Copper-clad ceramic-based circuit board with high heat dissipation performance

Abstract

The invention discloses a copper-clad ceramic-based circuit board with high heat dissipation performance. The copper-clad ceramic-based circuit board sequentially comprises a ceramic substrate made of an aluminum nitride-silicon carbide composite material, a composite copper-clad layer bonded on the surface of the ceramic substrate through a direct copper-clad process, a circuit layer and a multidirectional heat dissipation structure. Through the aluminum nitride-silicon carbide composite ceramic substrate, the array micropores, the coarsened copper foil, the graphene enhanced copper-clad layer and the photoetching circuit layer, the heat-conducting property and the bonding strength are remarkably improved, and the risk of thermal stress cracking is reduced. The conical heat dissipation through holes are combined with the nanometer aluminum oxide coating and the inclined design, heat flow distribution is optimized, and radiation heat dissipation is enhanced. The lateral heat dissipation fins are combined with the aluminum-based heat dissipation body and the three-dimensional graphene heat dissipation film, so that natural convection and radiation heat dissipation are enhanced. And the embedded heat pipe assembly is used for carrying out emphasized heat dissipation on a high-heat-flux area.

Description

Technical Field

[0001] The patent of this invention relates to the field of circuit board technology, specifically a copper-clad ceramic-based circuit board with high heat dissipation performance. Background Art

[0002] With the rapid development of electronic information technology, high-power, high-density integrated electronic devices have put forward higher requirements on the heat dissipation performance of circuit boards. Although traditional copper-clad ceramic-based circuit boards have certain heat dissipation capabilities, they still have obvious shortcomings when dealing with the high heat generated by high-power devices. In the existing technology, the interface bonding force between the ceramic substrate and the copper cladding layer is limited, which affects the heat conduction efficiency, and the heat dissipation path is single, mainly relying on the heat conduction of the substrate itself, making it difficult to quickly conduct concentrated heat. At the same time, conventional heat dissipation structures such as simple through-holes or flat heat sinks cannot form a multi-dimensional heat dissipation system, resulting in heat easily accumulating locally in the circuit layer, causing the device temperature to rise too high, affecting reliability and life. In addition, the material structure of the traditional copper cladding layer has limitations in thermal resistance control, lacks efficient enhanced heat dissipation design, and the substrate surface structure is single, which is not conducive to the dispersed conduction of heat.

[0003] Invention patent content

[0004] In order to overcome the shortcomings of the existing technical solutions, the patent of the present invention provides a copper-clad ceramic-based circuit board with high heat dissipation performance, which can effectively solve the problems raised by the background technology.

[0005] The technical solution adopted by the present invention to solve its technical problems is:

[0006] A copper-clad ceramic-based circuit board with high heat dissipation performance, comprising, in sequence, a ceramic substrate of an aluminum nitride-silicon carbide composite material, a composite copper-clad layer bonded to the surface of the ceramic substrate by a direct copper cladding process, a circuit layer, and a multi-directional heat dissipation structure;

[0007] The surface of the ceramic substrate is provided with an array of microporous structures, the composite copper clad layer is composed of a roughened copper foil and a graphene reinforcement layer, and the circuit layer is formed on the surface of the composite copper clad layer by a photolithography process;

[0008] The multi-directional heat dissipation structure includes conical heat dissipation holes, inverted pyramid-shaped heat dissipation bumps and lateral heat dissipation fins that penetrate the ceramic substrate. The aperture of the conical heat dissipation holes gradually expands from the circuit layer to the bottom of the substrate. The inverted pyramid-shaped heat dissipation bumps are distributed in an array between the composite copper clad layer and the circuit layer. The lateral heat dissipation fins are arranged at intervals along the circumference of the ceramic substrate and form a thermal conduction connection with the composite copper clad layer.

[0009] As a further description of the above technical solution, the aperture change rate of the conical heat dissipation hole is 0.05-0.2mm / mm, the inner surface of the conical heat dissipation hole is provided with a nano-aluminum oxide coating, and the axis of the conical heat dissipation hole forms an angle of 5-15° with the normal of the ceramic substrate.

[0010] As a further description of the above technical solution, the graphene reinforcement layer is a multi-layer corrugated structure, and copper nanowires are embedded between the layers of the graphene reinforcement layer.

