Method for manufacturing an active metal ceramic substrate

Abstract

To provide a method for manufacturing an active metal ceramic substrate. 【Solution means】The method for manufacturing an active metal ceramic substrate includes applying a first solder paste prepared by mixing a first metal solder material and a first organic medium to a ceramic substrate, drying the first solder paste to form a first partial solder layer; applying a second solder paste prepared by mixing a second metal solder material and a second organic medium to the first partial solder layer, drying the second solder paste to form a second partial solder layer; and disposing a conductive metal layer on the second partial solder layer to form an active metal ceramic substrate. The first metal solder material contains a first active metal. The second metal solder material contains metallic tin and metallic copper, and optionally contains a second active metal. The first metal solder material and the second metal solder material do not contain metallic silver.

Description

Technical Field

[0001] Cross - reference to related patent applications This application claims the benefit of priority to Taiwan Patent Application No. 113104571, filed on February 6, 2024. The entire content of the application identified above is incorporated herein by reference.

[0002] Some references, which may include patents, patent applications, and various publications, may be cited and discussed in the description of the present disclosure. The citation and / or discussion of such references are provided only for the purpose of clarifying the description of the present disclosure and do not admit that any such reference is "prior art" of the disclosure described herein. All references cited and discussed in this specification are incorporated herein by reference in their entirety to the same extent as if each reference were individually incorporated by reference.

[0003] The field of the present disclosure The present disclosure relates to a method for manufacturing a metal - ceramic substrate, and specifically to a method for manufacturing an active - metal ceramic substrate.

Background Art

[0004] With the promotion of energy - saving and carbon - reduction policies in various countries, the global market for electric vehicles (EVs) is currently booming. In recent years, as major automobile manufacturers have successively launched 800 - volt high - voltage vehicle products, the demand for silicon carbide (SiC) ceramic substrate materials has been rapidly increasing.

[0005] However, in power devices based on silicon carbide (SiC) ceramic substrate materials, the requirements for their voltage, frequency, and operating temperature are constantly increasing. Therefore, this ceramic substrate material is also required to be improved in terms of heat dissipation and reliability.

[0006] In related technologies, conventional direct-bonding-copper (DBC) ceramic substrates are fabricated by eutectic bonding, and there is no bonding material between the copper layer and the ceramic substrate. However, during high-temperature operation, large thermal stresses often occur due to the difference in the coefficients of thermal expansion between the copper layer and the ceramic substrate (such as Al2O3 or AlN). This thermal stress causes the copper layer to peel off from the surface of the ceramic substrate. Therefore, conventional direct-bonding-copper (DBC) ceramic substrates cannot meet the packaging requirements of high temperature, high power, high heat dissipation, and high reliability.

[0007] Currently, conventional direct-bonding-copper (DBC) ceramic substrates are gradually being replaced by active metal brazing (AMB) substrate materials. The active metal elements (such as Ti, Zr, Ta, Nb, V, or Hf) of the active metal brazing substrate material can wet the side surface of the ceramic substrate, thereby enabling the brazing of an ultra-thick copper foil to the ceramic substrate at a high temperature. The brazing layer formed between the ultra-thick copper foil and the ceramic substrate by the active metal brazing process has high connection strength.

[0008] In conventional active metal brazing paste materials, typically, silver-copper-titanium (Ag-Cu-Ti) metal composite materials are used. In the above silver-copper-titanium metal composite material, the silver content usually exceeds 50 wt% (weight percentage concentration) and may exceed 70 wt%.

[0009] The brazing temperature of conventional active metal brazing paste materials employing silver-copper-titanium (Ag-Cu-Ti) metal composite materials is usually above 900 °C (for example, 915 °C). Since the brazing layer formed from conventional active metal brazing paste materials contains a large amount of silver (i.e., precious metal), the material and manufacturing costs of active metal brazing ceramic substrates remain high. Furthermore, the problem of electromigration due to silver (Ag) residues after the etching process has long been an issue to be solved. [Prior Art Documents] [Patent Documents] [Patent Document 1] US Patent Application Publication No. 2022 / 0362891 A1 [Patent Document 2] US Patent Application Publication No. 2023 / 0171887 A1 [Patent Document 3] US Patent Application Publication No. 2023 / 0031736 A1 [Patent Document 4] US Patent No. 11,393,738 B2 SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0010] In response to the above technical drawbacks, the present disclosure provides a method for manufacturing an active metal ceramic substrate. MEANS FOR SOLVING THE PROBLEMS

