CN119317021A

CN119317021A - Active metal brazing substrate material containing aluminum element and method for manufacturing the same

Info

Publication number: CN119317021A
Application number: CN202310856292.8A
Authority: CN
Inventors: 毛植葳; 张宗颖; 魏仲和; 徐明义; 黄琦雯
Original assignee: Tong Hsing Electronic Industries Ltd
Current assignee: Tong Hsing Electronic Industries Ltd
Priority date: 2023-07-13
Filing date: 2023-07-13
Publication date: 2025-01-14

Abstract

The application discloses an active metal hard soldering substrate material containing aluminum element and a manufacturing method thereof. The substrate material comprises a ceramic substrate layer, a first hard welding layer, a second hard welding layer and a conductive metal layer which are sequentially stacked. The first brazing layer comprises a first metal composite material comprising metallic silver (Ag), metallic copper (Cu) and a first active metal component. The silver content is not less than 50 parts by weight based on 100 parts by weight of the total weight of the first metal composite. The second brazing layer comprises a second metal composite material which comprises metal aluminum (Al), metal copper (Cu) and a second active metal component and does not comprise metal silver. The aluminum content is not less than 40 parts by weight based on 100 parts by weight of the total weight of the second metal composite. The total thickness of the first and second hard welding layers is not less than 12 microns and the thickness of the first hard welding layer is not less than 5 microns. Therefore, the use amount of silver is effectively reduced, the brazing temperature is reduced to below 900 ℃, the influence of high temperature on metal performance is reduced, and meanwhile, the material and manufacturing cost is reduced.

Description

Active metal brazing substrate material containing aluminum element and manufacturing method thereof

Technical Field

The present application relates to a substrate material, and more particularly, to an Active Metal Brazing (AMB) substrate material containing aluminum element and a method of manufacturing the same.

Background

Under the promotion of energy saving and carbon reduction policies of various countries, the global electric vehicle market is actively developed. As high voltage vehicle type products of 800 Volts (Volts) are being introduced by various factories in recent years, the demand for silicon carbide (SiC) ceramic substrate materials is rapidly growing. However, power components based on silicon carbide (SiC) ceramic substrate materials are continually increasing in terms of voltage, frequency, and operating temperature requirements, such that ceramic substrate materials are also required to have better heat dissipation capabilities and reliability.

A Direct-Bonding-Copper (DBC) ceramic substrate, which has been widely used in the past, is manufactured by a eutectic Bonding method, and there is no adhesive material between the Copper layer and the ceramic substrate. However, during high temperature operation, a large thermal stress tends to be generated due to the difference in thermal expansion coefficient between the copper layer and the ceramic substrate (e.g., al2O3 or AlN), resulting in peeling of the copper layer from the surface of the ceramic substrate. Therefore, it has been difficult for conventional direct copper-clad ceramic substrates to meet the packaging requirements of high temperature, high power, high heat dissipation and high reliability.

Currently, the dominant substrate materials are gradually moving from direct copper-clad ceramic substrates to active metal brazing (ACTIVE METAL Brazing, AMB) substrate materials.

The active metal brazing substrate material utilizes the characteristic that active metal elements (such as Ti, zr, ta, nb, V, hf and the like) can wet the surface of the ceramic substrate, and the ultra-thick copper foil is brazed on the ceramic substrate at high temperature. The hard soldering layer formed between the copper layer and the ceramic substrate by the active metal hard soldering process has higher connection strength.

Among the common active metal braze paste materials, silver copper titanium (Ag-Cu-Ti) is a commonly used metal composite. In the silver copper titanium metal composites described above, the silver content is typically in excess of 50% (weight percent concentration), even up to 70%.

The brazing temperatures typically used for active metal braze paste materials using silver copper titanium typically need to be above 900C (e.g., 915C). The solder layer formed by the active metal brazing contains a large amount of metallic silver (noble metal), so that the material cost and the manufacturing cost of the active metal brazing ceramic substrate are high. Further, electromigration problems caused by the metallic silver remaining after the etching process have been the subject of a continued need.

Disclosure of Invention

The application aims to solve the technical problem of providing an active metal brazing substrate material containing aluminum element and a manufacturing method thereof, which reduce the consumption of metallic silver and the brazing temperature to below 900 ℃ so as to reduce the influence of high temperature on the metal performance and simultaneously reduce the material cost and the manufacturing process cost.

