Metal-ceramic substrate having double brazing layers and method for manufacturing the same

Abstract

To provide a metal-ceramic substrate having double brazing layers with superior adhesive strength, and a method for manufacturing the same.SOLUTION: A first brazing layer is formed from a first active metal solder and an organic dispersion medium, and the first active metal solder includes silver, copper, and a first active metal. Based on a total weight of the first active metal solder being 100 wt.%, an amount of the silver ranges from 10 wt.% to 60 wt.%. A second brazing layer is formed from a second active metal solder and another organic dispersion medium, and the second active metal solder includes copper and a second active metal, but the second active metal solder is free of silver.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a metal ceramic substrate having a double brazing layer and a manufacturing method thereof, and more particularly to a metal ceramic substrate having a double brazing layer with excellent adhesive strength and a manufacturing method thereof. [Background technology]

[0002] Driven by energy conservation and carbon reduction policies in various countries, the global electric vehicle market is developing vigorously. In recent years, major automakers have been launching 800-volt high-voltage vehicles one after another, which has led to a rapid growth in the demand for silicon carbide (SiC) ceramic substrate materials. . Summary of the Invention [Problem to be solved by the invention]

[0003] However, the electrical characteristics of power components that use silicon carbide (SiC) ceramic substrate materials As pressure, frequency, and operating temperature requirements increase, ceramic substrate materials are being required to provide better heat dissipation capabilities and reliability.

[0004] Conventionally, the widely used direct-bonding-copper (DBC) ceramic substrate is fabricated by the eutectic bonding method, and no bonding material exists between the copper layer and the ceramic substrate.

[0005] However, during high temperature operation, the copper layer and the ceramic substrate (Al 2 O 3 Due to the difference in thermal expansion coefficient between copper and ceramic materials (such as AlN), large thermal stress is often generated, which causes the copper layer to peel off from the surface of the ceramic substrate. Therefore, traditional copper direct bonded ceramic substrates cannot meet the packaging requirements of high temperature, high power, high heat dissipation, and high reliability.

[0006] The current mainstream substrate materials are gradually shifting from copper direct bonding ceramic substrates to active metal brazing (AMB) substrate materials.

[0007] Common active metal brazing substrate materials usually contain metallic silver. The silver content of active metal brazing substrate materials usually exceeds 50% by weight (weight% concentration), and in some cases, it can even reach 70%. However, when the silver content is high, the cost of active metal brazing ceramic substrate materials increases, and there are concerns about electromigration in the silver within the solder layer.

[0008] Therefore, in order to overcome the above-mentioned drawbacks, how to reduce the silver content in the solder layer by improving the composition and structural design of the solder layer has become one of the important issues in this technical field.

[0009] In view of the above technical problems and considering the drawbacks of the prior art, an object of the present invention is to provide a metal ceramic substrate having a double brazing layer and a manufacturing method thereof.

Means for Solving the Problems

[0010] In view of the above problems, the present invention has the following configuration.

[0011] 1. A metal ceramic substrate comprising a ceramic substrate layer and a double brazing layer including an active metal layer and a conductive metal layer, wherein the active metal layer includes a first brazing layer and a second brazing layer, the first brazing layer is formed from a first active metal solder and an organic dispersion medium, the first active metal solder includes metallic silver, metallic copper, and a first active metal, and when the total weight of the first active metal solder is 100% by weight, the silver content is 10% - 60% by weight, the second brazing layer is formed from a second active metal solder and another organic dispersion medium, the second active metal solder includes metallic copper and a second active metal, and the second active metal solder does not include metallic silver, The conductive metal layer is provided with the active metal layer between the ceramic substrate layer and the conductive metal layer. The first brazing layer is in contact with the ceramic substrate layer, and the second brazing layer is in contact with the conductive metal layer. A metal-ceramic substrate having a double brazing layer, characterized by the above.

[0012] 2. Also, in the first active metal solder, the weight ratio of the metallic silver to the metallic copper is greater than 1. A metal-ceramic substrate having a double brazing layer according to 1, characterized by the above.

