forming film bulk acoustic resonator

AssigneeNingbo Semiconductor International Corporation

InventorXiaochuan WANG

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Abstract

Methods for forming a film bulk acoustic resonator (FBAR) are provided. In the method, formation of several mutually overlapped and hence connected sacrificial material layers above and under a resonator sheet facilitates the removal of the sacrificial material layers. Cavities left after the removal overlap at a polygonal area with non-parallel sides. This reduces the likelihood of boundary reflections of transverse parasitic waves causing standing wave resonance in the FBAR, thereby enhancing its performance in parasitic wave crosstalk. Further, according to the disclosure, the FBAR is enabled to be integrated with CMOS circuitry and hence exhibits higher reliability.

Claims9

Dependent claims

A method of fabricating a film bulk acoustic resonator, comprising:

providing a substrate;
forming on the substrate a first sacrificial material layer and a first insulating material layer surrounding the first sacrificial material layer;
forming a resonator sheet on the first sacrificial material layer, wherein the resonator sheet partially extends over the first insulating material layer;
forming on the resonator sheet a second sacrificial material layer and a second insulating material layer surrounding the second sacrificial material layer, wherein the second sacrificial material layer partially overlies the first sacrificial material layer, and wherein projections of the second sacrificial material layer and the first sacrificial material layer along a direction normal to the substrate overlap at a polygonal area;
forming a capping layer;
and
forming an opening in the capping layer and removing the second sacrificial material layer and the first sacrificial material layer via the opening.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 17/012,623Filed 4 Sep 2020
Priority: CN 201511003828.328 Dec 2015
Published: 24 Dec 2020
Term ends: Not estimatedThe source records don’t support an estimate.

Classification12 codes

H03H 3/02
For the manufacture of electromechanical resonators or networks: for the manufacture of piezoelectric or electrostrictive resonators or networks
H03H 9/02118
Means for compensation or elimination of undesirable effects: of lateral leakage between adjacent resonators
H03H 9/0504
Holders or supports: for bulk acoustic wave devices
H03H 9/171
Having a single resonator: implemented with thin-film techniques, i.e. of the film bulk acoustic resonator [FBAR] type

Family

Application15/390,050Division · filed 23 Dec 2016
Application17/012,623Division
US 10,784,832 B2Related patent
US 11,569,790 B2Related patent
US 2017/0207764 A1Published application
US 2020/0403594 A1This patent

From the US filing history. Foreign family members aren’t listed.

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