High-performance thermally managed printed circuit board with integrated cooling structures
Patent Information
- Application Number
- PCT/US2026/020193
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-03-24
- Filing Date
- 2026-03-20
- Publication Date
- 2026-10-01
Smart Images
Figure US2026020193_01102026_PF_FP_ABST
Abstract
Description
[0001] PCT Specification
[0002] High-Performance Thermohy Managed Printed Circuit Board with integrated Cooling Structures
[0003] Applicant / Inventor: Nicholas Michael D’Onofrio
[0004] Priority: U.S. Provisional Application No. 63 / 776,925 filed March 24, 2025 TECHNICAL HELD
[0005] The present disclosure relates to thermal management for printed circuit boards and PCB-like electronic substrates, including rigid, flexible, rigid-flex, curved, folded, conduit-like, and three-dimensional substrates. More particularly, the disclosure relates to multilayer architectures that incorporate thermally conductive electrically insulating regions, solid-state thermal pathways, and integrated cooling structures such as liquid-flow passages, sealed two-phase regions, vapor chambers, and hybrid cooling arrangements for removing heat from surface -mounted, embedded, stacked, or otherwise thermally coupled heat sources.
[0006] BACKGROUND
[0007] Power-dense electronics, including compute accelerators, graphics processors, power conversion stages, radio-frequency systems, avionics, industrial automation equipment, automotive electronics, batter -interface electronics, high-power lighting, and communication hardware, increasingly require thermal management approaches that fit within severe volumetric, electrical-isolation, and reliability constraints. Conventional approaches often rely on external heat sinks, cold plates, thermal interface materials, metalcore substrates, or add-on cooling structures attached outside the circuit substrate. These approaches can add stack height, increase thermal interface resistance, reduce packaging density, complicate routing, and create reliability concerns under thermal cycling, shock, vibration, or pressure variation.
[0008] Many known board-level cooling concepts also assume that meaningful heat spreading requires electrically conductive pathways or thick metal structures. Such assumptions can conflict with electrical isolation requirements at solder pads, traces, high-voltage nodes, die attach sites, or embedded conductor regions. Generic via farms, filled vias, thermal fillers, and bonded cold plates may provide only partial relief and often fail to support the combination of dielectric strength, manufacturability, internal heat collection, pressure containment, serviceability, and system integration required for high-value electronics.
[0009] Known liquid-cooled assemblies also tend to place coolant structures outside the board rather than integrating the substrate itself into tire thermal transport architecture. Similarly, many sealed two-phase devices, vapor chambers, and microchannel components are packaged as separate units and are not configured to cooperate with multilayer routing, embedded components, dielectric breakdown requirements, or non-planar substrate geometries. There remains a need for architectures in which a circuit substrate can itself participate as an active thermal transport structure while preserving electrical isolation, supporting diverse materials and fonn factors, and enabling both liquid and vapor-phase heat rejection.
[0010] There is therefore a need for printed circuit board structures, systems, and fabrication methods that provide one or more of the following: efficient heat transfer through thermally conductive electricallyinsulating regions; thermal pathways that terminate at internal layers or cooling regions without requiring full-thickness traversal; integrated liquid, vapor, or hybrid cooling structures within or directly coupled to the board; compatibility with flexible, curved, multi-sided, and conduit-like geometries; and adaptability to conventional, semi-additive, additive, laminated, molded, printed, and hybrid manufacturing methods. SUMMARY
[0011] Tire present disclosure provides thermally managed printed circuit boards, circuit substrates, themial management systems, and methods of fabrication and use. In various embodiments, a substrate includes one or more thermally conductive electrically insulating regions that maintain electrical isolation while enabling heat transfer from one or more heat-source regions to one or more cooling interfaces. The cooling interface can include a pumped-liquid cavity, liquid channel network, dielectric-fluid region, sealed working-fluid region, vapor chamber, capillary-assisted region, heat pipe region, condenser-coupled structure, or hybrid arrangement combining two or more thermal transport mechanisms.
[0012] In some embodiments, one or more thermally conductive structures are disposed within, upon, or through selected layers of a multilayer substrate. Such structures can include dielectric posts, fdled or unfilled vias, blind vias, buried vias, thermally conductive columns, metallic structures, ceramic structures, graphitic structures, printed thennal features, spreaders, meshes, lattices, and combinations thereof. The thermal structures can route heat from a component pad, die surface, embedded component, package substrate region, or other heat -input region toward a fluid or vapor cooling region. At least a portion of the thermal path can terminate at or adjacent to an internal layer that is thermally coupled to, or directly contacts, a cooling region without requiring that portion to traverse the full thickness of the substrate. In some embodiments, coolant passages, cavities, reservoirs, or wetted chambers are formed within the substrate or in one or more structures bonded to the substrate. The passage geometry can include microfeatures, macrofeatures, roughened surfaces, porous regions, fins, ridges, channels, manifolds, plenums, turbulence promoters, phase-change features, condensers, wicks, capillary structures, or returnflow structures. Tire cooling region can be configured for positive gauge pressure, low-pressure operation, sub-atmospheric operation, vacuum operation, or combinations thereof, and can be sized for microflow, moderate flow, or high-volume flow according to the intended fonn factor.