[0011] As a further description of the above technical solution, the lateral heat dissipation fins include an aluminum-based heat sink and a three-dimensional graphene heat dissipation film. The aluminum-based heat sink is connected to the side of the ceramic substrate through a thermal interface material. The three-dimensional graphene heat dissipation film is coated on the outer surface of the aluminum-based heat sink. The extension direction of the lateral heat dissipation fins is at an angle of 30-45° to the surface of the ceramic substrate.

[0012] As a further description of the above technical solution, the bottom side length of the inverted pyramid-shaped heat dissipation bump is 50-200 μm, the aspect ratio is 1.2-1.8, and the spacing between adjacent inverted pyramid-shaped heat dissipation bumps is 1.5-2 times the side length.

[0013] As a further description of the above technical solution, the multi-directional heat dissipation structure also includes a heat pipe assembly embedded in the ceramic substrate, the heat pipe assembly includes an evaporation section and a condensation section, the evaporation section is located below the high heat flux density area of the circuit layer, and the condensation section extends to the lateral heat dissipation fins.

[0014] As a further description of the above technical solution, a transition layer is provided at the interface between the ceramic substrate and the composite copper cladding layer, and the transition layer includes a copper alloy layer with a thickness of 2-5 μm, a titanium nitride diffusion barrier layer with a thickness of 0.5-1.2 μm and a diamond particle reinforcement layer, and the particle size of the diamond particle reinforcement layer is 3-8 μm.

[0015] As a further description of the above technical solution, the surface of the circuit layer is provided with a selective heat dissipation coating and an aluminum oxide-silicon dioxide composite coating, the thickness of the selective heat dissipation coating is 10-30 μm, and the thickness of the aluminum oxide-silicon dioxide composite coating is 5-15 μm.

[0016] Compared with the existing technology, the beneficial effects of the present invention are:

[0017] The copper-clad ceramic-based circuit board with high heat dissipation performance of the present invention has at least one of the following beneficial effects during use:

[0018] This copper-clad ceramic-based circuit board utilizes an aluminum nitride-silicon carbide composite ceramic substrate, arrayed micropores, roughened copper foil, a graphene-enhanced copper cladding layer, and a photolithographic circuit layer to significantly improve thermal conductivity and bonding strength, reducing the risk of thermal stress cracking. Conical heat dissipation vias, combined with a nano-alumina coating and an angled design, optimize heat flow distribution and enhance radiative heat dissipation. Inverted pyramid-shaped heat dissipation bumps increase the heat dissipation area, promoting the conversion of lateral heat flow to longitudinal conduction. Lateral heat dissipation fins, combined with an aluminum-based heat sink and a three-dimensional graphene heat dissipation film, enhance natural convection and radiative heat dissipation. Embedded heat pipe assemblies provide targeted heat dissipation in areas of high heat flux density. Furthermore, the transition layer utilizes a copper alloy, a titanium nitride diffusion barrier layer, and a diamond particle reinforcement layer to further match the thermal expansion coefficient, prevent atomic diffusion, and improve the interface thermal conductivity. A selective heat dissipation coating and an aluminum oxide-silicon dioxide composite coating enhance radiative heat dissipation and provide protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the overall structure of a copper-clad ceramic-based circuit board with high heat dissipation performance according to the present invention;

[0020] Figure 2 This is a schematic diagram of the exploded structure of a copper-clad ceramic-based circuit board with high heat dissipation performance in the present invention;

[0021] Figure 3 This is a schematic diagram of the first side structure of a copper-clad ceramic-based circuit board with high heat dissipation performance according to the present invention;

[0022] Figure 4 This is a schematic diagram of the second side structure of a copper-clad ceramic-based circuit board with high heat dissipation performance according to the patent of this invention.

[0023] Numbers in the figure:

[0024] 1. Ceramic substrate; 2. Composite copper clad layer; 3. Circuit layer; 4. Multi-directional heat dissipation structure; 5. Graphene reinforcement layer; 6. Heat pipe assembly; 7. Conical heat dissipation through-hole; 8. Arrayed microporous structure; 9. Selective heat dissipation coating; 10. Lateral heat dissipation fins; 11. Inverted pyramid-shaped heat dissipation bumps. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0026] like Figure 1-4As shown, the patent of the present invention provides a copper-clad ceramic-based circuit board with high heat dissipation performance, which includes a ceramic substrate 1 of aluminum nitride-silicon carbide composite material, a composite copper-clad layer 2 bonded to the surface of the ceramic substrate 1 by a direct copper cladding process, a circuit layer 3 and a multi-directional heat dissipation structure 4.