[0011] To solve the above problems, one of the technical aspects adopted by the present disclosure is to provide a method for manufacturing an active metal ceramic substrate. This method includes a step of applying a first solder paste prepared by mixing a first metal solder material and a first organic medium to a side surface (surface) of a ceramic substrate, drying the first solder paste to form a first sub-solder layer; a step of applying a second solder paste prepared by mixing a second metal solder material and a second organic medium to a side surface of the first sub-solder layer that is away from (the far side of) the ceramic substrate, drying the second solder paste to form a second sub-solder layer; and a step of disposing a conductive metal layer on a side surface of the second sub-solder layer that is away from the first sub-solder layer to form the active metal ceramic substrate. The first metal solder material contains a first active metal and does not contain metallic silver (Ag). The thickness of the first sub-solder layer is 1 micrometer to 10 micrometers. The second metal solder material contains metallic tin (Sn) and metallic copper (Cu), selectively contains a second active metal, and this second metal solder material does not contain metallic silver (Ag). The thickness of the second sub-solder layer is 6 micrometers to 24 micrometers.

[0012] Therefore, in the method for manufacturing an active metal ceramic substrate provided by the present disclosure, "applying a first solder paste to the side surface of the ceramic substrate, drying the first solder paste to form a first partial solder layer, wherein the first solder paste is prepared by mixing a first metal solder material and a first organic medium, the first metal solder material contains a first active metal but does not contain metallic silver (Ag), and the thickness of the first partial solder layer is 1 micrometer to 10 micrometers", and "applying a second solder paste to the side surface of the first partial solder layer away from the ceramic substrate, drying the second solder paste to form a second partial solder layer, wherein the second solder paste is prepared by mixing a second metal solder material and a second organic medium, the second metal solder material contains metallic tin (Sn) and metallic copper (Cu), optionally contains a second active metal, the second metal solder material does not contain metallic silver (Ag), and the thickness of the second partial solder layer is 6 micrometers to 24 micrometers", thereby the metal solder layer of the active metal ceramic substrate does not require the use of metallic silver (Ag).

[0013] Due to the configurations of the first partial solder layer and the second partial solder layer in the above metal solder layer, the metal solder layer can improve the bonding strength between the ceramic substrate and the conductive metal layer. Since the metal solder layer does not contain metallic silver (Ag), it is worth mentioning that the problem of electromigration caused by silver residues in the related art can be effectively avoided, and the manufacturing cost can be reduced.

[0014] Finally, the active metal ceramic substrate of the present disclosure can be applied to high-power modules for energy conversion, electric vehicles, and charging systems by etching a circuit pattern on the ceramic substrate through exposure and development.

[0015] These and other aspects of the present disclosure will become apparent from the following description of the embodiments in conjunction with the following drawings and their description, provided that modifications and variations may be made without departing from the spirit and scope of the novel concepts of the present disclosure.

Brief Description of the Drawings

[0016] The described embodiments can be better understood by referring to the following description and the accompanying drawings.

[0017] [Figure 1] It is a flowchart of a method for manufacturing an active metal ceramic substrate according to one embodiment of the present disclosure. [Figure 2A] It is a schematic diagram showing a method for manufacturing an active metal ceramic substrate according to an embodiment of the present disclosure. [Figure 2B] It is a schematic diagram showing a method for manufacturing an active metal ceramic substrate according to an embodiment of the present disclosure. [Figure 2C] It is a schematic diagram showing a method for manufacturing an active metal ceramic substrate according to an embodiment of the present disclosure. [Figure 2D] It is a schematic diagram showing a method for manufacturing an active metal ceramic substrate according to an embodiment of the present disclosure. [Figure 2E] It is a schematic diagram showing a method for manufacturing an active metal ceramic substrate according to an embodiment of the present disclosure. [Figure 3] It is a schematic diagram showing two metal solder layers respectively formed on both sides of an active metal ceramic substrate according to an embodiment of the present disclosure.