[0013] In some embodiments, the substrate is rigid. In other embodiments, the substrate is flexible, semi-flexible, rigid-flex, articulated, curved, folded, wrapped around an edge or comer, toroidal, conduit-like, hollowcore, or otherw ise non-planar. The substrate can form part of a housing, structural member, enclosure, robotic skin, vehicle structure, wearable platform, pipe-like body, or other device architecture in which electrical and thermal functions are integrated.
[0014] In some embodiments, electronic components or assemblies are mounted to the substrate, partially embedded in the substrate, or fully embedded within the substrate. Such components can include integrated circuits, chiplets, power semiconductors, passive components, sensors, antennas, optoelectronic devices, stacked modules, or combinations thereof. Electrical routing can extend outward, upward, laterally, or through selected layers from the embedded or mounted structures. One or more protective layers, corrosion-mitigation layers, removable process layers, dielectric barriers, or surface -conditioning layers can be used to protect wetted regions, die surfaces, bond interfaces, or high-voltage features.
[0015] The disclosure also provides system-level implementations in which the thermally managed substrate cooperates with one or more manifolds, ports, connectors, pumps, condensers, valves, housings, externalheat-rejection structures, sensors, control circuitry, and telemetry systems. The disclosed concepts are applicable across a wide power range, including sub-100 watt electronics, moderate -power systems, and high-power devices in which thermal density, dielectric isolation, packaging volume, environmental sealing, and system reliability are significant design constraints.
[0016] Unless expressly stated otherwise, tire embodiments described herein are non-limiting examples. Features described in connection with one embodiment can be combined with features described in connection with another embodiment. References to liquid cooling, vapor cooling, dielectric cooling, direct cooling, indirect cooling, embedded cooling, or external heat rejection are intended to include combinations and variations thereof. Dimensional ranges, material examples, process examples, pressure examples, and flow examples are illustrative and are not intended to narrow the claims unless explicitly recited.
[0017] BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The accompanying drawings illustrate representative embodiments and are not limiting. The same reference numerals may refer to the same or similar structures across different figures.
[0019] FIG. 1 is a cross-sectional view of a multilayer printed circuit board coupled to a liquid coolant chamber. FIG. 2 is a cross-scctional view of a substrate in which a thermal path terminates at an internal cooling layer.
[0020] FIG. 3 is a cross-scctional view of a substrate including a sealed working-fluid region.
[0021] FIG. 4 is a plan view or partial perspective view of an edge-wrapping or comer-transition coolant architecture.
[0022] FIG. 5 is a cross-sectional view of a substrate configured for direct coupling to an exposed die or passivated die surface.
[0023] FIG. 6 is a cross-sectional view of a substrate including an embedded component and outward and / or upward thermal and electrical routing.
[0024] FIG. 7 is a cross-sectional view of a flexible or rigid-flex implementation.
[0025] FIG. 8 is a system view, including a cross-sectional or partially sectional representation, of a system including a manifold, port, connector, and external heat-rejection structure.
[0026] FIG. 9 is a cross-sectional view of a conduit -like or hollow-core substrate geometry .
[0027] Description of ths Embodiments
[0028] IG. 1
[0029] FIG. 1 illustrates a multilayer printed circuit board coupled to a liquid coolant chamber. An integrated circuit 1 is disposed on a multilayer substrate including one or more thermally conductive dielectric layers 2, one or more conductive circuit layers 3, a thermally conductive dielectric network 4, a thermally conductive layer 5, and a thermally conductive protective layer 6. A fluid channel 7 is defined between the substrate-side structure and an opposing channel wall 8. A thermally conductive transfer member 9 may? extend from the region of the integrated circuit 1 toward the thermally conductive layer 5 to provide a reduced-resistance heat path. Heat generated by the integrated circuit 1 may be conducted through thethermally conductive material stack, distributed through the thermally conductive dielectric network 4, and transferred to coolant flowing through the fluid channel 7.
[0030] FIG, 2
[0031] FIG. 2 illustrates a substrate in which a thermal path terminates at an internal cooling layer. An integrated circuit 10 is supported by a structure including a thermally conductive dielectric layer 11, a conductive circuit layer 12, a thermally conductive dielectric network 13, and an internal cooling layer 14. Tire internal cooling layer 14 may be a solid thermal dissipation layer formed from a conductive material, a dielectric material, or another thermally conductive material. The internal cooling layer 14 may receive heat from upper layers and spread or transfer that heat within the structure. In some embodiments, the internal cooling layer 14 may additionally provide structural reinforcement, bonding enhancement, or both. An opposing wall 15 may be spaced from the substrate to define a cooling region therebetween, or may serve as a thermally coupled structural boundary.
[0032] FIG, 3
[0033] FIG. 3 illustrates a substrate including a sealed working -fluid region. An integrated circuit 16 is thermally coupled through a thermally conductive dielectric layer 17, a conductive circuit layer 18, a thermally conductive dielectric network 19, and a thermally conductive layer 20 to a chamber structure bounded at least in part by a thermally conductive chamber wall 23. One or more of the dielectric network 19 and the thermally conductive layer 20 may form part of a multi-layer thermally conductive network that spreads or redirects heat before transfer to the chamber structure. Protective layers 21 and 22 may line, isolate, or protect surfaces exposed to a working fluid. The sealed region may function as a vapor chamber, phasechange chamber, or other enclosed heat-transfer region.
