# US 12,004,290 B2 · Multilayer board > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,004,290 B2 - Document ID: US12004290B2 - Status: Granted - Kind: B2 - Application number: 17/514,211 - Filed: 2021-10-29 - Published: 2022-02-17 - Granted: 2024-06-04 - Earliest claimed: 2019-07-10 - Assignees: Murata Manufacturing Co., Ltd. - Applicants: Murata Manufacturing Co., Ltd. - Inventors: Nobuyuki Tenno; Nobuo Ikemoto; Takahiro Baba - Web page: https://patentgrep.com/patent/US12004290B2 ## CPC - H01P 3/085: {Triplate lines} - H05K 1/0237: {High frequency adaptations (H05K1/0216 takes precedence)} - H01P 3/08: Microstrips; Strip lines - H01P 3/088: {Stacked transmission lines} - H05K 1/024: {Dielectric details, e.g. changing the dielectric material around a transmission line} - H05K 1/0298: {Multilayer circuits} - H10W 70/60: Insulating or insulated package substrates; Interposers; Redistribution layers (leadframes H10W70/40) - H05K 1/036: {Multilayers with layers of different types} - H05K 2201/0195: Dielectric or adhesive layers comprising a plurality of layers, e.g. in a multilayer structure - H01P: WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE (operating at optical frequencies G02B) - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 ## Abstract In a multilayer board, a transmission line includes layers including a first insulator layer, a first joining material layer in contact with a first surface of the first insulator layer, and a second joining material layer in contact with a second surface of the first insulator layer. A signal conductor of the transmission line is on the first surface of the first insulator layer, a relative permittivity of the second joining material layer is lower than a relative permittivity of the first joining material layer, and an adhesion strength between the first insulator layer and the first joining material layer is higher than an adhesion strength between the first insulator layer and the second joining material layer. ## Claims ### Claim 1 A multilayer board comprising: a transmission line including a plurality of layers including a first insulator layer, a first joining material layer in contact with a first surface of the first insulator layer, and a second joining material layer in contact with a second surface of the first insulator layer; wherein a signal conductor of the transmission line is provided on the first surface of the first insulator layer; a relative permittivity of the second joining material layer is lower than a relative permittivity of the first joining material layer; and an adhesion strength between the first insulator layer and the first joining material layer is higher than an adhesion strength between the first insulator layer and the second joining material layer. ### Claim 2 (depends on 1) The multilayer board according to claim 1, wherein the second joining material layer is closer to a surface layer in a stacking direction than is the first joining material layer. ### Claim 3 (depends on 2) The multilayer board according to claim 2, wherein a Young's modulus of the second joining material layer is smaller than a Young's modulus of the first joining material layer. ### Claim 4 (depends on 3) The multilayer board according to claim 3, wherein the Young's modulus of the second joining material layer is about 0.1 GPa, and the Young's modulus of the first joining material layer is about 3 GPa. ### Claim 5 (depends on 1) The multilayer board according to claim 1, wherein the plurality of layers are stacked on top of one another; the plurality of layers include the first insulator layer, a second insulator layer, a third insulator layer, the first joining material layer between the first surface of the first insulator layer and the second insulator layer, and the second joining material layer between the second surface of the first insulator layer and the third insulator layer. ### Claim 6 (depends on 5) The multilayer board according to claim 5, wherein the relative permittivity of the second joining material layer is lower than relative permittivities of the first insulator layer and the third insulator layer; and a thickness of the second joining material layer is less than a total thickness of the first insulator layer and the third insulator layer. ### Claim 7 (depends on 5) The multilayer board according to claim 5, wherein the relative permittivity of the second joining material layer is lower than relative permittivities of the first insulator layer and the third insulator layer; and a thickness of the second joining material layer is less than a thickness of the first insulator layer. ### Claim 8 (depends on 5) The multilayer board according to claim 5, wherein the relative permittivity of the second joining material layer is lower than relative permittivities of the first insulator layer and the third insulator layer; and a thickness of the second joining material layer is less than a thickness of the third insulator layer. ### Claim 9 (depends on 5) The multilayer board according to claim 5, wherein the second and third insulating layers are made of polyimide or liquid crystal polymer. ### Claim 10 (depends on 1) The multilayer board according to claim 1, further comprising: a first ground conductor; wherein the first joining material layer is between the signal conductor and the first ground conductor in a stacking direction. ### Claim 11 (depends on 1) The multilayer board according to claim 1, further comprising: a second ground conductor; wherein the second joining material layer is between the signal conductor and the second ground conductor in a stacking direction. ### Claim 12 (depends on 1) The multilayer board according to claim 1, wherein the first insulating layer is made of polyimide or liquid crystal polymer. ### Claim 13 (depends on 1) The multilayer board according to claim 1, wherein a portion of the multilayer board is bent in a stacking direction. ### Claim 14 (depends on 1) The multilayer board according to claim 1, wherein the first joining material layer is a prepreg layer of polyimide or liquid crystal polymer. ### Claim 15 (depends on 1) The multilayer board according to claim 1, wherein the second joining material layer is made of fluorine resin. ### Claim 16 (depends on 1) The multilayer board according to claim 1, wherein a Young's modulus of the first joining material layer is smaller than a Young's modulus of the second insulator layer; the relative permittivity of the first joining material layer is lower than a relative permittivity of the second insulator layer; and a thickness of the first joining material layer is less than a thickness of the second insulator layer. ### Claim 17 (depends on 16) The multilayer board according to claim 16, wherein the Young's modulus of the second joining material layer is about 0.1 GPa, and the Young's modulus of the first joining material layer is about 3 GPa.