Active metal brazing substrate material containing aluminum element and method of manufacturing the same

Abstract

The application discloses an active metal brazing substrate material containing aluminum element and a manufacturing method thereof. The substrate material comprises a ceramic substrate layer, a first brazing layer, a second brazing layer and a conductive metal layer which are sequentially stacked. The first brazing layer comprises a first metal composite material containing metal silver (Ag), metal copper (Cu) and a first active metal component. The content of silver is not less than 50 parts by weight based on the total weight of the first metal composite material being 100 parts by weight. The second brazing layer comprises a second metal composite material containing metal aluminum (Al), metal copper (Cu) and a second active metal component, and does not contain metal silver. The content of aluminum is not less than 40 parts by weight based on the total weight of the second metal composite material being 100 parts by weight. The total thickness of the first and second brazing layers is not less than 12 microns, and the thickness of the first brazing layer is not less than 5 microns. In this way, the amount of silver is effectively reduced, the brazing temperature is reduced to below 900 DEG C, the influence of high temperature on the metal performance is reduced, and the material and process costs are reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to a substrate material, in particular to an active metal brazing (AMB) substrate material containing aluminum element and a manufacturing method thereof. BACKGROUND

[0002] Under the promotion of energy-saving and carbon-reducing policies in various countries, the global electric vehicle market is developing vigorously. With the launch of 800-volt (Volts) high-voltage vehicle products by major automakers in recent years, the demand for silicon carbide (SiC) ceramic substrate materials has grown rapidly. However, the power components based on silicon carbide (SiC) ceramic substrate materials continue to improve in terms of voltage, frequency, and operating temperature requirements, making ceramic substrate materials also need to have better heat dissipation capacity and reliability.

[0003] The direct-bonding-copper (DBC) ceramic substrate widely used in the past is prepared by eutectic bonding method, and there is no bonding material between the copper layer and the ceramic substrate. However, during high-temperature operation, large thermal stress often occurs between the copper layer and the ceramic substrate (such as Al2O3 or AlN) due to the difference in thermal expansion coefficient, which leads to the peeling of the copper layer from the surface of the ceramic substrate. Therefore, the traditional direct-bonding-copper ceramic substrate has been difficult to meet the packaging requirements of high temperature, high power, high heat dissipation, and high reliability.

[0004] Currently, the mainstream substrate material is gradually shifting from direct-bonding-copper ceramic substrate to active metal brazing (AMB) substrate material.

[0005] Active metal brazing substrate material utilizes the property of active metal elements (such as Ti, Zr, Ta, Nb, V, Hf, etc.) that can wet the surface of the ceramic substrate, and super-thick copper foil is brazed on the ceramic substrate at high temperature. The brazing layer formed between the copper layer and the ceramic substrate by the active metal brazing process has higher connection strength.

[0006] In common active metal brazing paste materials, silver-copper-titanium (Ag-Cu-Ti) is a commonly used metal composite material. In the above silver-copper-titanium metal composite material, the content of silver is usually more than 50% (weight percentage concentration), even as high as 70%.

[0007] The brazing temperature of silver-copper-titanium generally used for active metal brazing paste material usually needs to reach more than 900℃ (such as 915℃). The solder layer formed by the above active metal brazing contains a large amount of metal silver (noble metal), making the material cost and manufacturing cost of the active metal brazing ceramic substrate high. Moreover, the electromigration problem caused by the metal silver remaining after the etching process is also a subject that needs to be solved. SUMMARY

[0008] The technical problem to be solved by the present application is to provide an active metal brazing substrate material containing aluminum element and a manufacturing method thereof, which reduces the amount of silver metal, reduces the brazing temperature to below 900℃, thereby reducing the influence of high temperature on the metal, and at the same time, reduces the material cost and the process cost.

[0009] To solve the above technical problems, one of the technical solutions adopted by the present application is to provide an active metal brazing substrate material containing aluminum element, comprising: a ceramic substrate layer; an active metal layer, comprising: a first brazing layer disposed on one side surface of the ceramic substrate layer; wherein the composition of the first brazing layer comprises a first metal composite material comprising silver (Ag), copper (Cu) and a first active metal component; based on the total weight of the first metal composite material being 100 parts by weight, the content of silver is not less than 50 parts by weight; and a second brazing layer disposed on the side surface of the first brazing layer away from the ceramic substrate layer; wherein the composition of the second brazing layer comprises a second metal composite material comprising aluminum (Al), copper (Cu) and a second active metal component; based on the total weight of the second metal composite material being 100 parts by weight, the content of aluminum is not less than 40 parts by weight, and the second metal composite material does not contain silver; wherein the total thickness of the first brazing layer and the second brazing layer is at least not less than 12 microns, and the thickness of the first brazing layer is at least not less than 5 microns; and a conductive metal layer disposed on the side surface of the second brazing layer away from the first brazing layer.

[0010] Optionally, based on the total weight of all metal components in the active metal layer being 100wt%, the content of aluminum is between 25wt% and 48wt%, the content of silver is not more than 50wt%, the total content of the first active metal component and the second active metal component is between 0.3wt% and 8wt%, and the copper (Cu) is the remaining metal component.

