Ceramic copper-clad laminate and preparation method therefor

Abstract

The present application relates to the technical field of power electronics, and specifically relates to a ceramic copper-clad laminate and a preparation method therefor. The ceramic copper-clad laminate comprises: a solder layer, which is made of solder paste, wherein the solder paste comprises a high-entropy alloy compound, and the chemical formula of the high-entropy alloy compound is CuaAlbSncNidPeMofTig, where 7≤g≤25wt%, and a+b+c+d+e+f+g=100%; and a ceramic substrate, which comprises zirconium oxide having a mass fraction of 6-12%.

Description

Ceramic-clad copper laminate and its preparation method

[0001] This application claims priority to Chinese Patent Application No. 202411999628.7, filed on December 31, 2024, entitled "Ceramic Copper-Clad Laminate and Method for Preparing Ceramic Copper-Clad Laminate", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to a ceramic copper-clad laminate and a method for preparing the ceramic copper-clad laminate, belonging to the field of electronic power technology. Background Technology

[0003] Ceramic-clad copper laminates have advantages such as high strength, good chemical stability, and high thermal conductivity, making them an ideal substrate material for power devices. They can serve as physical supports for chips, circuit connections, and heat dissipation channels.

[0004] In related technologies, direct copper cladding (DBC) and active metal brazing (AMB) are generally used to connect ceramics and copper foil. However, during the preparation process using the AMB process, problems such as process interruption due to the high activity of titanium and violent reaction with ceramics, blackening of ceramics after solder layer etching, and poor reliability are prone to occur.

[0005] Therefore, the current methods for preparing ceramic copper-clad laminates still need improvement. Summary of the Invention

[0006] To address or partially address the problems existing in related technologies, this application provides a ceramic copper-clad laminate and a method for preparing the ceramic copper-clad laminate, which can avoid the occurrence of board breakage and blackening of ceramic after etching during the preparation of the ceramic copper-clad laminate, and can improve the reliability of the ceramic copper-clad laminate.

[0007] The first aspect of this application provides a ceramic copper-clad laminate, the ceramic copper-clad laminate comprising: a solder layer, the solder layer being made of solder paste, the solder paste comprising a high-entropy alloy compound, the high-entropy alloy compound having the chemical formula: Cu a Al b Sn c Ni d P e Mo f Ti g , wherein 7≤g≤25wt%, and a+b+c+d+e+f+g=100%; ceramic matrix, wherein the ceramic matrix comprises 6%-12% zirconium oxide by mass.

[0008] In conjunction with the first aspect, in one possible implementation of the first aspect, in the high-entropy alloy compound, 35≤a≤65wt%, 10≤b≤35wt%, 10≤c≤25wt%, 0.1≤d≤10wt%, 0.05≤e≤3wt%, and 0≤f≤10wt%.

[0009] In conjunction with the first aspect, in one possible implementation of the first aspect, the solder paste further includes a binder comprising 75-98 wt% solvent, 0.1-20 wt% dispersant, 0.05-15 wt% thickener, 0.05-3 wt% surfactant and 0-10 wt% thixotropic agent.

[0010] In conjunction with the first aspect, in one possible implementation of the first aspect, the solder paste satisfies any one of the following conditions: the solvent includes one or more of terpineol, tributyl citrate, diethylene glycol butyl ether, and diethylene glycol butyl ether acetate; the dispersant includes one or more of oleic acid, stearic acid, and polyethylene glycol; the thickener includes one or more of ethyl cellulose, acrylic resin, cyclodextrin, and alkanes; the surfactant includes one or more of Tween 20, Span 80, and sodium dodecylbenzene sulfonate; and the thixotropic agent includes one or more of polyamide wax, modified polyurea, and hydrogenated castor oil.

[0011] In conjunction with the first aspect, in one possible implementation of the first aspect, the high-entropy alloy compound in the solder paste has a mass fraction of 60%-95%, and the binder has a mass fraction of 5%-40%.

[0012] In conjunction with the first aspect, in one possible implementation of the first aspect, the solder paste has a melting point range of 700-960°C and a particle size range of 0.3-60 μm.

[0013] In conjunction with the first aspect, in one possible implementation of the first aspect, the thickness of the ceramic substrate is 0.2-2 mm.

