Composite structure coated with heat dissipation material on one side of ceramic substrate

Abstract

The present invention provides a composite structure coated with a heat dissipation material on one side of a ceramic substrate, comprising a ceramic substrate; a first heat dissipation layer bonded to a surface of the ceramic substrate; and a second heat dissipation layer bonded to the surface of the first heat dissipation layer that is not in contact with the ceramic substrate. Aluminum is used as the metal of an intermediate layer, so that easy processing and bonding can be achieved, waste heat generated under high-power use is released, and the effect of protecting elements is achieved. The composite structure of the present invention can achieve excellent heat dissipation characteristics even in harsh environments such as high operating voltage, high operating current and high power, and is beneficial to lightweight and cost reduction.

Description

Composite structure with heat dissipation material coated on one side of a ceramic substrate Technical Field

[0001] The present invention relates to a composite structure in which a ceramic substrate is coated with a heat dissipation material on one side, and in particular to a composite structure which utilizes a thick aluminum layer as an intermediate layer to effectively bond the layers of an electronic component while maintaining heat dissipation performance. Background Art

[0002] In the fields of electronics, aerospace, automobiles, and the chemical industry, ceramic materials coated with metals, alloys, or other materials (e.g., high thermal conductivity ceramics) have a variety of uses and applications. For example, they can be used as electronic components or other composite materials, thereby enabling the components or materials to obtain the excellent properties of metals, alloys, or other materials while retaining the excellent properties of ceramics, such as electrical conductivity, thermal conductivity, heat dissipation, corrosion resistance, and wear resistance.

[0003] Especially in the field of electric vehicles, since the electronic components in the electric vehicle system will generate a lot of heat under high voltage, high current and high power use, good heat dissipation performance can effectively increase the service life of the electronic components.

[0004] In the prior art, to prevent substrate cracking or delamination problems caused by the different thermal expansion coefficients of different metals, alloys, or other materials, ceramic substrates are typically coated on both sides with the same metal, alloy, or other material, such as copper or aluminum. Both copper and aluminum have excellent electrical and thermal conductivity, with copper having superior electrical and thermal conductivity compared to aluminum, making it theoretically a more ideal metal layer material.

[0005] However, copper metal has disadvantages such as high hardness, difficulty in processing and joining, heavy weight, easy to peel off, and high cost.

[0006] In comparison, aluminum offers advantages such as high activity, ease of diffusion bonding, good plasticity, a low melting point, softness and ease of processing, and light weight. Furthermore, aluminum is relatively inexpensive. Furthermore, aluminum is also easier to bond with other materials or components, such as copper, aluminum, or silicon carbide, or the heat sinks they create, including fins, vapor chambers, and heat sinks.

[0007] Therefore, in light of these technical bottlenecks, the inventors have leveraged the aforementioned material properties to develop an improved composite structure for electric vehicle electronic components. Using aluminum as the bonding layer solves the existing problems of copper metal, which is difficult to process and bond and prone to flaking, while also significantly reducing the cost and weight of copper. Furthermore, while aluminum's thermal conductivity is slightly lower than copper, it still outperforms other metals, making it an ideal alternative material for effectively dissipating the substantial heat generated by electric vehicle electronic components under high voltage, high current, and high power conditions.

[0008] In summary, a composite structure is needed that has excellent heat dissipation performance and can ensure the safety, efficiency and reliability of electronic components during high power operation.

[0009] Summary of the Invention

[0010] In view of the problems encountered in the prior art, the present invention provides an improved composite structure, in which at least two layers of metal, alloy, or high thermal conductivity material with excellent heat dissipation properties are bonded to one side of a ceramic substrate. By using aluminum as the metal of the intermediate layer, the goals of easy processing and bonding, reduced weight, and lower cost can be achieved.

[0011] According to the present invention, a composite structure with a heat dissipation material coated on one side of a ceramic substrate includes: a ceramic substrate; a first heat dissipation layer bonded to one surface of the ceramic substrate; and a second heat dissipation layer bonded to the other surface of the first heat dissipation layer that is not in contact with the ceramic substrate.

[0012] In one embodiment of the present invention, the second heat dissipation layer may be in the form of a plate-shaped, column-shaped, or needle-shaped heat-dissipating device.