[0011] Optionally, in the active metal layer, the thickness ratio between the thickness of the first brazing layer and the thickness of the second brazing layer is between 15%~50%: 50%~85%.

[0012] Optionally, the first active metal component and the second active metal component are respectively selected from at least one of the following material group: titanium (Ti), zirconium (Zr), tantalum (Ta), niobium (Nb), vanadium (V), hafnium (Hf) and hydrides of the above-mentioned metals.

[0013] Optionally, the ceramic substrate layer is at least one of a silicon nitride ceramic substrate, a silicon carbide ceramic substrate, an aluminum nitride ceramic substrate and an aluminum oxide ceramic substrate; and the conductive metal layer is at least one of a metal copper foil, a metal aluminum foil and a copper-aluminum alloy foil.

[0014] Optionally, the active metal layer needs to be heated to a brazing temperature not greater than 900° C., and the ceramic substrate layer and the conductive metal layer have a peel strength of not less than 50 N / cm when welded by the active metal layer.

[0015] Optionally, during vacuum and high-temperature sintering, the first active metal component in the first brazing layer can wet the side surface of the ceramic substrate layer and react with the ceramic material of the ceramic substrate layer to enhance the bonding strength between the active metal layer and the ceramic substrate layer; the second brazing layer can react with the metal component of the conductive metal layer at the interface to produce a micron-scale eutectic reaction to form a strong eutectic structure, thereby enabling the active metal layer to be tightly bonded to the conductive metal layer.

[0016] In order to solve the above-mentioned technical problems, another technical solution adopted in the present application is to provide a method for manufacturing an active metal brazing substrate material, comprising: implementing a first brazing layer preparation operation, including: applying a first active solder paste on one side surface of a ceramic substrate layer, and drying to form a first brazing layer; wherein the first active solder paste comprises a first active solder powder, which is composed of metal silver powder, metal copper powder and a first active metal powder; wherein the content of the metal silver powder is not less than 50 parts by weight based on 100 parts by weight of the first active solder powder; implementing a second brazing layer preparation operation, including: applying a second active solder paste on one side surface of the first brazing layer away from the ceramic substrate layer, and drying to form a second brazing layer; wherein the second active solder paste The paste includes a second active solder powder, which is composed of metal aluminum powder, metal copper powder and a second active metal powder; wherein the content of the metal aluminum powder is not less than 40 parts by weight based on 100 parts by weight of the second active solder powder; wherein the second active solder powder does not contain metal silver powder; and a conductive metal layer preparation operation is implemented, which includes: setting a conductive metal layer on the side surface of the second brazing layer away from the first brazing layer, and brazing the conductive metal layer on the ceramic substrate layer through an active metal layer composed of the first brazing layer and the second brazing layer under a vacuum high-temperature sintering process; wherein the sum of the thicknesses of the first brazing layer and the second brazing layer is at least not less than 12 microns and the thickness of the first brazing layer is not less than 5 microns.

[0017] Optionally, the weight ratio of the metal silver powder, the metal copper powder, and the first active metal powder in the first active solder powder is 50-75:20-48:2-5; and the weight ratio of the metal aluminum powder, the metal copper powder, and the second active metal powder in the second active solder powder is 45-75:20-50:0.5-5.

[0018] Optionally, the processing procedure of the vacuum high-temperature sintering comprises a first-stage heat treatment procedure with a temperature condition not greater than 500°C and a second-stage heat treatment procedure with a temperature condition not less than 800°C.

[0019] The active metal brazing substrate material containing aluminum element and the manufacturing method thereof provided by the present application can effectively reduce the amount of silver metal by the design of the first brazing layer and the second brazing layer, and reduce the brazing temperature to below 900°C, thereby reducing the influence of high temperature on the metal properties and reducing the material cost and the process cost.

[0020] For further understanding of the features and technical contents of the present application, please refer to the following detailed description and drawings of the present application. However, the drawings provided are only for reference and illustration, and are not used to limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The schematic diagram of the active metal brazing substrate material of the present application.

[0022] Figure 2 The schematic diagram of the ceramic substrate with active metal layers on both sides.

[0023] Figures 3A to 3D The schematic diagram of the manufacturing process of the substrate material of the present application. DETAILED DESCRIPTION

[0024] The following is an explanation of the embodiments disclosed in the present application through specific specific embodiments. Those skilled in the art can understand the advantages and effects of the present application from the contents disclosed in this specification. The present application can be implemented or applied through other different specific embodiments, and the details in this specification can also be modified and changed based on different viewpoints and applications without deviating from the concept of the present application. In addition, the drawings of the present application are only simple schematic illustrations and are not depicted according to actual dimensions. It is stated in advance. The following embodiments will further explain the relevant technical content of the present application in detail, but the disclosed contents are not intended to limit the scope of protection of the present application. It should be understood that although terms such as "first", "second", and "third" may be used herein to describe various materials or parameters, these materials or parameters should not be limited by these terms. These terms are mainly used to distinguish one material from another, or one parameter from another.