In order to solve the technical problems, the application provides an active metal brazing substrate material containing aluminum, which comprises a ceramic substrate layer, an active metal layer, a first brazing layer, a second brazing layer and a conductive layer, wherein the active metal layer comprises a first brazing layer and is arranged on one side surface of the ceramic substrate layer, 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 the metal silver is not less than 50 parts by weight based on 100 parts by weight of the total weight of the first metal composite material, the second brazing layer is arranged on one side surface of the first brazing layer, which is far away from the ceramic substrate layer, the second brazing layer comprises a second metal composite material containing metal aluminum (Al), metal copper (Cu) and a second active metal component, the content of the metal aluminum is not less than 40 parts by weight based on 100 parts by weight of the total weight of the second metal composite material, the content of the metal silver is not less than 50 parts by weight based on the total weight of the second metal composite material, the second brazing layer is not less than one micron, the first brazing layer is not less than one micron thick, and the second brazing layer is not always arranged on one side surface of the first brazing layer is not less than 12 micron thick.

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

Optionally, in the active metal layer, a thickness ratio between the thickness of the first hard welding layer and the thickness of the second hard welding layer is 15% -50%: 50% -85%.

Optionally, the first active metal component and the second active metal component are each 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 foregoing metals.

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.

Optionally, a brazing temperature at which the active metal layer is heated is not greater than 900 ℃, and the ceramic substrate layer and the conductive metal layer have a peel strength of not less than 50N/cm by welding of the active metal layer.

Optionally, in a vacuum high temperature sintering process, the first active metal component in the first hard welding layer can wet the side surface of the ceramic substrate layer and react with the ceramic material of the ceramic substrate layer to promote the bonding force between the active metal layer and the ceramic substrate layer, and the second hard welding layer can react with the metal component of the conductive metal layer in a micron-sized eutectic way at an interface to form a firm eutectic structure, so that the active metal layer can be tightly bonded with the conductive metal layer.

In order to solve the above technical problems, another technical solution adopted in the present application is to provide a method for manufacturing an active metal brazing substrate material, comprising performing a first brazing layer preparation operation, including coating 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 composed of a metal silver powder, a metal copper powder and a first active metal powder, wherein the metal silver powder is contained in an amount of not less than 50 parts by weight based on 100 parts by weight of the first active solder powder, performing a second brazing layer preparation operation comprising applying a second active solder paste to a surface of a side of the first brazing layer remote from the ceramic substrate layer and drying to form a second brazing layer, wherein the second active solder paste comprises a second active solder powder composed of a metal aluminum powder, a metal copper powder and a second active metal powder, wherein the metal aluminum powder is contained in an amount of 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 a metal silver powder, and performing a conductive metal layer preparation operation comprising disposing a conductive metal layer on a surface of a side of the second brazing layer remote from the first brazing layer and subjecting the conductive metal layer to a high temperature sintering process under the first brazing layer and the ceramic substrate layer, the thickness of the first and second layers plus always at least not less than 12 microns and the thickness of the first layer plus not less than 5 microns.

The metal copper powder comprises, by weight, 50-75:20-48:2-5 of the first active metal powder, 45-75:20-50:0.5-5 of the second active metal powder, and the metal aluminum powder comprises the second active solder powder.

Optionally, the treatment process of the vacuum high-temperature sintering comprises a first-stage heat treatment process with the temperature condition not more than 500 ℃ and a second-stage heat treatment process with the temperature condition not less than 800 ℃.

The active metal hard welding substrate material containing the aluminum element and the manufacturing method thereof have the advantages that the use level of metal silver can be effectively reduced through the design of the first hard welding layer and the second hard welding layer, and the hard welding temperature is reduced to be below 900 ℃, so that the influence of high temperature on metal performance is reduced, and meanwhile, the material cost and the manufacturing process cost are reduced.

For a further understanding of the nature and the technical aspects of the present application, reference should be made to the following detailed description of the application and to the accompanying drawings, which are provided for purposes of reference only and are not intended to limit the application.

Drawings

FIG. 1 is a schematic diagram of an active metal brazing substrate material according to an embodiment of the application.

FIG. 2 is a schematic diagram of a ceramic substrate having active metal layers on both surfaces.

Fig. 3A to 3D are schematic views illustrating a substrate material manufacturing process according to an embodiment of the application.

