# US 12,009,795 B2 · Method of manufacturing acoustic wave device with multi-layer piezoelectric substrate > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,009,795 B2 - Document ID: US12009795B2 - Status: Granted - Kind: B2 - Application number: 17/119,904 - Filed: 2020-12-11 - Published: 2021-04-15 - Granted: 2024-06-11 - Earliest claimed: 2019-10-10 - Assignees: Skyworks Solutions, Inc. - Applicants: Skyworks Solutions, Inc. - Inventors: Benjamin Paul Abbott; Rei Goto - Web page: https://patentgrep.com/patent/US12009795B2 ## CPC - H03H 3/08: for the manufacture of resonators or networks using surface acoustic waves - H03H 9/02574: {of combined substrates, multilayered substrates, piezoelectrical layers on not-piezoelectrical substrate} - H03H 9/02551: {of quartz substrates} - H03H 9/02559: {of lithium niobate or lithium-tantalate substrates} - H03H 9/02834: {of temperature influence (cut angles H03H9/02543)} - H03H 9/14541: {Multilayer finger or busbar electrode} - H03H 9/6483: {Ladder SAW filters} - H10N 30/40: with electrical input and electrical output, e.g. functioning as transformers - H03H 2003/0435: {of a piezoelectric layer} - H10N 30/50: having a stacked or multilayer structure - H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P) - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR ## Abstract A surface acoustic wave device is disclosed. The surface acoustic wave device can include a single crystal support layer, an intermediate single crystal layer positioned over the single crystal support layer, a lithium based piezoelectric layer positioned over the intermediate single crystal layer, and an interdigital transducer electrode positioned over the lithium based piezoelectric layer, the surface acoustic wave device configured to generate a surface acoustic wave. The single crystal layer can be a quartz layer, such as a z-propagation quartz layer. A thermal conductivity of the single crystal support layer is greater than a thermal conductivity of the intermediate single crystal layer, and the thermal conductivity of the single crystal support layer is greater than a thermal conductivity of the lithium based piezoelectric layer. ## Claims ### Claim 1 A method of manufacturing an acoustic wave device, the method comprising: bonding a support substrate to a first side of a z-propagation quartz layer with a first Euler angle φ in a range from 40° to 50°, a second Euler angle θ in a range from 85° to 95°, and a third Euler angle ψ in a range of 85° to 95°; bonding a lithium based piezoelectric layer to a second side of the z-propagation quartz layer, the second side being opposite to the first side; and forming an interdigital transducer electrode to a side of the lithium based piezoelectric layer that is opposite the z-propagation quartz layer. ### Claim 2 (depends on 1) The method of claim 1 further comprising thinning the z-propagation quartz layer after the bonding of the support substrate to the first side of the z-propagation quartz layer. ### Claim 3 (depends on 1) The method of claim 1 further comprising thinning the lithium based piezoelectric layer after the bonding of the lithium based piezoelectric layer to the second side of the z-propagation quartz layer. ### Claim 4 (depends on 1) The method of claim 1 wherein bonding the support substrate to the first side of the z-propagation quartz layer is performed such that an adhesion layer is positioned between the support substrate and the first side of the z-propagation quartz layer. ### Claim 5 (depends on 1) The method of claim 1 wherein bonding the lithium based piezoelectric layer to the second side of the z-propagation quartz layer is performed such that an adhesion layer is positioned between the lithium based piezoelectric layer and the second side of the z-propagation quartz layer. ### Claim 6 (depends on 1) The method of claim 1 wherein the support substrate includes silicon. ### Claim 7 (depends on 1) The method of claim 1 wherein the support substrate has a higher thermal conductivity than both the z-propagation quartz layer and the lithium based piezoelectric layer. ### Claim 8 (depends on 1) The method of claim 1 wherein the support substrate has a thickness that is greater than a combined thickness of the z-propagation quartz layer and the lithium based piezoelectric layer. ### Claim 9 (depends on 1) The method of claim 1 wherein the support substrate is a silicon layer or an aluminum nitride layer. ### Claim 10 (depends on 1) The method of claim 1 wherein the lithium based piezoelectric layer has a thickness in a range from 0.1λ to 2λ, λ being a wavelength of a wave generated by the acoustic wave device. ### Claim 11 A method of manufacturing an acoustic wave device, the method comprising: bonding a single crystal support substrate to a first side of an intermediate single crystal layer with a first Euler angle φ in a range from 40° to 50°, a second Euler angle θ in a range from 85° to 95°, and a third Euler angle ψ in a range of 85° to 95°; bonding a lithium based piezoelectric layer to a second side of the intermediate single crystal layer, the second side being opposite to the first side; and forming an interdigital transducer electrode to a side of the lithium based piezoelectric layer that is opposite the intermediate single crystal layer. ### Claim 12 (depends on 11) The method of claim 11 further comprising thinning the intermediate single crystal layer after the bonding of the single crystal support substrate to the first side of the intermediate single crystal layer. ### Claim 13 (depends on 11) The method of claim 11 further comprising thinning the lithium based piezoelectric layer after the bonding of the lithium based piezoelectric layer to the second side of the intermediate single crystal layer. ### Claim 14 (depends on 11) The method of claim 11 wherein the bonding the single crystal support substrate to the first side of the intermediate single crystal layer is performed such that an adhesion layer is positioned between the single crystal support substrate and the first side of the intermediate single crystal layer. ### Claim 15 (depends on 11) The method of claim 11 wherein the bonding the lithium based piezoelectric layer to the second side of the intermediate single crystal layer is performed such that an adhesion layer is positioned between the lithium based piezoelectric layer and the second side of the intermediate single crystal layer. ### Claim 16 (depends on 11) The method of claim 11 wherein the single crystal support substrate includes silicon. ### Claim 17 (depends on 11) The method of claim 11 wherein the single crystal support substrate has a higher thermal conductivity than both the intermediate single crystal layer and the lithium based piezoelectric layer. ### Claim 18 (depends on 11) The method of claim 11 wherein the single crystal support substrate has a thickness that is greater than a combined thickness of the intermediate single crystal layer and the lithium based piezoelectric layer. ### Claim 19 (depends on 11) The method of claim 11 wherein the single crystal support substrate is a silicon layer or an aluminum nitride layer. ### Claim 20 (depends on 11) The method of claim 11 wherein the lithium based piezoelectric layer has a thickness in a range from 0.1λ to 2λ, λ being a wavelength of a wave generated by the acoustic wave device.