[0025] Active Metal Brazing Substrate Materials

[0026] See also Figure 1 As shown, an embodiment of the present application provides an active metal brazing substrate material 100 containing aluminum, comprising a ceramic substrate layer 1, an active metal layer 2, and a conductive metal layer 3. The active metal layer 2 is disposed between the ceramic substrate layer 1 and the conductive metal layer 3 to connect the ceramic substrate layer 1 and the conductive metal layer 3 together.

[0027] More specifically, the active metal layer 2 includes a first brazing layer 21 and a second brazing layer 22. The first brazing layer 21 is disposed on one side of the ceramic substrate layer 1, the second brazing layer 22 is disposed on a side of the first brazing layer 21 that is away from the ceramic substrate layer 1, and the conductive metal layer 3 is disposed on a side of the second brazing layer 22 that is away from the first brazing layer 21.

[0028] It is worth mentioning that although the first brazing layer 21, the second brazing layer 22 and the conductive metal layer 3 are sequentially provided on one side surface of the ceramic substrate layer 1 in this embodiment, the present application is not limited thereto. Figure 2 As shown, in another embodiment of the present application, another first brazing layer 21', another second brazing layer 22', and another conductive metal layer 3' can also be sequentially provided on the other side surface of the ceramic substrate layer 1 to form a symmetrical substrate structure with active metal layers on both sides.

[0029] Ceramic substrate layer

[0030] Further, the ceramic substrate layer 1 can be, for example, at least one of a silicon nitride (SiN) ceramic substrate, a silicon carbide (SiC) ceramic substrate, an aluminum nitride (AlN) ceramic substrate, and an aluminum oxide (Al2O3) ceramic substrate. In the present embodiment, the ceramic substrate layer 1 is preferably a silicon nitride (SiN) ceramic substrate. In addition, the thickness T1 of the ceramic substrate layer 1 can be, for example, between 100 micrometers and 1000 micrometers, but the present application is not limited thereto.

[0031] First brazing layer

[0032] Please continue to see Figure 1 As shown, the first brazing layer 21 comprises a first metal composite. The first metal composite comprises: a metal silver (Ag), a metal copper (Cu), and a first active metal ingredient.

[0033] It is worth mentioning that the first brazing layer 21 can further comprise a small amount of metal aluminum (Al), which can be, for example, diffused into the first brazing layer 21 from the second brazing layer 22 along the copper defects by melting in the process of vacuum sintering of the active metal brazing substrate material.

[0034] Further, the first active metal ingredient can be, for example, at least one selected from the group consisting of: titanium (Ti), zirconium (Zr), tantalum (Ta), niobium (Nb), vanadium (V), hafnium (Hf), and hydrides of the above-mentioned metals. In addition, the hydrides of the metals can be, for example, at least one of titanium hydride (TiH2), zirconium hydride (ZrH2), tantalum hydride (TaH2), niobium hydride (NbH), vanadium hydride (VH2), and hafnium hydride (H2Hf2).

[0035] In some embodiments of the present application, the first active metal ingredient is preferably at least one of titanium (Ti) and titanium hydride (TiH2). Accordingly, the first brazing layer 21 can also be referred to as a silver-copper-titanium brazing layer (Ag-Cu-Ti paste).

[0036] In terms of content, the first metal composite is the main component of the first brazing layer 21. For example, the weight percentage concentration of the first metal composite in the first brazing layer 21 is at least not less than 80 wt%, and preferably not less than 90 wt%.

[0037] Further, in the first brazing layer 21, based on the total weight of the first metal composite being 100 parts by weight, the content of the metal silver (Ag) is at least not less than 50 parts by weight, and preferably between 50 parts by weight and 75 parts by weight. In terms of thickness, the thickness T21 of the first brazing layer 21 is at least not less than 5 micrometers, and preferably between 5 micrometers and 24 micrometers.

[0038] According to the above configuration, since the first braze layer 21 in contact with the ceramic substrate layer 1 contains metal silver (Ag) in a specific content and has a thickness in a specific range, the bonding force between the ceramic substrate layer 1 and the conductive metal layer 3 can be improved. If the content of metal silver (Ag) in the first braze layer 21 is too low or the thickness is too thin, the first braze layer 21 will not be able to make the active metal braze substrate material 100 exhibit the desired physical properties. If the content of metal silver (Ag) in the first braze layer 21 is too high or the thickness is too thick, it will result in excessive material cost and manufacturing cost of the active metal braze substrate material 100.

[0039] It is worth mentioning that the first active metal component (such as Ti) in the first braze layer 21 can wet the surface of the ceramic substrate layer 1 during vacuum sintering and react with the ceramic material (such as SiN) to form compounds such as titanium nitride (TiN), titanium silicide (TiSi), or titanium disilicide (TiSi2), thereby improving the bonding force between the active metal layer 2 and the ceramic substrate layer 1.

[0040] On the other hand, since the first braze layer 21 contains active metal, the electrical impedance of the active metal braze substrate material 100 can be made smaller.

[0041] Further, the metal silver (Ag) in the first braze layer 21 can react with the metal copper (Cu) to form a silver-copper alloy (Ag-Cu alloy).