Modes for Carrying Out the Invention

[0018] The present disclosure will be described in more detail in the following examples, which are intended merely as illustrations. This is because numerous modifications and variations to the examples will be apparent to those skilled in the art. Similar numbers in the drawings indicate similar components throughout the drawings. As used throughout the description of this specification and the appended claims, the meanings of "a," "an," and "the" include plural references unless the context clearly dictates otherwise, and the meaning of "in" includes "in" and "on." Headings or subheadings may be used in this specification for the convenience of the reader, but they shall not affect the scope of the present disclosure.

[0019] The terms used in this specification generally have their ordinary meanings in the relevant technical field. In case of conflict, this specification prevails, including any definitions given herein. The same thing may be expressed in multiple ways. Alternative phrases and synonyms may be used for any term discussed in this specification, and no special significance is imposed as to whether the term is detailed or discussed in this specification. An explanation by one or more synonyms does not exclude the use of other synonyms. The use of examples anywhere in this specification, including examples of any term, is merely illustrative and in no way limits the scope and meaning of the present disclosure or the scope and meaning of any exemplified term. Similarly, the present disclosure is not limited to the various embodiments given herein. Ordinal numbers such as "first," "second," or "third" may be used to describe various components, signals, etc., but such terms are merely for distinguishing one component / signal from another and are not intended to impose, nor should they be construed to impose, any substantial limitation on the components, signals, etc.

[0020] [Method for manufacturing an active metal ceramic substrate] As shown in FIGS. 1 and 2A to 2E, an embodiment of the present disclosure provides a method for manufacturing an active metal ceramic substrate including steps S110, S120, S130, S140, and S150.

[0021] As shown in FIGS. 1 and 2A, step S110 includes preparing a ceramic substrate 1. The ceramic substrate 1 can be at least any 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.

[0022] In this embodiment, the ceramic substrate 1 is preferably a silicon nitride (SiN) ceramic substrate. Furthermore, the thickness T1 of the ceramic substrate 1 is 100 micrometers to 1000 micrometers.

[0023] As shown in FIGS. 1 and 2B, step S120 includes applying a first solder paste to the side surface of the ceramic substrate 1 and drying the first solder paste at a high temperature so that the first solder paste is formed into a first partial solder layer 2a to remove a substantial amount of the organic solvent in the first solder paste.

[0024] The first solder paste is prepared by mixing a first metal solder material and a first organic medium. The first metal solder material contains a first active metal and is preferably formed only by the first active metal. In addition, the first solder paste does not contain metallic silver (Ag).

[0025] In some embodiments, the first active metal can be selected from the group consisting of titanium (Ti), zirconium (Zr), tantalum (Ta), niobium (Nb), vanadium (V), hafnium (Hf), and metal hydrides of any one of the above metals. For example, the metal hydride can be selected from the group consisting of titanium hydride (TiH2), zirconium hydride (ZrH2), tantalum hydride (TaH2), niobium hydride (NbH), vanadium hydride (VH2), and hafnium hydride (H2Hf2). Preferably, the first active metal is at least one of titanium (Ti) and titanium hydride (TiH2).

[0026] In this embodiment, the first active metal is dispersed in the first organic medium in the form of metal powder, and the first solder paste is prepared.

[0027] Furthermore, the first organic medium includes a paste former, a thixotropic agent, and an organic solvent.

[0028] In the first organic medium, the weight ratio of the paste former, the thixotropic agent, and the organic solvent is 20 - 30:1 - 5:50 - 70.

[0029] The paste former can be 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 former is ethyl cellulose.

[0030] The thixotropic agent can be selected from the group consisting of polyamide wax, hydrogenated castor oil, and polyurea. Preferably, the thixotropic agent is polyamide wax.

[0031] The organic solvent can be selected from the group consisting of ethylene glycol butyl ether acetate, diethylene glycol, triethanolamine, butyl cellosolve, tert - butanol, N,N - dimethylformamide, terpineol, and nonylphenol polyethylene glycol ether. Preferably, the organic solvent is terpineol or ethylene glycol butyl ether acetate.