Detailed Description

The following embodiments of the present application are described in terms of specific examples, and those skilled in the art will appreciate the advantages and effects of the present application from the disclosure herein. The application is capable of other and different embodiments and its several details are capable of modifications and various other uses and applications, all of which are obvious from the description, without departing from the spirit of the application. The drawings of the present application are merely schematic illustrations, and are not intended to be drawn to actual dimensions. The following embodiments will further illustrate the related art content of the present application in detail, but the disclosure is not intended to limit the scope of the present application. It should be understood that, although terms such as "first," "second," "third," and the like may be used herein to describe various materials or parameters, these materials or parameters should not be limited by these terms. These terms are used primarily to distinguish one material from another, or one parameter from another.

Active metal brazing substrate material

Referring to fig. 1, an active metal brazing substrate material 100 containing aluminum element is provided, and includes 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, and is used for connecting the ceramic substrate layer 1 and the conductive metal layer 3 together.

More specifically, the active metal layer 2 includes a first solder mask layer 21 and a second solder mask layer 22. Wherein the first hard soldering layer 21 is disposed on one side surface of the ceramic substrate layer 1, the second hard soldering layer 22 is disposed on one side surface of the first hard soldering layer 21 away from the ceramic substrate layer 1, and the conductive metal layer 3 is disposed on one side surface of the second hard soldering layer 22 away from the first hard soldering layer 21.

It should be noted that, in the present embodiment, the first hard solder layer 21, the second hard solder layer 22 and the conductive metal layer 3 are sequentially disposed on one side surface of the ceramic substrate layer 1, but the present application is not limited thereto. For example, as shown in fig. 2, in another embodiment of the present application, another first hard solder layer 21', another second hard solder layer 22', and another conductive metal layer 3' may be sequentially disposed on the other surface of the ceramic substrate layer 1, so as to form a symmetrical substrate structure having active metal layers on both sides.

Ceramic substrate layer

Further, the ceramic substrate layer 1 may be 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 (Al ₂O₃) ceramic substrate, for example. In this 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 may be, for example, between 100 micrometers and 1000 micrometers, but the present application is not limited thereto.

First hard solder layer

With continued reference to fig. 1, the first braze layer 21 comprises a first metal composite. The first metal composite material comprises metallic silver (Ag), metallic copper (Cu) and a first active metal component.

It should be noted that the composition of the first brazing layer 21 may further include a small amount of aluminum (Al), which may be, for example, melted first during the vacuum sintering process for preparing the active metal brazing substrate material, and diffused into the first brazing layer 21 from the second brazing layer 22 along the defects of copper.

Further, the first active metal component may 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 metals. The metal hydride may be at least one of titanium hydride (TiH ₂), zirconium hydride (ZrH ₂), tantalum hydride (TaH ₂), niobium hydride (NbH), vanadium hydride (VH ₂), and hafnium hydride (H ₂Hf₂), for example.

In some embodiments of the application, the first active metal component is preferably at least one of titanium (Ti) and titanium hydride (TiH ₂). Accordingly, the first braze layer 21 may also be referred to as a silver-copper-titanium braze layer (Ag-Cu-Ti paste).

Over a range of contents, the first metal composite is the main composition of the first braze layer 21. For example, the weight percent concentration of the first metal composite in the first braze layer 21 is at least not less than 80wt%, and preferably not less than 90wt%.

Further, in the first brazing layer 21, the content of the metallic silver (Ag) is at least not less than 50 parts by weight, and preferably is between 50 parts by weight and 75 parts by weight, based on 100 parts by weight of the total weight of the first metal composite. The thickness T21 of the first braze layer 21 is at least not less than 5 microns, and preferably between 5 and 24 microns, over a range of thicknesses.

According to the above configuration, since the first brazing layer 21 in contact with the ceramic substrate layer 1 contains metallic silver (Ag) in a specific content or more and has a thickness in a specific range or more, the bonding force of the ceramic substrate layer 1 and the conductive metal layer 3 can be enhanced. If the content of silver (Ag) in the first brazing layer 21 is too low or the thickness is too thin, the first brazing layer 21 cannot make the active metal brazing substrate material 100 exhibit the physical properties. If the content of silver (Ag) in the first brazing layer 21 is too high or the thickness is too thick, the material cost and the manufacturing cost of the active metal brazing substrate material 100 are too high.

