# US 2017/0257975 A1 · Reduced thermal transfer to peltier cooled fets > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0257975 A1 - Document ID: US20170257975A1 - Status: Published application - Kind: A1 - Application number: 15/601,256 - Filed: 2017-05-22 - Published: 2017-09-07 - Earliest claimed: 2014-05-02 - Assignees: Honeywell International Inc. - Applicants: Honeywell International Inc. - Inventors: Peter Charles Strickland; Sergiy Borysenko; Bradley Jessup - Web page: https://patentgrep.com/patent/US20170257975A1 ## CPC - H05K 7/20: Modifications to facilitate cooling, ventilating, or heating - H05K 1/0204: {using means for thermal conduction connection in the thickness direction of the substrate (H05K1/0207 takes precedence)} - H05K 1/0209: {External configuration of printed circuit board adapted for heat dissipation, e.g. lay-out of conductors, coatings} - H05K 3/06: the conductive material being removed chemically or electrolytically, e.g. by photo-etch process {(semi-additive methods H05K3/108)} - H05K 2201/062: Means for thermal insulation, e.g. for protection of parts - H05K 2201/09063: Holes or slots in insulating substrate not used for electrical connections - H05K 2201/10121: Optical component, e.g. opto-electronic component - H05K 2201/10219: Thermoelectric component - Y10T 29/49156: with selective destruction of conductive paths - Y10T 29/49361: Tube inside tube - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A printed circuit board for use with a cooling device configured to cool at least one device is provided. The printed circuit board includes a substrate having a first surface and a second surface opposing the first surface; a ground plane on the first surface of the substrate, and circuitry in a circuit-region on the second surface of the substrate. The ground plane includes a patterned-region that is patterned with an array of holes. The circuitry is configured for use with the at least one device to be cooled. When a first side of the cooling device contacts the ground plane, and when the at least one device to be cooled contacts the circuitry, a reduced cross-sectional area of the patterned-region prevents heat from a second side of the cooling device from degrading performance of the at least one device. ## Claims ### Claim 1 A method to reduce transfer of heat to a device to be cooled by the cooling device, the method comprising: contacting a hot side of the cooling device to a first surface of a thermally conductive structure; attaching a cool side of the cooling device to a ground plane of a printed circuit board, wherein the ground plane includes a patterned-region patterned with an array of holes with some desired ratio of metal to gap; contacting one of at least one solid-region of the ground plane of the printed circuit board to a second surface of the structure, wherein the one of at least one solid-region of the ground plane surrounds an outer perimeter of the patterned-region; attaching the device to be cooled to circuitry on a second surface of the printed circuit board, the second surface of the printed circuit board opposing the first surface of the printed circuit board; reducing heat flowing from the first surface of the structure to the second surface of the structure and to the cool side of the cooling device by a reduced cross-sectional area of the patterned-region; and reducing heat flowing from the first surface of the structure to the second surface of the structure and to the device to be cooled by the reduced cross-sectional area of the patterned-region. ### Claim 2 (depends on 1) The method of claim 1, wherein the first surface of the thermally conductive structure is a bottom surface of a cavity in the structure, and wherein a thickness of the cooling device is approximately a depth of the cavity in the structure, wherein: contacting the hot side of the cooling device to the first surface of the thermally conductive structure comprises: contacting the hot side of the cooling device to the bottom surface of the cavity, and wherein attaching the cool side of the cooling device to the at least a portion of the patterned-region, and contacting the one of at least one solid-region of the ground plane of the printed circuit board to the second surface of the structure comprises: placing the printed circuit board over the cavity; and attaching one of the at least one solid-region of the ground plane to the second surface of the structure. ### Claim 3 The method of 1, wherein contacting the hot side of the cooling device to the first surface of the thermally conductive structure comprises: contacting the hot side of a Peltier device to the first surface of the thermally conductive structure, wherein attaching the cool side of the cooling device to at least the portion of the patterned-region of the ground plane of the printed circuit board comprises: attaching the cool side of the Peltier device to at least the portion of the patterned-region of the ground plane of the printed circuit board, wherein attaching the device to be cooled to circuitry on the second surface of the printed circuit board comprises: attaching a field effect transistor (FET) to be cooled to a source microstrip, drain micro-strip, and a ground connection, wherein the ground connection extends through a substrate of the printed circuit board to contact the ground plane, the method further comprising: terminating electromagnetic waves propagating in the source microstrip and the drain microstrip in the array of holes patterned in the patterned-region of ground plane, wherein a pitch of the spacing is less than a quarter of wavelength of the electromagnetic wave propagating in the source microstrip and the drain microstrip. ### Claim 4 (depends on 1) The method of claim 1, wherein attaching the device to be cooled to the circuitry on the second surface of the printed circuit board includes attaching the device to a ground connection, extending through a substrate of the printed circuit board to contact the ground plane. ### Claim 5 (depends on 1) The method of claim 1, wherein the one of at least one solid-region of the ground plane includes a first-solid-region surrounding an outer perimeter of the patterned-region, and a second-solid-region surrounded by an inner perimeter of the patterned-region, wherein attaching the cool side of the cooling device to the at least the portion of the patterned-region of the ground plane comprises: attaching the cool side of the cooling device to the at least a portion of the patterned-region of the ground plane; and attaching the cool side of the cooling device to the second-solid-region. ### Claim 6 (depends on 5) The method of claim 5, wherein contacting the one of at least one solid-region of the ground plane of the printed circuit board to the second surface of the structure comprises: contacting the first-solid-region of the ground plane to the second surface of the structure. ### Claim 7 (depends on 5) The method of claim 5, wherein the first surface of the thermally conductive structure is a bottom surface of a cavity in the structure, and wherein a thickness of the cooling device is approximately a depth of the cavity in the structure, wherein: contacting the hot side of the cooling device to the first surface of the thermally conductive structure comprises: contacting the hot side of the cooling device to the bottom surface of the cavity, and wherein attaching the cool side of the cooling device to the at least a portion of the patterned-region, and contacting the one of at least one solid-region of the ground plane of the printed circuit board to the second surface of the structure comprises: placing the printed circuit board over the cavity; and attaching one of the at least one solid-region of the ground plane to the second surface of the structure, where the method further comprises: terminating electromagnetic waves propagating in the source microstrip and the drain microstrip in the array of holes patterned in the patterned-region of ground plane, wherein a pitch of the spacing is less than a quarter of wavelength of the electromagnetic wave propagating in a dielectric substrate of the printed circuit board. ### Claim 8 A method of forming a printed circuit board configured to prevent heat from degrading performance of at least one device to be cooled, the method comprising: forming at least one solid-region of a ground plane on a first surface of a dielectric substrate; forming a patterned-region on the ground plane on the first surface of the dielectric substrate, wherein the patterned-region abruptly transitions from the at least one solid-region; forming circuitry on a second surface of the dielectric substrate, the second surface opposing the first surface; and forming a ground connection from the circuitry on the first surface to the second surface of the substrate. ### Claim 9 (depends on 8) The method of claim 8, wherein forming the at least one solid-region of a ground plane on a first surface of a substrate comprises: depositing a layer of metal on the first surface of the dielectric substrate, wherein forming a patterned-region on the ground plane comprises: etching an array of holes in the deposited layer of metal, the array of holes being surrounded by the at least one solid-region. ### Claim 10 (depends on 8) The method of claim 8, wherein forming the circuitry on a second surface of the dielectric substrate comprises: depositing a layer of metal on the second surface of the dielectric substrate, patterning the layer of metal on the second surface to form the circuitry; and etching an array of holes in at least a portion of the circuitry.