Metal ceramic substrate with double brazing layer and manufacturing method thereof

Abstract

A metal ceramic substrate having a double brazing layer with excellent adhesion and a method for manufacturing the same. [Solution] The first brazing layer is formed from 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, and when the total weight of the first active metal solder is 100% by weight, the content of metallic silver is 10% by weight to 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 contains metallic copper and a second active metal, and the second active metal solder does not contain metallic silver.

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 difference in thermal expansion coefficient between the copper layer and the ceramic substrate (such as Al2O3 or AlN) often generates large thermal stress, 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] Currently, the mainstream substrate material is gradually shifting from copper direct bonded 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 is usually more than 50% by weight (weight percent concentration), and even up to 70%. However, high silver content increases the cost of active metal brazing ceramic substrate materials, and there are concerns about electromigration of silver in the solder layer.

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

[0009] SUMMARY OF THE PRESENT DISCLOSURE In view of the above technical problems and taking into account the shortcomings of the prior art, the present invention aims to provide a metal-ceramic substrate with a double brazing layer and a manufacturing method thereof. [Means for solving the problem]

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

[0011] 1. A metal-ceramic substrate having a dual brazing layer including a ceramic substrate layer, an active metal layer, and a conductive metal layer, 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 the content of the metallic silver is 10% by weight to 60% by weight when the total weight of the first active metal solder is 100% 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 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, characterized in that

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

[0013] 3. If 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. 3. A metal-ceramic substrate having a double brazing layer according to claim 1 or 2.

[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. 4. A metal ceramic substrate having a double brazing layer according to any one of 1. to 3. above.

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

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

[0017] 7. Also, a portion of the first active metal in the first brazing layer diffuses to the bonding surface between the first brazing layer and the ceramic substrate layer to form an alloy. 7. A metal ceramic substrate having a double brazing layer according to any one of 1. to 6.

[0018] 8. Also, 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. 8. A metal ceramic substrate having a double brazing layer according to any one of 1. to 7.

[0019] 9. Also, the second active metal in a portion of the second brazing layer diffuses to the joining surface between the second brazing layer and the conductive metal layer to form an alloy. 9. A metal ceramic substrate having a double brazing layer according to any one of 1. to 8. above.

[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 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, and the first active metal solder includes a first active metal solder and an organic dispersing medium. The total weight of the conductive 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 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; 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. 2. A method for manufacturing a metal-ceramic substrate having a double brazing layer, comprising: Effect of the Invention

[0021] The beneficial effects of the present invention include that, according to the metal ceramic substrate with a double brazing layer and the manufacturing method thereof provided by the present invention, the first active metal solder contains 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 content of metallic silver is 10 to 60% by weight, and the second active metal solder contains metallic copper and a second active metal, but does not contain metallic silver, thereby improving the bonding strength between the ceramic substrate layer and the conductive metal layer.

[0022] In order to more clearly understand the features and technical contents of the present invention, please refer to the following detailed description of the present invention and the drawings. However, the attached drawings are merely illustrative for ease of understanding, and the present invention is not limited to the contents of the attached drawings. [Brief description of the drawings]

[0023] [Figure 1] FIG. 2 is a schematic side view of a metal-ceramic substrate with a dual braze layer of the present invention. [Diagram 2] FIG. 2 is a schematic side view of a metal-ceramic substrate with dual brazing layers according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] The following is a specific example for illustrating the implementation of the "metal-ceramic substrate with double brazing layers" introduced in the present invention. Those skilled in the art can understand the advantages and effects of the present invention from the contents described in this specification.

[0025] The present invention may be implemented or applied through other different specific embodiments. Various detailed descriptions in this embodiment may be modified and changed in various ways based on various viewpoints and applications without departing from the concept of the present invention, and such modified inventions are also within the technical scope of the present invention. In addition, as previously mentioned, the drawings of the present invention are merely schematic diagrams and are not necessarily drawn based on actual size.

[0026] The following embodiments will further describe the technical contents related to the present invention in detail, but the contents described therein are not intended to limit the scope of the present invention. Moreover, the term "or" used in the embodiments includes any one or more combinations of the relevant listed items according to the actual situation.

