Patent ID: 11923826
Assignee: NINGBO SEMICONDUCTOR INTERNATIONAL CORPORATION
Field: Basic communication processes (Electrical engineering)
Classification: CPC H | IPC H

Claim 8:
9. A method for fabricating a film bulk acoustic resonator, comprising:
providing a third substrate;
forming a piezoelectric stacked layer-structure on the third substrate, wherein the piezoelectric stacked layer-structure includes a second electrode layer, a piezoelectric layer, and a first electrode layer which are sequentially formed on the third substrate;
forming a support layer on the piezoelectric stacked layer-structure;
forming a first opening through the support layer;
forming a first trench at a bottom of the first opening, wherein the first trench passes through the first electrode layer and the piezoelectric layer;
bonding a first substrate on the support layer and covering the first opening to form a first cavity;
removing the third substrate to expose the second electrode layer;
forming a dielectric layer on an exposed surface of the second electrode layer;
forming a second opening through the dielectric layer and over the first cavity;
forming a second trench at a bottom of the second opening over the first cavity, wherein the second trench passes through the second electrode layer and the piezoelectric layer, a region encircled by the first trench and the second trench is an effective working region of the film bulk acoustic resonator; and projections of the first trench and the second trench on a bottom surface of the first substrate include two junctions, and at each junction, adjacent ends of the first and second trenches are connected or have a spacing there-between; and
bonding a second substrate on the dielectric layer and covering the second opening to form a second cavity.