Cermet substrate and method for producing same

Abstract

The invention discloses a metal ceramic substrate and a manufacturing method thereof. The metal ceramic substrate comprises a ceramic substrate layer, a metal solder layer and a conductive metal layer. The metal solder layer includes a first sub-solder layer and a second sub-solder layer. The first sub-solder layer is disposed on the ceramic substrate layer. The composition of the first sub-solder layer includes a first metal solder including metal copper (Cu) and an active metal, and not including metal silver (Ag); wherein the thickness of the first sub-solder layer is greater than 6 microns. The second sub-solder layer is disposed on the first sub-solder layer. The composition of the second sub-solder layer comprises a second metal solder which comprises metal tin (Sn) and metal copper (Cu) and does not comprise metal silver (Ag); wherein the second sub solder layer is larger than 6 microns. The conductive metal layer is disposed on the second sub-solder layer. Therefore, the problem of electromigration can be effectively avoided, and the manufacturing cost can be reduced.

Description

Technical Field

[0001] The present application relates to a substrate, and in particular to a metal ceramic substrate and a manufacturing method thereof. Background Art

[0002] Driven by energy-saving and carbon-reduction policies worldwide, the global electric vehicle market is booming. With major automakers launching 800-volt high-voltage models in recent years, demand for silicon carbide (SiC) ceramic substrate materials has grown rapidly.

[0003] However, the voltage, frequency, and operating temperature requirements for power components based on silicon carbide (SiC) ceramic substrate materials are constantly increasing, requiring the ceramic substrate materials to have better heat dissipation capabilities and reliability.

[0004] The widely used direct-bonding-copper (DBC) ceramic substrates are manufactured using eutectic bonding, with no adhesive material between the copper layer and the ceramic substrate. However, during high-temperature operation, the different thermal expansion coefficients between the copper layer and the ceramic substrate (such as Al2O3 or AlN) often generate significant thermal stress, causing the copper layer to peel from the ceramic substrate surface. As a result, traditional direct-bonding-copper ceramic substrates have been unable to meet the packaging requirements of high temperature, high power, high heat dissipation, and high reliability.

[0005] Currently, the mainstream substrate materials are gradually shifting from direct copper-clad ceramic substrates to active metal brazing (AMB) substrate materials.

[0006] Active metal brazing substrate materials utilize the wettability of active metal elements (such as Ti, Zr, Ta, Nb, V, and Hf) to braze ultra-thick copper foil onto the ceramic substrate at high temperatures. The brazing layer formed between the copper layer and the ceramic substrate through the active metal brazing process provides a higher bond strength.

[0007] Among common active metal brazing paste materials, silver-copper-titanium (Ag-Cu-Ti) is a commonly used metal composite material. In the above-mentioned silver-copper-titanium metal composite material, the silver content is usually more than 50% (weight percentage concentration), and even as high as 70%.

[0008] Active metal brazing pastes typically use silver, copper, and titanium, often at temperatures exceeding 900°C (e.g., 915°C). The solder layer formed by active metal brazing contains a significant amount of silver (a precious metal), resulting in high material and manufacturing costs for active metal brazing ceramic substrates. Furthermore, electromigration caused by residual silver from the etching process remains a persistent issue. Summary of the Invention

[0009] The technical problem to be solved by the present application is to provide a metal ceramic substrate and a manufacturing method thereof in view of the deficiencies in the prior art.

[0010] The present application discloses a metal ceramic substrate, comprising: a ceramic substrate layer; a metal solder layer, comprising: a first sub-solder layer, disposed on one side surface of the ceramic substrate layer; wherein the first sub-solder layer is composed of a first metal solder, the first metal solder comprising: metallic copper (Cu) and an active metal, and does not comprise metallic silver (Ag); wherein the thickness of the first sub-solder layer is greater than 6 microns; and a second sub-solder layer, disposed on one side surface of the first sub-solder layer away from the ceramic substrate layer; wherein the second sub-solder layer is composed of a second metal solder, the second metal solder comprising: metallic tin (Sn) and metallic copper (Cu), and does not comprise metallic silver (Ag); wherein the second sub-solder layer is greater than 6 microns; and a conductive metal layer, disposed on one side surface of the second sub-solder layer away from the first sub-solder layer.