[0042] Furthermore, the first metal composite material of the first braze layer 21 can be formed, for example, by mixing and vacuum sintering of metal silver powder (Ag metal powder), metal copper powder (Cu metal powder), metal titanium powder (Ti metal powder), and / or silver-copper alloy (Ag-Cu alloy).

[0043] Second braze layer

[0044] Please continue to refer to Figure 1 As shown, the composition of the second braze layer 22 contains a second metal composite material. The second metal composite material contains: metal aluminum (Al), metal copper (Cu), and a second active metal component, and preferably consists only of metal aluminum, metal copper, and the second active metal component.

[0045] It is worth mentioning that in a preferred embodiment of the present application, the second metal composite material of the second braze layer 22 does not contain any metal silver (Ag).

[0046] Further, as mentioned above, the metallic aluminum (Al) of the second braze layer can be, for example, first melted during the vacuum sintering process for preparing the active metal braze base material, and then diffused into the first braze layer 21 at least partially along the defects of the metallic copper (Cu), but the present application is not limited thereto.

[0047] Further, similar to the first active metal component, the second active metal component can be, for example, at least one selected from a material group consisting of: titanium (Ti), zirconium (Zr), tantalum (Ta), niobium (Nb), vanadium (V), hafnium (Hf), and hydrides of the above-mentioned metals.

[0048] Further, the hydride of the metal can be, for example, at least one of titanium hydride (TiH2), zirconium hydride (ZrH2), tantalum hydride (TaH2), niobium hydride (NbH), vanadium hydride (VH2), and hafnium hydride (H2Hf2).

[0049] In some embodiments of the present application, the second active metal component is preferably titanium (Ti). Accordingly, the second braze layer 22 can also be referred to as an aluminum-copper-titanium braze layer (Al-Cu-Ti paste).

[0050] In terms of content, the second metal composite is the main component of the second braze layer 22. For example, the weight percentage concentration of the second metal composite in the second braze layer 22 is at least not less than 80 wt%, and preferably not less than 90 wt%.

[0051] Further, in the second braze layer 22, based on the total weight of the second metal composite being 100 parts by weight, the content of the metallic aluminum (Al) is at least not less than 40 parts by weight, and preferably between 40 parts by weight and 75 parts by weight. In terms of thickness, the thickness T22 of the second braze layer 22 is at least not less than 10 microns, and preferably between 10 microns and 24 microns.

[0052] It is worth mentioning that the metallic aluminum (Al) and the metallic copper (Cu) in the second braze layer 22 can react during the vacuum sintering process to form an aluminum-copper alloy (Al-Cu alloy). In addition, the second braze layer 22 can have a micron-level eutectic reaction with the metal component (such as metallic copper) of the conductive metal layer 3 at the interface (such as eutectic reaction of aluminum and copper), so that the second braze layer 22 can be tightly combined with the conductive metal layer 3.

[0053] Furthermore, the second metal composite of the second braze layer 22 can be formed by mixing and vacuum sintering of Al metal powder, Cu metal powder, Ti metal powder, and / or Al-Cu alloy. In addition, the second active metal component (e.g., Ti) in the second braze layer 22 can diffuse through the first braze layer 21 to the ceramic substrate layer 1 during vacuum sintering and react with the ceramic material (e.g., SiN) to form compounds such as TiN, TiSi, or TiSi2, thereby improving the bonding between the active metal layer 2 and the ceramic substrate layer 1.

[0054] Thickness ratio and metal component content of the active metal layer

[0055] In another aspect, the total thickness of the active metal layer 2 (i.e., the sum of the thickness T21 of the first braze layer 21 and the thickness T22 of the second braze layer 22) is at least not less than 12 microns, and preferably at least not less than 15 microns, and more preferably between 15 microns and 32 microns. The content of each metal component in the active metal layer 2 is affected by the thickness ratio between the thickness T21 of the first braze layer 21 and the thickness T22 of the second braze layer 22. The thickness ratio between the thickness T21 of the first braze layer 21 and the thickness T22 of the second braze layer 22 is preferably 15% to 50% : 50% to 85% (and the sum is 100%), and more preferably 20% to 45% : 55% to 80%. Accordingly, based on the total weight of all metal components in the active metal layer 2 being 100 wt%, the content of the metal aluminum (Al) is between 25 wt% and 48 wt%. The content of the metal silver (Ag) is not more than 50 wt%, and preferably between 15 wt% and 48 wt%. The total content of the first and second active metal components (e.g., titanium metal) is between 0.3 wt% and 8 wt%, and preferably between 0.5 wt% and 5 wt%. The metal copper (Cu) is the remaining metal component. The addition of the metal silver (Ag) can serve as a stabilizer to improve device performance.

[0056] According to the above configuration, the second braze layer 22 is disposed between the first braze layer 21 and the conductive metal layer 3. The second braze layer 22 includes the metal aluminum (Al) and does not include the metal silver (Ag). The second braze layer 22 occupies a thickness that is effective to reduce the content of the metal silver in the active metal layer 2, thereby effectively reducing the material cost and manufacturing cost of the active metal braze ceramic substrate, and effectively improving the electromigration problem caused by the residual metal silver. Furthermore, the second braze layer 22 can firmly connect the first braze layer 21 and the conductive metal layer 3 together.