[0013] In one embodiment of the present invention, the ceramic substrate is first bonded to the first heat dissipation layer, and then the first heat dissipation layer is bonded to the second heat dissipation layer; or, the ceramic substrate, the first heat dissipation layer and the second heat dissipation layer are bonded simultaneously.

[0014] In one embodiment of the present invention, the ceramic substrate is an insulating heat dissipation ceramic substrate.

[0015] In one embodiment of the present invention, the thickness of the first heat dissipation layer is in the millimeter order.

[0016] In one embodiment of the present invention, the material of the ceramic substrate includes one or more of aluminum oxide, aluminum nitride, silicon carbide, silicon nitride, silicon oxynitride, silicon dioxide, boron nitride, beryllium oxide, and zirconium oxide toughened alumina (ZTA).

[0017] In one embodiment of the present invention, the main material of the first heat dissipation layer is aluminum.

[0018] In one embodiment of the present invention, the second heat dissipation layer is made of a material having a thermal conductivity of 150 W / mk or more, such as aluminum alloy, copper alloy, or high thermal conductivity ceramic (such as silicon carbide). Preferably, the density of the material is less than 4 g / cm 3 .

[0019] In one embodiment of the present invention, the ceramic substrate and the first heat dissipation layer, and the first heat dissipation layer and the second heat dissipation layer are bonded to each other using heating and optionally pressure.

[0020] In one embodiment of the present invention, the heating method includes electric heating, infrared quartz tube heating, high frequency induction heating, infrared vacuum heating, arc heating, and magnetron electron beam heating.

[0021] In one embodiment of the present invention, the bonding method further includes AMB, DBC, DPC, DBA, diffusion bonding, friction welding, laser cladding, or ultrasonic welding.

[0022] In summary, the composite structure of the present invention bonds thick aluminum with excellent processing and bonding properties and excellent heat dissipation performance to a ceramic substrate, and bonds another metal, alloy, or high thermal conductivity material with excellent heat dissipation performance to the thick aluminum layer. This enables the composite structure of the present invention to achieve excellent heat dissipation characteristics even in harsh environments such as high operating voltage, current, and high power, and is conducive to lightweighting and cost reduction.

[0023] The effects of the present invention are not limited to the above-mentioned effects, and those skilled in the art can clearly understand other effects not mentioned from the description of the scope of claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG1 is a perspective view showing a composite structure in which a ceramic substrate is coated with a double layer of heat dissipation material on one side according to a first embodiment of the present invention.

[0025] FIG2 is a perspective view showing a composite structure in which a ceramic substrate is coated with a double layer of heat dissipation material on one side and the second heat dissipation layer is a heat spreader according to a second embodiment of the present invention.

[0026]

Explanation of symbols

[0027] 1: Ceramic substrate

[0028] 10: First heat dissipation layer

[0029] 11,11': Second heat dissipation layer DETAILED DESCRIPTION

[0030] Advantages and features of the present invention and methods for implementing the same will be more clearly understood from the embodiments described below with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments, but can be implemented in various forms.

[0031] In the absence of any contradiction, the technical features in any embodiment of the present invention may be combined with other embodiments of the present invention.

[0032] 1 , according to a first embodiment of the present invention, a composite structure is provided in which a heat dissipation material is coated on a single surface of a ceramic substrate. The composite structure includes: a ceramic substrate 1 in the form of a flat plate; a first heat dissipation layer 10 bonded to one surface of the ceramic substrate 1; and a second heat dissipation layer 11 bonded to the other surface of the first heat dissipation layer 10 that is not in contact with the ceramic substrate 1.

[0033] The material of the ceramic substrate 1 may be an insulating heat dissipating ceramic substrate, for example, comprising one or more of alumina, aluminum nitride, silicon carbide, silicon nitride, silicon oxynitride, silicon dioxide, boron nitride, beryllium oxide, and zirconium oxide toughened alumina (ZTA).

[0034] In one embodiment of the present invention, the first heat dissipation layer 10 may be, for example, aluminum, preferably millimeter-thick aluminum.

[0035] In high-current electronic components, in addition to its excellent processing and bonding properties as an intermediate layer between the ceramic substrate 1 and the second heat sink layer 11, as previously mentioned, aluminum, a particularly excellent heat dissipation metal, is preferably used for the first heat sink 10 to suppress heat generation during power-on. Therefore, the thick aluminum layer bonded to the ceramic substrate 1 as the first heat sink 10 provides excellent heat dissipation, protecting the component from overheating and enhancing its reliability and lifespan.

