# US 9,049,805 B2 · Thermally-conductive particles in printed wiring boards > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,049,805 B2 - Document ID: US9049805B2 - Status: Granted - Kind: B2 - Application number: 13/599,475 - Filed: 2012-08-30 - Published: 2014-03-06 - Granted: 2015-06-02 - Earliest claimed: 2012-08-30 - Assignees: Lockheed Martin Corporation - Applicants: David Findley; Robert James Hill - Inventors: David Findley; Robert James Hill - Web page: https://patentgrep.com/patent/US9049805B2 ## CPC - H05K 3/284: {for encapsulating mounted components (H05K1/185 takes precedence)} - H05K 3/4626: {characterised by the insulating layers or materials (H05K3/4688 takes precedence)} - H05K 1/0203: {Cooling of mounted components (H05K1/0272 takes precedence)} - H05K 1/0373: {containing additives, e.g. fillers (H05K1/036 takes precedence)} - H05K 3/3447: Lead-in-hole components - H05K 2201/0209: Inorganic, non-metallic particles - H05K 2201/029: Woven fibrous reinforcement or textile - Y10T 29/49124: On flat or curved insulated base, e.g., printed circuit, etc. - 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 wiring board (PWB) can be fabricated with enhanced thermal characteristics that can enable the use of higher performance electronic components and/or a smaller packaging configuration. A substrate layer of the PWB includes a matrix material and optional reinforcing fibers embedded in the matrix material. The matrix material and/or the reinforcing fibers may include thermally-conductive particles such as nanodiamonds that increase the thermal conductivity of the substrate layer. Holes may be formed through the substrate layer for receiving and/or electrically connecting electronic components. The thermally-conductive particles are sized sufficiently small to allow the formation of the holes through the substrate layer using conventional equipment and processes such as drilling. The PWB may also include a protective coating that comprises thermally-conductive particles. The thermally-conductive particles described herein can reduce the need for heavy and bulky metal thermal layers in a manufacturing-friendly manner. ## Claims ### Claim 1 A multilayer printed wiring board, comprising: an electrically insulating substrate layer comprising a matrix material and diamond particles, the substrate layer further comprising reinforcing fibers embedded in the matrix material, wherein at least some of the diamond particles are distributed within the reinforcing fibers; an electrically conductive trace layer bonded with the substrate layer; a hole formed at least partially through the substrate layer to accommodate electrical connection of the trace layer to an electronic component and/or to another electrically conductive trace layer. ### Claim 2 (depends on 1) The multilayer printed wiring board of claim 1, wherein at least some of the diamond particles are distributed within the matrix material. ### Claim 3 (depends on 1) The multilayer printed wiring board of claim 1, further comprising: a plurality of electrically conductive trace layers stacked one over another, wherein portions of the substrate layer are interposed between successive trace layers, and the hole is formed through at least one interposed portion. ### Claim 4 (depends on 1) The multilayer printed wiring board of claim 1, further comprising: an electronic component electrically connected to the trace layer; a protective coating disposed over at least a portion of the electronic component, wherein the protective coating comprises diamond particles. ### Claim 5 (depends on 1) The multilayer printed wiring board of claim 1, wherein the diamond particles are nanodiamonds. ### Claim 6 (depends on 1) The multilayer printed wiring board of claim 1, wherein the concentration of diamond particles is higher in a first portion of the substrate layer than in a second portion of the substrate layer. ### Claim 7 (depends on 3) The multilayer printed wiring board of claim 3, wherein the electrically conductive trace layers are metal layers and are the only substantially metal layers within the thickness of the substrate layer. ### Claim 8 (depends on 4) The multilayer printed wiring board of claim 4, wherein diamond particles are distributed within the matrix material. ### Claim 9 (depends on 6) The multilayer printed wiring board of claim 6, wherein the first portion is at a component side of the substrate layer and the second portion is at an opposite side of the substrate layer. ### Claim 10 (depends on 6) The multilayer printed wiring board of claim 6, wherein the first portion is a thermal region of the substrate layer that underlies an electronic component of the wiring board. ### Claim 11 A multilayer printed wiring board, comprising: a substrate layer comprising a matrix material, reinforcing fibers embedded in the matrix material, and thermally-conductive three-dimensional nanoparticles distributed throughout substantially the entire thickness of the substrate layer; and an electrically conductive trace layer bonded with the substrate layer, wherein at least some of the nanoparticles are nanodiamonds distributed within the reinforcing fibers. ### Claim 12 (depends on 11) The multilayer printed wiring board of claim 11, wherein the nanoparticles are nanodiamonds. ### Claim 13 (depends on 11) The multilayer printed wiring board of claim 11, wherein the nanoparticles are present in the substrate layer in an amount from 0.5 wt % to 85 wt %. ### Claim 14 (depends on 11) The multilayer printed wiring board of claim 11, further comprising: an electronic component electrically connected to the trace layer; a protective coating disposed over at least a portion of the electronic component, wherein the protective coating comprises thermally-conductive particles. ### Claim 15 (depends on 13) The multilayer printed wiring board of claim 13, wherein the nanoparticles are present in the substrate layer in an amount of at least 50 wt %. ### Claim 16 A multilayer printed wiring board, comprising: an electrically insulating substrate layer comprising a matrix material and reinforcing fibers embedded in the matrix material, wherein the reinforcing fibers include nanodiamonds mixed within a base fiber material; and an electrically conductive trace layer bonded with the substrate layer, wherein the nanodiamonds have an aspect ratio of about 5 or less and comprise a material having a thermal conductivity of at least 400 W/K-m. ### Claim 17 (depends on 16) The multilayer printed wiring board of claim 16, wherein the reinforcing fibers are woven together as a fiber sheet embedded in the matrix material, the base fiber material is glass. ### Claim 18 (depends on 16) The multilayer printed wiring board of claim 16, further comprising: an electronic component electrically connected to the trace layer; a protective coating disposed over at least a portion of the electronic component; and nanodiamonds distributed within the matrix material, within the protective coating, or within both.