# US 2021/0281237 A1 · Acoustic wave device and manufacturing method thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0281237 A1 - Document ID: US20210281237A1 - Status: Published application - Kind: A1 - Application number: 17/193,492 - Filed: 2021-03-05 - Published: 2021-09-09 - Earliest claimed: 2020-03-06 - Assignees: Epistar Corporation - Applicants: Epistar Corporation - Inventors: TA-CHENG HSU; WEI-SHOU CHEN; CHUNG-JEN CHUNG; CHIA-MIN CHANG - Web page: https://patentgrep.com/patent/US20210281237A1 ## CPC - H03H 9/02015: {Characteristics of piezoelectric layers, e.g. cutting angles} - H03H 9/174: {Membranes} - H03H 3/02: for the manufacture of piezoelectric or electrostrictive resonators or networks (H03H3/08 takes precedence) - H03H 9/0514: {consisting of mounting pads or bumps} - H03H 9/0547: {consisting of a vertical arrangement (H03H9/0566 takes precedence)} - H03H 9/1035: {the enclosure being defined by two sealing substrates sandwiching the piezoelectric layer of the BAW device} - H03H 2003/023: {the resonators or networks being of the membrane type} - H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P) ## Abstract An acoustic wave device, includes piezoelectric layer having an upper piezoelectric surface and a lower piezoelectric surface; an upper electrode formed on the upper piezoelectric surface; a lower electrode; a support layer including a non-monocrystalline insulating material; and a lower cover, wherein the lower electrode and the support layer formed between the lower cover and the lower piezoelectric surface. ## Claims ### Claim 1 An acoustic wave device, comprising: a piezoelectric layer, comprising an upper piezoelectric surface and a lower piezoelectric surface; an upper electrode formed on the upper piezoelectric surface; a lower electrode; a support layer, comprising a non-monocrystalline insulating material; and a lower cover, wherein the lower electrode and the support layer formed between the lower cover and the lower piezoelectric surface. ### Claim 2 (depends on 1) The acoustic wave device of claim 1, wherein the lower cover comprises a groove. ### Claim 3 (depends on 2) The acoustic wave device of claim 2, wherein the groove does not overlap with the support layer in a thickness direction of the lower cover. ### Claim 4 (depends on 2) The acoustic wave device of claim 2, further comprising a passive element in the groove. ### Claim 5 (depends on 1) The acoustic wave device of claim 1, wherein the lower electrode comprises an upper electrode surface and a lower electrode surface, the whole upper electrode surface is a first plane at a first fixed horizontal position, and the whole lower electrode surface is a second plane at a second fixed horizontal position. ### Claim 6 (depends on 1) The acoustic wave device of claim 1, wherein the support layer comprises an upper support surface, the lower electrode formed between the lower piezoelectric surface and the upper support surface. ### Claim 7 (depends on 1) The acoustic wave device of claim 1, further comprising an upper cover, wherein the upper electrode is formed between the upper cover and the upper piezoelectric surface, and the upper cover comprises a groove. ### Claim 8 (depends on 7) The acoustic wave device of claim 7, further comprising a passive element in the groove. ### Claim 9 (depends on 1) The acoustic wave device of claim 1, further comprising a cavity formed between the support layer and the lower cover, wherein the support layer comprises a first inner sidewall and a second inner sidewall opposite to the first inner sidewall and separated from the first inner sidewall by the cavity. ### Claim 10 (depends on 9) The acoustic wave device of claim 9, wherein the upper electrode is formed on the cavity, extends beyond the first inner sidewall and does not exceed the second inner sidewall. ### Claim 11 (depends on 1) The acoustic wave device of claim 1, further comprising a conductive structure formed on the upper piezoelectric surface, and electrically connected to the upper electrode and the lower electrode. ### Claim 12 (depends on 11) The acoustic wave device of claim 11, further comprising an opening in the piezoelectric layer, wherein the conductive structure comprises a conductive layer and a plurality of conductive pads, wherein the conductive layer fills the opening and extends on the upper piezoelectric surface, one of the conductive pads is electrically connected to the upper electrode, and another one of the conductive pads is electrically connected to the lower electrode through the conductive layer. ### Claim 13 (depends on 12) The acoustic wave device of claim 12, further comprising an upper cover and a plurality of conductive elements formed in the upper cover, wherein the conductive elements are electrically connected to the conductive pads respectively. ### Claim 14 (depends on 13) The acoustic wave device of claim 13, wherein the upper cover comprises an upper surface, and the acoustic wave device further comprises a plurality of contact pads formed on the upper surface and electrically connected to the conductive elements respectively. ### Claim 15 A manufacturing method of an acoustic wave device, comprising: providing a substrate; forming a piezoelectric layer on the substrate by epitaxial growth, wherein the piezoelectric layer comprises an upper piezoelectric surface and a lower piezoelectric surface; forming an upper electrode on the upper piezoelectric surface; forming an upper cover on the upper electrode; removing the substrate; forming a lower electrode on the lower piezoelectric surface; forming a support layer on the lower piezoelectric surface; and forming a lower cover on the lower electrode and the support layer. ### Claim 16 (depends on 15) The manufacturing method of an acoustic wave device of claim 15, wherein the step of forming a support layer on the lower piezoelectric surface comprises forming a non-monocrystalline insulating material on the lower piezoelectric surface. ### Claim 17 (depends on 15) The manufacturing method of an acoustic wave device of claim 15, wherein the step of forming a lower electrode on the lower piezoelectric surface is before the step of forming a support layer on the lower piezoelectric surface. ### Claim 18 (depends on 15) The manufacturing method of an acoustic wave device of claim 15, wherein the step of forming a support layer on the lower piezoelectric surface is after removing the substrate. ### Claim 19 (depends on 15) The manufacturing method of an acoustic wave device of claim 15, wherein the lower cover comprises a groove. ### Claim 20 (depends on 15) The manufacturing method of an acoustic wave device of claim 15, wherein the upper cover comprises a groove.