[0011] Optionally, based on the total weight of the first metal solder being 100 weight percent, the ratio of the metal copper (Cu) content to the active metal content is between 80%:20% and 50%:50%; wherein, based on the total weight of the second metal solder being 100 weight percent, the ratio of the metal tin (Sn) content to the metal copper (Cu) content is between 80%:20% and 30%:70%.

[0012] Optionally, based on the total weight of the first metal solder being 100 weight percent, the ratio of the metal copper (Cu) content to the active metal content is between 65%:35% and 55%:45%; wherein, based on the total weight of the second metal solder being 100 weight percent, the ratio of the metal tin (Sn) content to the metal copper (Cu) content is between 80%:20% and 65%:35%; wherein, the metal solder layer completely does not contain metal silver.

[0013] Optionally, the content of the metallic copper in the first sub-solder layer is greater than the content of the metallic copper in the second sub-solder layer.

[0014] Optionally, the thickness of the first sub-solder layer is between 10 micrometers and 18 micrometers, and the thickness of the second sub-solder layer is between 10 micrometers and 18 micrometers.

[0015] Optionally, the active metal is selected from at least one of the material group consisting of: titanium, zirconium, tantalum, niobium, vanadium, hafnium and hydrides of the above metals; wherein the ceramic substrate layer is at least one of the material group consisting of: silicon nitride ceramic substrate, silicon carbide ceramic substrate, aluminum nitride ceramic substrate and aluminum oxide ceramic substrate; wherein the conductive metal layer is selected from at least one of the material group consisting of: metal copper foil, metal aluminum foil and copper-aluminum alloy foil.

[0016] The present application also discloses a method for manufacturing a metal-ceramic substrate, comprising applying a first solder paste onto a side surface of a ceramic substrate, and drying the first solder paste at a high temperature to form a first sub-solder layer; wherein the first solder paste comprises a first metal solder and a first organic medium, the first metal solder comprising: metallic copper (Cu) and an active metal, and excluding metallic silver (Ag); wherein the thickness of the first sub-solder layer is greater than 6 microns; applying a second solder paste onto a side surface of the first sub-solder layer away from the ceramic substrate layer, and drying the second solder paste at a high temperature to form a second sub-solder layer; wherein the second solder paste comprises a second metal solder and a second organic medium, and the second metal solder comprising: metallic tin (Sn) and metallic copper (Cu), and excluding metallic silver (Ag); wherein the second sub-solder layer is greater than 6 microns; and disposing a conductive metal layer on a side surface of the second sub-solder layer away from the first sub-solder layer.

[0017] Optionally, in the first sub-solder layer, the weight percentage concentration of the first metal solder is not less than 70 wt %; in the second sub-solder layer, the weight percentage concentration of the second metal solder is not less than 70 wt %.

[0018] Optionally, based on the total weight of the first metal solder being 100 weight percent, the ratio of the metal copper (Cu) content to the active metal content is between 80%:20% and 50%:50%; wherein, based on the total weight of the second metal solder being 100 weight percent, the ratio of the metal tin (Sn) content to the metal copper (Cu) content is between 80%:20% and 30%:70%.

[0019] Optionally, the manufacturing method of the metal ceramic substrate further includes: implementing a vacuum high-temperature sintering process to tightly connect the conductive metal layer to the ceramic substrate layer through a metal solder layer composed of the first sub-solder layer and the second sub-solder layer; wherein the operating temperature of the vacuum high-temperature sintering is between 600°C and 900°C.