[0013] 3. Also, when the total weight of the first active metal solder is 100% by weight, the content of the first active metal is 2 to 4% by weight. A metal-ceramic substrate having a double brazing layer according to 1 or 2, characterized by the above.

[0014] 4. Also, when the total weight of the second active metal solder is 100% by weight, the content of the metallic copper is not higher than 95% by weight. A metal-ceramic substrate having a double brazing layer according to any one of 1 to 3, characterized by the above.

[0015] 5. Also, the ratio of the thickness of the first brazing layer to the second brazing layer is 1:1 to 1:2. A metal-ceramic substrate having a double brazing layer according to any one of 1 to 4, characterized by the above.

[0016] 6. Also, a part of the metallic silver in the first brazing layer diffuses to the joint surface between the first brazing layer and the second brazing layer to form a silver-copper alloy. A metal-ceramic substrate having a double brazing layer according to any one of 1 to 5, characterized by the above.

[0017] 7. Also, a part of the first active metal in the first brazing layer diffuses to the joint surface between the first brazing layer and the ceramic substrate layer to form an alloy. A metal-ceramic substrate comprising the double brazing layer according to any one of 1 to 6, characterized in that...

[0018] 8. Further, a part of the second active metal in the second brazing layer diffuses to the joint surface between the second brazing layer and the first brazing layer to form an alloy. A metal-ceramic substrate comprising the double brazing layer according to any one of 1 to 7, characterized in that...

[0019] 9. Further, a part of the second active metal in the second brazing layer diffuses to the joint surface between the second brazing layer and the conductive metal layer to form an alloy. A metal-ceramic substrate comprising the double brazing layer according to any one of 1 to 8, characterized in that...

[0020] 10. Also, a first active metal solder paste is applied onto the ceramic substrate to form a first brazing layer on the ceramic substrate. The first active metal solder paste contains a first active metal solder and an organic dispersion medium. The first active metal solder contains metallic silver, metallic copper, and a first active metal. The total weight of the first active metal solder is 100% by weight, and the content of the metallic silver is 10 to 60% by weight. A second active metal solder paste is applied onto the first brazing layer to form a second brazing layer on the first brazing layer. The second active metal solder paste contains a second active metal solder and another organic dispersion medium. The second active metal solder contains metallic copper and a second active metal, and does not contain metallic silver. A conductive metal layer is provided on the second brazing layer, and a brazing process is performed to obtain a metal-ceramic substrate having a double brazing layer. The first active metal solder paste contains a first active metal solder and an organic dispersion medium. The first active metal solder contains metallic silver, metallic copper, and a first active metal. The total weight of the first active metal solder is 100% by weight, and the content of the metallic silver is 10 to 60% by weight. The total weight of the first active metal solder is 100% by weight, and the content of the metallic silver is 10 to 60% by weight. A second active metal solder paste is applied onto the first brazing layer to form a second brazing layer on the first brazing layer. The second active metal solder paste contains a second active metal solder and another organic dispersion medium. The second active metal solder contains metallic copper and a second active metal, and does not contain metallic silver. A conductive metal layer is provided on the second brazing layer, and a brazing process is performed to obtain a metal-ceramic substrate having a double brazing layer. A method for manufacturing a metal-ceramic substrate having a double brazing layer, characterized in that...

Advantages of the Invention

[0021] As a beneficial effect of the present invention, according to the metal ceramic substrate with a double brazing layer provided by the present invention and its manufacturing method, the first active metal solder contains metallic silver, metallic copper, and a first active metal. When the total weight of the first active metal solder is 100% by weight, the content of metallic silver is 10 to 60% by weight. And the second active metal solder contains metallic copper and a second active metal, and the second active metal solder does not contain metallic silver. Therefore, the bonding strength between the ceramic substrate layer and the conductive metal layer can be improved.

[0022] For a clearer understanding of the features and technical content of the present invention, please refer to the following detailed description and drawings related to the present invention. However, the attached drawings are merely illustrative for ease of understanding and do not limit the present invention to the content of the attached drawings.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Embodiments for Carrying out the Invention

[0024] The following shows a specific example for explaining the implementation of the "metal ceramic substrate with a double brazing layer" introduced in the present invention. A person skilled in the art can understand the advantages and effects of the present invention from the content described in this specification.