It should be noted that the first active metal component (e.g., ti) in the first hard mask layer 21 may wet the surface of the ceramic substrate layer 1 during the vacuum sintering process and react with the ceramic material (e.g., siN) to form a compound such as titanium nitride (TiN), titanium silicide (TiSi), or titanium disilicide (TiSi ₂), so as to enhance the bonding force between the active metal layer 2 and the ceramic substrate layer 1.

On the other hand, since the first brazing layer 21 contains an active metal, the electrical resistance of the active metal brazing substrate material 100 can be made smaller.

Further, the metallic silver (Ag) and the metallic copper (Cu) in the first solder layer 21 may react to form a silver-copper alloy (Ag-Cu alloy).

The first metal composite material of the first hard mask layer 21 may be formed by, for example, 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).

Second hard solder layer

With continued reference to fig. 1, the second braze layer 22 comprises a second metal composite. The second metal composite material comprises metal aluminum (Al), metal copper (Cu) and a second active metal component, and preferably consists of only metal aluminum, metal copper and the second active metal component.

It should be noted that, in a preferred embodiment of the present application, the second metal composite material of the second hard solder layer 22 does not contain any metallic silver (Ag).

Further, as described above, the metal aluminum (Al) of the second brazing layer may be melted first during the vacuum sintering process for preparing the active metal brazing substrate material, and then diffused into the first brazing layer 21 at least partially along the defect of the metal copper (Cu), but the present application is not limited thereto.

Further, the second active metal component may 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 metals, similarly to the first active metal component.

The metal hydride may be at least one of titanium hydride (TiH ₂), zirconium hydride (ZrH ₂), tantalum hydride (TaH ₂), niobium hydride (NbH), vanadium hydride (VH ₂), and hafnium hydride (H ₂Hf₂), for example.

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

Over a range of contents, the second metal composite is the primary composition of the second braze layer 22. For example, the weight percent concentration of the second metal composite in the second braze layer 22 is at least not less than 80wt%, and preferably not less than 90wt%.

Further, in the second brazing layer 22, 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, based on 100 parts by weight of the total weight of the second metal composite material. 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, over a range of thicknesses.

It should be noted that the metal aluminum (Al) and the metal copper (Cu) in the second brazing layer 22 may react during the vacuum sintering process to form an aluminum-copper alloy (Al-Cu alloy). In addition, the second brazing layer 22 may perform a micro eutectic reaction (such as a eutectic reaction between aluminum and copper) with the metal component (such as copper) of the conductive metal layer 3 at the interface, so that the second brazing layer 22 can be tightly bonded with the conductive metal layer 3.

Furthermore, the second metal composite material of the second hard mask layer 22 may be formed by, for example, mixing and vacuum sintering of metal aluminum powder (Al metal powder), metal copper powder (Cu metal powder), metal titanium powder (Ti metal powder), and/or aluminum copper alloy (Al-Cu alloy). In addition, the second active metal component (e.g., ti) in the second brazing layer 22 may diffuse into the ceramic substrate layer 1 through the first brazing layer 21 during the vacuum sintering process and react with the ceramic material (e.g., siN) to form a compound such as titanium nitride (TiN), titanium silicide (TiSi), or titanium disilicide (TiSi 2), thereby enhancing the bonding force of the active metal layer 2 with the ceramic substrate layer 1.

Thickness ratio of active metal layer and content of metal component

From another perspective, 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 brazing layer 21 and the thickness T22 of the second brazing layer 22. The thickness ratio between the thickness T21 of the first hard welding layer 21 and the thickness T22 of the second hard welding layer 22 is preferably 15% -50%, 50% -85% (and the sum is 100%), and particularly preferably 20% -45%, 55% -80%. Accordingly, the content of the metallic aluminum (Al) is 25wt% to 48wt% based on 100wt% of the total weight of all metal components in the active metal layer 2. The content of metallic silver (Ag) is not more than 50wt%, and preferably between 15wt% and 48wt%. The sum of the contents of the first and second active metal components (e.g., titanium metal) is between 0.3wt% and 8wt%, and preferably between 0.5wt% and 5wt%. The metal copper (Cu) is the rest metal component. Wherein the addition of metallic silver (Ag) may be used as a stabilizer (stabilizer) to improve device performance.

