# US 10,371,468 B2 · Co-extruded microchannel heat pipes > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,371,468 B2 - Document ID: US10371468B2 - Status: Granted - Kind: B2 - Application number: 13/308,519 - Filed: 2011-11-30 - Published: 2013-05-30 - Granted: 2019-08-06 - Earliest claimed: 2011-11-30 - Assignees: Palo Alto Research Center Incorporated - Applicants: David Eric Schwartz; Ranjeet Balakrishna Rao - Inventors: David Eric Schwartz; Ranjeet Balakrishna Rao - Web page: https://patentgrep.com/patent/US10371468B2 ## CPC - F28F 21/08: of metal - B23P 15/26: heat exchangers {or the like (making heat exchangers by methods covered by other subclasses B21D53/02)} - F28D 15/0233: {the conduits having a particular shape, e.g. non-circular cross-section, annular (F28D15/0241, F28D15/0266 take precedence)} - F28D 15/04: with tubes having a capillary structure - F28F 21/062: {the heat-exchange apparatus employing tubular conduits} - H10W 40/73: for cooling by change of state - B23P 2700/09: Heat pipes - F28D 15/046: {characterised by the material or the construction of the capillary structure} - F28F 2255/16: extruded - F28F 2260/02: having microchannels - F28F: DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION (water and air traps, air venting F16) - B23P: METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS (arrangements for copying or controlling B23Q) - F28D: HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT (fluid heaters having heat generating means and heat transferring means F24H; furnaces F27; details of heat-exchange apparatus of general) - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 ## Abstract A microchannel heat pipe formed on a substrate surface using co-extruding a primary material and a secondary material such that the primary material forms side wall portions that are spaced apart by the secondary material, and an upper wall portion is formed across the upper ends of the side walls to form a composite structure. After the primary material hardens, the secondary material is removed, whereby the hardened primary material forms a pipe body having an elongated central channel defined between opposing end openings. A working fluid is then inserted into the elongated central channel, and sealing structures are then formed over both end openings to encapsulate the working fluid. ## Claims ### Claim 1 A microchannel heat pipe disposed on a substrate, the microchannel heat pipe comprising: an elongated pipe body including first and second elongated side wall portions that are disposed on a surface of the substrate and separated by an elongated central channel, and an upper wall portion extending between said first and second elongated side wall portions over the elongated central channel, whereby the elongated central channel is defined by the first and second elongated side wall portions, the upper wall portion and a portion of the substrate surface extending between said first and second elongated side portions; and a working fluid encapsulated inside the elongated central channel, wherein the first and second elongated side wall portions and the upper wall portion comprise an integral structure consisting of a common hardened extrudable material, and wherein the common hardened extrudable material comprises at least one of a paste and an ink including one or more of silver, copper, nickel, tin, aluminum, steel, alumina, silicates, glasses, carbon black, polymers and wax. ### Claim 2 (depends on 1) The microchannel heat pipe of claim 1, wherein the elongated pipe body has a nominal width in the range of 10 micrometers to 500 micrometers, a length in the range of 100 micrometers to 20 centimeters, and a nominal height in the range of 25 micrometers to 500 micrometers. ### Claim 3 (depends on 2) The microchannel heat pipe of claim 2, wherein the elongated pipe body has a nominal width in the range of 30 micrometers to 200 micrometers, a length in the range of 10 to 100 millimeters, and a nominal height in the range of 30 micrometers to 200 micrometers. ### Claim 4 (depends on 1) The microchannel heat pipe of claim 1, wherein the first and second elongated side wall portions and the upper wall portion comprise a cross-sectional shape that is one of semi-circular, square, rectangular, trapezoidal and triangular. ### Claim 5 (depends on 1) The microchannel heat pipe of claim 1, wherein the first and second elongated side wall portions and the upper wall portion comprise a sintered metal. ### Claim 6 (depends on 1) The microchannel heat pipe of claim 1, wherein the first and second elongated side wall portions and the upper wall portion comprise a polymer. ### Claim 7 (depends on 