[0032] Specifically, in the first solder paste, the weight ratio of the first metal solder material to the first organic medium is 70:30 - 95:5, preferably 80:20 - 90:10.

[0033] The first solder paste is preferably formulated to have a viscosity of 50 mPa·s to 300 mPa·s (at room temperature of 25 °C) so that it can be easily applied to the ceramic substrate 1 and shape formation can be easily achieved.

[0034] In one embodiment of the present disclosure, the first solder paste can be applied to the side surface of the ceramic substrate 1 by screen printing and dried at a high temperature of 90 °C to 110 °C for 5 to 15 minutes. As a result, most of the organic solvent in the first solder paste volatilizes, and the first partial solder layer 2a can be formed. The thickness T21 of the first partial solder layer 2a is 1 micrometer to 10 micrometers, preferably 1 micrometer to 6 micrometers.

[0035] As shown in FIGS. 1 and 2C, step S130 includes applying the second solder paste to the side surface of the first partial solder layer 2a away from the ceramic substrate 1 and drying the second solder paste at a high temperature so that the second solder paste is formed into the second partial solder layer 2b to remove a substantial amount of the organic solvent in the second solder paste.

[0036] The second solder paste is prepared by mixing a second metal solder material and a second organic medium. The second metal solder material includes metallic tin (Sn) and metallic copper (Cu), and selectively includes a second active metal.

[0037] Preferably, the second metal solder material is composed of metallic tin (Sn), metallic copper (Cu), and a second active metal, and the second solder paste does not contain metallic silver (Ag).

[0038] In the second metal solder material, the weight ratio of metallic tin (Sn), metallic copper (Cu), and the second active metal is 20-50:40-70:0.5-10, preferably 32.5-42.5:52.5-62.5:2-8. For example, the weight ratio of metallic tin (Sn), metallic copper (Cu), and the second active metal is 37.5:57.5:5, but the present disclosure is not limited thereto.

[0039] In some embodiments, the second active metal can be selected from the group consisting of titanium (Ti), zirconium (Zr), tantalum (Ta), niobium (Nb), vanadium (V), hafnium (Hf), and any one of the above metal hydrides. For example, the metal hydride can be selected from the group consisting of titanium hydride (TiH2), zirconium hydride (ZrH2), tantalum hydride (TaH2), niobium hydride (NbH), vanadium hydride (VH2), and hafnium hydride (H2Hf2). Preferably, the second active metal is at least one of titanium (Ti) and titanium hydride (TiH2).

[0040] In this embodiment, metallic tin (Sn), metallic copper (Cu), and the second active metal are dispersed in the second organic medium in the form of metal powders to prepare the second solder paste.

[0041] Specifically, the second organic medium includes a paste former, a thixotropic agent, and an organic solvent. In the second organic medium, the weight ratio of the paste former, the thixotropic agent, and the organic solvent is 20-30:1-5:50-70. The material types of the paste former, the thixotropic agent, and the organic solvent are the same as those of the first organic medium in the first solder paste, and thus will not be repeated here.

[0042] More specifically, in the second solder paste, the weight ratio of the second metal solder material to the second organic medium is 70:30-95:5, preferably 80:20-90:10.

[0043] The second solder paste is preferably formulated to have a viscosity of 50 mPa·s to 300 mPa·s (at a room temperature of 25°C) so that the second solder paste can be easily applied to the first partial solder layer 2a and shape formation can be easily achieved.

[0044] In one embodiment of the present disclosure, the second solder paste can be applied to the side surface of the first partial solder layer 2a by screen printing and can be dried at a high temperature of 90°C to 110°C for 5 to 15 minutes. As a result, most of the organic solvent in the second solder paste volatilizes, and the second partial solder layer 2b can be formed.

[0045] The thickness T22 of the second partial solder layer 2b is 6 micrometers to 24 micrometers, preferably 18 micrometers to 24 micrometers.

[0046] Preferably, the thickness T22 of the second partial solder layer 2b is greater than the thickness T21 of the first partial solder layer 2a. The thickness ratio of the thickness T22 of the second partial solder layer 2b to the thickness T21 of the first partial solder layer 2a (i.e., T22 / T21) is in the range of 1.5 to 5, preferably in the range of 2 to 4, and more preferably in the range of 2.5 to 3.5.