[0027] In order to overcome the difference in thermal expansion coefficient of traditional copper direct bonded ceramic substrate 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 double brazing layers.

[0028] For metal-ceramic substrates, the first active metal solder paste and the second active metal solder paste are The use of a solder ensures good adhesion between the copper layer and the ceramic substrate.

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

[0030] 1, the metal ceramic substrate with double brazing layers 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 disposed 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 contacts the ceramic substrate layer 1, and the second brazing layer 22 contacts the conductive metal layer 3.

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

[0033] 2, the metal-ceramic substrate with double brazing layers can be a symmetrical structure. The ceramic substrate layer 1 is provided on both sides with a first brazing layer 21, 21', a second brazing layer 22, 22' and a conductive metal layer 3, 3', respectively. In this way, the metal-ceramic substrate can be used to manufacture a package structure with conductive layers on both sides.

[0034] <Ceramic substrate layer> The ceramic substrate layer 1 may be a silicon nitride (SiN) ceramic substrate, a silicon carbide (SiC) ceramic substrate, an aluminum nitride (AlN) ceramic substrate, or an alumina (Al2O3) ceramic substrate, preferably a silicon-containing ceramic substrate, more preferably a silicon nitride ceramic substrate. The thickness of the ceramic substrate layer 1 may be 100 microns to 1000 microns, but the present invention is not limited thereto.

[0035] <Active metal layer> Providing the active metal layer 2 can improve the bonding strength between the ceramic substrate layer 1 and the conductive metal layer 3. If the active metal layer 2 is too thin, the bonding strength between the ceramic substrate layer 1 and the conductive metal layer 3 decreases. If the active metal layer 2 is too thick, the material cost of the active metal layer 2 becomes too high and it is not suitable for mass production.

[0036] For this reason, the thickness of the active metal layer 2 is 6 microns or more, and the thickness of the active metal layer 2 is 10 microns to 30 microns, and may be, for example, 12 microns, 14 microns, 16 microns, 18 microns, 20 microns, 22 microns, 24 microns, 26 microns, or 28 microns. Moreover, the thickness of the active metal layer 2 is more preferably 18 microns to 24 microns.

[0037] In addition, the thickness ratio 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 the present invention is not limited to this in order to achieve the desired effect at lower material costs.

[0038] <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 includes metallic silver (Ag), metallic copper (Cu), and (first active metal). The content of metallic silver (Ag) is greater than the content of metallic copper (Cu), and the content of metallic copper (Cu) is greater 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 10-60% by weight. This shows that the content of silver in the active metal solder of the present invention is relatively low, which can reduce the material cost of the metal ceramic substrate with the double brazing layer and also reduce the probability of electronic transition of metallic silver.

[0041] Specifically, if the total weight of the first active metal solder is 100% by weight, the metallic silver content 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 portion of the metallic silver in the first braze layer 21 can diffuse to the faying surface of the first braze layer 21 and the second braze layer 22 and form an alloy with the metal atoms in the second braze layer 22 .

[0043] This can further increase the bonding strength between the first brazing layer 21 and the second brazing layer 22. For example, the metallic silver in the first brazing layer 21 is bonded to the second brazing layer 22. It is possible to form metallic copper and silver-copper alloys.

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

[0045] Specifically, the metallic copper content 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 weight%, 4 weight%, 6 weight%, or 8 weight%. Preferably, the content of the first active metal is 2 to 4 weight% when the total weight of the first active metal solder is 100 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, which can help fill defects in the ceramic substrate layer 1 or the second brazing layer 22, and even react with the ceramic substrate layer 1 or the second brazing layer 22. Meanwhile, the addition of the first active metal can also reduce the electrical impedance of the first brazing layer 21.

[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 joining surface (interface) between the first brazing layer 21 and the ceramic substrate layer 1, thereby forming a metal silicide or metal nitride with silicon atoms or nitrogen atoms in the ceramic substrate layer 1.