[0025] The present invention may be implemented or applied through other different specific embodiments. Various detailed descriptions in this embodiment can be modified and changed in various ways based on various viewpoints and applications without departing from the concept of the present invention. However, the inventions with such modifications and changes are also considered to belong to the technical scope of the present invention. Also, as previously described, the drawings of the present invention are merely schematic diagrams and are not necessarily drawn based on actual dimensions.

[0026] The following embodiments will further elaborate on the related technical content of the present invention, but the content described herein is not intended to limit the scope of the present invention. Furthermore, the term "or" used in this embodiment includes any one or a combination of multiple relevant listed items according to the actual situation.

[0027] In order to overcome the differences in the thermal expansion coefficients of conventional copper-directly bonded ceramic substrates and solve the problem that the copper layer is easily peeled off from the ceramic substrate, the present invention provides a metal-ceramic substrate with a double brazing layer.

[0028] In the metal-ceramic substrate, by using the first active metal solder paste and the second active metal solder paste, a good bonding force between the copper layer and the ceramic substrate is ensured.

[0029] Therefore, the metal-ceramic substrate with a double brazing layer can be applied to some packaging structures with requirements for high temperature, high power, and high reliability. In this specification, for the convenience of comparison, the bonding force between the copper layer and the ceramic substrate is quantified as the tensile strength of the metal-ceramic substrate.

[0030] Referring to FIG. 1, the metal-ceramic substrate with a double brazing layer of the present invention includes a ceramic substrate layer 1, an active metal layer 2, and a conductive metal layer 3. The active metal layer 2 is provided between the ceramic substrate layer 1 and the conductive metal layer 3 and has the effect of bonding the ceramic substrate layer 1 and the conductive metal layer 3.

[0031] The active metal layer 2 includes a first brazing layer 21 and a second brazing layer 22. The first brazing layer 21 is in contact with the ceramic substrate layer 1, and the second brazing layer 22 is in contact with the conductive metal layer 3.

[0032] In FIG. 1, the active metal layer 2 and the conductive metal layer 3 are provided only on one side of the ceramic substrate layer 1. However, the metal ceramic substrate of the present invention is not limited thereto. As shown in FIG. 2, the active metal layer 2 and the conductive metal layer 3 can also be provided on both opposite sides of the ceramic substrate layer 1.

[0033] Referring to FIG. 2, a metal ceramic substrate provided with a double brazing layer can be formed into a symmetric structure. On both sides of the ceramic substrate layer 1, the first brazing layers 21, 21', the second brazing layers 22, 22', and the conductive metal layers 3, 3' are respectively provided. In this way, a package structure having conductive layers on both sides can be manufactured using the metal ceramic substrate.

[0034] <Ceramic substrate layer> The ceramic substrate layer 1 can be a silicon nitride (SiN) ceramic substrate, a silicon carbide (SiC) ceramic substrate, an aluminum nitride (AlN) ceramic substrate, or an alumina (Al 2 O 3 ) ceramic substrate, preferably a silicon-containing ceramic substrate, more preferably a silicon nitride ceramic substrate. Also, the thickness of the ceramic substrate layer 1 can be 100 microns to 1000 microns, but the present invention is not limited thereto.

[0035] <Active metal layer> By providing the active metal layer 2, the bonding strength between the ceramic substrate layer 1 and the conductive metal layer 3 can be improved. If the thickness of the active metal layer 2 is too thin, the bonding strength between the ceramic substrate layer 1 and the conductive metal layer 3 will decrease. If the thickness of the active metal layer 2 is too thick, the material cost of the active metal layer 2 will be too high and it is not suitable for mass production.

[0036] Therefore, the thickness of the active metal layer 2 is 6 microns or more, the thickness of the active metal layer 2 is 10 microns to 30 microns, for example, the thickness of the active metal layer 2 may be 12 microns, 14 microns, 16 microns, 18 microns, 20 microns, 22 microns, 24 microns, 26 microns or 28 microns. Further, it is more preferable that the thickness of the active metal layer 2 is 18 microns to 24 microns.