[0047] The first partial solder layer 2a and the second partial solder layer 2b are combined to form the metal solder layer 2.

[0048] In the metal solder layer 2, with the total weight of the first metal solder material and the second metal solder material being 100% by weight (i.e., the total weight of metallic tin, metallic copper, the first active metal, and the second active metal is 100 weight percent), the content of metallic tin is in the range of 35% by weight to 70% by weight, the content of metallic copper is in the range of 20% by weight to 65% by weight, and the total content of the first active metal and the second active metal is in the range of 1% by weight to 20% by weight.

[0049] In an embodiment of the present disclosure, it is worth mentioning that the metal solder layer 2 does not contain metallic silver (Ag).

[0050] As shown in FIG. 2D, in step S140, the conductive metal layer 3 can be connected to the ceramic substrate 1 through the metal solder layer 2 formed by the first partial solder layer 2a and the second partial solder layer 2b, and the conductive metal layer 3 is arranged on a side surface of the second partial solder layer 2b away from the first partial solder layer 2a so that an active metal ceramic substrate E can be formed.

[0051] The conductive metal layer 3 can be a metal copper foil, a metal aluminum foil, or a copper-aluminum 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 can be, for example, 50 micrometers to 1200 micrometers, but the present disclosure is not limited thereto.

[0052] Step S150 includes performing a high-temperature vacuum sintering process to firmly brazing the conductive metal layer 3 to the ceramic substrate 1 through the metal solder layer 2 formed by the first partial solder layer 2a and the second partial solder layer 2b.

[0053] The operating temperature of the high-temperature vacuum sintering process is 600°C to 900°C, preferably 700°C to 900°C.

[0054] In the above high-temperature vacuum sintering process, it is worth mentioning that the active metal (such as Ti) in the first partial solder layer 2a can wet the surface of the ceramic substrate 1, and the active metal can react with a ceramic material (such as SiN) to form compounds such as titanium nitride (TiN), titanium silicon oxide (TiSi), or titanium disilicate (TiSi2). Thereby, the bonding force between the conductive metal layer 3 and the ceramic substrate 1 can be improved.

[0055] In addition, when in the high-temperature vacuum sintering process, the metallic tin (Sn) and metallic copper (Cu) in the second partial solder layer 2b melt and react in a fluid state, and as a result, the conductive metal layer 3 and the ceramic substrate 1 have a good bonding force.

[0056] For example, when the operating temperature of the high-temperature vacuum sintering process is higher than 600 °C, the metallic tin can first react with the metallic copper to form a Cu3Sn alloy. Furthermore, the Cu3Sn alloy can react with more metallic tin to form a Cu6Sn5 alloy. Thereby, the second partial solder layer 2b and the conductive metal layer 3 can be more firmly connected, and the bonding force between the conductive metal layer 3 and the ceramic substrate 1 can be improved.

[0057] According to the above configuration, the metal solder layer 2 can improve the bonding force between the ceramic substrate 1 and the conductive metal layer 3.

[0058] Note that since the metal solder layer 2 does not contain metallic silver (Ag), the problem of electromigration caused by silver residues in the related art can be effectively avoided, and the manufacturing cost can be reduced.

[0059] In addition, in this embodiment, the first partial solder layer 2a, the second partial solder layer 2b, and the conductive metal layer 3 are sequentially arranged only on one side surface of the ceramic substrate 1. However, the present disclosure is not limited thereto. For example, as shown in FIG. 3, in other embodiments of the present disclosure, on the other side surface of the ceramic substrate 1, another first partial solder layer 2a', another second partial solder layer 2b', and another conductive metal layer 3' can also be sequentially arranged. Thereby, an active metal ceramic substrate E' in which the metal solder layer 2 is arranged on each of both side surfaces of the ceramic substrate 1 can be formed.

Example

[0060] [Experimental Data and Test Results] Hereinafter, it will be described in detail with reference to Example 1. However, the present disclosure is not limited thereto.