[0036] In one embodiment of the present invention, the second heat dissipation layer 11 may be made of a material having a thermal conductivity of 150 W / mk or higher, including but not limited to aluminum alloy, copper alloy, and high thermal conductivity ceramics (such as silicon carbide). More preferably, the thermal conductivity of the material is 150 W / mk or higher and the density is less than 4 g / cm 3 , because materials with low density are relatively light, which helps meet the demand for lightweighting.

[0037] In one embodiment of the present invention, the ceramic substrate 1 is first bonded to the first heat dissipation layer 10 , and then the first heat dissipation layer 10 is bonded to the second heat dissipation layer 11 ; alternatively, the ceramic substrate 1 , the first heat dissipation layer 10 and the second heat dissipation layer 11 can be bonded simultaneously.

[0038] The bonding method using the first heat dissipation layer 10 composed mainly of aluminum as the intermediate layer has the following advantages: First, aluminum is highly active and easily diffuses into the ceramic substrate, allowing it to adhere evenly to the ceramic substrate, which helps to improve the bonding strength; second, aluminum has good plasticity and a low melting point, which facilitates the processing process; third, aluminum is light in weight, which can reduce the weight of the entire electronic component, especially in weight-sensitive applications such as portable electronic devices and automobiles; fourth, aluminum is relatively low in cost.

[0039] The ceramic substrate 1 and the first heat dissipation layer 10 , and the first heat dissipation layer 10 and the second heat dissipation layer 11 are each bonded to each other using heating and optionally pressure.

[0040] In an embodiment where the ceramic substrate 1 is first bonded to the first heat dissipation layer 10 and then the first heat dissipation layer 10 is bonded to the second heat dissipation layer 11 , the bonding method may include the following steps:

[0041] a) placing a first heat dissipation layer 10 on the lower surface of the ceramic substrate 1;

[0042] b) contacting the other surface of the first heat dissipation layer 10 that is not in contact with the ceramic substrate 1 with a mold;

[0043] c) optionally pressing the first heat dissipation layer 10 toward the ceramic substrate 1 through a tool;

[0044] d) heating the mold to conduct heat to the first heat dissipation layer 10 so that the lower surface of the ceramic substrate 1 is bonded to the first heat dissipation layer 10;

[0045] e) placing the second heat dissipation layer 11 on the lower surface of the first heat dissipation layer 10 that is not in contact with the ceramic substrate 1;

[0046] f) contacting the other surface of the second heat dissipation layer 11 that is not in contact with the first heat dissipation layer 10 with the mold;

[0047] g) optionally pressurizing the second heat dissipation layer 11 toward the first heat dissipation layer 10 on the ceramic substrate 1 through a tool;

[0048] h) heating the mold to conduct heat to the second heat dissipation layer 11 , so that the first heat dissipation layer 10 and the second heat dissipation layer 11 are bonded together.

[0049] In addition, in an embodiment in which the ceramic substrate 1, the first heat dissipation layer 10, and the second heat dissipation layer 11 are bonded simultaneously, the bonding method may include the following steps:

[0050] a′) placing a first heat dissipation layer 10 on the lower surface of the ceramic substrate 1;

[0051] b') placing the second heat dissipation layer 11 on the lower surface of the first heat dissipation layer 10 that is not in contact with the ceramic substrate 1;

[0052] c') contacting the other surface of the second heat dissipation layer 11 that is not in contact with the first heat dissipation layer 10 with a mold;

[0053] d′) optionally pressing the second heat dissipation layer 11 and the first heat dissipation layer 10 toward the ceramic substrate 1 through a tool;

[0054] e′) heating the mold to conduct heat to the second heat dissipation layer 11 and the first heat dissipation layer 10 , so that the ceramic substrate 1 , the first heat dissipation layer 10 and the second heat dissipation layer 11 are bonded simultaneously.

[0055] In one embodiment of the present invention, the tool can be, for example, a laminate, made of a conductor, and does not produce solid solution, diffusion, or eutectic reaction with the first heat dissipation layer 10 and the second heat dissipation layer 11 during processing. In addition, the melting point of the first heat dissipation layer 10 and the second heat dissipation layer 11 is lower than 80% of the melting point temperature of the tool.

