Composite structure in which one side of ceramic substrate is coated with conductive material

Abstract

The present invention provides a composite structure in which one side of a ceramic substrate is coated with a conductive material. The composite structure comprises: a ceramic substrate; a first conductive layer bonded to a surface of the ceramic substrate; and a second conductive layer bonded to another surface of the first conductive layer which is not in contact with the ceramic substrate. A special conductor is used as the material for an intermediate layer, so that it is possible to achieve easy processing and bonding while maintaining heat dissipation performance and conductivity, and the objective of effectively dredging a high current, high voltage and high power is achieved.

Description

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

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

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

[0003] Especially in the field of electric vehicles, the electronic components in electric vehicle systems generate a lot of heat, so good heat dissipation performance is required to maintain the temperature of the electronic components within a safe range. In addition, the high operating voltage, high operating current, and high power requirements of electric vehicles require electronic components to have excellent electrical conductivity, which can effectively withstand and channel high voltage, high current, and high power, thereby extending 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, both sides of the ceramic substrate are usually coated with the same metal, alloy, or other material, such as copper or aluminum. This is because copper and aluminum both have good electrical and thermal conductivity. Among them, copper has better electrical conductivity than aluminum and is therefore theoretically a more ideal metal layer material.

[0005] Generally speaking, to withstand and conduct high voltage, high current, and high power, electric vehicle electronic components require thick metal or conductor layers (e.g., copper layers at least 0.3mm thick). However, using a copper layer as thick as 0.03mm for the metal or conductor layers of electronic components is already difficult to process, as copper metal has disadvantages such as high hardness, difficulty in machining and bonding, heavy weight, and easy peeling. Furthermore, copper metal is also relatively expensive.

[0006] In comparison, aluminum metal has advantages such as high activity, easy diffusion bonding, good plasticity, low melting point, softness and ease of processing, and light weight. Furthermore, aluminum metal is also relatively low in cost. Furthermore, aluminum metal is also easier to bond with other materials or components, such as copper, aluminum, or silicon carbide, or the heat sinks made from them.

[0007] Therefore, in light of the aforementioned technical bottlenecks, the inventors have developed an improved composite structure for electric vehicle electronic components by leveraging the aforementioned material properties. Taking the prior art electronic component consisting of 0.8mm thick copper clad on a ceramic substrate as an example, replacing the 0.3mm thick copper with a special conductor (e.g., aluminum) can resolve the prior art copper's difficulties in machining and bonding, as well as its tendency to peel, while also significantly reducing the cost and weight of the copper. Furthermore, while aluminum's conductivity is slightly lower than copper's, it still outperforms other metals, making it an ideal alternative material for withstanding and conducting the high currents, voltages, and powers typically carried solely by thick copper materials.

[0008] In summary, a composite structure is needed that has excellent heat dissipation and electrical conductivity to ensure the safety, efficiency, and reliability of electronic components during 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 conductors with excellent electrical conductivity or heat dissipation are bonded to one side of a ceramic substrate. By using a special conductor (such as aluminum) as an intermediate layer, it is possible to achieve easy processing and bonding while effectively conducting high current, high voltage and high power.

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

[0012] In one embodiment of the present invention, a thickness ratio of the first conductive layer to the second conductive layer is in a range of 1:1 to 1:10.

[0013] In one embodiment of the present invention, the thickness of the second conductive layer is greater than 0.05 mm.

[0014] In one embodiment of the present invention, the second conductive layer is further patterned.

[0015] 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).

[0016] In one embodiment of the present invention, the material of the first conductive layer has a conductivity less than 4×10 7 S / m, and the material of the second conductive layer has a conductivity greater than 4×10 7 S / m conductor.

[0017] In one embodiment of the present invention, the ceramic substrate and the first conductive layer, and the first conductive layer and the second conductive layer are bonded to each other using heating and optionally pressure.

[0018] 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.

[0019] 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.

[0020] In summary, the composite structure of the present invention is achieved by bonding a special conductor (e.g., thick aluminum) having excellent processing and bonding properties and excellent electrical conductivity and heat dissipation properties to a ceramic substrate, and bonding another conductor having excellent electrical conductivity and heat dissipation properties to the special conductor layer. This enables the composite structure of the present invention to achieve excellent electrical conductivity and heat dissipation properties even in harsh environments such as high operating voltage, current, and high power, and is conducive to lightweighting and cost reduction.