[0034] HG.4
[0035] FIG. 4 illustrates an edge-wrapping or comer-transition coolant architecture. One or more integrated circuits 24 and 34 may be located on different faces of a non -planar substrate or structure. The structure may include thermally conductive dielectric layers 25 and 33, thermally conductive dielectric networks 27 and 36, conductive circuit layers 26 and 35, a thermally conductive fluid chamber wall 28, an opposing wall 29, and one or more thermally conductive transfer members 37. External heat-dissipation fins 30 may be attached to an outer region to improve heat rejection to the surrounding environment. Insulative separators 31 and 32 may electrically isolate adjacent conductive regions while permitting thermal transfer through neighboring thermally conductive structures. Hie cooling architecture may wrap around an edge, comer, bend, or other transition instead of being limited to a planar substrate.
[0036] FIG. S
[0037] FIG. 5 illustrates a substrate configured for direct coupling to an exposed die or passivated die surface. An integrated circuit 38 is positioned so that heat may be transferred directly or near-directly to a thermally conductive chamber wall 39. Electrical and structural layers may include a thermally conductive dielectric layer 40, a conductive circuit layer 41, and a thermally conductive dielectric structure 42, which may fomi part of a multi-layer thermally conductive network, together with a thermally conductive structural support layer 43. The die surface, passivation surface, or another exposed heat-generating region may be coupled with reduced thermal resistance to the chamber wall 39.HG. S
[0038] FIG. 6 illustrates a substrate including an embedded component and outward and / or upward thermal and electrical routing. Tire structure may include an embedded integrated circuit 57, a thermally conductive dielectric pathway 45 extending toward a thermally conductive protective layer 44, conductive circuit layers 46, 48, 50, 51, 53, and 55, thermally conductive dielectric layers 47, 49, 52, and 54, and a second thermally conductive protective layer 56. Electrical routing may extend outward, upward, laterally, or in other directions through surrounding conductive layers rather than being confined to a single plane. The thermally conductive dielectric pathway 45 may provide a heat-transfer path from the embedded integrated circuit 57 toward the thermally conductive protective layer 44, and surrounding thermally conductive layers may cooperate to form a distributed thermal network for spreading and removing heat from tire embedded integrated circuit 57.
[0039] IG. 7
[0040] FIG. 7 illustrates a flexible or rigid-flex implementation. A thermally conductive chamber wall 58, such as a vapor chamber wall or other heat-transfer wall, may be integrated with flexible thermally conductive dielectric layers 59, 61, 64, and 66, flexible conductive layers 60 and 65, a thermally conductive protective layer 62, and an integrated circuit 63. The structure may include a flexible portion, a rigid portion, or a transition between rigid and flexible regions. Tire flexible conductive layers may maintain electrical continuity through a bend region while the thermally conductive chamber wall 58 maintains a heat-transfer function. The thermally conductive protective layer 62 may additionally spread heat over a broader surface area to reduce local surface temperatures, for example in wearable devices or other usercontacting electronics.
[0041] FIG. 3
[0042] FIG. 8 illustrates a system including a manifold, port, connector, and external heat-rejection structure. One or more integrated circuits 67 and 78 may be coupled to a layered structure including thermally conductive dielectric layers 68 and 69, a conductive circuit layer 70, a thermally conductive network layer 71, a thermally conductive protective layer 74, a conductive circuit layer 75, a thermally conductive layer 76, and a thermally conductive fluid-channel wall 77. The system may further include a chassis wall 72, a fluid port 73, a fluid pump 79, and a manifold or reservoir 80. The thermally conductive network layer 71 may distribute heat laterally within the structure, while the thermally conductive layer 76 and the thermally conductive fluid-channel wall 77 transfer heat toward a coolant flow region. The fluid port 73 may provide a connection to external tubing, piping, or another fluid interface, and the manifold or reservoir 80 may distribute, collect, or buffer coolant within the system.
[0043] HG, S
[0044] FIG. 9 illustrates a conduit -like or hollow-corc substrate geometry. Tire structure may define an internal passage and may support electronics along one or more wall regions surrounding the hollow’ core.