[0020] In summary, the beneficial effect of the present application is that the metal ceramic substrate and the manufacturing method thereof provided by the present application can completely eliminate the need for metal silver (Ag) in the metal solder layer of the metal ceramic substrate through the technical solutions of "a first sub-solder layer, which is arranged on one side surface of the ceramic substrate layer; wherein the composition of the first sub-solder layer includes a first metal solder, and the first metal solder includes: metal copper (Cu) and active metal, and does not include metal silver (Ag); wherein the thickness of the first sub-solder layer is greater than 6 microns" and "a second sub-solder layer, which is arranged on the side surface of the first sub-solder layer away from the ceramic substrate layer; wherein the composition of the second sub-solder layer includes a second metal solder, and the second metal solder includes: metal tin (Sn) and metal copper (Cu), and does not include metal silver (Ag); wherein the second sub-solder layer is greater than 6 microns".

[0021] The design of the first and second sub-solder layers within the metal solder layer enhances the bonding strength between the ceramic substrate layer and the conductive metal layer. Notably, since the metal solder layer does not contain silver (Ag), it effectively avoids electromigration issues encountered in prior art and reduces manufacturing costs.

[0022] To further understand the features and technical content of this application, please refer to the following detailed description and drawings of this application. However, such description and drawings are only used to illustrate this application and do not limit the scope of protection of this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of a metal-ceramic substrate according to an embodiment of the present application.

[0024] Figure 2 Schematic diagram of a metal ceramic substrate with metal solder layers on both sides.

[0025] Figures 3A to 3D Schematic diagram of the manufacturing process of the metal ceramic substrate according to an embodiment of the present application. DETAILED DESCRIPTION

[0026] The following is an explanation of the implementation methods of the "metal ceramic substrate and its manufacturing method" disclosed in this application through specific specific embodiments. Those skilled in the art can understand the advantages and effects of this application from the content disclosed in this specification. This 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 departing from the concept of this application. In addition, the drawings of this application are only simple schematic illustrations and are not depicted according to actual dimensions. It is stated in advance. The following implementation methods will further explain the relevant technical content of this application in detail, but the disclosed content is not intended to limit the scope of protection of this application.

[0027] It should be understood that although terms such as "first," "second," and "third" may be used herein to describe various components or signals, these components or signals should not be limited by these terms. These terms are primarily used to distinguish one component from another, or one signal from another. In addition, the term "or" as used herein may include any one or more combinations of the associated listed items, as appropriate.

[0028] Metal ceramic substrate

[0029] See also Figure 1 As shown, the present application provides a metal ceramic substrate E, comprising: a ceramic substrate layer 1, a metal solder layer 2, and a conductive metal layer 3. The metal solder 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.

[0030] More specifically, the metal solder layer 2 includes a first sub-solder layer 21 and a second sub-solder layer 22. The first sub-solder layer 21 is disposed on one side of the ceramic substrate layer 1, the second sub-solder layer 22 is disposed on a side of the first sub-solder 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 sub-solder layer 22 that is away from the first sub-solder layer 21. In other words, the first sub-solder layer 21 and the second sub-solder layer 22 are stacked on top of each other, with the first sub-solder layer 21 in contact with the ceramic substrate layer 1, and the second sub-solder layer 22 in contact with the conductive metal layer 3.

[0031] It is worth mentioning that although the first sub-solder layer 21, the second sub-solder layer 22, and the conductive metal layer 3 are sequentially arranged on one side surface of the ceramic substrate layer 1 in this embodiment, the present application is not limited thereto. Figure 2As shown, in another embodiment, another first sub-solder layer 21', another second sub-solder 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 metal ceramic substrate E' having metal solder layers 2 on both sides.

[0032] Ceramic substrate layer

[0033] The ceramic substrate layer 1 may 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 (Al 2 O 3 ) ceramic substrate.

[0034] In this embodiment, the ceramic substrate layer 1 is 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.

[0035] First sub-solder layer

[0036] The first sub-solder layer 21 is an active metal layer, based on copper (Cu) and containing an active metal. Specifically, the first sub-solder layer 21 comprises a first metal solder and a first organic medium. The first metal solder comprises copper (Cu) and an active metal. Optionally, the first metal solder comprises copper and an active metal and does not contain silver (Ag).