[0021] The effects of the present invention are not limited to the above effects, and those skilled in the art can clearly understand other effects not mentioned from the description of the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] 1 is a perspective view showing a composite structure in which a heat dissipation material is coated on one side of a ceramic substrate according to a first embodiment of the present invention;

[0023] 2 is a perspective view showing a composite structure in which a conductive material is coated on one side of a ceramic substrate according to a second embodiment of the present invention;

[0024] FIG3 is a perspective view showing a composite structure of a ceramic substrate coated with a conductive material on one side in the prior art, wherein both the first conductive layer and the second conductive layer are patterned; and

[0025] FIG. 4 is a perspective view showing a composite structure in which a ceramic substrate is coated with a conductive material on one side according to a third embodiment of the present invention, wherein only the second conductive layer is patterned.

[0026] [Description of symbols] 1: Ceramic substrate 1': Ceramic substrate of the prior art 10: First heat dissipation layer 11: Second heat dissipation layer 20: First conductive layer 20': First conductive layer of the prior art 21: Second conductive layer 21': Second conductive layer of the prior art DETAILED DESCRIPTION

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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).

[0031] In one embodiment of the present invention, the first heat dissipation layer 10 may be, for example, aluminum, preferably millimeter-thick aluminum.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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:

[0038] a) placing a first heat dissipation layer 10 on the lower surface of the ceramic substrate 1;

[0039] 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;

[0040] c) optionally pressing the first heat dissipation layer 10 toward the ceramic substrate 1 through a tool;

[0041] 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;

[0042] 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;

[0043] 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;

[0044] g) optionally pressurizing the second heat dissipation layer 11 toward the first heat dissipation layer 10 on the ceramic substrate 1 through a tool;

[0045] 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.

[0046] 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:

[0047] a′) placing a first heat dissipation layer 10 on the lower surface of the ceramic substrate 1;

[0048] 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;

[0049] 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;

[0050] d′) optionally pressing the second heat dissipation layer 11 and the first heat dissipation layer 10 toward the ceramic substrate 1 through a tool;

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] Electric heating

[0057] 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.

[0058] Infrared quartz tube heating

[0059] 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.

[0060] High frequency induction heating

[0061] 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.

[0062] Infrared vacuum heating

[0063] 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.

[0064] Arc heating

[0065] 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.

[0066] Magnetron electron beam heating

[0067] 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.

[0068] 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.

[0069] Active Metal Brazing (AMB)

[0070] 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.

[0071] Direct Bonded Copper (DBC)

[0072] 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.

[0073] Direct Plated Copper (DPC)

[0074] Copper is sputtered onto a ceramic substrate using semiconductor process technology, thereby bonding the ceramic substrate and the copper.

[0075] Direct Bonded Aluminum (DBA)

[0076] 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.

[0077] Friction Welding

[0078] 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.

[0079] Laser Cladding

[0080] 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.

[0081] Ultrasonic Welding

[0082] 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.

[0083] 2 , according to a second embodiment of the present invention, a composite structure is provided in which a conductive 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 conductive layer 20 bonded to one surface of the ceramic substrate 1; and a second conductive layer 21 bonded to the other surface of the first conductive layer 20 that is not in contact with the ceramic substrate 1.

[0084] The ceramic substrate 1 of the second embodiment of the present invention may have the same characteristics as the ceramic substrate 1 of the first embodiment of the present invention, and therefore will not be described in detail.

[0085] The ceramic substrate 1 and the first conductive layer 20, and the first conductive layer 20 and the second conductive layer 21 of the second embodiment of the present invention can be bonded using the same bonding methods as 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 of the first embodiment of the present invention, and therefore will not be described in detail.

[0086] In one embodiment of the present invention, the first conductive layer 20 may have a conductivity less than 4×10 7 S / m conductor, such as aluminum, preferably millimeter-thick aluminum. The second conductive layer 21 can be a conductor with a conductivity greater than 4×10 7 The conductor of S / m, such as copper, is preferably millimeter-thick copper.

[0087] The thickness ratio of the second conductive layer 21 to the first conductive layer 20 is in the range of 1:1 to 10:1. Preferably, the thickness of the second conductive layer 21 is greater than 0.05 mm.

[0088] Generally speaking, when thick copper is bonded to one side of a ceramic substrate for conductivity in the prior art, the following problems exist: First, copper has a relatively high hardness, so a thick copper layer is not conducive to processing; second, copper is a relatively expensive material, so using a thick copper layer increases costs; third, a thick copper layer increases the weight of the entire electronic component, making it unsuitable for weight-sensitive applications such as portable electronic devices and electric vehicles; and fourth, a thick copper layer is prone to peeling, reducing the reliability of the electronic component.