[0014] In conjunction with the first aspect, in one possible implementation of the first aspect, the provision of the copper layer includes: providing a copper-containing material; the thickness of the copper-containing material is 0.1 mm to 5 mm, wherein the copper-containing material is selected from one or more of copper sheets, high thermal conductivity copper-based composite materials, and high thermal conductivity copper-based alloys.

[0015] A second aspect of this application provides a method for preparing a ceramic copper-clad laminate, comprising providing a ceramic substrate; depositing solder paste on the surface of the ceramic substrate, the solder paste comprising a high-entropy alloy compound; depositing a copper layer on the surface of the solder paste away from the ceramic substrate; and performing brazing to obtain the ceramic copper-clad laminate.

[0016] In conjunction with the second aspect, in one possible implementation of the second aspect, the process of applying solder paste to the surface of the ceramic substrate is screen printing, wherein the thickness of the solder paste applied to the surface of the ceramic substrate by screen printing is 6-25 μm; the brazing process is vacuum brazing, wherein the temperature of the vacuum brazing process is 850-1060°C, and the time of the vacuum brazing process is 0.5-3 h.

[0017] The technical solution provided in this application may include the following beneficial effects:

[0018] This application discloses a ceramic copper-clad laminate and a method for preparing the ceramic copper-clad laminate. The ceramic copper-clad laminate includes a solder layer, which is made of solder paste. The solder paste includes a high-entropy alloy compound with the chemical formula Cu. a Al b Sn c Ni d P e Mo f Ti g Wherein, 7≤g≤25wt%, and a+b+c+d+e+f+g=100%; ceramic matrix, the ceramic matrix includes 6%-12% zirconium oxide by mass, which can avoid the breakage of the ceramic copper-clad laminate during the preparation process and the blackening of the ceramic after etching, and can improve the reliability of the ceramic copper-clad laminate.

[0019] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0020] The above and other objects, features and advantages of this application will become more apparent from the more detailed description of exemplary embodiments thereof in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments thereof.

[0021] Figure 1 is a schematic flowchart illustrating the preparation method of the ceramic copper-clad laminate according to an embodiment of this application;

[0022] Figure 2 is a schematic diagram of the structure of the ceramic copper-clad laminate after etching, as shown in an embodiment of this application;

[0023] Figure 3 is a schematic diagram of the weld layer structure of the ceramic copper-clad laminate shown in the embodiment of this application. Detailed Implementation

[0024] Embodiments of this application will now be described in more detail with reference to the accompanying drawings. While embodiments of this application are shown in the drawings, it should be understood that this application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to make this application more thorough and complete, and to fully convey the scope of this application to those skilled in the art.

[0025] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a” and “the” as used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0026] It should be understood that although the terms "first," "second," "third," etc., may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0027] In related technologies, the ceramic substrate materials commonly used in the field of electronic device packaging technology include alumina, toughened alumina, aluminum nitride, silicon nitride, and silicon carbide. Among them, although alumina ceramics do not have the same thermal conductivity and coefficient of thermal expansion as aluminum nitride and silicon nitride, they have good mechanical strength, good insulation properties, low dielectric loss, and a bending strength of ≥300MPa. In particular, the bending strength of alumina-toughened alumina ceramics is ≥500MPa. Furthermore, alumina ceramics have low manufacturing costs and are widely used in microelectronic packaging, such as LED packaging and some power semiconductor packaging.

[0028] In the industry, most copper-clad alumina substrates using the DBC process suffer from generally low ultrasonic yield (approximately 90%) and poor reliability. Meanwhile, the AMB process for preparing copper-clad alumina substrates is prone to issues such as board breakage due to differences in the content and distribution of active elements, and etching blackening due to variations in zirconium oxide content in ZTA ceramics. These problems limit the development and commercialization of copper-clad alumina substrates with high yield and reliability. Traditional DBC processes result in copper-clad laminates with a single interface composition, high brittleness, and low thermal tolerance. Atmospheric plasma spraying and other technologies are inefficient, time-consuming to achieve the required metal layer thickness, unsuitable for mass production, and indirectly costly. Furthermore, the raw materials have strict requirements regarding oxygen content, and their current-carrying and heat dissipation capabilities are inferior to oxygen-free pure copper.

[0029] In previous processes, copper and ceramic could be effectively bonded using Cu, Sn, and Ti. Controlling the Sn content reduced the titanium content, leading to a decrease in the thermal conductivity of the solder layer, which directly increased the thermal resistance of the copper-clad laminate. However, excessive Ti during manufacturing resulted in high Ti reactivity, causing a violent reaction between titanium and ceramic, which could easily lead to problems such as board breakage and ceramic blackening after solder layer etching. Therefore, it is necessary to change the manufacturing method to reduce the probability of board breakage and avoid the problem of ceramic blackening after solder layer etching.