[0045] Integrated circuits 81 and 92 may be associated with surrounding thermally conductive dielectric layers 82, 83, 89, and 96, conductive circuit layers 84, 88, 90, 95, 97, 99, and 101, thermally conductive chamber walls 85 and 93, vapor chambers 86 and 94, athermally conductive protective layer 91, and a thermally conductive network and fluid-channel wall 100. A directly cooled integrated circuit 87 and a directly fluid-cooled integrated circuit 98 may be disposed in different w all regions of the conduit -like structure. Different sides or regions of the hollow -core body may employ different cooling modes, including conductive spreading, vapor-chamber transport, and direct fluid cooling.Reference Ssges
[0046] 1 integrated circuit
[0047] 2 thermally conductive dielectric layer 3 conductive circuit layer
[0048] 4 thermally conductive dielectric network 5 thermally conductive layer
[0049] 6 thermally conductive protective layer 7 fluid channel
[0050] 8 opposing channel wall
[0051] 9 thermally conductive transfer member 10 integrated circuit
[0052] 11 thermally conductive dielectric layer 12 conductive circuit layer
[0053] 13 thermally conductive dielectric network 14 internal cooling layer
[0054] 15 opposing wall
[0055] 16 integrated circuit
[0056] 17 thermally conductive dielectric layer 18 conductive circuit layer
[0057] 19 thermally conductive dielectric network 20 thermally conductive layer
[0058] 21 protective layer
[0059] 22 protective layer
[0060] 23 thermally conductive chamber wall 24 integrated circuit
[0061] 25 thermally conductive dielectric layer 26 conductive circuit layer
[0062] 27 thermally conductive dielectric network 28 thermally conductive fluid chamber wall 29 opposing wall
[0063] 30 external heat-dissipation finsinsulative separator
[0064] insulative separator
[0065] thermally conductive dielectric layer integrated circuit
[0066] conductive circuit layer
[0067] thermally conductive dielectric network thermally conductive transfer member integrated circuit
[0068] thermally conductive chamber wall thermally conductive dielectric layer conductive circuit layer
[0069] thermally conductive dielectric structure thermally conductive structural support layer thermally conductive protective layer thermally conductive dielectric pathway conductive circuit layer
[0070] thermally conductive dielectric layer conductive circuit layer
[0071] thermally conductive dielectric layer conductive circuit layer
[0072] conductive circuit layer
[0073] thermally conductive dielectric layer conductive circuit layer
[0074] thermally conductive dielectric layer conductive circuit layer
[0075] thermally conductive protective layer embedded integrated circuit
[0076] thermally conductive chamber wall flexible thermally conductive dielectric layer flexible conductive layer
[0077] flexible thermally conductive dielectric layerthermally conductive protective layer integrated circuit
[0078] flexible thermally conductive dielectric layer flexible conductive layer
[0079] flexible thermally conductive dielectric layer integrated circuit
[0080] thermally conductive dielectric layer thermally conductive dielectric layer conductive circuit layer
[0081] thermally conductive network layer chassis wall
[0082] fluid port
[0083] thermally conductive protective layer conductive circuit layer
[0084] thermally conductive layer
[0085] thermally conductive fluid-channel wall integrated circuit
[0086] fluid pump
[0087] manifold or reservoir
[0088] integrated circuit
[0089] thermally conductive dielectric layer thermally conductive dielectric layer conductive circuit layer
[0090] thermally conductive chamber wall vapor chamber
[0091] directly cooled integrated circuit conductive circuit layer
[0092] thermally conductive dielectric layer conductive circuit layers
[0093] thermally conductive protective layer integrated circuit93 thermally conductive chamber wall
[0094] 94 vapor chamber
[0095] 95 conductive circuit layers
[0096] 96 thermally conductive dielectric layer
[0097] 97 conductive circuit layers
[0098] 98 directly fluid-cooled integrated circuit
[0099] 99 conductive circuit layer
[0100] 100 thermally conductive network and fluid-channel wall
[0101] 101 conductive circuit layer
[0102] DETAILED DESCRIPTION
[0103] A, General Architecture
[0104] In various embodiments, the disclosed substrate comprises a multilayer stack -up having conductive routing layers, electrically insulating layers, and one or more thermally functional regions. The stack -up can be implemented using conventional PCB laminates, ceramic-containing laminates, polymer composites, flexible films, rigid-flex constructions, molded interconnect structures, additive or semiadditive structures, and combinations thereof. Electrically insulating regions can include thermally conductive dielectrics, ceramic-filled polymers, ceramic sheets, sol-gel-derived layers, polyimide-based materials, epoxies, cyanate esters, PTFE -containing materials. 1 iqu i cl-cry stal polymer materials, silicones, glass-containing composites, alumina, aluminum nitride, boron nitride -containing materials, silicon nitride-containing materials, diamond-containing materials, graphitic insulating composites, and other insulating media suitable for the intended electrical and thennal environment.
[0105] The thermally conductive electrically insulating regions can be located under pads, under die attach regions, adjacent to conductors, around high-voltage nodes, between routing layers, within cavities, or at interfaces between a heat source and a cooling interface. Such regions can be monolithic, layered, graded, patterned, anisotropic, isotropic, or composite. In some embodiments, the dielectric region includes at least two distinct insulating materials selected to provide different functions, such as thermal transport, dielectric strength, process compatibility, flexibility, corrosion resistance, moisture resistance, or coefficient-of-thermal -expansion management.
[0106] Thermally conductive structures can be disposed in, on, or between layers of the stack -up. These structures can comprise metallic materials, ceramic materials, composite materials, pyrolytic graphitic materials, carbon-based structures, plated features, deposited features, printed features, pressed-in features, or combinations thereof. Tire structures can form isolated posts, arrays of posts, vias, blind or buried structures, lattices, sheets, meshes, spreaders, local heat collectors, regional heat collectors, or distributed heat-spreading networks. In some embodiments, the structures cooperate with one or more dielectric regions to route heat while preserving electrical isolation from conductors or from coolant. A heat source region can correspond to, for example, a package attach site, a die attach site, a direct -die interface, a power module region, an LED attachment region, an RF device region, an embedded component, or a thermally significant area of the substrate. A thermal path can extend from such a regionto one or more cooling interfaces. Tire thermal path can include one or more vertical, lateral, angled, curved, stepped, branched, or distributed segments. In some embodiments, at least a portion of the thermal path terminates at or adjacent to an internal layer or internal cavity wall rather than passing completely through the thickness of the substrate.