[0037] In addition, the ratio of the thickness of the first brazing layer 21 to the second brazing layer 22 in the active metal layer 2 may be 1:1 to 1:2, but in order to achieve the desired effect at a lower material cost, the present invention is not limited thereto.

[0038] <The first brazing layer> The first brazing layer 21 is formed from a first active metal solder and an organic dispersion medium.

[0039] The first active metal solder contains metallic silver (Ag), metallic copper (Cu), and (the first active metal). The content of metallic silver (Ag) is more than the content of metallic copper (Cu), and the content of metallic copper (Cu) is more than the content of the first active metal.

[0040] The total weight of the first active metal solder is 100% by weight, and the content of metallic silver is 10 to 60% by weight. From this, it can be seen that the silver content in the active metal solder of the present invention is relatively low. Therefore, the material cost of the metal-ceramic substrate provided with the double brazing layer can be reduced, and the probability of electron migration of metallic silver can also be reduced.

[0041] Specifically, when the total weight of the first active metal solder is 100% by weight, the content of metallic silver may be 15% by weight, 20% by weight, 25% by weight, 30% by weight, 35% by weight, 40% by weight, 45% by weight, 50% by weight or 55% by weight.

[0042] During the vacuum sintering process, a part of the metallic silver in the first brazing layer 21 can diffuse to the joint surface between the first brazing layer 21 and the second brazing layer 22, and form an alloy with the metal atoms in the second brazing layer 22.

[0043] Thereby, the bonding force between the first brazing layer 21 and the second brazing layer 22 can be further enhanced. For example, the metallic silver in the first brazing layer 21 can form a silver-copper alloy with the metallic copper in the second brazing layer 22.

[0044] In this embodiment, when the total weight of the first active metal solder is 100% by weight, the content of metallic copper is 30 - 80% by weight, and the content of the first active metal is 1 - 10% by weight.

[0045] Specifically, the content of metallic copper can be 35% by weight, 40% by weight, 45% by weight, 50% by weight, 55% by weight, 60% by weight, 65% by weight, 70% by weight, or 75% by weight.

[0046] Specifically, the content of the first active metal may be 2% by weight, 4% by weight, 6% by weight, or 8% by weight. Preferably, when the total weight of the first active metal solder is 100% by weight, the content of the first active metal is 2 - 4% by weight.

[0047] It should be noted that the first active metal has a low melting point and preferentially forms a molten state during the vacuum sintering process. Therefore, it helps to fill the defects of the ceramic substrate layer 1 or the second brazing layer 22, and in extreme cases, it can also react with the ceramic substrate layer 1 or the second brazing layer 22. On the other hand, by adding the first active metal, the electrical impedance of the first brazing layer 21 can also be reduced.

[0048] Specifically, the first active metal is selected from the group consisting of metallic titanium (Ti), metallic zirconium (Zr), metallic tantalum (Ta), metallic niobium (Nb), metallic vanadium (V), and metallic hafnium (Hf).

[0049] During the vacuum sintering process, a portion of the first active metal can diffuse to the joint surface (interface) between the first brazing layer 21 and the ceramic substrate layer 1, whereby metal silicides or metal nitrides formed by silicon atoms or nitrogen atoms are formed in the ceramic substrate layer 1.

[0050] Similarly, a portion of the first active metal may also diffuse to the joint surface between the first brazing layer 21 and the second brazing layer 22 and react to form an alloy. In this way, a good joining effect can be obtained between the ceramic substrate layer 1 and the conductive metal layer 3.

[0051] In a preferred embodiment, the first active metal is titanium metal. For example, during the vacuum sintering process, after titanium metal diffuses into the ceramic substrate layer 1, it combines with silicon atoms or nitrogen atoms to form titanium silicide (TiSi), or titanium nitride (TiN), or titanium disilicate (TiSi 2 ). In addition, after titanium metal diffuses into the second brazing layer 22, it can form a titanium-copper alloy with copper atoms in the second brazing layer 22, but the present invention is not limited thereto.