[0030] To address the aforementioned issues, this application provides a ceramic copper-clad laminate and a method for preparing the ceramic copper-clad laminate, which can avoid issues such as laminate breakage and blackening of the ceramic after etching during the preparation process, and can improve the reliability of the ceramic copper-clad laminate.

[0031] The technical solutions of the embodiments of this application are described in detail below with reference to the accompanying drawings.

[0032] In one aspect of this application, a ceramic copper-clad laminate is provided, comprising: a solder layer made of solder paste, the solder paste comprising a high-entropy alloy compound having the chemical formula: Cu a Al b Sn c Ni d P e Mo f Ti g Wherein, 7≤g≤25wt%, and a+b+c+d+e+f+g=100%; ceramic matrix, the ceramic matrix includes 6%-12% zirconium oxide by mass fraction, by controlling the Ti content in the solder paste, the problem of brittle fracture due to excessive stress release during the process can be reduced; and, titanium has high activity, in addition to reacting with alumina, it will react with the lattice oxygen of zirconium oxide to form TiO. x ZrO 2-x . And ZrO 2- x It appears black, and a higher zirconium oxide content will cause the ceramic to turn black after etching. Therefore, controlling the Ti content can improve the yield in batch production and further reduce costs.

[0033] Specifically, unlike traditional alloys that use a single element as the matrix, high-entropy alloys are composed of five or more elements (generally no more than 13) in equiatomic or non-equiatomic ratios. These alloys possess high mixing entropy, resulting in significant lattice distortion due to the differences in the properties of the added elements. This high mixing entropy facilitates the formation of a relatively stable solid solution structure, thereby increasing resistance to atomic migration and enhancing diffusion difficulty. Due to the combined characteristics of different atoms and concentrations, high-entropy alloys exhibit a cocktail effect that regulates performance. High-entropy alloy compounds possess a multi-principal-element high mixing entropy effect, which can reduce the content of intermetallic compound phases, improve solder layer plasticity, enhance reliability, and increase thermal conductivity while reducing thermal resistance. The use of this multi-principal-element high mixing entropy effect results in copper-clad laminates with good plasticity, high reliability under thermal shock, fewer intermetallic compounds, low phonon thermal conductivity at heterogeneous interfaces, high electronic thermal conductivity, and high overall thermal conductivity.

[0034] Specifically, in the preparation of high-entropy alloy compound overlays, when the content of the active element Ti in the high-entropy alloy powder is 0, Ti-containing active materials, such as pure titanium powder or titanium hydride, can be added during the preparation process. The titanium hydride can be ultrafine titanium hydride prepared by high-energy ball milling under vacuum or inert atmosphere, so that the obtained high-entropy alloy compound contains the element Ti. This high-entropy alloy compound can provide the active element Ti in the preparation of ceramic copper-clad laminates. The particle size of titanium hydride is less than or equal to 30 μm, preferably 2-15 μm, and more preferably 3-10 μm.

[0035] Furthermore, in the high-entropy alloy compound, 35≤a≤65wt%, 10≤b≤35wt%, 10≤c≤25wt%, 0.1≤d≤10wt%, 0.05≤e≤3wt%, and 0≤f≤10wt%.

[0036] In one possible implementation, the chemical formula of the high-entropy alloy compound is: Cu a Al b Sn c Ni d P e Mo f Ti g Among them, 40≤a≤55wt%, 15≤b≤25wt%, 12≤c≤18wt%, 0.5≤d≤3wt%, 0.1≤e≤1.5wt%, 0.5≤f≤2wt%, 7≤g≤12wt%, and a+b+c+d+e+f+g=100%.

[0037] In one possible embodiment, the solder paste further includes a binder comprising 75-98 wt% of a solvent, preferably 80%-95 wt%, more preferably 85-90 wt%; 0.1-20 wt% of a dispersant, preferably 1-10 wt%, more preferably 2-6 wt%; 0.05-15 wt% of a thickener, preferably 1-10 wt%, more preferably 2-6 wt%; 0.05-3 wt% of a surfactant, preferably 0.5-2 wt%, more preferably 1-2 wt%; and 0-10 wt% of a thixotropic agent, preferably 0.5-5%, more preferably 0.8-4 wt%.

