Bulk acoustic wave resonator and method for manufacturing the same

A method for manufacturing a bulk acoustic wave resonator, comprising:

• sequentially forming a second electrode layer, a piezoelectric layer and a first electrode layer, wherein the first electrode layer and the second electrode layer are respectively located on a first side and a second side of the piezoelectric layer opposite to each other in a first direction;
• performing a patterning process on the first electrode layer to form a first electrode and an additional electrode, and forming a gap between the first electrode and the additional electrode, so that the first electrode and the additional electrode are spaced apart from each other and electrically isolated from each other;
• forming a carrier structure on the first side of the piezoelectric layer and a side of the first electrode layer away from the second electrode layer, with a portion of the carrier structure being filled in the gap, and forming a first cavity between the piezoelectric layer and the carrier structure, with a portion of the first electrode being located in the first cavity;
• performing a patterning process on the second electrode layer to form a second electrode;
• forming one or more conductive pads on the second side of the piezoelectric layer, wherein the one or more conductive pads at least comprise an interconnection pad, the interconnection pad is electrically connected to the second electrode, and extends through the second electrode and the piezoelectric layer to be electrically connected to the additional electrode;
• bonding a cover structure to the second side of the piezoelectric layer, and forming a second cavity between the cover structure and the piezoelectric layer, wherein the cover structure comprises a cover bonding layer and a cover substrate, the cover bonding layer is disposed between the cover substrate and the piezoelectric layer in the first direction, and a portion of the second electrode layer is located in the second cavity;
• forming a first connection via hole and a second connection via hole extending through the carrier structure;
• and
• forming a first conductive connector and a second conductive connector on a side of the piezoelectric layer away from the cover structure, wherein the first conductive connector is electrically connected to the first electrode through the first connection via hole, the second conductive connector is electrically connected to the additional electrode through the second connection via hole, and the further electrically connected to the second electrode through the additional electrode and the interconnection pad,
• wherein the cover bonding layer is bonded to portions of surfaces of the piezoelectric layer and the one or more conductive pads, and a part of the one or more conductive pads has an embedded portion, the embedded portion is covered by the cover bonding layer.