# US 2019/0357381 A1 · Multi-layer piezoelectric substrate with heat dissipation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0357381 A1 - Document ID: US20190357381A1 - Status: Published application - Kind: A1 - Application number: 16/414,622 - Filed: 2019-05-16 - Published: 2019-11-21 - Earliest claimed: 2018-05-21 - Assignees: Skyworks Solutions, Inc. - Applicants: Skyworks Solutions, Inc. - Inventors: Keiichi Maki; Rei Goto; Gong Bin Tang; Yosuke Hamaoka - Web page: https://patentgrep.com/patent/US20190357381A1 ## CPC - H03H 9/02574: {of combined substrates, multilayered substrates, piezoelectrical layers on not-piezoelectrical substrate} - H03H 9/02834: {of temperature influence (cut angles H03H9/02543)} - H03H 9/64: using surface acoustic waves - H03H 7/54: Modifications of networks to reduce influence of variations of temperature - H03H 9/6413: {SAW comb filters} - H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P) ## Abstract Aspects of this disclosure relate to a filter that includes an acoustic wave device with a multi-layer substrate with heat dissipation. The multi-layer substrate includes a support substrate (e.g., a quartz substrate), a piezoelectric layer, an interdigital transducer electrode on the piezoelectric layer, and a thermally conductive layer configured to dissipate heat associated with the acoustic wave device. The thermally conductive layer is disposed between the support substrate and the piezoelectric layer. The thermally conductive layer has a thickness that is greater than 10 nanometers and less than a thickness of the piezoelectric layer. ## Claims ### Claim 1 A filter with a multi-layer substrate with heat dissipation, the filter comprising an acoustic wave device that includes: a support substrate; a piezoelectric layer; an interdigital transducer electrode on the piezoelectric layer; and a thermally conductive layer configured to dissipate heat associated with the acoustic wave device, the thermally conductive layer having a higher thermal conductivity than the support substrate, the thermally conductive layer being disposed between the support substrate and the piezoelectric layer, and the thermally conductive layer having a thickness that is greater than 10 nanometers and less than a thickness of the piezoelectric layer; the filter being arranged as a band pass filter configured to filter a radio frequency signal. ### Claim 2 (depends on 1) The filter of claim 1 wherein the support substrate is a quartz substrate. ### Claim 3 (depends on 1) The filter of claim 1 wherein the acoustic wave device is configured to generate an acoustic wave having a wavelength of λ, and the thickness of the thermally conductive layer is less than 0.03 λ. ### Claim 4 (depends on 1) The filter of claim 1 wherein the piezoelectric layer has a higher thermal conductivity than the support substrate. ### Claim 5 (depends on 1) The filter of claim 1 wherein the support substrate includes at least one of silicon, aluminum nitride, silicon nitride, magnesium oxide spinel, magnesium oxide crystal, or diamond. ### Claim 6 (depends on 1) The filter of claim 1 wherein the acoustic wave device further includes a temperature compensating layer having a positive temperature coefficient of frequency, the temperature compensating layer being disposed between the piezoelectric layer and the support substrate. ### Claim 7 (depends on 6) The filter of claim 6 wherein the temperature compensating layer is a silicon dioxide layer. ### Claim 8 (depends on 6) The filter of claim 6 wherein the temperature compensating layer is disposed between the piezoelectric layer and the thermally conductive layer. ### Claim 9 (depends on 6) The filter of claim 6 wherein the temperature compensating layer is disposed between the thermally conductive layer and the support substrate. ### Claim 10 (depends on 1) The filter of claim 1 wherein the acoustic wave device further includes a first temperature compensating layer disposed between the piezoelectric layer and the thermally conductive layer, and a second temperature compensating layer disposed between the thermally conductive layer and the support substrate. ### Claim 11 (depends on 1) The filter of claim 1 wherein the thermally conductive layer includes a metal. ### Claim 12 (depends on 1) The filter of claim 1 wherein the thermally conductive layer has a thermal conductivity in a range from 140 W/mK to 425 W/mK. ### Claim 13 (depends on 1) The filter of claim 1 wherein the thermally conductive layer has a thermal conductivity that is at least 10 times a thermal conductivity of the piezoelectric layer. ### Claim 14 (depends on 1) The filter of claim 1 wherein the piezoelectric layer is a lithium tantalate layer. ### Claim 15 (depends on 1) The filter of claim 1 wherein the filter is arranged such that a maximum surface temperature of a filter chip that includes the filter is less than 60° Celsius during operation of the filter. ### Claim 16 (depends on 1) The filter of claim 1 wherein the acoustic wave device is a surface acoustic wave device. ### Claim 17 A surface acoustic wave device with a temperature compensated multi-layer substrate with heat dissipation, the surface acoustic wave device comprising: a support substrate; a piezoelectric layer; an interdigital transducer electrode on the piezoelectric layer; a thermally conductive layer configured to dissipate heat associated with the surface acoustic wave device, the thermally conductive layer having a higher thermal conductive than the support substrate, the thermally conductive layer being disposed between the support substrate and the piezoelectric layer, and the thermally conductive layer having a thickness that is greater than 10 nanometers and less than a thickness of the piezoelectric layer; and a temperature compensating layer having a positive temperature coefficient of frequency, the temperature compensating layer and the interdigital transducer electrode being disposed on opposite sides of the piezoelectric layer. ### Claim 18 (depends on 17) The surface acoustic wave device of claim 17 wherein the piezoelectric layer is a lithium tantalate layer and the support substrate is a quartz layer. ### Claim 19 (depends on 17) The surface acoustic wave device of claim 17 wherein the surface acoustic wave device is configured to generate a surface acoustic wave having a wavelength of λ, and the thickness of the thermally conductive layer is less than 0.03 λ. ### Claim 20 A radio frequency module comprising: a radio frequency switch configured to pass a radio frequency signal; a surface acoustic wave filter configured to filter the radio frequency signal, the surface acoustic wave filter including a surface acoustic wave resonator configured to generate a surface acoustic wave having a wavelength of λ, the surface acoustic wave resonator including support substrate, a piezoelectric layer, and a thermally conductive layer configured to dissipate heat associated with the surface acoustic wave resonator, the thermally conductive layer being disposed between the quartz substrate and the piezoelectric layer, and the thermally conductive layer having a thickness in a range between 10 nanometers and 0.03 λ; and a package enclosing the surface acoustic wave filter and the radio frequency switch.