[0027] The surface of the ceramic substrate 1 is provided with an arrayed microporous structure 8. The composite copper clad layer 2 is composed of a roughened copper foil and a graphene reinforcement layer 5. The circuit layer 3 is formed on the surface of the composite copper clad layer 2 by a photolithography process.

[0028] The aluminum nitride (AlN) and silicon carbide (SiC) of the ceramic substrate 1 of this embodiment are both highly thermally conductive materials (AlN thermal conductivity is about 170-200W / m·K, SiC is about 120-150W / m·K), and after compounding, they have both high thermal conductivity and mechanical strength. The arrayed microporous structure 8 forms micropores by laser processing or chemical etching, which increases the surface area, promotes the diffusion of heat into the interior of the substrate, and reduces the interfacial thermal resistance. The roughened copper foil of the composite copper clad layer 2 is roughened by a chemical or electrochemical roughening process to increase the surface roughness of the copper foil and enhance the bonding strength with the ceramic substrate 1. The graphene of the graphene enhancement layer 5 is embedded in the copper foil in a layered form to form an efficient heat conduction channel in the vertical direction.

[0029] The multi-directional heat dissipation structure 4 includes a conical heat dissipation through hole 7 penetrating the ceramic substrate 1, an inverted pyramid-shaped heat dissipation bump 11 and a lateral heat dissipation fin 10. The aperture of the conical heat dissipation through hole 7 gradually expands from the circuit layer 3 to the bottom of the substrate. The inverted pyramid-shaped heat dissipation bump 11 is distributed in an array between the composite copper clad layer 2 and the circuit layer 3. The lateral heat dissipation fin 10 is arranged at intervals along the circumference of the ceramic substrate 1 and forms a thermal conduction connection with the composite copper clad layer 2.

[0030] The aperture of the tapered heat dissipation vias 7 in this embodiment gradually expands from the circuit layer 3 toward the bottom, utilizing thermal expansion to accelerate the diffusion of heat through the vias toward the bottom of the substrate. The inverted pyramid-shaped heat dissipation bumps 11 are formed through photolithography and electroplating processes. Their geometry (aspect ratio of 1.2-1.8) increases the contact area, converting lateral heat flow into longitudinal conduction. Lateral heat dissipation fins 10 are spaced circumferentially along the substrate, achieving three-dimensional heat dissipation through contact between the fins and the external environment (such as air or a heat sink).

[0031] The composite material and microporous structure of the ceramic substrate 1 improve thermal conductivity by 40%-60%, while reducing the risk of thermal stress cracking. The graphene-enhanced copper cladding reduces local hotspot temperatures by 15%-25%, and the roughened copper foil enhances bonding strength by over 30%. The multi-directional heat dissipation structure 4 achieves three-dimensional heat dissipation in vertical, horizontal, and lateral directions through the synergistic effect of tapered through-holes, pyramidal bumps, and fins, improving overall heat dissipation capacity by 50%-80%.

[0032] It is further explained that the aperture variation rate of the conical heat dissipation hole 7 is 0.05-0.2 mm / mm, the inner surface of the conical heat dissipation hole 7 is provided with a nano-aluminum oxide coating, and the axis of the conical heat dissipation hole 7 forms an angle of 5-15° with the normal of the ceramic substrate 1.

[0033] The tapered through-holes, with a diameter variation of 0.05-0.2 mm / mm, optimize heat flux distribution and avoid increases in thermal resistance due to sudden changes in aperture diameter. A nano-alumina coating (50-100 nm thick) is deposited on the inner walls of the through-holes via atomic layer deposition (ALD), reducing surface radiation thermal resistance and enhancing infrared heat dissipation efficiency. The through-holes, angled at a 5-15° angle between the axis and the substrate normal, direct heat flow toward the lateral fins, reducing vertical heat accumulation.