According to the above configuration, the second brazing layer 22 is provided between the first brazing layer 21 and the conductive metal layer 3. The second braze layer 22 includes metallic aluminum (Al) and does not include metallic silver (Ag). The second brazing layer 22 occupies a certain thickness, so that the content of metallic silver in the active metal layer 2 can be effectively reduced, the material cost and the manufacturing cost of the active metal brazing ceramic substrate can be effectively reduced, and the electromigration problem caused by metallic silver residues can be effectively improved. Furthermore, the second brazing layer 22 can firmly connect the first brazing layer 21 and the conductive metal layer 3 together.

Also, in some embodiments of the present application, the active metal layer 2 may be brazed at a brazing temperature (brazing temperature) of not more than 900 ℃ due to the increase of aluminum content, and preferably between 820 ℃ and 890 ℃. In one embodiment, the brazing temperature at which the active metal layer 2 is heated is 855 ℃, but not limited thereto. Accordingly, since the active metal layer 2 has a lower brazing temperature than the prior art, the influence of high temperature on the metal performance can be effectively improved.

Conductive metal layer

With continued reference to fig. 1, the conductive metal layer 3 is disposed on a side surface of the second solder mask 22 remote from the first solder mask 21. The conductive metal layer 3 may be, for example, a metal copper foil (metal copper foil), a metal aluminum foil (metal aluminum foil), or a copper-aluminum alloy foil (cu—al alloy foil). In this embodiment, the conductive metal layer 3 is preferably a metal copper foil.

In addition, the thickness T3 of the conductive metal layer 3 may be, for example, between 50 micrometers and 800 micrometers, but the present application is not limited thereto.

It is worth mentioning that the conductive metal layer 3 (e.g. oxygen-free red copper) may be sintered at high temperature, for example, by vacuum, and brazed to the ceramic substrate layer 1 through the active metal layer 2.

For example, the vacuum high temperature sintering process may include a first stage heat treatment process and a second stage heat treatment process. Wherein the temperature condition of the first stage heat treatment process is not more than 500 ℃ and the temperature condition of the second stage heat treatment process is not less than 800 ℃ and is required to be within a proper brazing temperature range.

According to the configuration, the active metal brazing substrate material containing the aluminum element provided by the embodiment of the application can effectively reduce the use level of metal silver and reduce the brazing temperature to below 900 ℃, thereby reducing the influence of high temperature on metal performance and simultaneously reducing the material cost and the manufacturing process cost.

It should be noted that the term "brazing temperature" of the active metal layer 2 as used herein refers to a temperature at which a metal component is melted and sufficiently flowable to wet the surface of a workpiece (e.g., a ceramic substrate). In general, a temperature at which the welding temperature is higher than 450 ℃ is referred to as a brazing temperature. The brazing temperature may be, for example, a ternary gold phase diagram of three metal components, with the desired brazing temperature, determining the appropriate weight percent concentration of each of the metal materials. Or, a ternary gold phase diagram composed of three metal components is obtained by finding out a proper brazing temperature range through the known weight percentage concentration of the metal materials. For example, a suitable brazing temperature, i.e., a temperature above the liquidus temperature of the ternary metal component of the braze filler, may provide sufficient fluidity to the braze filler, but the application is not limited thereto.

Method for manufacturing active metal hard welding substrate material

The structural features and material characteristics of the active metal brazing substrate material are described above, and the method for manufacturing the active metal brazing substrate material of the present application will be described below.

As shown in fig. 3A to 3D, the embodiment of the application also provides a method for manufacturing an active metal brazing substrate material, which includes step S110, step S120, step S130, and step S140. It should be noted that the order and the actual operation manner of the steps carried in the present embodiment may be adjusted according to the requirements, and are not limited to the steps carried in the present embodiment.

As shown in fig. 3A, the step S110 is to provide a ceramic substrate layer 1. The ceramic substrate layer 1 may be 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 (Al ₂O₃) ceramic substrate, for example. Preferably, in this embodiment, the ceramic substrate layer 1 is a silicon nitride (SiN) ceramic substrate.

As shown in fig. 3B, the step S120 is to perform a first brazing layer preparation operation, which includes coating a first active solder paste on one side surface of the ceramic substrate layer 1, drying the first active solder paste at a high temperature, and removing most of the organic solvent in the first active solder paste to form a first brazing layer 21.