[0052] <The second brazing layer> The second brazing layer 22 is formed from a second active metal solder and other organic dispersion media. The second brazing layer 22 is provided between the first brazing layer 21 and the conductive metal layer 3 to prevent problems caused by electron transfer of metallic silver in the first brazing layer 21 to the conductive metal layer 3.

[0053] The second active metal solder contains metallic copper (Cu) and a second active metal, and the second active metal solder does not contain metallic silver (Ag). Among these, the content of metallic copper (Cu) is more than the content of the second active metal. When the total weight of the second active metal solder is 100% by weight, the content of metallic copper does not exceed 95% by weight.

[0054] Specifically, the content of metallic copper can be 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 85 wt%, or 90 wt%.

[0055] During the vacuum sintering process, a part of the metallic copper in the second brazing layer 22 diffuses to the joint surface between the first brazing layer 21 and the second brazing layer 22 and can form an alloy with the metal atoms in the first brazing layer 21. Thereby, the bonding force between the first brazing layer 21 and the second brazing layer 22 can be further increased.

[0056] For example, the metallic copper in the second brazing layer 22 may form a silver-copper alloy with the metallic silver in the first brazing layer 21.

[0057] In this embodiment, assuming that the total weight of the second active metal solder is 100 wt%, the content of the second active metal is 1 - 10 wt%.

[0058] Specifically, the content of the second active metal may be 2 wt%, 4 wt%, 6 wt%, or 8 wt%. Preferably, when the total weight of the second active metal solder is 100 wt%, the content of the second active metal is 2 - 4 wt%.

[0059] It should be noted that the second active metal has a low melting point and preferentially forms a molten state during the vacuum sintering process. Therefore, it helps to fill the defects in the first brazing layer 21 or the conductive metal layer 3, and in extreme cases, it can react with the first brazing layer 21 or the conductive metal layer 3. On the other hand, by adding the second active metal, the electrical impedance of the second brazing layer 22 can also be reduced.

[0060] Specifically, the second active metal is metallic titanium (Ti), metallic zirconium (Zr), metallic tantalum (Ta), metallic niobium (Nb), metallic vanadium (V), and metallic hafnium It is selected from the group consisting of (Hf).

[0061] During the vacuum sintering process, a part of the second active metal can diffuse to the joint surface between the first brazing layer 21 and the second brazing layer 22 and form an alloy with the metal atoms of the first brazing layer 21.

[0062] Also, a part of the second active metal in the second brazing layer 22 can diffuse to the joint surface between the second brazing layer 22 and the conductive metal layer 3 and form an alloy with the metal atoms in the conductive metal layer 3. In this way, a good bonding effect can be obtained between the ceramic substrate layer 1 and the conductive metal layer 3.

[0063] In a preferred embodiment, the second active metal is metallic titanium. For example, during the vacuum sintering process, after metallic titanium diffuses into the first brazing layer 21, a titanium-copper alloy can be formed with the copper atoms in the first brazing layer 21.

[0064] Also, after metallic titanium diffuses into the conductive metal layer 3, a titanium-copper alloy can be formed with the copper atoms in the conductive metal layer 3, but it is not limited thereto.

[0065] <Conductive metal layer> The conductive metal layer 3 is provided on the ceramic substrate layer 1 via the active metal layer 2. Specifically, examples of the conductive metal layer 3 include a metallic copper foil, a metallic aluminum foil, or a copper-aluminum alloy foil. In a preferred embodiment, the conductive metal layer 3 is preferably a metallic copper foil.

[0066] Also, the thickness of the conductive metal layer 3 is 50 μm to 1200 μm, preferably 200 μm to 800 μm, but it is not limited thereto.

[0067] <Method for manufacturing a metal-ceramic substrate provided with a double brazing layer> In step S1, first, a first active metal solder paste for forming the first soldering layer 21 is prepared. The first active metal solder paste contains the first active metal solder and an organic dispersion medium.