[0038] In one possible implementation, the solder paste satisfies any one of the following conditions: the solvent includes one or more of terpineol, tributyl citrate, diethylene glycol butyl ether, and diethylene glycol butyl ether acetate; the dispersant includes one or more of oleic acid, stearic acid, and polyethylene glycol; the thickener includes one or more of ethyl cellulose, acrylic resin, cyclodextrin, and alkanes; the surfactant includes one or more of Tween 20, Span 80, and sodium dodecylbenzene sulfonate; and the thixotropic agent includes one or more of polyamide wax, modified polyurea, and hydrogenated castor oil.

[0039] In one possible implementation, the solder paste contains 60%-95% high-entropy alloying compound by mass, preferably 75%-90%, and the binder by mass is 5%-40%, preferably 10%-25%.

[0040] In this application, all figures disclosed herein, whether or not the words “approximately” or “about” are used, are approximate values. Each figure may vary by less than 10% or by a difference that is considered reasonable by a person skilled in the art, such as 1%, 2%, 3%, 4%, or 5%.

[0041] Specifically, the binder in solder paste can be made by mixing solvents, surfactants, dispersants, thickeners, and thixotropic agents through electromagnetic water bath heating, stirring, and filtration.

[0042] In one possible implementation, the solder paste has a melting point range of 700-960℃, preferably 750-900℃, more preferably 750-820℃. The particle size range is 0.3-60µm, preferably 0.8µm-25µm, more preferably 0.8-20µm. The particle size distribution range is (D90-D10) / D50: 1.2-2.3, preferably 1.5-2.2, more preferably 1.7-2.1. This solder paste has a suitable melting point and particle size distribution. A suitable particle size distribution can improve the density of the screen printing area and facilitate the volatilization and degassing of the organic carrier. The screen printing thickness can affect the final solder layer thickness, ultimately improving the reliability of the ceramic copper-clad laminate.

[0043] In one possible implementation, the viscosity range of the solder paste is 20 Pas to 500 Pas, preferably 40 Pas to 150 Pas, and more preferably 60 Pas to 90 Pas. Solder paste with a suitable viscosity range is beneficial for screen printing, can improve screen printing performance, and can make the resulting surface to be soldered have better uniformity and leveling.

[0044] In one possible implementation, the ceramic copper-clad laminate further includes a copper layer made of a copper-containing material with a thickness of 0.1 mm to 5 mm. The copper-containing material is selected from one or more of copper sheets, high thermal conductivity copper-based composite materials, and high thermal conductivity copper-based alloys.

[0045] In another aspect of this application, a method for preparing a ceramic copper-clad laminate is proposed, comprising: providing a ceramic substrate; depositing solder paste on the surface of the ceramic substrate; depositing a copper layer on the side of the solder paste away from the ceramic substrate; and performing brazing to obtain a ceramic copper-clad laminate. This achieves good welding between the ceramic substrate and the copper layer, resulting in a high-performance ceramic copper-clad laminate.

[0046] Specifically, referring to Figure 1, the preparation method of the ceramic copper-clad laminate may include the following steps:

[0047] S100: Provides a ceramic matrix.

[0048] According to some embodiments of this application, a ceramic matrix is ​​provided in this step. The type of ceramic matrix is ​​not particularly limited. For example, the ceramic matrix may include ceramic materials such as alumina, zirconium oxide, toughened alumina, ceramic silicon nitride, aluminum nitride, and silicon carbide. Specifically, the thickness of the alumina ceramic can be 0.2-2 mm, preferably 0.32-1.5 mm, and preferably alumina ceramic containing 99%, 96%, or 95% alumina. The zirconium oxide content in the zirconium-toughened alumina ceramic can be 6%-12%, preferably 7%-9%.

[0049] According to some embodiments of this application, the high-entropy alloy compound in the solder paste can be prepared by the following method: The high-entropy alloy is repeatedly melted and homogenized at 1200℃-1500℃ using an electromagnetic vacuum melting process, and then powdered using a vacuum atomization method. After atomization, the high-entropy alloy compound needs to pass through an ultra-cold zone before entering a powder collection container. The ultra-cold zone cools at a rate of 80℃ / s-300℃ / s, preferably 150℃ / s-300℃ / s, more preferably 150℃ / s-200℃ / s. The high-speed gas can be nitrogen, argon, or a mixture of both, with a purity ≥99.9999%. The collected powder is then sieved to a suitable particle size using a classifying vibrating sieve at 500-3000Hz to obtain a suitable high-entropy alloy compound.