The first active solder paste is prepared by mixing and blending the first active solder powder and organic components (such as paste, organic solvent and thixotropic agent), and blending to a proper viscosity (such as 50-300 mPa.s) so that the solder paste is easy to coat on the ceramic substrate layer 1.

For example, the first active solder paste may be coated on the surface of the ceramic substrate by screen printing and dried at a temperature of 90 to 110 ℃ for 5 to 15 minutes to volatilize most of the organic solvent in the first active solder paste, thereby forming the first hard solder layer 21.

In some embodiments of the application, a weight ratio between the first active solder powder and the organic component may be, for example, between 70% and 95% to 5% to 30%, and preferably between 75% and 90% to 10% to 25%.

The first active solder powder (forming the first metal composite material) is a powder formed by mixing a metal silver powder (Ag metal powder), a metal copper powder (Cu metal powder), and a first active metal powder (e.g., metal titanium powder). The weight ratio of silver (Ag): copper (Cu): the first active metal powder (Ti, tiH ₂) may be, for example, between 50-75:20-48:2-5, and in one embodiment 68:28:4, but the application is not limited thereto.

Among the organic components, the weight ratio of the paste-forming agent to the organic solvent to the thixotropic agent may be, for example, 20% to 30% to 50% to 70% to 1% to 5%.

Wherein the paste may be at least one selected from the group consisting of silicone oil, white oil, polyvinyl alcohol, acrylic resin, nitrocellulose, ethylcellulose, dimethyl phthalate, and carboxymethyl cellulose. Preferably, the paste is ethylcellulose. The organic solvent may be at least one selected from the group consisting of ethylene glycol butyl ether acetate, diethylene glycol, triethanolamine, butyl cellosolve, t-butanol, N-dimethylformamide, terpineol, and nonylphenol polyethylene glycol ether. Preferably, the organic solvent is terpineol or ethylene glycol butyl ether acetate. The thixotropic agent may be at least one selected from the group of materials consisting of polyamide wax, hydrogenated castor oil, and polyurea. Preferably, the thixotropic agent is a polyamide wax.

However, the present application is not limited to the above embodiments, and the present application is within the scope of the present application as long as the active solder powder and the organic component can be formulated into the active solder paste with a viscosity suitable for coating on the ceramic substrate, so as to facilitate the formation of the hard solder layer, i.e. to meet the protection spirit of the present application.

As shown in fig. 3C, the step S130 is to perform a second brazing layer preparation operation, which includes applying a second active solder paste on a surface of the first brazing layer 21 far from the ceramic substrate layer 1, drying the second active solder paste at a high temperature, and removing most of the organic solvent in the second active solder paste to form a second brazing layer 22.

The second active solder paste is prepared by blending the second active solder powder and the organic component to a suitable viscosity (e.g. 50-300 mpa·s) so as to facilitate coating on the first hard solder layer 21.

For example, the second active solder paste may be coated on the first brazing layer 21 by screen printing and dried at a temperature of 90 to 110 ℃ for 5 to 15 minutes to volatilize most of the organic solvent in the second active solder paste, thereby forming the second brazing layer 22.

In some embodiments of the application, a weight ratio between the second active solder powder and the organic component may be, for example, between 70% and 95% to 5% to 30%, and preferably between 75% and 90% to 10% to 25%.

The second active solder powder (forming the second metal composite material) is a powder formed by mixing a metal aluminum powder (Al metal powder), a metal copper powder (Cu metal powder), and a second active metal powder (e.g., metal titanium powder). The weight ratio of aluminum (Al) to copper (Cu) to the second active metal powder (Ti, tiH ₂) may be, for example, 45-75:20-50:0.5-5. For example, in some embodiments, the weight ratio of Al to Cu to Ti may be, for example, [48:47:5], [50:49:0.5], [72:23:5], [72:24:4], but the application is not limited thereto.

It should be noted that the second active solder powder does not contain metallic silver powder.

The proportion and the material types of the organic components in the second active solder paste are similar to those of the organic components in the first active solder paste, and are not described herein.

As shown in fig. 3D, 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 hard solder layer 22 away from the first hard solder layer 21, and hard soldering the conductive metal layer 3 on the ceramic substrate layer 1 through an active metal layer 2 formed by the first hard solder layer 21 and the second hard solder layer 22 under a vacuum high temperature sintering process. The conductive metal layer 3 may be, for example, a metal copper foil, a metal aluminum foil or a copper aluminum foil.