[0057] In some embodiments of the present application, the active metal layer 2 can be brazed at a brazing temperature of not greater than 900°C, and preferably between 820°C and 890°C, due to the increased aluminum content. In a specific embodiment, the active metal layer 2 is heated to a brazing temperature of 855°C, but the present application is not limited thereto. Accordingly, the active metal layer 2 can effectively improve the effects of high temperature on metal properties due to its lower brazing temperature compared to prior art.

[0058] Conductive metal layer

[0059] Please continue to refer to Figure 1 As shown, the conductive metal layer 3 is disposed on a side surface of the second brazing layer 22 away from the first brazing layer 21. The conductive metal layer 3 can be, for example, a metal copper foil, a metal aluminum foil, or a Cu-Al alloy foil. In the present embodiment, the conductive metal layer 3 is preferably a metal copper foil.

[0060] In addition, the thickness T3 of the conductive metal layer 3 can be, for example, between 50 microns and 800 microns, but the present application is not limited thereto.

[0061] It is worth mentioning that the conductive metal layer 3 (e.g., oxygen-free copper) can be, for example, brazed to the ceramic substrate layer 1 through the active metal layer 2 by vacuum high-temperature sintering.

[0062] For example, the vacuum high-temperature sintering process can include a first stage heat treatment process and a second stage heat treatment process. The temperature condition of the first stage heat treatment process is not greater than 500°C, and the temperature condition of the second stage heat treatment process is not less than 800°C, and needs to be within the appropriate brazing temperature range.

[0063] According to the above configuration, the active metal brazing substrate material containing aluminum elements provided by the embodiments of the present application can effectively reduce the amount of silver metal and reduce the brazing temperature to below 900°C, thereby reducing the effects of high temperature on metal properties, and at the same time, reducing the material cost and the process cost.

[0064] It is worth mentioning that the "brazing temperature" of the active metal layer 2 referred to in this article refers to the temperature at which the metal components are melted and have sufficient fluidity to wet the surface of the workpiece (such as a ceramic substrate). Generally speaking, the brazing temperature higher than 450℃ is called the brazing temperature. The brazing temperature can be determined, for example, by the desired brazing temperature, the ternary phase diagram of the three metal components, and the appropriate weight percentage concentration of each of the metal materials. Or, by the ternary phase diagram of the three metal components, the known weight percentage concentration of the metal materials, and the appropriate brazing temperature range. For example, the appropriate brazing temperature is higher than the liquidus temperature of the ternary metal components of the brazing filler metal, which can make the brazing filler metal have sufficient fluidity, but the application is not limited thereto.

[0065] Method for manufacturing active metal brazing substrate material

[0066] The above is the structural characteristics and material characteristics of the active metal brazing substrate material, and the manufacturing method of the active metal brazing substrate material of the present application will be described below.

[0067] As shown in Figures 3A to 3D , the embodiment of the present application also provides a method for manufacturing an active metal brazing substrate material, which comprises steps S110, S120, S130, and S140. It must be pointed out that the order of each step in this embodiment and the actual operation mode can be adjusted according to the needs, and is not limited to the embodiment.

[0068] As shown in Figure 3A , the step S110 is to provide a ceramic substrate layer 1. The ceramic substrate layer 1 can be, for example, at least one of a silicon nitride (SiN) ceramic substrate, a silicon carbide (SiC) ceramic substrate, an aluminum nitride (AlN) ceramic substrate, and an aluminum oxide (Al2O3) ceramic substrate. Preferably, in this embodiment, the ceramic substrate layer 1 is a silicon nitride (SiN) ceramic substrate.

[0069] As shown in Figure 3B , the step S120 is to implement a first brazing layer preparation operation, which comprises: applying a first active solder paste to one side surface of the ceramic substrate layer 1, and drying the first active solder paste at high temperature to remove most of the organic solvents in the first active solder paste to form a first brazing layer 21.

[0070] The first active solder paste is prepared by mixing and blending first active solder powder and organic components (such as paste-forming agents, organic solvents, and thixotropic agents), and the viscosity is adjusted to an appropriate value (such as 50-300 mPa·s) to make the solder paste easy to apply to the ceramic substrate layer 1.

[0071] For example, the first active solder paste can be coated on the surface of the ceramic substrate by screen printing, and dried at a temperature of 90-110°C for 5-15 minutes to volatilize most of the organic solvents in the first active solder paste, thereby forming the first brazing layer 21.

[0072] In some embodiments of the present application, the weight ratio between the first active solder powder and the organic component can be, for example, between 70-95%:5-30%, and preferably between 75-90%:10-25%.

[0073] The first active solder powder (forming the first metal composite material described above) is a powder formed by mixing a silver metal powder, a copper metal powder, and a first active metal powder (such as a titanium metal powder). The weight ratio of silver (Ag): copper (Cu): first active metal powder (Ti, TiH2) can be, for example, between 50-75:20-48:2-5, and in a specific embodiment, 68:28:4, but the present application is not limited thereto.

[0074] In the organic component, the weight ratio between the paste-forming agent: organic solvent: thixotropic agent can be, for example, between 20-30%:50-70%:1-5%.