[0068] The first active metal solder contains the aforementioned metallic silver, metallic copper, and a first active metal. In a plurality of embodiments, the first active metal solder is a combination of metallic silver powder, metallic copper powder, and active metal powder.

[0069] In other embodiments, the first active metal solder may be a combination of at least one of metallic silver powder, metallic copper powder, and silver-copper alloy powder and the first active metal powder.

[0070] As described above, the content of metallic silver in the first active metal solder is 10 to 60% by weight (when the total weight of the first active metal solder is 100% by weight). And the weight ratio of metallic silver (Ag) to metallic copper (Cu) is greater than 1, and the weight ratio of metallic copper (Cu) to the first active metal is greater than 1.

[0071] The organic dispersion medium can assist in the dispersion of the first active metal solder and help to form the first active metal solder paste into the active metal layer 2. Specifically, examples of the organic dispersion medium include a paste former, an organic solvent, and a thixotropic agent, etc. are included.

[0072] When the total weight of the organic dispersion medium is 100% by weight, the content of the ointment (paste) former is 20 to 30% by weight, the content of the organic solvent is 50 to 70% by weight, and the content of the thixotropic agent is 1 to 5% by weight.

[0073] For example, the ointment 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 ointment former is ethyl cellulose.

[0074] The organic solvent is a group of glycol ethers that 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. Preferably, the organic solvent is terpineol or ethylene glycol butyl ether acetate.

[0075] 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.

[0076] After mixing the first active metal solder and the organic dispersion medium at a weight ratio of 70% - 95%:5% - 30%, a first active metal solder paste having a viscosity of 50 mPa·s - 300 mPa·s is formed. Preferably, the weight ratio of the first active metal solder to the organic dispersion medium is 75% - 90%:10% - 25%.

[0077] However, the present invention is not limited to the above embodiments as long as the first active solder powder and the organic components can be prepared into a first active solder paste having a viscosity suitable for coating on the ceramic substrate layer 1. That is, in order to facilitate the formation of the first soldering layer 21, as long as it conforms to the protective spirit of the present invention, it belongs to the technical scope of the present invention.

[0078] In step S2, the first active metal solder paste is applied onto the ceramic substrate layer 1 by screen printing and dried at a temperature of 90°C - 110°C for 5 minutes - 15 minutes, so that most of the organic solvents in the first active metal solder paste volatilize, and the first soldering layer 21 is formed.

[0079] In step S3, a second active metal solder paste is prepared, and the second active metal solder paste is used to form the above-mentioned second brazing layer 22. The second active metal solder paste contains the above-mentioned second active metal solder and an organic dispersion medium.

[0080] The second active metal solder contains the aforementioned metallic copper and a second active metal. In a plurality of embodiments, the second active metal solder is a combination of metallic copper powder and a second active metal powder.

[0081] As described above, the content of metallic copper in the second active metal solder is not less than 85% by weight, and the second active metal solder (based on the case where the total weight of the second active metal solder is 100% by weight) has a higher metallic copper content than the second active metal powder. is based).

[0082] The organic dispersion medium can assist in the dispersion of the second active metal solder and help the second active metal solder paste to form the second brazing layer 22. Specifically, the organic dispersion medium includes the above-mentioned paste former, organic solvent, and thixotropic agent, but no further details will be described here.

[0083] After mixing the second active metal solder and the organic dispersion medium at a weight ratio of 70% - 95%: 5% - 30%, a second active metal solder paste with a viscosity of 50 mPa·s - 300 mPa·s is formed. Preferably, the weight ratio of the second active metal solder to the organic dispersion medium is 75% - 90%: 10% - 25%.

[0084] However, the present invention is not limited to the above embodiments. As long as the second active solder powder and the organic component can be blended into a second active solder paste having a viscosity suitable for coating on the first brazing layer 21 to facilitate the formation of the second brazing layer 22 and conform to the spirit of protection of the present invention, it shall be deemed to belong to the technical scope of the present invention.