The vacuum high temperature sintering process may include, for example, a first stage heat treatment process and a second stage heat treatment process. Wherein the temperature condition of the first stage heat treatment process is not more than 500 ℃ and the temperature condition of the second stage heat treatment process is not less than 800 ℃.

More specifically, the temperature condition of the first stage heat treatment process is 300 ℃ to 500 ℃ and the treatment time is 30 minutes to 240 minutes. The temperature conditions of the second stage heat treatment process are 800-915 ℃ (required in a proper brazing temperature range), and the treatment time is 30-240 minutes. The temperature rise rate of the heat treatment program may be, for example, 5 to 30 ℃. The cooling rate after the vacuum high-temperature sintering is finished can be, for example, 2-30 ℃ per minute.

It should be noted that during the vacuum sintering process, the organic components in the first and second hard solder layers are at least partially gasified, and the first and second active metal components (e.g., ti) may wet the surface of the ceramic substrate layer 1 and react with the ceramic material (e.g., siN) to form a compound such as titanium nitride (TiN), titanium silicide (TiSi), or titanium disilicide (TiSi ₂) to enhance the bonding force between the active metal layer 2 and the ceramic substrate layer 1. In addition, the second brazing layer 22 may perform a micro eutectic reaction (such as a eutectic reaction between aluminum and copper) with the metal component (such as copper) of the conductive metal layer 3 at the interface, so as to form a firm eutectic structure, so that the active metal layer 2 can be tightly combined with the conductive metal layer 3.

It should be noted that the total thickness of the active metal layer 2 (i.e. the sum of the thickness T21 of the first hard mask layer 21 and the thickness T22 of the second hard mask layer 22) is at least not less than 12 microns, and preferably between 15 microns and 32 microns. Furthermore, a thickness ratio of the thickness T21 of the first hard mask layer 21 to the thickness T22 of the second hard mask layer 22 is 15% -50%, 50% -85% (and 100% in total).

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

According to the technical scheme provided by the embodiment of the application, the consumption of the metal silver can be reduced, and the brazing temperature is reduced to below 900 ℃, so that the influence of high temperature on the metal performance is reduced, and meanwhile, the material cost and the manufacturing process cost are effectively reduced.

Experimental data and test results

Hereinafter, the present application will be described in detail with reference to examples 1 to 4 and comparative examples 1 to 3. The examples are experimental groups that can demonstrate the technical effects of the present application, while the comparative examples are worse. However, the following examples are only for aiding in understanding the present application, but the present application is not limited thereto.

Example 1 active metal brazing substrate materials comprising a first braze layer and a second braze layer were prepared according to the conditions of table 1. The preparation method comprises the steps of coating a first active soldering 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) on the surface of a ceramic substrate, and forming the first hard soldering layer after drying at a high temperature. Then, a second active 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) was coated on the first brazing layer, and after drying at high temperature, the second brazing layer was formed. And then, a metal copper foil is further arranged on the second hard welding layer to form a laminated material, and then, the laminated material is sintered at a vacuum high temperature to finally form the active metal hard welding substrate material.

In example 1, the temperature condition of the first stage heat treatment procedure in the vacuum high temperature sintering was 450 ℃ and the treatment time was 30 minutes. The temperature condition of the second stage heat treatment program was 855 ℃ and the treatment time was 60 minutes. Further, the ceramic substrate is a silicon nitride (SiN) ceramic substrate having a thickness of 304 μm. The thickness of the first braze layer was 6 microns, the thickness of the second braze layer was 12 microns, and the thickness of the metal copper foil was 500 microns. Wherein the brazing material is heated at a brazing temperature of 855 ℃.

Examples 2 to 3 and comparative examples 1 to 3 were prepared in substantially the same manner as in example 1, except for the weight ratio and the kind of the metal component, the thickness of the brazing layer and the brazing temperature.

The active metal brazing substrate materials prepared in the above examples and comparative examples were then subjected to peel strength testing, which was performed to test the bonding strength of the brazing layer between the metal copper foil and the ceramic substrate. The measurement temperature was 25℃as measured in accordance with JIS-C-6481. If the peel strength test results are >100N/cm, the bond strength is assessed as good. If the peel strength test result falls within the range of 50-100N/cm, the bonding strength is evaluated as normal. Also, if the peel strength test result is <50N/cm, the bonding strength is evaluated as poor.