[0037] Furthermore, in some embodiments of the present application, the active metal 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 aforementioned metals. Furthermore, the metal hydride may 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).

[0038] Optionally, the active metal is preferably at least one of titanium (Ti) and titanium hydride (TiH2).

[0039] The weight percentage concentration of the first metal solder in the first sub-solder layer 21 is at least not less than 70 wt %, preferably not less than 80 wt %, and particularly preferably not less than 90 wt %.

[0040] In addition, with the total weight of the first metal solder being 100 weight percent, the ratio of the content of the metal copper (Cu) to the content of the active metal is between 80%:20% and 50%:50% (that is, the content of the active metal is 20 to 50 weight percent). Preferably, the ratio of the content of the metal copper (Cu) to the content of the active metal is between 65%:35% and 55%:45%. For example, the content of the metal copper to the content of the active metal is 60%:40%. That is, in the first metal solder, the ratio of the content of the metal copper (Cu) to the content of the active metal is greater than 1, but the present application is not limited thereto.

[0041] Furthermore, the thickness T21 of the first sub-solder layer 21 is greater than 6 micrometers, preferably greater than 8 micrometers, and particularly preferably between 10 micrometers and 18 micrometers.

[0042] Second sub-solder layer

[0043] The second sub-solder layer 22 is a tin-copper metal layer.

[0044] Specifically, the second sub-solder layer 22 comprises a second metal solder and a second organic medium. The second metal solder comprises tin (Sn) and copper (Cu). Preferably, the second metal solder comprises tin and copper and does not contain silver (Ag).

[0045] The weight percentage concentration of the second metal solder in the second sub-solder layer 22 is at least not less than 70 wt %, preferably not less than 80 wt %, and particularly preferably not less than 90 wt %.

[0046] Furthermore, based on 100 weight percent of the total weight of the second metal solder, the ratio of the tin (Sn) content to the copper (Cu) content is between 80%:20% and 30%:70% (i.e., the tin content is 30-80 weight percent). Preferably, the ratio of the tin (Sn) content to the copper (Cu) content is between 80%:20% and 65%:35%. For example, the tin content to the copper content is 75%:25%.

[0047] In a preferred embodiment of the present application, the content of metallic copper (Cu) in the first sub-solder layer 21 (e.g., 55-65%) is greater than the content of metallic copper (Cu) in the second sub-solder layer 22 (e.g., 20-35%), but the present application is not limited thereto.

[0048] Furthermore, the thickness T22 of the second sub-solder layer 22 is greater than 6 micrometers, preferably greater than 8 micrometers, and particularly preferably between 10 micrometers and 18 micrometers.

[0049] Furthermore, the total thickness of the metal solder layer 2 (i.e., the sum of the thickness T21 of the first sub-solder layer 21 and the thickness T22 of the second sub-solder layer 22) is greater than 12 microns, preferably greater than 16 microns, and particularly preferably between 20 microns and 36 microns.

[0050] Conductive metal layer

[0051] Please continue reading Figure 1 As shown, the conductive metal layer 3 is disposed on a surface of the second brazing layer 22 that is away from the first brazing layer 21 .

[0052] The conductive metal layer 3 can be, for example, a copper foil, an aluminum foil, or a Cu-Al alloy foil. In this embodiment, the conductive metal layer 3 is preferably a copper foil. Furthermore, the thickness T3 of the conductive metal layer 3 can be, for example, between 50 microns and 1200 microns, but the present application is not limited thereto.

[0053] By designing the first sub-solder layer 21 and the second sub-solder layer 22 in the metal solder layer 2, the metal solder layer 2 can enhance the bonding strength between the ceramic substrate layer 1 and the conductive metal layer 3. It is worth mentioning that since the metal solder layer 2 does not contain silver (Ag), it can effectively avoid the electromigration problem in the prior art and reduce manufacturing costs.