[0061] The preparation method of Example 1 includes applying a first solder paste containing a first metal solder material and a first organic medium to the side surface of a ceramic substrate according to the conditions shown in Table 1, and drying this first solder paste at a high temperature to form a first partial solder layer. The first metal solder material is titanium (Ti) powder (i.e., an active metal), and the thickness of the first partial solder layer is 6 micrometers. In addition, the ceramic substrate is a silicon nitride ceramic substrate. Next, a second solder paste containing a second metal solder material and a second organic medium is applied to the first partial solder layer and dried at a high temperature to form a second partial solder layer. The second metal solder material contains tin (Sn) powder, copper (Cu) powder, and titanium (Ti) powder in a weight ratio of 37.5:57.5:5, and the thickness of the second partial solder layer is 18 micrometers. In each of the first solder paste and the second solder paste, the weight ratio of the metal solder material to the organic medium is 80:20. In the organic medium, the paste former is ethyl cellulose, the organic solvent is ethylene glycol butyl ether acetate, and the thixotropic agent is polyamide wax. The weight ratio of the paste former, the organic solvent, and the thixotropic agent is 25:60:15. The first solder paste and the second solder paste do not contain metallic silver. Then, a metal copper foil is further disposed on the second partial solder layer to form an active metal ceramic substrate. In Example 1, further, the active metal ceramic substrate is sintered at a high temperature in a vacuum at a brazing temperature of 855°C. Next, the temperature of the active metal ceramic substrate is lowered to room temperature, and a tensile strength test of the active metal ceramic substrate is performed.

[0062] Using the tensile strength test, the tensile strength between the metal copper foil and the ceramic substrate is measured in accordance with the JIS-C-6481 standard. The measurement temperature is 25°C. When the tensile strength exceeds 100 N / cm, it is evaluated that the bonding strength is good. If the tensile strength is in the range of 50 N / cm to 100 N / cm, the bonding strength is evaluated as normal. When the tensile strength is less than 50 N / cm, it is evaluated that the bonding strength is poor.

[0063]

Table 1

[0064] From the test results shown in Table 1, the active metal ceramic substrate of Example 1 has a tensile force of 106 N / cm and good tensile strength performance.

[0065] It is worth mentioning that the above-mentioned active metal ceramic substrate of Example 1 can have good tensile strength performance even if the metal solder layer does not contain metallic silver, which is a breakthrough from the limitation of using metallic silver in the active metal layer in the related art.

[0066] [Beneficial Effects of the Embodiment] In conclusion, in the method for manufacturing an active metal ceramic substrate provided by the present disclosure, "applying a first solder paste to the side surface of the ceramic substrate, drying the first solder paste to form a first partial solder layer, wherein the first solder paste is prepared by mixing a first metal solder material and a first organic medium, the first metal solder material contains a first active metal but does not contain metallic silver (Ag), and the thickness of the first partial solder layer is 1 micrometer to 10 micrometers", and "applying a second solder paste to the side surface of the first partial solder layer away from the ceramic substrate, drying the second solder paste to form a second partial solder layer, wherein the second solder paste is prepared by mixing a second metal solder material and a second organic medium, the second metal solder material contains metallic tin (Sn) and metallic copper (Cu), selectively contains a second active metal, the second metal solder material does not contain metallic silver (Ag), and the thickness of the second partial solder layer is 6 micrometers to 24 micrometers", whereby the metal solder layer of the active metal ceramic substrate does not require the use of metallic silver (Ag).

[0067] Due to the structures of the first partial solder layer and the second partial solder layer in the above-mentioned metal solder layer, the metal solder layer can improve the bonding strength between the ceramic substrate and the conductive metal layer. Since the metal solder layer does not contain metallic silver (Ag), it is worth mentioning that the problem of electromigration caused by silver residues in related technologies can be effectively avoided, and the manufacturing cost can be reduced.

[0068] Finally, the active metal ceramic substrate of the present disclosure can be applied to high-power modules for energy conversion, electric vehicles, and charging systems by etching circuit patterns on the ceramic substrate through exposure and development.

[0069] The above description of the exemplary embodiments of the present disclosure is presented for purposes of illustration and description only and is not intended to be exhaustive or to limit the present disclosure to the precise form disclosed. Many modifications and variations are possible in light of the above teachings.