[0085] In step S4, the second active metal solder paste may be applied onto the first brazing layer 21 by screen printing. It is dried at a temperature of 90°C to 110°C for 5 to 15 minutes. As a result, most of the organic solvents in the second active metal solder paste volatilize, thereby forming the second brazing layer 22.

[0086] In step S5, a conductive metal layer 3 is provided on the second brazing layer 22, and a brazing process is performed to fix the conductive metal layer 3 onto the ceramic substrate layer 1.

[0087] The brazing process consists of a first-stage heat treatment process and a second-stage heat treatment process that can be carried out in a vacuum environment.

[0088] The temperature condition of the first-stage heat treatment process is 500°C or lower, and the temperature condition of the second-stage heat treatment process is 900°C to 1100°C (brazing temperature range). The temperature of the second-stage heat treatment process is higher than the temperature of the first-stage heat treatment process.

[0089] Specifically, the temperature condition of the first-stage heat treatment process is 300°C to 500°C, and the treatment time is 30 to 60 minutes. The temperature condition of the second-stage heat treatment process is 900°C to 960°C, and the treatment time is 60 to 240 minutes.

[0090] Also, the heating rate of the above stage heat treatment process can be, for example, 5°C / min to 30°C / min. The cooling rate after the vacuum sintering is completed can be, for example, 2°C / min to 30°C / min.

[0091] During the brazing process, a part of the organic dispersion medium evaporates, the first active metal wets the surface of the ceramic substrate layer 1, and at the same time, it reacts with the ceramic substrate layer 1 to enhance the bonding force between the active metal layer 2 and the ceramic substrate layer 1.

[0092] Also, a eutectic reaction on the micron scale occurs at the bonding surface between the second active metal and the metal component of the conductive metal layer 3, and a strong eutectic structure is formed to firmly bond the active metal layer 2 and the conductive metal layer 3.

[0093] <Test Examples 1 to 6> In order to compare the effects of the composition and soldering temperature of the first soldering layer 21 and the second soldering layer 22 on the tensile strength of the metal ceramic substrate, metal ceramic substrates of Test Examples 1 to 6 were produced based on the above-described steps S1 to S5.

[0094] The metal ceramic substrates of Test Examples 1 to 6 have a ceramic substrate layer 1 made of a silicon nitride ceramic substrate, the first soldering layer 21 has a thickness of 12 microns, the second soldering layer 22 has a thickness of 12 microns, and the conductive metal layer 3 is a copper metal layer.

[0095] When preparing the first active metal solder paste, ethyl cellulose is used as the paste former, ethylene glycol butyl ether acetate is used as the organic solvent, and polyamide wax is used as the thixotropic agent. When the total weight of the organic dispersion medium is 100% by weight, the organic dispersion medium contains 25% by weight of the paste former, 60% by weight of the organic solvent, and 2.5% by weight of the thixotropic agent.

[0096] When preparing the second active metal solder paste, ethyl cellulose is used as the paste former. Ethylene glycol butyl ether acetate is used as the organic solvent, and polyamide wax is used as the thixotropic agent.

[0097] When the total weight of the organic dispersion medium is 100% by weight, the organic dispersion medium contains 25% by weight of the paste former, 60% by weight of the organic solvent, and 2.5% by weight of the thixotropic agent.

[0098] The specific components of the first soldering layer 21 and the second soldering layer 22, and the soldering temperature in the soldering process are shown in Table 1. Also, the tensile strength of the metal ceramic substrate was measured at a temperature of 25°C in accordance with the JIS-C-6481 standard, and the results are shown in Table 1.

[0099]

Table 1

[0100] According to the results in Table 1, when the first brazing layer 21 contains metallic silver (10 wt% - 60 wt%) and the second brazing layer 22 does not contain metallic silver, the tensile strength of the double brazed layer of the metal ceramic substrate may exceed 200 N / cm.

[0101] Even at a lower brazing temperature (900°C - 960°C), the metal ceramic substrate with a double brazing layer can still maintain the expected tensile strength.