[0054] Method for manufacturing metal ceramic substrate

[0055] The above is a description of the structural characteristics and material characteristics of the metal-ceramic substrate, and the following is a description of the manufacturing method of the metal-ceramic substrate of the present application.

[0056] See also Figures 3A to 3D As shown, the embodiment of the present application also provides a method for manufacturing a metal ceramic substrate, which includes step S110, step S120, step S130 and step S140.

[0057] like Figure 3A As shown, step S110 includes providing a ceramic substrate layer 1. The ceramic substrate layer 1 can 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 (Al2O3) ceramic substrate, and is preferably a silicon nitride (SiN) ceramic substrate.

[0058] like Figure 3BAs shown, the step S120 includes: coating a first solder paste on one side surface of the ceramic substrate layer 1 , and drying the first solder paste at a high temperature to remove most of the organic solvent in the first solder paste to form a first sub-solder layer 21 .

[0059] The first solder paste is prepared by mixing a first metal solder and a first organic medium (e.g., a paste, an organic solvent, and a thixotropic agent), and the first solder paste is prepared to a suitable viscosity (e.g., 50-300 mPa·s) so that the solder paste can be easily coated on the ceramic substrate layer 1.

[0060] For example, the first solder paste can be applied to the surface of the ceramic substrate layer 1 by screen printing and dried at a temperature of 90°C to 110°C for 5 to 15 minutes to volatilize most of the organic solvent in the first solder paste, thereby forming the first sub-solder layer 21.

[0061] In some embodiments of the present application, a weight ratio between the first metal solder and the first organic medium may be, for example, between 70:30 and 95:5, and preferably between 80:20 and 90:10.

[0062] The first metal solder comprises: copper (Cu) and an active metal. Preferably, the first metal solder comprises copper and an active metal and does not comprise silver (Ag).

[0063] Based on 100 weight percent of the total weight of the first metal solder, the ratio of the copper (Cu) content to the active metal content is between 80%:20% and 50%:50%. Preferably, the ratio of the copper (Cu) content to the active metal content is between 65%:35% and 55%:45%. For example, the copper content to the active metal content is 60%:40%.

[0064] In the first organic medium, the weight ratio of the paste-forming agent: the organic solvent: the thixotropic agent may be, for example, 20% to 30%: 50% to 70%: 1% to 5%.

[0065] The paste-forming agent may be, for example, 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.

[0066] The organic solvent may be, for example, at least one selected from the group consisting of butyl glycol acetate, diethylene glycol, triethanolamine, butyl cellosolve, tert-butyl alcohol, N,N-dimethylformamide, terpineol, and nonylphenol polyglycol ether. Preferably, the organic solvent is selected from terpineol or butyl glycol acetate.

[0067] The thixotropic agent may be, for example, at least one selected from the group consisting of polyamide wax, hydrogenated castor oil, and polyurea. Preferably, the thixotropic agent is polyamide wax.

[0068] However, the present application is not limited to the above-mentioned embodiments. As long as the metal solder and the organic medium can be mixed into a solder paste with a viscosity suitable for coating on the ceramic substrate to facilitate the formation of a solder layer, it complies with the protection spirit of the present application and falls within the scope of protection of the present application.

[0069] like Figure 3C As shown, the step S130 includes: applying a second solder paste on the surface of the first sub-solder layer 21 away from the ceramic substrate layer 1, and drying the second solder paste at a high temperature to remove most of the organic solvent in the second solder paste to form a second sub-solder layer 22.

[0070] The second solder paste is prepared by mixing a second metal solder and a second organic medium (such as a paste, an organic solvent, and a thixotropic agent) to a suitable viscosity (such as 50-300 mPa·s) to facilitate coating on the first sub-solder layer 21 .

[0071] For example, the second solder paste can be applied on the first sub-solder layer 21 by screen printing and dried at a temperature of 90°C to 110°C for 5 minutes to 15 minutes to volatilize most of the organic solvent in the second solder paste, thereby forming the second sub-solder layer 22.