[0089] Therefore, compared to the existing technology that completely uses a thick copper layer as a single conductive layer, in the second embodiment of the present invention, a portion of the copper layer is replaced by a special conductor (such as an aluminum layer). By using a thinner copper layer (i.e., the second conductive layer 21) in combination with a special conductor that is also an excellent conductive material, such as an aluminum layer (i.e., the first conductive layer 20), requirements can be met and costs can be reduced.

[0090] For example, if the thickness of the thick copper layer is 0.8mm, replacing 0.3mm of it with aluminum as the first conductive layer 20 and reducing the thickness of the thick copper layer as the second conductive layer 21 to 0.5mm can significantly reduce the copper cost and weight. While aluminum's conductivity is slightly lower than copper's, it still has good electrical conductivity compared to other metals. Therefore, in certain applications, using aluminum as the conductive layer can still effectively share the high current, high voltage, and high power requirements of thick copper.

[0091] Referring to Figure 3, a perspective view of a conventional composite structure having a ceramic substrate 1' coated on one side with a conductive material is shown. To meet specific circuit design requirements, the first conductive layer 20' and the second conductive layer 21' on the ceramic substrate 1', similar to the composite structure of the second embodiment of the present invention, are patterned into identical patterns. Patterning involves removing exposed or unexposed portions of the conductive layer, such as by laser ablation or chemical etching, to preserve the conductive layer in the remaining patterned areas.

[0092] However, in the prior art shown in FIG3 , etching the thick aluminum layer and the thick copper layer simultaneously may result in the following problems: First, due to the large amount of thick copper and thick aluminum materials, etching them simultaneously will increase the consumption of etching solution, thereby increasing process costs and having a certain impact on the environment (such as waste liquid); Second, compared to copper, aluminum has a lower mechanical strength, which means that aluminum circuits may be more likely to bend, deform, or break.

[0093] Therefore, in order to improve the above problem, referring to FIG4 , a composite structure according to a third embodiment of the present invention is obtained by improving the composite structure of the prior art shown in FIG3 , except that only the second conductive layer 21 is patterned, and the first conductive layer 20 is not patterned.

[0094] In a third embodiment of the present invention, the special conductor layer, such as the thick aluminum layer (i.e., the first conductive layer 20), is retained intact, and only the thick copper layer (i.e., the second conductive layer 21) is patterned. This composite structure has the following advantages: First, compared to the thick aluminum layer, the thick copper layer has higher mechanical strength and durability. Even after patterning, it can provide good structural support and stability, making the special-purpose circuit more robust and reliable under vibration, impact, and other mechanical stresses. Second, the metal (e.g., copper) in the etching solution can be separated and recycled, and the recycled metal can be reused to manufacture new conductive patterns, reducing material waste and thus reducing costs.

[0095] In summary, the composite structure of the present invention has a special conductor (such as thick aluminum) with excellent processing and bonding properties and excellent electrical conductivity and heat dissipation properties bonded to one side of the ceramic substrate, and another conductor with excellent electrical conductivity and heat dissipation properties bonded to the other side of the special conductor layer. This enables the composite structure of the present invention to achieve excellent electrical conductivity and heat dissipation characteristics even in harsh environments such as high operating voltage, current, and high power, and is conducive to lightweighting and cost reduction.

[0096] 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 conductive material is coated on one side of a ceramic substrate, comprising: Ceramic substrate; a first conductive layer bonded to the surface of the ceramic substrate; as well as The second conductive layer is bonded to the other surface of the first conductive layer that is not in contact with the ceramic substrate.

2. The composite structure according to claim 1, wherein: A thickness ratio of the first conductive layer to the second conductive layer is in a range of 1:1 to 1:

10.

3. The composite structure according to claim 1, wherein: The thickness of the second conductive layer is greater than 0.05 mm.

4. The composite structure according to claim 1, wherein: The second conductive layer is further patterned.

5. The composite structure according to claim 1, 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.

6. The composite structure of claim 1, wherein: The material of the first conductive layer has a conductivity of less than 4×10 7 Conductor of S / m.

7. The composite structure of claim 1, wherein: The material of the second conductive layer has a conductivity greater than 4×10 7 Conductor of S / m.

8. The composite structure of claim 1, wherein: The ceramic substrate and the first conductive layer, and the first conductive layer and the second conductive layer are each bonded to each other using heat and optionally pressure.

9. The composite structure according to claim 8, 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 8, wherein: The bonding method further includes AMB, DBC, DPC, DBA, diffusion bonding, friction welding, laser cladding, or ultrasonic welding.

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