[0075] The paste-forming agent can be at least one selected from the group consisting of silicone oil, white oil, polyvinyl alcohol, acrylic resin, nitrocellulose, ethyl cellulose, dimethyl phthalate, and carboxymethyl cellulose. Preferably, the paste-forming agent is ethyl cellulose. The organic solvent can be at least one selected from the group consisting of ethylene glycol butyl ether acetate, diethylene glycol, triethanolamine, butyl cellosolve, t-butyl alcohol, N,N-dimethylformamide, terpineol, and nonylphenol polyglycol ether. Preferably, the organic solvent is terpineol or ethylene glycol butyl ether acetate. The thixotropic agent can be at least one selected from the group consisting of polyamide wax, hydrogenated castor oil, and polyurea. Preferably, the thixotropic agent is polyamide wax.

[0076] However, the present application is not limited to the above-described embodiments, as long as the active solder powder and the organic component are formulated into an active solder paste with a suitable viscosity for coating on a ceramic substrate to facilitate the formation of a brazing layer, which is within the scope of the present application.

[0077] For example, the first active solder paste can be coated on the surface of the ceramic substrate by screen printing, and dried at a temperature of 90-110°C for 5-15 minutes to volatilize most of the organic solvents in the first active solder paste, thereby forming the first brazing layer 21. Figure 3CAs shown, the step S130 is to perform a second hard solder layer preparation operation, which includes: applying a second active solder paste on the side surface of the first hard solder layer 21 away from the ceramic substrate layer 1, and drying the second active solder paste through high temperature, so as to remove most of the organic solvents in the second active solder paste, thereby forming a second hard solder layer 22.

[0078] The second active solder paste is prepared by mixing the second active solder powder and the organic component to a suitable viscosity (e.g. 50-300 mPa·s) for facilitating the application on the first hard solder layer 21.

[0079] For example, the second active solder paste can be applied on the first hard solder layer 21 by screen printing, and dried at a temperature of 90-110°C for 5-15 minutes, so as to volatilize most of the organic solvents in the second active solder paste, thereby forming the second hard solder layer 22.

[0080] In some embodiments of the present application, the weight ratio between the second active solder powder and the organic component can be, for example, between 70%-95%:5%-30%, and preferably between 75%-90%:10%-25%.

[0081] The second active solder powder (forming the second metal composite material) is a powder formed by mixing aluminum metal powder, copper metal powder, and a second active metal powder (e.g. titanium metal powder). The weight ratio between aluminum (Al): copper (Cu): second active metal powder (Ti, TiH2) can be, for example, between 45-75:20-50:0.5-5. For example, in some specific embodiments, the weight ratio between Al:Cu:Ti can be, for example, [48:47:5], [50:49:0.5], [72:23:5], [72:24:4], but the present application is not limited thereto.

[0082] It is worth mentioning that the second active solder powder does not contain silver metal powder.

[0083] The proportion and type of the organic component in the second active solder paste are similar to those of the organic component in the first active solder paste, which will not be described herein.

[0084] As Figure 3DAs shown, the step S140 is to perform a conductive metal layer preparation operation, which includes: disposing a conductive metal layer 3 on a side surface of the second braze layer 22 away from the first braze layer 21, and hard soldering the conductive metal layer 3 to the ceramic substrate layer 1 through the active metal layer 2 composed of the first braze layer 21 and the second braze layer 22 under a vacuum high-temperature sintering process. The conductive metal layer 3 can be, for example, a copper foil, an aluminum foil, or a copper-aluminum alloy foil.

[0085] The vacuum high-temperature sintering process can include, for example, a first-stage heat treatment process and a second-stage heat treatment process. The temperature condition of the first-stage heat treatment process is not greater than 500°C, and the temperature condition of the second-stage heat treatment process is not less than 800°C.

[0086] More specifically, the temperature condition of the first-stage heat treatment process is 300°C to 500°C, and the processing time is 30 minutes to 240 minutes. The temperature condition of the second-stage heat treatment process is 800°C to 915°C (within a suitable hard soldering temperature range), and the processing time is 30 minutes to 240 minutes. In addition, the heating rate of the above heat treatment process can be, for example, 5 to 30°C / min. The cooling rate after the vacuum high-temperature sintering can be, for example, 2 to 30°C / min.

[0087] It is worth mentioning that during the vacuum sintering process, the organic components in the first and second braze layers are at least partially gasified, and the first and second active metal components (e.g., Ti) can wet the surface of the ceramic substrate layer 1 and react with the ceramic material (e.g., SiN) to form compounds such as titanium nitride (TiN), titanium silicide (TiSi), or titanium disilicide (TiSi2), thereby improving the bonding strength of the active metal layer 2 and the ceramic substrate layer 1. In addition, the second braze layer 22 can have a micron-level eutectic reaction (e.g., eutectic reaction of aluminum and copper) with the metal components (e.g., copper) of the conductive metal layer 3 at the interface to form a firm eutectic structure, so that the active metal layer 2 can be tightly bonded to the conductive metal layer 3.