[0050] Similarly, a portion of the first active metal may also diffuse to the bonding surface between the first brazing layer 21 and the second brazing layer 22 and react to form an alloy. In this way, a good bonding 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 metallic titanium. For example, during the vacuum sintering process, metallic titanium can be combined with silicon atoms or nitrogen atoms to form titanium silicide (TiSi), silicon nitride (TiN), or titanium disilicate (TiSi2) after diffusing into the ceramic substrate layer 1. Also, metallic titanium can be combined with copper atoms in the second brazing layer 22 to form a titanium-copper alloy after diffusing into the second brazing layer 22, but the present invention is not limited thereto.

[0052] <Second brazing layer> The second brazing layer 22 is formed of 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 electronic transition of the 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, but does not contain metallic silver (Ag). The content of metallic copper (Cu) is greater than the content of the second active metal, and the content of metallic copper does not exceed 95% by weight when the total weight of the second active metal solder is 100% by weight.

[0054] Specifically, the metallic copper content 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 portion of the metallic copper in the second brazing layer 22 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 first brazing layer 21. This can further increase the bonding strength between the first brazing layer 21 and the second brazing layer 22.

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

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

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

[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, so it can help fill the defects in the first brazing layer 21 or the conductive metal layer 3, and even react with the first brazing layer 21 or the conductive metal layer 3. Meanwhile, the addition of the second active metal can also reduce the electrical impedance of the second brazing layer 22.

[0060] Specifically, the second active metal is titanium metal (Ti), zirconium metal (Zr), tantalum metal (Ta), niobium metal (Nb), vanadium metal (V), and hafnium metal. (Hf).

[0061] During the vacuum sintering process, a portion of the second active metal can diffuse to the joint interface 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 portion of the second active metal in the second brazing layer 22 can diffuse to the bonding 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, which can form a titanium-copper alloy with copper atoms in the first brazing layer 21 after the metallic titanium diffuses into the first brazing layer 21 during, for example, a vacuum sintering process.

[0064] Furthermore, after the metallic titanium is diffused into the conductive metal layer 3, it can form a titanium-copper alloy with the copper atoms in the conductive metal layer 3, but is not limited to this.

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

[0066] Furthermore, the thickness of the conductive metal layer 3 is 50 μm to 1200 μm, and preferably 200 μm to 800 μm, but is not limited to this.

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

[0068] The first active metal solder includes the aforementioned metallic silver, metallic copper, and the first active metal, hi some 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 the first active metal powder with at least one of a metallic silver powder, a metallic copper powder, and a silver-copper alloy powder.

[0070] As described above, the content of metallic silver in the first active metal solder is 10 to 60 weight % (when the total weight of the first active metal solder is 100 weight %). Also, 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 help disperse the first active metal solder and help shape the first active metal solder paste to form the active metal layer 2. Specifically, the organic dispersion medium can include a paste forming agent, an organic solvent, a thixotropic agent, etc. Examples include:

[0072] The content of ointment (paste) forming agent when the total weight of the organic dispersion medium is 100% 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 may be selected from the group consisting of silicone oil, white oil, polyvinyl alcohol, acrylic resin, nitrocellulose, ethylcellulose, dimethyl phthalate, and carboxymethylcellulose. Preferably, the ointment former is ethylcellulose.

[0074] The organic solvent is a group of glycol ethers that may 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 may be selected from the group consisting of polyamide wax, hydrogenated castor oil, and polyurea. Preferably, the thixotropic agent is a polyamide wax.

[0076] After mixing the first active metal solder and the organic dispersion medium in 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 and the organic dispersion medium is 75%-90%:10%-25%.

[0077] However, the present invention is not limited to the above embodiment, as long as the first active solder powder and the organic component can be prepared into a first active solder paste having a viscosity suitable for application onto the ceramic substrate layer 1. That is, as long as it complies with the protective spirit of the present invention to facilitate the formation of the first brazing layer 21, it falls within 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 to 110°C for 5 to 15 minutes, thereby volatilizing most of the organic solvent in the first active metal solder paste, and forming a first brazing layer 21.

[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 includes the above-mentioned second active metal solder and an organic dispersion medium.

[0080] The second active metal solder includes the aforementioned metallic copper and a second active metal, hi some embodiments, the second active metal solder is a combination of metallic copper powder and a second active metal powder.