TABLE 1

Test results and discussion

As can be seen from the test results of Table 1, the metal components of the first brazing layer of examples 1 to 4 were Ag-Cu-Ti (or TiH ₂₎, the weight ratios thereof were all within the range of 50 to 75:20 to 48:2 to 5. The metal components of the second brazing layer were Al-Cu-Ti, the weight ratios thereof 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. The active metal brazing substrate materials of examples 1 and 4 were both within the range of 50 to 100N/cm in terms of peel strength, and thus the bonding strength was evaluated as normal. The active metal brazing substrate materials of examples 2 and 3 were both greater than 100N/cm in terms of peel strength, and thus the bonding strength was evaluated as good.

The metal components used in the first and second hard coats of comparative example 1 were all Al-Cu-Ti, and Ag-Cu-Ti was not used. The Al content in the second brazing layer of comparative example 2 was 23%, which was lower than 40% as desired. The thicknesses of the first and second hard coats of comparative example 3 add up to 12 microns. The active metal brazing substrate materials of comparative examples 1-3 were all less than 50N/cm in peel strength test results, and therefore, the bonding strength was evaluated as poor.

Advantageous effects of the embodiments

The active metal hard welding substrate material containing the aluminum element and the manufacturing method thereof have the advantages that the use level of metal silver can be effectively reduced through the design of the first hard welding layer and the second hard welding layer, and the hard welding temperature is reduced to be below 900 ℃, so that the influence of high temperature on metal performance is reduced, and meanwhile, the material cost and the manufacturing process cost are reduced. More specifically, the second brazing layer is arranged between the first brazing layer and the conductive metal layer. The second brazing layer comprises metallic aluminum (Al) and does not comprise metallic silver (Ag). The second hard welding layer occupies a certain thickness, so that the content of metallic silver in the active metal layer can be reduced, the material cost and the manufacturing cost of the active metal hard welding ceramic substrate can be effectively reduced, and the electromigration problem caused by silver residues can be effectively improved. Finally, the Active Metal Brazing (AMB) substrate material provided by the embodiment of the application can be further used for scribing a circuit pattern on a ceramic substrate in an exposure and development mode, and can be applied to high-power modules, electric vehicles, charging systems and the like for energy conversion.

The above disclosure is only a preferred embodiment of the present application and is not intended to limit the scope of the present application, so that all equivalent technical changes made by the specification and drawings of the present application are included in the scope of the present application.

Claims

1. An active metal brazing substrate material containing aluminum element, 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 metal silver (Ag), metal copper (Cu) and a first active metal component; based on 100 parts by weight of the total weight of the first metal composite material, the content of the metal silver is not less than 50 parts by weight; 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 metal aluminum (Al), metal copper (Cu), and a second active metal component; based on 100 parts by weight of the total weight of the second metal composite material, the content of the metal aluminum is not less than 40 parts by weight, and the second metal composite material does not contain metal silver;

wherein the sum of the 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 at least not less than 5 micrometers; 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 is characterized in that, based on the total weight of all metal components in the active metal layer being 100wt%, the content of the metal aluminum is between 25wt% and 48wt%, the content of the metal 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 metal copper (Cu) is the remaining metal component.

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

4. The active metal brazing substrate material according to claim 1 is characterized in that the first active metal component and the second active metal component are respectively 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 is 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 is characterized in that a brazing temperature at which the active metal layer needs to be heated is not greater than 900°C, and the ceramic substrate layer and the conductive metal layer have a peel strength of not less than 50N/cm through welding of the active metal layer.

7. The active metal brazing substrate material according to any one of claims 1 to 6 is characterized in that, during vacuum 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 force 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 at the micrometer level 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 comprises: performing a first brazing layer preparation operation, comprising: coating a first active solder paste on a 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 a metal silver powder, a metal copper powder, and a first active metal powder; wherein based on 100 parts by weight of the first active solder powder, the content of the metal silver powder is not less than 50 parts by weight;

Implementing a second brazing layer preparation operation, comprising: coating a second active solder paste on a surface of the first brazing layer away from the ceramic substrate layer, and drying the coating to form a second brazing layer; wherein the second active solder paste comprises a second active solder powder, which is composed of a metal aluminum powder, a 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 a metal silver powder; and

Implementing 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 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;

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 is characterized in that 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 treatment procedure 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.