[0102] [Beneficial Effects of the Embodiment] One of the advantageous effects of the present invention is that the metal ceramic substrate having a double brazing layer provided by the present invention and its manufacturing method have the technical features that "the first active metal solder contains metallic silver, metallic copper, and the first active metal", "assuming that the total weight of the first active metal solder is 100 wt%, the content of metallic silver is 10 - 60 wt%", and "the second active metal solder contains metallic copper and the second active metal, and does not contain metallic silver", thereby improving the bonding strength between the ceramic substrate layer and the conductive metal layer.

[0103] The above-described content is only a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, all technical modifications made with reference to the specification and drawings of the present invention are equivalent to the present invention and are included in the technical scope of the present invention.

Explanation of Reference Numerals

[0104] 1 Ceramic substrate layer 2, 2' Active metal layer 21, 21' First brazing layer 22, 22' Second brazing layer 3, 3' Conductive metal layer​​

Claims

1. A metal ceramic substrate having a dual braze layer including a ceramic substrate layer, an active metal layer, and a conductive metal layer, the active metal layer includes a first braze layer and a second braze layer; The first brazing layer is formed from a first active metal solder and an organic dispersion medium, the first active metal solder includes metallic silver, metallic copper, and a first active metal, and the content of the metallic silver is 10 wt% to 60 wt% when the total weight of the first active metal solder is 100 wt%; the second brazing layer is formed from a second active metal solder and another organic dispersion medium, the second active metal solder includes metallic copper and a second active metal, and the second active metal solder does not include metallic silver; The conductive metal layer is such that the active metal layer is provided between the ceramic substrate layer and the conductive metal layer, the first brazing layer is in contact with the ceramic substrate layer, and the second brazing layer is in contact with the conductive metal layer. A metal-ceramic substrate having a double brazing layer,

2. In the first active metal solder, the weight ratio of the metallic silver to the metallic copper is greater than 1.

2. The metal-ceramic substrate with double brazing layers according to claim 1.

3. When the total weight of the first active metal solder is 100% by weight, the content of the first active metal is 2 to 4% by weight.

2. The metal-ceramic substrate with double brazing layers according to claim 1.

4. When the total weight of the second active metal solder is 100 wt %, the content of the metallic copper is not higher than 95 wt %.

2. The metal-ceramic substrate with double brazing layers according to claim 1.

5. The thickness ratio of the first brazing layer to the second brazing layer is 1:1 to 1:

2.

2. The metal-ceramic substrate with double brazing layers according to claim 1.

6. A portion of the metallic silver in the first brazing layer diffuses to a joint surface between the first brazing layer and the second brazing layer to form a silver-copper alloy.

2. The metal-ceramic substrate with double brazing layers according to claim 1.

7. A portion of the first active metal in the first brazing layer diffuses to the bonding surface of the first brazing layer and the ceramic substrate layer to form an alloy.

2. The metal-ceramic substrate with double brazing layers according to claim 1.

8. A portion of the second active metal in the second brazing layer diffuses to the joint surface between the second brazing layer and the first brazing layer to form an alloy.

2. The metal-ceramic substrate with double brazing layers according to claim 1.

9. A portion of the second active metal in the second brazing layer diffuses to a joining surface of the second brazing layer and the conductive metal layer to form an alloy.

2. The metal-ceramic substrate with double brazing layers according to claim 1.

10. applying a first active metal solder paste onto a ceramic substrate to form a first braze layer on the ceramic substrate; the first active metal solder paste includes a first active metal solder and an organic dispersing medium; The first active metal solder includes metallic silver, metallic copper, and a first active metal, the total weight of the first active metal solder is 100% by weight, and the content of the metallic silver is 10 to 60% by weight; applying a second active metal solder paste onto the first brazing layer to form a second brazing layer on the first brazing layer; The second active metal solder paste includes a second active metal solder and another organic dispersing medium, the second active metal solder includes metallic copper and a second active metal, and the second active metal solder does not include metallic silver; A conductive metal layer is placed on the second brazing layer, and a brazing process is performed to obtain a metal-ceramic substrate with a double brazing layer.

1. A method for manufacturing a metal-ceramic substrate having a double brazing layer, comprising:

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