[0056] To prevent adhesion between the tool and the metal layer, the tool can be treated with nickel plating or a release agent. Alternatively, adhesion between the metal layer and the tool can be avoided without heating the metal layer above its melting point.

[0057] In one embodiment of the present invention, the conductor includes one or more of molybdenum, molybdenum alloys, tungsten, tungsten alloys, tantalum, tantalum alloys, graphite, silicon, and silicon carbide.

[0058] The above-mentioned heating methods can include electric heating, infrared quartz tube heating, high-frequency induction heating, infrared vacuum heating, arc heating, and magnetron electron beam heating. Examples of heating methods are described below.

[0059] Electric heating

[0060] A method of converting electrical energy into thermal energy for heating. When current passes through a metal conductor, energy is generated due to the collision of electrons in the conductor, which ultimately causes heat generation.

[0061] Infrared quartz tube heating

[0062] The electromagnetic radiation heat is combined with a transparent quartz tube heater. Its working principle is to heat the quartz tube by turning on the power, and transmit the infrared radiation energy to the heated object in the form of thermal radiation.

[0063] High frequency induction heating

[0064] High frequency, also known as high-frequency wave, refers to electromagnetic wave with a frequency greater than 100 kHz. Its working principle is to generate induced current inside the heated object under the action of high-frequency electric field, thereby generating resistive heat.

[0065] Infrared vacuum heating

[0066] Its working principle is to use an infrared radiation heater in a vacuum environment, and the infrared radiation energy generated by the radiation heater directly acts on the heated object.

[0067] Arc heating

[0068] Heat is generated by arc discharge. Arc is achieved by applying voltage between two electrodes to form a current path for gas discharge, producing a strong arc discharge phenomenon, thereby generating high temperature and heat energy.

[0069] Magnetron electron beam heating

[0070] By controlling the high-speed electron beam to collide with the object to be heated, the kinetic energy of the electron beam is converted into thermal energy.

[0071] Alternatively, the methods for bonding the ceramic substrate 1 and the first heat dissipation layer 10, and the first heat dissipation layer 10 and the second heat dissipation layer 11, may further include AMB, DBC, DPC, DBA, diffusion bonding, friction welding, laser cladding, or ultrasonic welding. Examples of bonding methods are described below.

[0072] Active Metal Brazing (AMB)

[0073] By adding active metals such as titanium to the solder, the interface between the ceramic and metal can be wetted and reacted, improving the wettability of the ceramic and thus allowing the ceramic substrate to be bonded to the metal.

[0074] Direct Bonded Copper (DBC)

[0075] During the sintering process, oxygen is introduced between copper and ceramic to form a copper-oxygen eutectic liquid, which reacts with the ceramic substrate to generate composite oxides such as CuAlO2 or CuAl2O4 as solder, which wets the interface between the copper foil and the ceramic, thereby bonding the ceramic substrate to the copper.

[0076] Direct Plated Copper (DPC)

[0077] Copper is sputtered onto a ceramic substrate using semiconductor process technology, thereby bonding the ceramic substrate and the copper.

[0078] Direct Bonded Aluminum (DBA)

[0079] The surface of the ceramic substrate is brought into contact with liquid aluminum. At this time, aluminum can quickly wet the ceramic surface, that is, aluminum and ceramic have good wettability, thereby bonding the ceramic substrate and aluminum.

[0080] Friction Welding

[0081] Mechanical friction motion is used to generate heat on the friction surface, and the materials are plastically deformed under the action of frictional heat and pressure to join together.

[0082] Laser Cladding

[0083] A high-power laser is used to heat the substrate, and metal powder is fed into the molten pool formed by the laser beam heating. After the molten metal powder cools down, a layer of other metal material is melted onto the surface of the original substrate.

[0084] Ultrasonic Welding

[0085] Ultrasonic waves refer to sound waves with a frequency exceeding 20 kHz. They are converted into high-frequency signals. Under high-frequency vibration, friction between molecules at the bonding interface generates frictional heat, causing the materials to undergo plastic deformation and bond together.