[0072] In some embodiments of the present application, a weight ratio between the second metal solder and the second organic medium may be, for example, between 70:30 and 95:5, and preferably between 80:20 and 90:10.

[0073] The second metal solder includes metal tin (Sn) and metal copper (Cu). Preferably, the second metal solder is composed of metal tin and metal copper, and does not include metal silver (Ag).

[0074] Based on the total weight of the second metal solder as 100 weight percent, the ratio of the tin (Sn) content to the copper (Cu) content is between 80%:20% and 30%:70%. Preferably, the ratio of the tin (Sn) content to the copper (Cu) content is between 80%:20% and 65%:35%. For example, the ratio of the tin content to the copper content is 75%:25%. The composition and material type of the second organic medium in the second solder paste are similar to those of the first organic medium in the first active solder paste and are not further described here.

[0075] like Figure 3D As shown, the step S140 includes: disposing a conductive metal layer 3 on a surface of the second sub-solder layer 22 away from the first sub-solder layer 21, so that the conductive metal layer 3 can be connected to the ceramic substrate layer 1 through the first sub-solder layer 21 and the second sub-solder layer 22.

[0076] The conductive metal layer 3 may be, for example, a copper foil, an aluminum foil, or a copper-aluminum alloy foil. In this embodiment, the conductive metal layer 3 is preferably a copper foil.

[0077] The step S140 further includes: performing a vacuum high-temperature sintering process to more tightly connect the conductive metal layer 3 to the ceramic substrate layer 1 through a metal solder layer 2 composed of the first sub-solder layer 21 and the second sub-solder layer 22 .

[0078] The operating temperature of the vacuum high temperature sintering may be, for example, between 600°C and 900°C, and preferably between 700°C and 900°C.

[0079] It is worth mentioning that during the vacuum high-temperature sintering process, the active metal (e.g., Ti) in the first sub-solder layer 21 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 enhancing the bonding strength between the conductive metal layer 3 and the ceramic substrate layer 1. Furthermore, the metal tin (Sn) and metal copper (Cu) in the second sub-solder layer 22 can melt and become fluid during the vacuum high-temperature sintering process, reacting to form a better bonding strength between the conductive metal layer 3 and the ceramic substrate layer 1.

[0080] For example, when the vacuum high-temperature sintering temperature is greater than 600°C, the tin metal can first react with the copper metal to form a Cu3Sn alloy. This Cu3Sn alloy then reacts with more tin metal to form a Cu6Sn5 alloy. This allows the second sub-solder layer 22 to bond more tightly to the conductive metal layer 3, thereby enhancing the bonding strength between the conductive metal layer 3 and the ceramic substrate layer 1.

[0081] According to the above configuration, the metal solder layer 2 can enhance the bonding strength between the ceramic substrate layer 1 and the conductive metal layer 3. It is worth mentioning that since the metal solder layer 2 does not contain silver (Ag), it can effectively avoid the electromigration problem in the prior art and reduce manufacturing costs.

[0082] Experimental Data and Test Results The following describes the contents of this application in detail with reference to Test Examples 1 to 3.

[0083] The preparation method of Test Example 1 includes applying a first solder paste containing a first metal solder and a first organic medium to the surface of a ceramic substrate according to the conditions in Table 1 and drying at high temperature to form a first sub-solder layer. The first metal solder comprises copper powder and titanium powder in a weight ratio of 60:40, and the thickness of the first sub-solder layer is 12 microns. The ceramic substrate is a silicon nitride ceramic substrate. Then, applying a second solder paste containing a second metal solder and a second organic medium to the first sub-solder layer and drying at high temperature to form a second sub-solder layer. The second metal solder comprises tin powder and copper powder in a weight ratio of 75:25, and the thickness of the second sub-solder layer is 12 microns. In both the first and second solder pastes, the weight ratio of the metal solder to the organic medium is 80:20. The organic medium comprises ethyl cellulose as the paste-forming agent, ethylene glycol butyl acetate as the organic solvent, and polyamide wax as the thixotropic agent. The weight ratio of paste: organic solvent: thixotropic agent was 25:60:15. Neither the first nor the second solder paste contained silver. A copper foil was then placed on the second sub-solder layer to form a metal-ceramic substrate. Test Example 1 further subjected the metal-ceramic substrate to vacuum high-temperature sintering at a brazing temperature of 855°C, followed by cooling to room temperature and conducting a tensile test.