[0088] It is worth mentioning that the total thickness of the active metal layer 2 (i.e., the sum of the thickness T21 of the first braze layer 21 and the thickness T22 of the second braze layer 22) is at least not less than 12 microns, and preferably between 15 microns and 32 microns. Furthermore, the thickness ratio of the thickness T21 of the first braze layer 21 and the thickness T22 of the second braze layer 22 is between 15% to 50%: 50% to 85% (and the total is 100%).

[0089] In addition, based on the total weight of all metal components in the active metal layer 2 being 100 wt%, the content of the metal aluminum (Al) is between 25 wt% and 48 wt%. The content of the metal silver (Ag) is not more than 50 wt%, and preferably between 15 wt% and 48 wt%. The total content of the first and second active metal components (e.g., titanium metal) is between 0.3 wt% and 8 wt%, and preferably between 0.5 wt% and 5 wt%. The metal copper (Cu) is the remainder of the metal components.

[0090] Accordingly, the technical solution provided by the embodiments of the present application can reduce the amount of silver, reduce the brazing temperature to below 900°C, thereby reducing the influence of high temperature on the metal, and effectively reducing the material cost and the process cost.

[0091] Experimental data and test results

[0092] Hereinafter, the content of the present application will be described in detail with reference to Examples 1-4 and Comparative Examples 1-3. Among them, the examples are experimental groups that can prove the technical effects of the present application, and the comparative examples are groups with poor conditions. However, the following examples are only used to help understand the present application, but the present application is not limited thereto.

[0093] Example 1: According to the conditions of Table 1, an active metal brazing substrate material including a first brazing layer and a second brazing layer is prepared. The preparation method includes: applying a first active solder paste containing 68 parts by weight of silver powder (Ag), 28 parts by weight of copper powder (Cu), and 4 parts by weight of titanium powder (Ti) to the surface of a ceramic substrate, and after high-temperature drying, forming the first brazing layer. Then, a second active solder paste containing 48 parts by weight of aluminum powder (Al), 47 parts by weight of copper powder (Cu), and 5 parts by weight of titanium powder (Ti) is applied to the first brazing layer, and after high-temperature drying, the second brazing layer is formed. Then, a copper metal foil is further arranged on the second brazing layer to form a laminated material, and then the laminated material is subjected to vacuum high-temperature sintering to finally form the active metal brazing substrate material.

[0094] In Example 1, the temperature condition of the first stage heat treatment process in the vacuum high-temperature sintering is 450°C, and the processing time is 30 minutes. The temperature condition of the second stage heat treatment process is 855°C, and the processing time is 60 minutes. In addition, the ceramic substrate is a silicon nitride (SiN) ceramic substrate with a thickness of 304 microns. The thickness of the first brazing layer is 6 microns, the thickness of the second brazing layer is 12 microns, and the thickness of the copper metal foil is 500 microns. Among them, the brazing temperature of the heated brazing material is 855°C.

[0095] Examples 2 to 3 and Comparative Examples 1 to 3 were prepared in substantially the same manner as Example 1, except that the weight proportions and types of the metal components, the thickness of the brazing layer, and the brazing temperature were different.

[0096] The active metal brazing substrate materials prepared in the above examples and comparative examples were then subjected to a peel strength test, which is a test of the bonding strength of the brazing layer between the copper foil and the ceramic substrate. The test was performed in accordance with JIS-C-6481 at a temperature of 25°C. If the peel strength test result is > 100 N / cm, the bonding strength is evaluated as good. If the peel strength test result falls within the range of 50 to 100 N / cm, the bonding strength is evaluated as normal. If the peel strength test result is < 50 N / cm, the bonding strength is evaluated as poor.

[0097] Table 1

[0098]

[0099]

[0100] Test Results and Discussion

[0101] As can be seen from the test results in Table 1, the metal components of the first brazing layer in Examples 1 to 4 were Ag-Cu-Ti (or TiH 2) The weight proportions of the metal components of the second brazing layer were all within the range of 45 to 75 : 20 to 50 : 0.5 to 5. Furthermore, the thickness of the first brazing layer was not less than 6 micrometers. The active metal brazing substrate materials of Examples 1 and 4 had peel strength test results that fell within the range of 50 to 100 N / cm, and thus the bonding strength was evaluated as normal. Furthermore, the active metal brazing substrate materials of Examples 2 and 3 had peel strength test results that were greater than 100 N / cm, and thus the bonding strength was evaluated as good.

[0102] The metal components of the first and second brazing layers in Comparative Example 1 were all Al-Cu-Ti, and Ag-Cu-Ti was not used. The Al content in the second brazing layer in Comparative Example 2 was 23%, which is lower than the ideal value of 40%. The total thickness of the first and second brazing layers in Comparative Example 3 was 12 micrometers. The active metal brazing substrate materials of Comparative Examples 1 to 3 had peel strength test results that were less than 50 N / cm, and thus the bonding strength was evaluated as poor.

[0103] Advantages of the Examples

[0104] The active metal brazing (AMB) substrate material provided by the application can further be used to draw circuit patterns on a ceramic substrate by exposure and development, and can be applied to high-power modules, electric vehicles, charging systems, and the like.

[0105] The above disclosed content is only the preferred feasible embodiments of the application, and does not limit the patent application scope of the application, so any equivalent technical changes made by using the content of the application specification and drawings are included in the patent application scope of the application.