[0070] The above embodiments are selected and described to enable other persons skilled in the art to utilize the present disclosure and various embodiments with various modifications suitable for the intended specific uses. Alternative embodiments will be apparent to those skilled in the art of the present disclosure without departing from the spirit and scope thereof.

Description of Reference Numerals

[0071] E, E’: Active metal ceramic substrate 1: Ceramic substrate 2: Metal solder layer 2a, 2a’: First partial solder layer 2b, 2b’: Second partial solder layer 3, 3’: Conductive metal layer T1, T21, T22, T3: Thickness

Claims

1. A method for manufacturing an active metal ceramic substrate, comprising: applying a first solder paste prepared by mixing a first metal solder material and a first organic medium to a side surface of a ceramic substrate, and drying the first solder paste to form a first partial solder layer, wherein the first metal solder material contains a first active metal and does not contain metallic silver (Ag), and the thickness of the first partial solder layer is 1 micrometer to 10 micrometers; applying a second solder paste prepared by mixing a second metal solder material and a second organic medium to a side surface of the first partial solder layer that is away from the ceramic substrate, and drying the second solder paste to form a second partial solder layer, wherein the second metal solder material contains metallic tin (Sn) and metallic copper (Cu), optionally contains a second active metal, does not contain metallic silver (Ag), and the thickness of the second partial solder layer is 6 micrometers to 24 micrometers; disposing a conductive metal layer on a side surface of the second partial solder layer that is away from the first partial solder layer to form the active metal ceramic substrate. A method comprising the above steps.

2. The method according to claim 1, further comprising performing a high-temperature vacuum sintering process to solder the conductive metal layer to the ceramic substrate through the first partial solder layer and the second partial solder layer.

3. The method according to claim 2, wherein the operating temperature of the high-temperature vacuum sintering process is 600°C to 900°C.

4. The method according to claim 1, wherein the thickness of the second partial solder layer is greater than the thickness of the first partial solder layer, and the thickness ratio of the second partial solder layer to the first partial solder layer is in the range of 1.5 to 5.

5. The method according to claim 1, wherein the thickness of the first partial solder layer is 1 micrometer to 6 micrometers, and the thickness of the second partial solder layer is 18 micrometers to 24 micrometers.

6. The first active metal is selected from the group consisting of titanium (Ti), zirconium (Zr), tantalum (Ta), niobium (Nb), vanadium (V), hafnium (Hf), titanium hydride (TiH ２ ), zirconium hydride (ZrH ２ ), tantalum hydride (TaH ２ ), niobium hydride (NbH), vanadium hydride (VH ２ ), and hafnium hydride (H ２ Hf ２ ). The second active metal is selected from the group consisting of titanium (Ti), zirconium (Zr), tantalum (Ta), niobium (Nb), vanadium (V), hafnium (Hf), titanium hydride (TiH ２ ), zirconium hydride (ZrH ２ ), tantalum hydride (TaH ２ ), niobium hydride (NbH), vanadium hydride (VH ２ ), and hafnium hydride (H ２ Hf ２ ) The method according to claim 1.

7. The method according to claim 1, wherein the first solder paste has a viscosity of 50 mPa·s to 300 mPa·s, and the second solder paste has a viscosity of 50 mPa·s to 300 mPa·s.

8. In the first solder paste, the first metal solder material is formed only by the first active metal, and the first organic medium includes a paste former, a thixotropic agent, and an organic solvent, and a weight ratio of the paste former, the thixotropic agent, and the organic solvent is 20 to 30: 1 to 5: 50 to 70. The method according to claim 1.

9. In the second solder paste, the second metal solder material is formed by the metal tin (Sn), the metal copper (Cu), and the second active metal, and a weight ratio of the metal tin (Sn), the metal copper (Cu), and the second active metal is 20 to 50: 40 to 70: 0.5 to 10, and the second organic medium includes a paste former, a thixotropic agent, and an organic solvent, and a weight ratio of the paste former, the thixotropic agent, and the organic solvent is 20 to 30: 1 to 5: 50 to 70. The method according to claim 1.

10. In the second metal solder material, a weight ratio of the metal tin (Sn), the metal copper (Cu), and the second active metal is 32.5 to 42.5: 52.5 to 62.5: 2 to 8. The method according to claim 9.

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