[0034] Further, the graphene-enhanced layer 5 has a multi-layer, corrugated structure with copper nanowires embedded between the layers. The multi-layer, corrugated graphene is fabricated using chemical vapor deposition (CVD) to create a corrugated structure (with an interlayer spacing of 10-50 nm), increasing the interlayer contact area and mechanical toughness. The copper nanowires are embedded between the graphene layers using an electrochemical method to grow copper nanowires (20-50 nm in diameter) between them, forming a three-dimensional thermal network and enhancing lateral thermal conductivity.

[0035] It is further explained that the lateral heat dissipation fins 10 include an aluminum-based heat sink and a three-dimensional graphene heat dissipation film. The aluminum-based heat sink is connected to the side of the ceramic substrate 1 through a thermal interface material. The three-dimensional graphene heat dissipation film is coated on the outer surface of the aluminum-based heat sink. The extension direction of the lateral heat dissipation fins 10 is at an angle of 30-45° to the surface of the ceramic substrate 1.

[0036] The aluminum-based heat sink utilizes 6063 aluminum alloy (thermal conductivity approximately 200W / m·K) and is connected to the side of the substrate via a thermal interface material (such as silicone grease or solder) to rapidly dissipate heat. A three-dimensional graphene film is coated onto the aluminum substrate via chemical vapor deposition (CVD), leveraging graphene's high emissivity (>0.9) to enhance infrared heat dissipation. The fins extend at a 30-45° angle, optimizing airflow and enhancing natural convection cooling efficiency.

[0037] It is further explained that the bottom side length of the inverted pyramid-shaped heat dissipation bump 11 is 50-200μm, the aspect ratio is 1.2-1.8, and the spacing between adjacent inverted pyramid-shaped heat dissipation bumps 11 is 1.5-2 times the side length. The 50-200μm side length of the inverted pyramid bottom side is controlled by the photolithography process to ensure matching with the circuit layer 3 pad. The aspect ratio of 1.2-1.8 optimizes the conduction path of heat flow from the base to the top, avoiding heat flow concentration. The spacing of 1.5-2 times the side length balances the heat dissipation density and processing difficulty, preventing thermal interference between adjacent bumps.

[0038] It is further explained that the multi-directional heat dissipation structure 4 also includes a heat pipe assembly 6 embedded in the ceramic substrate 1, and the heat pipe assembly 6 includes an evaporation section and a condensation section. The evaporation section is located below the high heat flux density area of the circuit layer 3, and the condensation section extends to the lateral heat dissipation fins 10.

[0039] The evaporation section of the heat pipe assembly 6 is embedded beneath the circuit layer 3 (e.g., in the CPU or power device area), absorbing heat through the phase change of the working fluid. The condensation section extends to the lateral fins, dissipating heat through the fins. The embedded distribution system embeds the heat pipe into the ceramic substrate 1 through laser drilling, reducing external space usage.

[0040] It is further explained that a transition layer is provided at the interface between the ceramic substrate 1 and the composite copper cladding layer 2, and the transition layer includes a copper alloy layer with a thickness of 2-5 μm, a titanium nitride diffusion barrier layer with a thickness of 0.5-1.2 μm and a diamond particle reinforcement layer, and the particle size of the diamond particle reinforcement layer is 3-8 μm.

[0041] The copper alloy transition layer uses copper-tungsten alloy (CuW80 / 20) to match the coefficient of thermal expansion (CTE) of ceramic and copper, reducing thermal stress. A titanium nitride diffusion barrier layer is deposited via magnetron sputtering to prevent copper atoms from diffusing into the ceramic substrate. A diamond particle reinforcement layer embeds diamond particles (3-8μm in size) into the interface via electrophoretic deposition, boosting the local thermal conductivity to over 500W / m·K.

[0042] It is further explained that the surface of the circuit layer 3 is provided with a selective heat dissipation coating 9 and an alumina-silicon dioxide composite coating. The thickness of the selective heat dissipation coating 9 is 10-30 μm, and the thickness of the alumina-silicon dioxide composite coating is 5-15 μm. The selective heat dissipation coating 9 adopts a silicon carbide-graphene composite material (thickness 10-30 μm), and the high infrared emissivity (>0.9) promotes heat dissipation in the form of radiation. The alumina-silicon dioxide composite coating forms a dense protective layer (thickness 5-15 μm) through the sol-gel method to prevent circuit oxidation and assist in heat conduction.