[0050] The adhesive can be prepared as follows: First, slowly add the solvent to an electromagnetic water bath while stirring slowly at 30-100 rpm and heating to 60-120℃. Then, add the surfactant, dispersant, thickener, and thixotropic agent in sequence. After stirring each component at 300-600 rpm for 15 minutes, add the other components in sequence and repeat this step until all the above additives are added. Then, stir and mix at 800-1500 rpm for 3 hours, then stir at 500 rpm under vacuum for 1 hour, then cool to room temperature, and finally filter using a 300-mesh screen to obtain the adhesive.

[0051] Solder paste can be prepared as follows: Mix high-entropy alloy compound and binder in a certain proportion. First, use a vacuum planetary disperser to stir at 30-60 rpm for 15 minutes to stir the prepared binder until it foams. Then, slowly and evenly sprinkle the high-entropy alloy compound into the stirred binder. Stir at 100-300 rpm and disperse at 100-300 rpm for 2 hours to disperse and mix. Then, stir at 60 rpm and disperse at 500-1200 rpm, and then vacuum defoam. Finally, filter through a 120-mesh screen to obtain solder paste.

[0052] S200: Solder paste is applied to the surface of a ceramic substrate.

[0053] According to some embodiments of this application, solder paste is provided in this step, and solder paste is disposed on the surface of the ceramic substrate. Specifically, providing solder paste may include: providing a binder; dispersing a high-entropy alloy compound in the binder to obtain solder paste. For example, the components of the binder can be uniformly mixed to form a viscous liquid, and then the high-entropy alloy compound can be uniformly dispersed in the viscous liquid by means of mechanical stirring or the like.

[0054] According to some embodiments of this application, the process of setting solder paste is not particularly limited. For example, the process of setting solder paste may include screen printing, in which solder paste can be set on the surface of the ceramic substrate, with a screen printing thickness of 6-25um, preferably 8-19um, and more preferably 10-15um.

[0055] S300: A copper layer is formed on the surface of the solder paste away from the ceramic substrate.

[0056] According to some embodiments of this application, in this step, a copper layer is formed on the surface of the solder paste away from the ceramic substrate. The type of copper layer is not particularly limited. For example, the copper layer can be made of copper sheet with a thickness of 0.1mm-5mm, preferably 0.3mm-1mm, a copper purity of 99.96%, preferably 99.99%, and a copper grain size of 8-25um, preferably 10-15um. The copper layer can also be a high thermal conductivity copper-based composite material, a high thermal conductivity copper-based alloy, etc.

[0057] S400: Performs brazing to obtain a ceramic copper-clad laminate.

[0058] According to some embodiments of this application, the solder paste is brazed in this step to obtain a ceramic copper-clad laminate. The brazing process is not particularly limited; for example, when copper sheets are used as the copper layer, the brazing process can be vacuum brazing. The vacuum brazing temperature can be 850-1060°C, preferably 900-980°C, and the vacuum brazing time can be 30-180 min, preferably 45-75 min. The difference between the heating and cooling rates is ≤15°C / min, preferably ≤10°C / min, and more preferably ≤3°C / min. Besides vacuum brazing, inert gases can also be used, such as nitrogen, argon, hydrogen, or a combination of vacuum and nitrogen / argon / hydrogen, with a gas purity preferably of 99.999%. Using a vacuum brazing process can prevent the oxidation of metallic elements in the high-entropy alloy compound and the copper sheet.

[0059] Specifically, during vacuum brazing, a vacuum can be created in the furnace using mechanical pumps, roughing valves, Roots pumps, fore-stage valves, diffusion pumps, and main valves, achieving a vacuum of 10⁻³ Pa. The programmed temperature rise is then executed. After all organic matter has been thoroughly removed, the temperature reaches the solidus line of the high-entropy alloy compound. Following preheating, the temperature is slowly increased to the brazing temperature and maintained for a certain period to ensure thorough and uniform heating of the workpiece, facilitating a complete wetting reaction during brazing. During the cooling process from the brazing temperature to 600℃, the difference between the cooling rate and the heating rate should be ≤5℃, after which the furnace is cooled down.