[0084] The preparation methods of Test Example 2 and Test Example 3 are substantially the same as those of Test Example 1, and the differences are listed in Table 1 below.

[0085] The tensile test measures the tensile force between the copper foil and the ceramic substrate according to JIS-C-6481 at a temperature of 25°C. A tensile test result of >100 N / cm is considered good, while a result between 50 and 100 N / cm is considered normal. A result of <50 N / cm is considered poor.

[0086]

[0087] Test Results and Discussion From the test results in Table 1, it can be seen that the tensile force of the metal ceramic substrate of Test Example 1 is 106N / cm, which has better tensile performance than Test Examples 2 to 3. Test Example 1 shows that the first sub-solder layer and the second sub-solder layer need to be within a specific composition and thickness range to achieve better bonding between the metal copper foil and the ceramic substrate. The thickness of the first sub-solder layer and the second sub-solder layer of Test Example 2 are both relatively thin (6μm), which does not fall within the ideal range, so the tensile performance is poor. The thickness of the first sub-solder layer of Test Example 3 is relatively thin (6μm), which does not fall within the ideal range, so the tensile performance is poor.

[0088] It is worth mentioning that the metal ceramic substrate of the above test example 1 can still have good tensile performance even when the metal solder layer does not contain metallic silver, breaking through the limitation of the prior art that the active metal layer needs to use metallic silver.

[0089] Beneficial effects of this application

[0090] The beneficial effect of the present application is that the metal ceramic substrate and the manufacturing method thereof provided in the present application can completely eliminate the need for the use of metal silver (Ag) in the metal solder layer of the metal ceramic substrate through the technical solutions of "a first sub-solder layer, which is arranged on one side surface of the ceramic substrate layer; wherein the composition of the first sub-solder layer includes a first metal solder, and the first metal solder includes: metal copper (Cu) and active metal, and does not include metal silver (Ag); wherein the thickness of the first sub-solder layer is greater than 6 microns" and "a second sub-solder layer, which is arranged on the side surface of the first sub-solder layer away from the ceramic substrate layer; wherein the composition of the second sub-solder layer includes a second metal solder, and the second metal solder includes: metal tin (Sn) and metal copper (Cu), and does not include metal silver (Ag); wherein the second sub-solder layer is greater than 6 microns".

[0091] The design of the first and second sub-solder layers within the metal solder layer enhances the bonding strength between the ceramic substrate layer and the conductive metal layer. Notably, since the metal solder layer does not contain silver (Ag), it effectively avoids electromigration issues encountered in prior art and reduces manufacturing costs.

[0092] Finally, the metal ceramic substrate provided in the embodiment of the present application can be further used to etch circuit patterns on the ceramic substrate through exposure and development methods, and can be applied to high-power modules, electric vehicles and charging systems for energy conversion.

[0093] The contents disclosed above are only preferred feasible embodiments of the present application and do not limit the scope of the patent application of the present application. Therefore, all equivalent technical changes made using the contents of the description and drawings of the present application are included in the scope of the patent application of the present application.

Claims

1. A metal ceramic substrate, characterized in that: The metal ceramic substrate comprises: a ceramic substrate layer; A metal solder layer comprising: A first sub-solder layer is disposed on one side surface of the ceramic substrate layer; wherein the first sub-solder layer comprises a first metal solder, and the first metal solder comprises: Metal copper and active metal, and no metal silver; wherein the thickness of the first sub-solder layer is greater than 6 microns; and a second sub-solder layer, which is disposed on a surface of the first sub-solder layer away from the ceramic substrate layer; wherein the second sub-solder layer comprises a second metal solder, The second metal solder includes: metal tin and metal copper, and does not include metal silver; wherein, The second sub-solder layer is larger than 6 microns; and A conductive metal layer is disposed on a surface of the second sub-solder layer that is away from the first sub-solder layer.