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

[0082] The organic dispersion medium can help disperse the second active metal solder and help the second active metal solder paste form the second braze layer 22. Specifically, the organic dispersion medium includes the above-mentioned paste-forming agent, organic solvent, and thixotropic agent, which will not be described in further detail herein.

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

[0084] However, the present invention is not limited to the above embodiment. As long as the second active solder powder and the organic component can be mixed into a second active solder paste having a viscosity suitable for application onto the first brazing layer 21 to facilitate the formation of the second brazing layer 22, it is within the protective spirit of the present invention and therefore falls within 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 then dried at a temperature of 90°C to 110°C for 5 to 15 minutes, whereby most of the organic solvent in the second active metal solder paste is volatilized, 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 carried out to fix the conductive metal layer 3 onto the ceramic substrate layer 1.

[0087] The brazing process comprises 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 step is 500°C or lower, and the temperature condition of the second stage heat treatment step is 900°C to 1100°C (brazing temperature range), and the temperature of the second stage heat treatment step is higher than the temperature of the first stage heat treatment step.

[0089] Specifically, the temperature conditions for the first stage heat treatment are 300° C. to 500° C., and the treatment time is 30 to 60 minutes, while the temperature conditions for the second stage heat treatment are 900° C. to 960° C., and the treatment time is 60 to 240 minutes.

[0090] The temperature increase rate in the stepwise heat treatment process can be, for example, 5° C. / min to 30° C. / min. The temperature decrease rate after completion of vacuum sintering can be, for example, 2° C. / min to 30° C. / min.

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

[0092] In addition, a micron-scale eutectic reaction occurs at the joint interface between the second active metal and the metal component of the conductive metal layer 3, forming a strong eutectic structure 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 of the first brazing layer 21 and the second brazing layer 22 and the brazing temperature on the tensile strength of the metal ceramic substrate, metal ceramic substrates of Test Examples 1 to 6 were produced based on the above-mentioned steps S1 to S5.

[0094] In the metal ceramic substrates of test examples 1 to 6, the ceramic substrate layer 1 is a silicon nitride ceramic substrate, the first brazing layer 21 is 12 microns thick, the second brazing layer 22 is 12 microns thick, and the conductive metal layer 3 is a copper metal layer.

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

[0096] When preparing the second active metal solder paste, ethyl cellulose is used as the paste-forming agent, 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 dispersing medium is taken as 100% by weight, the organic dispersing medium contains 25% by weight of the paste forming agent, 60% by weight of the organic solvent, and 2.5% by weight of the thixotropic agent.

[0098] Specific components of the first brazing layer 21 and the second brazing layer 22 and the brazing temperature in the brazing process are shown in Table 1. In addition, 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% by weight to 60% by weight) and the second brazing layer 22 does not contain metallic silver, the double brazing layer can provide a tensile strength of the metal-ceramic substrate that exceeds 200 N / cm.

[0101] Even at lower brazing temperatures (900℃~960℃), the double brazing layer makes it possible to The metallic ceramic substrate can still maintain the expected tensile strength.

[0102] [Beneficial Effects of the Examples] One of the advantageous effects of the present invention is that the metal ceramic substrate having a double solder layer and the manufacturing method thereof provided by the present invention can improve the bonding strength between the ceramic substrate layer and the conductive metal layer due to the technical features that "the first active metal solder contains metallic silver, metallic copper, and a first active metal," "if the total weight of the first active metal solder is 100% by weight, the content of metallic silver is 10-60% 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."

[0103] The above description is merely a preferred embodiment of the present invention, and does not limit the technical scope of the present invention. Therefore, any technical modifications made by referring to the specification and drawings of the present invention are to be understood as being within the scope of the present invention. Any modifications are equivalent to the present invention and are included in the technical scope of the present invention. [Explanation of symbols]

[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 active metal layer is disposed between the ceramic substrate layer and the conductive metal layer, the first brazing layer and the ceramic substrate layer are in contact, and the second brazing layer and the conductive metal layer are in contact. 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 comprises 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 10-60% 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.

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

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