[0060] Specifically, the resulting ceramic copper-clad laminate has the characteristics of thermal resistance of less than 0.2℃*cm^2 / W, few voids, peel strength of more than 20N / mm, and good reliability.

[0061] According to some embodiments of this application, as shown in Figure 2, the ceramic copper-clad laminate was prepared using the above-mentioned solder paste. After the solder layer was etched, the ceramic did not turn black. Figure 3 shows a cross-section of the solder layer on the ceramic copper-clad laminate.

[0062] The following specific embodiments illustrate the solution of this application. It should be noted that these embodiments are for illustrative purposes only and should not be considered as limiting the scope of this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0063] Example 1

[0064] 1. Preparation of the binder: 88 wt% of diethylene glycol butyl ether acetate solvent was slowly added to an electromagnetic water bath and stirred slowly at 30 rpm until the temperature reached 80°C. Then, 1.2 wt% of sodium dodecylbenzene sulfonate surfactant, 5 wt% of stearic acid dispersant, 3 wt% of cyclodextrin thickener, and 2.8 wt% of hydrogenated castor oil thixotropic agent were added to the solvent in sequence. After each component was stirred at 300 rpm for 15 min, the other components were added in sequence. After all components were added, the mixture was stirred at 1200 rpm for 3 h. Then, a vacuum environment was created and the mixture was stirred at 500 rpm for 1 h. After stirring, the mixture was cooled to room temperature and filtered through a 300-mesh screen to obtain the binder.

[0065] 2. Preparation of solder paste: Cu 64.9 Al 15 Sn 12 Ni 0.9 P 0.2 Ti7 high-entropy alloy was powdered, and 87 wt% of the high-entropy alloy compound was added to 13 wt% of binder. First, the binder was stirred at 60 rpm for 15 minutes using a vacuum planetary disperser to stir until foaming. Then, the high-entropy alloy compound was slowly and evenly sprinkled into the stirred binder. The stirring speed was 120 rpm and the dispersion speed was 300 rpm. After 2 hours of dispersion and mixing, the stirring speed was 60 rpm and the dispersion speed was 800 rpm. Then, vacuum defoaming was performed, and the mixture was filtered through a 120-mesh screen to obtain solder paste.

[0066] 3. Screen print solder paste onto one side of a 0.32mm ZTA ceramic sheet containing 6% zirconia and dry it at 120℃ for 15 minutes. Then screen print solder paste onto the other side of the ceramic sheet and repeat the above steps. Cover the surface of the solder layer on both sides with oxygen-free pure copper with a thickness of 0.3mm. Place it in a vacuum brazing furnace for degreasing and debinding sintering. The vacuum degree is 10-3Pa, the pressure is 30N, and the temperature is 960℃ for 0.5 hours.

[0067] Example 2

[0068] This embodiment provides a solder paste and a ceramic copper-clad laminate, the preparation method of which is basically the same as that of Embodiment 1. The difference is that in the preparation of the ceramic copper-clad laminate, ZTA ceramic sheets containing 12% zirconium oxide are used.

[0069] Example 3

[0070] This embodiment provides a solder paste and a ceramic copper-clad laminate, the preparation method of which is basically the same as that of Embodiment 1, except that Cu is used in the preparation of the solder paste. 63.9 Al 15 Sn 12 Ni 0.9 P 0.2 A high-entropy alloy of Ti8 was prepared.

[0071] Example 4

[0072] This embodiment provides a solder paste and a ceramic copper-clad laminate, the preparation method of which is basically the same as that of Embodiment 1, except that Cu is used in the preparation of the solder paste. 60.9 Al 15 Sn 12 Ni 0.9 P 0.2 Ti 11 High-entropy alloys are prepared.

[0073] Example 5

[0074] This embodiment provides a solder paste and a ceramic copper-clad laminate, the preparation method of which is basically the same as that of Embodiment 1, except that Cu is used in the preparation of the solder paste. 46.9 Al 15 Sn 12 Ni 0.9 P 0.2 Ti 25 The high-entropy alloy was prepared, and in the preparation of the ceramic copper-clad laminate, ZTA ceramic sheets containing 12% zirconium oxide were used.

[0075] Comparative Example 1

[0076] This comparative example provides a solder paste and a ceramic copper-clad laminate, the preparation method of which is basically the same as that of Example 1. The difference is that in the preparation of the ceramic copper-clad laminate, ZTA ceramic sheets containing 5% zirconium oxide are used.