[0107] Co g Interfaces
[0108]
[0109] Ceding Regions
[0110] The cooling interface can be implemented in many ways. In some embodiments, the cooling interface comprises a pumped-liquid cavity, one or more coolant channels, a network of passages, a plenum, a chamber sealed by a cover or wall structure, or a manifold-fed internal flow path. In some embodiments, the cooling interface comprises a sealed working-fluid region configured for vapor-phase or two-phase thermal transport, optionally including a wick, capillary return structure, internal condenser region, or phase-separation feature. In some embodiments, the cooling interface comprises a hybrid arrangement that combines direct liquid cooling with a vapor chamber or other phase-change structure.
[0111] The coolant can be electrically conductive, weakly conductive, or electrically insulating, depending on the embodiment. In some embodiments, a dielectric coolant directly contacts a die surface, a passivated die surface, a thermally conductive coating, or another exposed thermal interface while maintaining electrical isolation. In other embodiments, the coolant is separated from electrically active features by one or more dielectric barriers, liners, coatings, or channel walls. Wetted surfaces can be metallic, ceramic, polymeric, coated, plated, passivated, textured, porous, or composite.
[0112] The cooling interface can be bounded by one or more internal surfaces that include fins, ridges, microfins, porous textures, posts, roughened regions, capillary structures, or turbulence -promoting features. Such features can be selected to increase wetted surface area, improve phase-change behavior, enhance mixing, guide return flow, increase pressure drop in selected regions, control flow distribution, or tailor thennal performance. Feature size can vary’ from microscale to macroscale according to the target application. A cooling region can be configured for a broad range of operating conditions. For example, some embodiments operate at low positive gauge pressure, moderate positive gauge pressure, near-atmospheric pressure, or sub-atmospheric pressure. Some embodiments are configured for vacuum or reduced-pressure conditions. Some embodiments accommodate modest flow rates, while others are configured for substantial flow rates, including at least about 1 gallon per minute, at least about 10 gallons per minute, at least about 50 gallons per minute, or other values appropriate to the form factor and system design. These values are illustrative and may vary widely.
[0113] C. ^ta aRaysrTsrrnmailon and Thermal Rooting
[0114] A notable aspect of many embodiments is that a thennal path, a coolant passage, or both need not traverse the entire thickness of the substrate. In some embodiments, a thermally conductive structure extends from a heat source region to an internal layer, cavity wall, spreader, or intermediate region that is itself thermally coupled to a liquid or vapor cooling region. Tire structure can terminate at that internal region. In some embodiments, a coolant passage likewise terminates at an internal layer or internal surface and does not form a full-thickness through-hole opening. Such architectures can preserve routing freedom, improve sealing flexibility, enable local reinforcement, reduce unwanted leakage paths, and facilitate integration of cooling regions within complex stack-ups.
[0115] The thermal routing architecture can be localized or distributed. For example, a first thermal path can collect heat from a die attach site, spread that heat laterally through one or more spreaders or plates, anddeliver heat into a fluid-facing surface. A second thermal path can simultaneously conduct heat from a power stage into an external housing or chassis. A third path can guide heat into a sealed two-phase region. These examples are illustrative only, and multiple paths can coexist within a single substrate. D. Mt -Hsrsar, texiisle, and Straciwal embedments
[0116] The disclosed concepts are not limited to flat boards. In some embodiments, the substrate wraps around an edge, transitions across a comer, bends over a radius, or assumes a curved or three-dimensional form. In some embodiments, the substrate comprises a flexible or rigid-flex construction and includes a flexible coolant network. In some embodiments, the substrate forms part of a conformal housing, wearable structure, robotic skin, articulated assembly, or enclosure wall. In some embodiments, the substrate assumes a conduit-likc, pipc-likc, toroidal, hollow-corc, or multi-sided geometry’ and carries both electrical and thermal functions along the structure.
[0117] Flexible embodiments can include discrete rigid islands, compliant interconnect regions, local thickening for pressure containment, selective reinforcement, and distributed fluid communication among multiple thermal regions. The substrate can cooperate with flexible tubing, embedded hoses, printed channels, fomred chambers, laminate cavities, or molded fluid structures. In some embodiments, multiple cooling interfaces share fluid communication, thermal communication, or both across a distributed flexible platform.
[0118]
[0119] Electronic components can be mounted to or integrated into the substrate in numerous ways. Examples include surface-mounted packages, chip-scale packages, bare die, passivated die, power modules, optical devices, magnetic components, sensors, antennas, and stacked or nested component assemblies. In some embodiments, one or more components or assemblies are embedded within the multilayer stack -up, and electrical routing extends outward, upward, laterally, or through additional layers to connect with other substrate regions or external interfaces.