2. The metal ceramic substrate according to claim 1, characterized in that Based on the total weight of the first metal solder being 100 weight percent, the ratio of the metal copper content to the active metal content is between 80%:20% and 50%:50%; wherein, based on the total weight of the second metal solder being 100 weight percent, the ratio of the metal tin content to the metal copper content is between 80%:20% and 30%:70%.

3. The metal ceramic substrate according to claim 1, characterized in that Based on the total weight of the first metal solder being 100 weight percent, the ratio of the metal copper content to the active metal content is between 65%:35% and 55%:45%; wherein, based on the total weight of the second metal solder being 100 weight percent, the ratio of the metal tin content to the metal copper content is between 80%:20% and 65%:35%; wherein the metal solder layer completely does not contain metal silver.

4. The metal ceramic substrate according to claim 1, characterized in that A content of the metallic copper in the first sub-solder layer is greater than a content of the metallic copper in the second sub-solder layer.

5. The metal ceramic substrate according to claim 1, characterized in that The thickness of the first sub-solder layer is between 10 micrometers and 18 micrometers, and the thickness of the second sub-solder layer is between 10 micrometers and 18 micrometers.

6. The metal ceramic substrate according to any one of claims 1 to 5, characterized in that: The active metal is selected from at least one of the material group consisting of titanium, zirconium, tantalum, niobium, vanadium, hafnium, and hydrides of the above metals; wherein the ceramic substrate layer is at least one of the material group consisting of a silicon nitride ceramic substrate, a silicon carbide ceramic substrate, an aluminum nitride ceramic substrate, and an aluminum oxide ceramic substrate; wherein the conductive metal layer is selected from at least one of the material group consisting of metal copper foil, metal aluminum foil, and copper-aluminum alloy foil.

7. A method for manufacturing a metal ceramic substrate, characterized in that: The manufacturing method of the metal ceramic substrate comprises: A first solder paste is applied to one surface of a ceramic substrate and dried at a high temperature to form a first sub-solder layer. The first solder paste comprises a first metal solder and a first organic medium. The first metal solder comprises copper and an active metal, but does not comprise silver. The thickness of the first sub-solder layer is greater than 6 microns. Applying a second solder paste on a surface of the first sub-solder layer away from the ceramic substrate layer, and drying the second solder paste at a high temperature to form a second sub-solder layer; wherein the second solder paste comprises a second metal solder and a second organic medium, and the second metal solder comprises tin and copper, and does not comprise silver; wherein the second sub-solder layer is larger than 6 microns; and A conductive metal layer is disposed on a surface of the second sub-solder layer away from the first sub-solder layer.

8. The method for manufacturing a metal ceramic substrate according to claim 7, wherein: In the first sub-solder layer, the weight percentage concentration of the first metal solder is not less than 70 wt %; in the second sub-solder layer, the weight percentage concentration of the second metal solder is not less than 70 wt %.

9. The method for manufacturing a metal ceramic substrate according to claim 8, wherein: Based on the total weight of the first metal solder being 100 weight percent, the ratio of the metal copper content to the active metal content is between 80%:20% and 50%:50%; wherein, based on the total weight of the second metal solder being 100 weight percent, the ratio of the metal tin content to the metal copper content is between 80%:20% and 30%:70%.

10. The method for manufacturing a metal ceramic substrate according to claim 8, wherein: The manufacturing method of the metal ceramic substrate further includes: implementing a vacuum high-temperature sintering process to tightly connect the conductive metal layer to the ceramic substrate layer through a metal solder layer composed of the first sub-solder layer and the second sub-solder layer; wherein the operating temperature of the vacuum high-temperature sintering is between 600°C and 900°C.

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