[0077] Comparative Example 2

[0078] This comparative example provides a solder paste and a ceramic copper-clad laminate, the preparation method of which is basically the same as that of Example 1. The difference is that in the preparation of the ceramic copper-clad laminate, ZTA ceramic sheets containing 13% zirconium oxide are used.

[0079] Comparative Example 3

[0080] This comparative example provides a solder paste and a ceramic copper-clad laminate, the preparation method of which is basically the same as that of Example 1, except that Cu is used in the preparation of the solder paste. 41.9 Al 15 Sn 12 Ni 0.9 P 0.2 Ti 30 The high-entropy alloy was prepared, and in the preparation of the ceramic copper-clad laminate, ZTA ceramic sheets containing 12% zirconium oxide were used.

[0081] Comparative Example 4

[0082] This comparative example provides a solder paste and a ceramic copper-clad laminate, the preparation method of which is basically the same as that of Example 1, except that Cu is used in the preparation of the solder paste. 44.9 Al 15 Sn 12 Ni 0.9 P 0.2 Ti 27 High-entropy alloys are prepared.

[0083] Test methods: Ultrasonic scanning test, peel strength test, thermal shock test, thermal resistance test, and blackening fracture test were performed on the ceramic copper-clad laminate. The defect rate of holes in the welded ceramic copper-clad laminate was calculated by determining the percentage of products with holes according to the methods in GB / T39240-2020 General Rules for Ultrasonic Testing of Non-destructive Testing. The peel strength of the ceramic copper-clad laminate was tested according to GB / T11363-2008 Test Method for Strength of Brazed Joints. The cold-side impact test was conducted using a thermal shock chamber in a temperature range of -55℃ to 150℃, with 30 minutes at -55℃ and 30 minutes at 150℃, followed by a 15-second transition period. Peel strength and thermal resistance were tested after 0 and 500 thermal shock cycles. The thermal resistance test was conducted in accordance with ASTM D5470 standard. The sample size was 2.7cm*2.7cm for copper and 2.8cm*2.8cm for ceramic. The rate of change of thermal resistance could be measured. The rate of change of thermal resistance is the percentage increase or decrease in the thermal resistance of the ceramic copper-clad laminate after 500 thermal shock cycles compared to the thermal resistance of the ceramic copper-clad laminate that has not undergone thermal shock.

[0084] Test method for blackening and breakage of ceramic copper-clad laminate: The pattern etching of the ceramic copper-clad laminate is carried out by immersion method. First, copper is etched with a solution of NaClO3, HCl and deionized water with a pH of 4-6. Then, the solder layer is etched with an etching solution, such as GH-Ti-Etching BT etching solution. The ceramic copper-clad laminate is immersed in the etching solution for 4 hours until the ceramic is exposed in the etching tank. After that, the ceramic copper-clad laminate is taken out, rinsed with pure water and dried with hot air. The etching tank is observed with an optical microscope to see if the color is uniform and is the color of ceramic. This is used to determine whether the ceramic copper-clad laminate has blackened. Record whether the pattern is broken after etching during the transfer process, or observe whether there are cracks in the etching tank under an optical microscope. This is used to determine whether the ceramic copper-clad laminate has broken.

[0085] The test results are shown in Table 1 below:

[0086] Table 1

[0087] 1) By comparing Examples 2, 5, and Comparative Example 3, it can be seen that the Ti content of the high-entropy alloy compound in the solder pastes of Examples 2 and 5 is 7% and 25%, respectively, while the Ti content of the high-entropy alloy compound in the solder paste of Comparative Example 3 is 30%. The experimental results in Table 1 show that the ceramic copper-clad laminates corresponding to Examples 2 and 5 did not break after etching; the ceramic copper-clad laminate corresponding to Comparative Example 3 broke after etching.

[0088] 2) By comparing Examples 1, 3, 4 and Comparative Example 4, it can be seen that the Ti content of the high-entropy alloy compound in the solder pastes of Examples 1, 3, and 4 is 7%, 8%, and 11%, respectively, while the Ti content of the high-entropy alloy compound in the solder paste of Comparative Example 4 is 27%. The experimental results in Table 1 show that the ceramic copper-clad laminates corresponding to Examples 1, 3, and 4 did not break after etching; however, the ceramic copper-clad laminate corresponding to Comparative Example 4 did break after etching.