[0120] A thermally significant interface can include a die surface, heat spreader, package lid, thermal pad, underfill-adjacent region, interposer region, or embedded module surface. Bonding can be accomplished using solder, sintered metal, nanoparticle pastes, transient-liquid-phase materials, diffusion bonds, conductive or non -conductive adhesives, brazes, welds, mechanical compression, compliant interface layers, or combinations thereof. In some embodiments, a nano-metal bond line is used between a heat source region and a thermal path, or between a thermal path and a cooling interface.
[0121] Protective layers can be removable or permanent. For example, a removable layer can protect a die surface or wetted surface during fabrication, testing, transport, or assembly and then be removed prior to operation. Permanent layers can provide dielectric protection, corrosion mitigation, wear resistance, erosion resistance, biofouling resistance, or chemical compatibility. Corrosion-mitigation structures can include coatings, diffusion barriers, plated metals, passivation layers, liners, polymers, composites, or multilayer barrier stacks.
[0122] Materials; Yhsc aessgs, aad
[0123]
[0124] Raages
[0125] Representative thicknesses, dimensions, and material properties can vary widely according to the target application. By way of non-limiting example, a dielectric layer can have a thickness from less than 25 micrometers to several millimeters. A thermally conductive structure can have a lateral dimension from afew micrometers to several millimeters. A coolant passage can have a hydraulic diameter selected from microchannel dimensions to dimensions comparable to tubing, ducts, or plenums used for relatively high flow rates. A cover, wall, or reinforcement layer can be selected to withstand the expected pressure differential, handling loads, and environmental conditions. Materials can be selected to provide a desired combination of thermal conductivity, dielectric breakdown strength, processability, corrosion resistance, mechanical compliance, and coefficient-of-thermal-expansion compatibility.
[0126] Examples of thermally conductive dielectric or insulating materials include aluminum nitride -filled polymers, boron nitride -filled polymers, alumina-based composites, silica-filled polymers, ceramic tapes, ceramic slurries, glass ceramics, polyimides with thermally conductive fillers, silicone composites, fluoropolymer composites, cyanate ester systems, and multilayer combinations thereof. Examples of thermally conductive structures include copper, copper alloys, silver, aluminum, molybdenum, tungsten, graphite, graphitic composites, sintered metal structures, plated metals, ceramics, ceramic-metal composites, and combinations thereof. These examples are illustrative and not exhaustive.
[0127] G. Pressure Management, Is atfom and K sabslity
[0128] In some embodiments, the cooling interface is designed for positive gauge pressure operation, such as at most about 150 psi, at most about 50 psi, at most about 15 psi, or other values suitable for the embodiment. In some embodiments, the cooling interface is designed for sub-atmospheric or vacuum operation. Prcssurc-containmcnt strategics can include wall thickening, local reinforcement, rib structures, support pillars, distributed posts, housings, covers, mechanical constraints, selective bonding, and pressure-balanced or reduced-pressure designs.
[0129] Electrical isolation and safety performance can be enhanced using geometry, material selection, surface shaping, field-control structures, creepage extensions, clearance management, encapsulation, coatings, and dielectric barriers. Surface or subsurface dielectric geometries can be shaped to improve voltage standoff, breakdown performance, or partial-discharge resistance. The disclosed structures can be used in low-voltage systems, intennediate-voltage systems, and relatively high-voltage systems, depending on design choices.
[0130] Reliability measures can include corrosion mitigation, moisture barriers, selective coating systems, sacrificial layers, removable process layers, dielectric coolants, compatible material sets, pump or valve control, leakage detection, humidity sensing, pressure sensing, and environmental sealing. The system can include monitoring and control structures configured to identify off-nominal thermal, electrical, or fluidic behavior and to respond by adjusting operating conditions.
[0131] K. Fabrication an Assembly
[0132] Fabrication can proceed by numerous routes. In some embodiments, a multilayer stack -up is assembled by lamination of dielectric and conductive layers, followed by drilling, plating, filling, patterning, milling, cavity formation, bonding, and sealing operations. In some embodiments, selected channels, cavities, or passage walls are formed before final lamination. In some embodiments, channels or cavities are formed after initial lamination by milling, laser machining, etching, ablation, additive deposition, molding, or a hybrid process. Covers, wall structures, and manifolds can be bonded by adhesive bonding, soldering, brazing, diffusion bonding, nano-metal bonding, transient-liquid-phase bonding, welding, compression sealing, overmolding, gasketing, or combinations thereof.Additive manufacturing can be used to co-form, co-fabricate, or co-integrate thermally conductive structures, dielectric regions, channel walls, reinforcement structures, manifolds, or component supports. Additive methods can include ink -based printing, aerosol deposition, extrusion, photopolymer-based processes, powder-bed processes, directed-energy deposition, binder-based processes, and combinations with subtractive or lamination processes. Such methods can be used alone or in hybrid manufacturing sequences.
[0133] Embedded components can be placed before, during, or after lamination, and routing can then be extended outward, upward, or laterally to connect to other regions of the stack -up. Selected surfaces can be temporarily protected during fabrication by removable layers. After assembly, fluid passages can be leak tested, pressure tested, vacuum tested, cleaned, dried, filled, evacuated, charged, sealed, or otherwise conditioned for operation, depending on the embodiment.