Claims

1. An active metal brazing substrate material containing aluminum, characterized in that: The active metal brazing substrate material comprises: a ceramic substrate layer; An active metal layer comprising: a first brazing layer disposed on one side surface of the ceramic substrate layer; wherein the first brazing layer comprises a first metal composite material comprising silver (Ag), copper (Cu), and a first active metal component; and the silver content is not less than 50 parts by weight based on 100 parts by weight of the first metal composite material; and a second brazing layer disposed on a surface of the first brazing layer away from the ceramic substrate layer; wherein the second brazing layer comprises a second metal composite material comprising aluminum (Al), copper (Cu), and a second active metal component; the aluminum content is not less than 40 parts by weight based on 100 parts by weight of the second metal composite material, and the second metal composite material does not contain silver; wherein the sum of the thicknesses of the first brazing layer and the second brazing layer is at least not less than 12 microns, and the thickness of the first brazing layer is at least not less than 5 microns; and A conductive metal layer is disposed on a surface of the second brazing layer that is away from the first brazing layer.

2. The active metal brazing substrate material according to claim 1, characterized in that Based on the total weight of all metal components in the active metal layer being 100 wt%, the content of the metal aluminum is between 25 wt% and 48 wt%, the content of the metal silver is no more than 50 wt%, the total content of the first active metal component and the second active metal component is between 0.3 wt% and 8 wt%, and the metal copper (Cu) is the remainder of the metal component.

3. The active metal brazing substrate material according to claim 1, characterized in that: In the active metal layer, a thickness ratio of the first brazing layer to the second brazing layer is between 15% and 50% and 50% and 85%.

4. The active metal brazing substrate material according to claim 1, characterized in that: The first active metal component and the second active metal component are each selected from at least one of the material group consisting of titanium (Ti), zirconium (Zr), tantalum (Ta), niobium (Nb), vanadium (V), hafnium (Hf), and hydrides of the above metals.

5. The active metal brazing substrate material according to claim 1, characterized in that: The ceramic substrate layer is at least one of a silicon nitride ceramic substrate, a silicon carbide ceramic substrate, an aluminum nitride ceramic substrate, and an aluminum oxide ceramic substrate; and the conductive metal layer is at least one of a metal copper foil, a metal aluminum foil, and a copper-aluminum alloy foil.

6. The active metal brazing substrate material according to claim 1, characterized in that The active metal layer needs to be heated to a brazing temperature not greater than 900° C., and the ceramic substrate layer and the conductive metal layer have a peel strength not less than 50 N / cm when welded by the active metal layer.

7. The active metal brazing substrate material according to any one of claims 1 to 6, characterized in that: During vacuum and high-temperature sintering, the first active metal component in the first brazing layer can wet the side surface of the ceramic substrate layer and react with the ceramic material of the ceramic substrate layer to enhance the bonding strength between the active metal layer and the ceramic substrate layer; the second brazing layer can react with the metal component of the conductive metal layer at the interface to produce a micron-scale eutectic reaction to form a strong eutectic structure, thereby enabling the active metal layer to be tightly bonded to the conductive metal layer.

8. A method for manufacturing an active metal brazing substrate material, characterized in that: The manufacturing method includes: performing a first brazing layer preparation operation, including: applying a first active solder paste on one side surface of a ceramic substrate layer and drying the paste to form a first brazing layer; wherein the first active solder paste includes a first active solder powder composed of metallic silver powder, metallic copper powder, and a first active metal powder; wherein the content of the metallic silver powder is not less than 50 parts by weight based on 100 parts by weight of the first active solder powder; A second brazing layer preparation operation is performed, comprising: applying a second active solder paste on a surface of the first brazing layer away from the ceramic substrate layer, and drying the paste to form a second brazing layer; wherein the second active solder paste comprises a second active solder powder composed of metal aluminum powder, metal copper powder, and a second active metal powder; wherein the content of the metal aluminum powder is not less than 40 parts by weight based on 100 parts by weight of the second active solder powder; wherein the second active solder powder does not contain metal silver powder; and Performing a conductive metal layer preparation operation, which includes: disposing a conductive metal layer on a surface of the second brazing layer away from the first brazing layer, and brazing the conductive metal layer to the ceramic substrate layer through an active metal layer composed of the first brazing layer and the second brazing layer under a vacuum high-temperature sintering process; The total thickness of the first brazing layer and the second brazing layer is at least not less than 12 micrometers, and the thickness of the first brazing layer is not less than 5 micrometers.

9. The method for manufacturing an active metal brazing substrate material according to claim 8, wherein: The weight ratio of the metal silver powder in the first active solder powder; the metal copper powder: the first active metal powder is between 50-75:20-48:2-5; the weight ratio of the metal aluminum powder in the second active solder powder; the metal copper powder: the second active metal powder is between 45-75:20-50:0.5-5.

10. The method for manufacturing an active metal brazing substrate material according to claim 8, wherein: The vacuum high temperature sintering process includes a first stage heat treatment process with a temperature condition not greater than 500° C. and a second stage heat treatment process with a temperature condition not less than 800° C.

Images