[0089] 3) By comparing Examples 1 and 2 with Comparative Examples 1 and 2, it can be seen that the ZTA ceramic sheets of Examples 1 and 2 contain 6% and 12% zirconium oxide, respectively, while the ZTA ceramic sheets of Comparative Examples 1 and 2 contain 5% and 13% zirconium oxide, respectively. The experimental results in Table 1 show that the copper-clad ceramic sheets corresponding to Examples 1 and 2 did not exhibit blackening or breakage after etching; the copper-clad ceramic sheet corresponding to Comparative Example 1 broke after etching, while the copper-clad ceramic sheet corresponding to Comparative Example 2 blackened after etching.

[0090] In summary, the high-entropy alloy compound Ti content in the solder paste is not less than 7% or not more than 25%, and the ceramic matrix includes 6%-12% zirconium oxide, which can prevent the ceramic matrix of the ceramic copper-clad laminate from breaking or turning black after etching, thereby improving the reliability of the ceramic copper-clad laminate, reducing its thermal resistance, and extending its service life.

[0091] Unless otherwise stated, all technical terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. All patents and publications referenced in this application are incorporated herein by reference in their entirety. The terms "comprising" or "including" are open-ended expressions, meaning they include the contents specified in this application but do not exclude other contents.

[0092] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

[0093] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A ceramic copper-clad laminate, characterized in that, The ceramic copper-clad laminate includes: The solder layer is made of solder paste, which includes a high-entropy alloying compound with the chemical formula Cu. a Al b Sn c Ni d P e Mo f Ti g , where 7≤g≤25wt%, and a+b+c+d+e+f+g=100%; A ceramic matrix comprising 6%-12% zirconium oxide by mass.

2. The ceramic copper-clad laminate according to claim 1, characterized in that, In the high-entropy alloy compound, 35≤a≤65wt%, 10≤b≤35wt%, 10≤c≤25wt%, 0.1≤d≤10wt%, 0.05≤e≤3wt%, and 0≤f≤10wt%.

3. The ceramic copper-clad laminate according to claim 1, characterized in that, The solder paste also includes a binder comprising 75-98 wt% solvent, 0.1-20 wt% dispersant, 0.05-15 wt% thickener, 0.05-3 wt% surfactant and 0-10 wt% thixotropic agent.

4. The ceramic copper-clad laminate according to claim 3, characterized in that, The solder paste satisfies any one of the following conditions: the solvent includes one or more of terpineol, tributyl citrate, diethylene glycol butyl ether, and diethylene glycol butyl ether acetate; the dispersant includes one or more of oleic acid, stearic acid, and polyethylene glycol; the thickener includes one or more of ethyl cellulose, acrylic resin, cyclodextrin, and alkanes; the surfactant includes one or more of Tween 20, Span 80, and sodium dodecylbenzene sulfonate; and the thixotropic agent includes one or more of polyamide wax, modified polyurea, and hydrogenated castor oil.

5. The ceramic copper-clad laminate according to claim 3, characterized in that, The solder paste contains 60%-95% by mass of the high-entropy alloy compound and 5%-40% by mass of the binder.

6. The ceramic copper-clad laminate according to claim 1, characterized in that, The solder paste has a melting point range of 700-960℃ and a particle size range of 0.3-60µm.

7. The ceramic copper-clad laminate according to claim 1, characterized in that, The thickness of the ceramic matrix is ​​0.2-2 mm.

8. The ceramic copper-clad laminate according to claim 1, characterized in that, It also includes a copper layer, which is made of a copper-containing material with a thickness of 0.1 mm to 5 mm. The copper-containing material is selected from one or more of copper sheets, high thermal conductivity copper-based composite materials, and high thermal conductivity copper-based alloys.

9. A method for preparing a ceramic copper-clad laminate, characterized in that, include: Provide ceramic matrix; Solder paste comprising a high-entropy alloy compound is disposed on the surface of the ceramic substrate. A copper layer is formed on the surface of the solder paste away from the ceramic substrate, and then brazing is performed to obtain the ceramic copper-clad laminate.

10. The method according to claim 9, characterized in that, The process of applying solder paste to the surface of the ceramic substrate is screen printing, wherein the screen printing thickness of the solder paste applied to the surface of the ceramic substrate by screen printing is 6-25um. The brazing process is a vacuum brazing process, wherein the temperature of the vacuum brazing process is 850-1060℃ and the time of the vacuum brazing process is 0.5-3h.

Images