[0134] k Systems, Co rols, aed Uss Ceses
[0135] System-level implementations can include the disclosed substrate together with one or more manifolds, fluid ports, connectors, pumps, condensers, valves, wicks, capillary return structures, reservoirs, controllers, sensors, housings, heat sinks, or chassis structures. Sensors can monitor temperature, pressure, flow, leakage, humidity, dielectric properties, electrical performance, or other operating conditions. Telemetry data can be generated locally or remotely and used to adjust pump speed, valve state, operating pressure, heat-rejection mode, coolant flow distribution, or other thcnnal -management variables.
[0136] Representative use cases include, without limitation, high-performance computing, Al accelerators, graphics processors, power electronics, automotive traction or charging electronics, avionics, satellite electronics, telecom equipment, industrial automation, robotics, wearable devices, military systems, medical devices, high-powcr lighting, imaging systems, edge computing, and combinations thereof. The same substrate family can support very different physical scales and power levels by varying materials, thicknesses, channel dimensions, pressure strategy, coolant selection, and system integration.
[0137]
[0138] EXAMPLES AMD USE CASES
[0139] Example 1. A rigid multilayer substrate includes a ceramic-filled dielectric region beneath a power semiconductor, a copper thermal network, and an internal liquid chamber sealed by a bonded cover. Heat collected from the semiconductor is delivered through the dielectric region and thermal network into a wetted cavity wall.
[0140] Example 2. A substrate includes an exposed die cooled by a dielectric liquid that directly contacts a passivated die surface while electrical routing remains isolated through surrounding dielectric structures. Example 3. A rigid-flex substrate includes multiple distributed cooling regions connected through a flexible coolant network and integrated into a conformal housing or robotic skin.
[0141] Example 4. A substrate includes embedded component assemblies and outward or upward routing to external interconnect regions while one or more internal thermal paths terminate at a liquid-facing internal laver.
[0142] Example 5. A conduit-like or hollow-core substrate carries both routing and thermal functions, with one or more thermal paths delivering heat to internal flow regions and, optionally, to an external chassis or housing.Example 6. A hybrid system combines a pumped-liquid chamber with a sealed two-phase region so that localized hotspots are spread through a vapor-phase structure and ultimately rejected through a liquid-cooled region or external heat-rejection structure.
Claims
CLAIMS1. A printed circuit board (PCB), comprising:a multilayer PCB stack-up including one or more thermally conductive electrically insulating regions configured to provide electrical isolation at one or more locations associated with electrical conductors, component attachment, or both;at least one cooling interface comprising a fluid-phase cooling interface, a vapor-phase cooling interface, or both; andone or more thermally conductive structures disposed in and / or on the multilayer PCB stack -up and configured to provide a thermal path between a heat source region and the at least one cooling interface,wherein at least a portion of the thermal path terminates at or adjacent to an internal layer that is thermally coupled to, or in direct contact with, a fluid or vapor cooling region without requiring the portion to traverse an entire thickness of the PCB.
2. Tire PCB of claim 1, wherein the one or more thermally conductive structures comprise vias and / or posts and athermal distribution structure.
3. The PCB of claim 1, wherein the one or more thermally conductive structures comprise vias and / or posts and exclude a thermal distribution structure as a distinct heat-transfer element.
4. Tire PCB of claim 1, wherein the at least one cooling interface includes embedded liquid coolant channels, a sealed two-phase region, or a hybrid arrangement including both.
5. The PCB of claim 1, wherein the at least one cooling interface comprises a channel network including one or more channels that terminate at an internal layer and do not form a full-thickness through-hole opening.
6. The PCB of claim 1, wherein the at least one cooling interface is shaped to wrap around an edge, a comer, or a curved transition of the PCB.
7. Tire PCB of claim 1, wherein the at least one cooling interface is configured to contact an exposed die surface or a passivated die surface, and wherein, in some embodiments, a dielectric coolant provides electrical isolation while allowing direct fluid contact with the exposed die surface or the passivated die surface.
8. The PCB of claim 1, wherein one or more electronic components and / or component assemblies are integrated into the multilayer PCB stack -up, and electrical routing extends outward, upward, and / or to one or more external interconnect regions.
9. The PCB of claim 1, wherein the one or more thermally conductive electrically insulating regions comprise a multi -material dielectric stack including at least two different electrically insulating materials selected from a ceramic material, a polymer dielectric, a filled polymer composite, or combinations thereof.
10. The PCB of claim 1, wherein the one or more thermally conductive electrically insulating regions include a removable protective layer configured to protect a die surface, athermal interface surface, or a wetted surface during fabrication or assembly and configured to be removed prior to operation.
11. The PCB of claim 1, wherein the at least one cooling interface is configured to contain a pressure differential including operation at a gauge pressure of at most 150 psi, at most 50 psi, or at most 15 psi, and wherein, in some embodiments, the at least one cooling interface is configured for sub- atmospheric pressure or vacuum operation.
12. The PCB of claim 1, further comprising a corrosion-mitigation layer associated with the at least one cooling interface, the corrosion-mitigation layer comprising a corrosion-resistant coating, a diffusion barrier, an electroplated layer, a passivation layer, a polymer liner, or combinations thereof.