[0043] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims, not the foregoing description, and is intended to encompass all variations within the meaning and range of equivalents of the claims. Any reference signs in the claims should not be construed as limiting the claim to which they relate.

Claims

1. A copper-clad ceramic-based circuit board with high heat dissipation performance, characterized by: The invention comprises, in sequence, a ceramic substrate of an aluminum nitride-silicon carbide composite material, a composite copper clad layer bonded to the surface of the ceramic substrate by a direct copper cladding process, a circuit layer, and a multi-directional heat dissipation structure; The surface of the ceramic substrate is provided with an array of microporous structures, the composite copper clad layer is composed of a roughened copper foil and a graphene reinforcement layer, and the circuit layer is formed on the surface of the composite copper clad layer by a photolithography process; The multi-directional heat dissipation structure includes conical heat dissipation holes, inverted pyramid-shaped heat dissipation bumps and lateral heat dissipation fins that penetrate the ceramic substrate. The aperture of the conical heat dissipation holes gradually expands from the circuit layer to the bottom of the substrate. The inverted pyramid-shaped heat dissipation bumps are distributed in an array between the composite copper clad layer and the circuit layer. The lateral heat dissipation fins are arranged at intervals along the circumference of the ceramic substrate and form a thermal conduction connection with the composite copper clad layer.

2. The copper-clad ceramic-based circuit board with high heat dissipation performance according to claim 1, characterized in that: The aperture variation rate of the conical heat dissipation through hole is 0.05-0.2 mm / mm, the inner surface of the conical heat dissipation through hole is provided with a nano-aluminum oxide coating, and the axis of the conical heat dissipation through hole forms an angle of 5-15 degrees with the normal of the ceramic substrate.

3. The copper-clad ceramic-based circuit board with high heat dissipation performance according to claim 1, characterized in that: The graphene reinforcement layer is a multi-layer corrugated structure, and copper nanowires are embedded between the layers of the graphene reinforcement layer.

4. The copper-clad ceramic-based circuit board with high heat dissipation performance according to claim 1, characterized in that: The lateral heat dissipation fins include an aluminum-based heat sink and a three-dimensional graphene heat dissipation film. The aluminum-based heat sink is connected to the side of the ceramic substrate through a thermal interface material. The three-dimensional graphene heat dissipation film is coated on the outer surface of the aluminum-based heat sink. The extension direction of the lateral heat dissipation fins forms an angle of 30-45° with the surface of the ceramic substrate.

5. The copper-clad ceramic-based circuit board with high heat dissipation performance according to claim 1, characterized in that: The bottom side length of the inverted pyramid-shaped heat dissipation bump is 50-200 μm, the aspect ratio is 1.2-1.8, and the spacing between adjacent inverted pyramid-shaped heat dissipation bumps is 1.5-2 times the side length.

6. The copper-clad ceramic-based circuit board with high heat dissipation performance according to claim 1, characterized in that: The multi-directional heat dissipation structure also includes a heat pipe assembly embedded in the ceramic substrate. The heat pipe assembly includes an evaporation section and a condensation section. The evaporation section is located below the high heat flux density area of the circuit layer, and the condensation section extends to the lateral heat dissipation fins.

7. The copper-clad ceramic-based circuit board with high heat dissipation performance according to claim 1, characterized in that: A transition layer is provided at the interface between the ceramic substrate and the composite copper cladding layer. The transition layer comprises a copper alloy layer with a thickness of 2-5 μm, a titanium nitride diffusion barrier layer with a thickness of 0.5-1.2 μm, and a diamond particle reinforcement layer. The particle size of the diamond particle reinforcement layer is 3-8 μm.

8. The copper-clad ceramic-based circuit board with high heat dissipation performance according to claim 1, characterized in that: The surface of the circuit layer is provided with a selective heat dissipation coating and an aluminum oxide-silicon dioxide composite coating. The thickness of the selective heat dissipation coating is 10-30 μm, and the thickness of the aluminum oxide-silicon dioxide composite coating is 5-15 μm.

Images