[0086] Alternatively, referring to FIG2 , in a second embodiment of the present invention, to enhance heat dissipation, the second heat dissipation layer 11 of the first embodiment may be replaced with a second heat dissipation layer 11′. The second heat dissipation layer 11′ may include a plate-shaped, columnar, or needle-shaped heat dissipation device. The heat dissipation device may be, for example, a fin, a vapor chamber, or a heat sink.

[0087] The composite structure of the present invention is characterized by utilizing the aforementioned heating method in conjunction with a mold, allowing the first heat dissipation layer 10 (e.g., aluminum) to be fully or partially melted at a rapid temperature increase, thereby coating a single surface of the ceramic substrate 1 with a thick layer of aluminum (first heat dissipation layer 10) without the need for sputtering or precious metal soldering. Similarly, the first heat dissipation layer 10 can also be bonded to the second heat dissipation layer 11 or a second heat dissipation layer 11' serving as a heat spreader, such as a heat sink.

[0088] Therefore, compared with the metallization methods of the prior art (such as AMB, DBC, DPC, etc.), the composite structure of the present invention has the following advantages: First, it is quickly prepared, which can improve production efficiency; second, since the metal or alloy (such as aluminum, copper alloy and aluminum alloy) softens or melts during the bonding process, the problem of stress cracking of the ceramic substrate during the bonding process is reduced; third, through rapid temperature control, the grain growth of the metal or alloy during the bonding process can be limited, thereby fully maintaining the electrical conductivity, thermal conductivity and ductility of the metal or alloy.

[0089] In summary, the composite structure of the present invention has thick aluminum with excellent processing and bonding properties and excellent heat dissipation properties bonded to one side of the ceramic substrate, and another metal, alloy, or high thermal conductivity material with excellent heat dissipation properties bonded to the other side of the thick aluminum layer. This enables the composite structure of the present invention to achieve excellent heat dissipation characteristics even in harsh environments such as high operating voltage, current, and high power, and is conducive to lightweighting and cost reduction.

[0090] Based on the above detailed description of the present invention, other modifications and variations will be apparent to those skilled in the art. However, it will be apparent that such other modifications and variations may be made without departing from the spirit and scope of the present invention.

Claims

1. A composite structure in which a heat dissipation material is coated on one side of a ceramic substrate, comprising: Ceramic substrate; A first heat dissipation layer is bonded to a surface of the ceramic substrate; as well as The second heat dissipation layer is bonded to the other surface of the first heat dissipation layer that is not in contact with the ceramic substrate.

2. The composite structure according to claim 1, wherein: The second heat dissipation layer is in the form of a plate-shaped, column-shaped or needle-shaped heat-dissipating device.

3. The composite structure according to claim 1 or 2, wherein: The ceramic substrate is first bonded to the first heat dissipation layer, and then the first heat dissipation layer is bonded to the second heat dissipation layer; or the ceramic substrate, the first heat dissipation layer and the second heat dissipation layer are bonded simultaneously.

4. The composite structure according to claim 1 or 2, wherein: The material of the ceramic substrate includes one or more of aluminum oxide, aluminum nitride, silicon carbide, silicon nitride, silicon oxynitride, silicon dioxide, boron nitride, beryllium oxide, and zirconium oxide toughened aluminum oxide.

5. The composite structure according to claim 1 or 2, wherein: The main material of the first heat dissipation layer is aluminum.

6. The composite structure according to claim 1 or 2, wherein: The second heat dissipation layer is composed of a material with a thermal conductivity of 150 W / mk or more, and the material includes aluminum alloy, copper alloy, or high thermal conductivity ceramics.

7. The composite structure according to claim 6, wherein: The high thermal conductivity ceramic includes silicon carbide.

8. The composite structure of claim 6, wherein: The second heat dissipation layer has a thermal conductivity of more than 150 W / mk and a density of less than 4 g / cm 3 material composition.

9. The composite structure according to claim 1 or 2, wherein: The ceramic substrate and the first heat dissipation layer, and the first heat dissipation layer and the second heat dissipation layer are each bonded to each other using a heating and optional pressure method, and wherein, The heating methods include electric heating, infrared quartz tube heating, high frequency induction heating, infrared vacuum heating, arc heating, and magnetron electron beam heating.

10. The composite structure of claim 9, wherein: The bonding method further includes AMB, DBC, DPC, DBA, diffusion bonding, friction welding, laser cladding, or ultrasonic welding.

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