13. The PCB of claim 1, wherein the multilayer PCB stack -up comprises a flexible substrate, a rigid-flex PCB, or a semi-flexible substrate configured to conform to a curved surface, and wherein the at least one cooling interface comprises a flexible channel network within the substrate.
14. The PCB of claim 1, wherein a bond line between a thermally conductive structure, a heat source region, and / or the at least one cooling interface comprises a nano-metal bonding material including sintered metal, nanoparticle paste, transient liquid phase material, or a nanometal composite adhesive.
15. The PCB of claim 1, wherein at least a portion of the one or more thermally conductive structures is co-fabricated, co-fonned, or co-integrated using additive manufacturing.
16. The PCB of claim 1, wherein surface or subsurface dielectric geometries are employed to improve voltage standoff, breakdown performance, or partial -discharge resistance.
17. The PCB of claim 1, wherein one or more surfaces bounding the at least one cooling interface include fins, ridges, microfins, porous textures, or combinations thereof.
18. The PCB of claim 1, wherein thermal conduction pathways extend from one or more heat-generating components to an external housing or chassis to dissipate heat to ambient air, water, or other environmental sinks.
19. The PCB of claim 1, wherein tire PCB has a multi-sided or non-planar geometry including angular, curved, toroidal, hollow-core, conduit-like, or pipe-like forms.
20. A thermally managed printed circuit board or PCB-like electronic substrate, comprising:a multilayer body including conductive routing and one or more electrically insulating regions; one or more cooling regions comprising a liquid-cooled cavity, a sealed working-fluid region configured for vapor-phase or two-phase thermal transport, or a hybrid cooling region; and one or more heat-transfer structures configured to thermally couple a heat source region of the multilayer body to the one or more cooling regions,wherein the one or more cooling regions are integrated within the multilayer body, directly coupled to the multilayer body, or both, and wherein the thennally managed printed circuit board or PCB-like electronic substrate is configured to remove heat without requiring an external cold plate to cover an entire exterior surface of the multilayer body.
21. The thennally managed printed circuit board or PCB-like electronic substrate of claim 20, wherein the multilayer body comprises a flexible substrate embedded in a flexible housing or robotic skin and forms a distributed thermal network comprising multiple cooling interfaces that share fluid communication, thermal coupling, or both across the flexible housing or robotic skin.
22. The thermally managed printed circuit board or PCB-like electronic substrate of claim 20, wherein vias and / or posts form a continuous network or lattice structure distributed across at least a portion of the multilayer body.
23. A thermal management system comprising:a printed circuit board according to any of claims 1-22; anda thermal interface assembly associated with the printed circuit board and configured to enable heat rejection from the printed circuit board via at least one cooling interface, the thermal interface assembly comprising at least one of:(i) a fluid handling assembly comprising at least one manifold, port, or connector configured to provide fluid communication for coolant flow to and / or from the at least one cooling interface of the printed circuit board; or(ii) a sealed working-fluid structure thermally coupled to the at least one cooling interface of the printed circuit board, the sealed working-fluid structure configured for vapor-phase or two-phase thermal transport,wherein the system is configured such that heat from tire printed circuit board is rejected through at least one of liquid convection in the at least one cooling interface, two-phase transport associated with the at least one cooling interface, or conduction to an external heat-rejection structure, without requiring the at least one cooling interface to cover an entire exterior surface of the printed circuit board.
24. The thermal management system of claim 23, wherein the thermal interface assembly includes the sealed working-fluid structure and further comprises a condenser, pump, wick, or capillary structure configured to return working fluid within the sealed working-fluid structure.
25. The thermal management system of claim 23, further comprising one or more sensors integrated with the printed circuit board or mounted to the printed circuit board, the one or more sensors including at least one of temperature, pressure, flow, leakage, humidity, dielectric property, or electrical performance sensors.
26. The thermal management system of claim 25, further comprising control circuitry configured to generate telemetry data based on the one or more sensors, and to adjust coolant flow, pump speed, valve state, operating pressure, or heat -rejection configuration based on the telemetry data.
27. The thermal management system of claim 23, wherein the thermal interface assembly is configured to operate at a gauge pressure of at most 15 psi and wherein, in some embodiments, the thermal interface assembly is configured to operate at sub-atmospheric pressure or vacuum conditions.
28. The thermal management system of claim 23, wherein the at least one cooling interface includes corrosion mitigation comprising a corrosion-resistant coating, a diffusion barrier, an electroplated layer, a passivation layer, a polymer liner, or combinations thereof.
29. A method of fabricating a thermally managed printed circuit board (PCB), comprising:forming a multilayer PCB stack -up that includes one or more thermally conductive electrically insulating regions;forming one or more thermally conductive structures within or upon the multilayer PCB stack -up to provide a thermal path from a heat source region to a cooling interface; andthermally interfacing at least a portion of the one or more thermally conductive structures with one or more cooling systems configured for fluid-phase or vapor-phase thermal transfer.
30. The method of claim 29, further comprising forming at least one coolant channel within the multilayer PCB stack-up. wherein the at least one coolant channel terminates at an internal layer and does not form a full-thickness through-hole opening.