1) The microchannel heat pipe of claim 1, wherein the working fluid comprises one of methanol, ethanol, water, acetone, and ammonia. ### Claim 8 (depends on 1) The microchannel heat pipe of claim 1, further comprising first and second sealing structures respectively disposed over opposing end openings defined in the pipe body that communicate with the elongated central channel. ### Claim 9 (depends on 8) The microchannel heat pipe of claim 8, wherein the first and second sealing structures respectively comprise one of epoxy, silicone and solder. ### Claim 10 A microchannel heat pipe disposed on a substrate, the microchannel heat pipe comprising: an elongated pipe body including first and second elongated side wall portions that are disposed on a surface of the substrate and separated by an elongated central channel, and an upper wall portion extending between said first and second elongated side wall portions over the elongated central channel, whereby the elongated central channel is defined by the first and second elongated side wall portions, the upper wall portion and a portion of the substrate surface extending between said first and second elongated side portions; and a working fluid encapsulated inside the elongated central channel, wherein the first and second elongated side wall portions and the upper wall portion comprise a polymer structure consisting of a hardened extruded polymer material. ### Claim 11 (depends on 10) The microchannel heat pipe of claim 10, wherein the elongated pipe body has a nominal width in the range of 10 micrometers to 500 micrometers, a length in the range of 100 micrometers to 20 centimeters, and a nominal height in the range of 25 micrometers to 500 micrometers. ### Claim 12 (depends on 11) The microchannel heat pipe of claim 11, wherein the elongated pipe body has a nominal width in the range of 30 micrometers to 200 micrometers, a length in the range of 10 to 100 millimeters, and a nominal height in the range of 30 micrometers to 200 micrometers. ### Claim 13 (depends on 10) The microchannel heat pipe of claim 10, wherein the first and second elongated side wall portions and the upper wall portion comprise a cross-sectional shape that is one of semi-circular, square, rectangular, trapezoidal and triangular. ### Claim 14 (depends on 10) The microchannel heat pipe of claim 10, wherein the working fluid comprises one of methanol, ethanol, water, acetone, and ammonia. ### Claim 15 (depends on 10) The microchannel heat pipe of claim 10, further comprising first and second sealing structures respectively disposed over opposing ends of elongated central channel. ### Claim 16 (depends on 15) The microchannel heat pipe of claim 15, wherein the first and second sealing structures respectively comprise one of epoxy, silicone and solder. ### Claim 17 A device comprising: a substrate having an upper surface; a heat generating region formed in the substrate; and a microchannel heat pipe disposed on the substrate, the microchannel heat pipe including: an elongated pipe body including first and second elongated side wall portions that are disposed on a surface of the substrate and separated by an elongated central channel, and an upper wall portion extending between said first and second elongated side wall portions over the elongated central channel, whereby the elongated central channel is defined by the first and second elongated side wall portions, the upper wall portion and a portion of the substrate surface extending between said first and second elongated side portions; and a working fluid encapsulated inside the elongated central channel, wherein the pipe body comprises at least one of a hardened paste and a hardened ink including one or more of silver, copper, nickel, tin, aluminum, steel, alumina, silicates, glasses, carbon black, polymers and wax, and wherein the elongated pipe body is disposed on the substrate such that the heat generating region is disposed under a first end of the microchannel heat pipe, and a second end of the microchannel heat pipe is disposed adjacent to a heat sink region of the device that is spaced from the heat generating region. ### Claim 18 (depends on 17) The device of claim 17, wherein the device comprises an integrated circuit including a central active region formed in the substrate under the first end of the microchannel heat pipe, and a peripheral inactive region disposed on the substrate and located under the second end of the microchannel heat pipe. ### Claim 19 (depends on 17) The device of claim 17, wherein the first and second elongated side wall portions and the upper wall portion comprise an integral structure consisting of a common material.