Method for manufacturing metal-ceramic bonding substrate

Abstract

To provide a method for manufacturing a metal-ceramic bonding substrate in which almost no unbonded portions occur between the ceramic substrate and the metal plate, and to provide a metal-ceramic bonding substrate in which almost no unbonded portions occur between the ceramic substrate and the metal plate.SOLUTION: Provided is a method for manufacturing the metal-ceramic bonding substrate according to the present invention, which comprises: forming a laminate on at least one surface of a ceramic substrate, in which, in the order listed, a first brazing material containing at least one metal selected from Ti, Zr, Hf, and Nb, a second brazing filler metal containing a metal consisting of Ag, Cu, and Sn, and a metal plate are arranged; then heating the laminate while applying a load in the thickness direction of the laminate; and thereby bonding the metal plate to the ceramic substrate.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing a metal-ceramic bonding substrate in which a ceramic substrate and a metal plate are bonded together via a brazing material. [Background technology]

[0002] Power modules are used to control the large amounts of electric power used in electric vehicles, trains, machine tools, etc., and the electric circuit boards used in such power modules are metal-ceramic bonded substrates, in which a metal plate is bonded to the surface of a ceramic substrate.

[0003] One technique for joining a ceramic substrate and a metal plate is the "active brazing method." In this method, a brazing material containing an active metal is heated to a certain temperature to form a molten mass. The active metal contained in the molten mass reacts chemically with the ceramic substrate, wetting and spreading the material, thereby joining the ceramic substrate and the metal plate.

[0004] Another known active brazing method is to add a low-melting-point metal to a brazing filler metal containing an active metal to lower the melting point of the brazing filler metal itself, thereby improving wetting and spreading. For example, Prior Art Document 1 describes a method for manufacturing a metal-ceramic bonding substrate in which a nitride ceramic substrate and a Cu member are bonded using a brazing filler metal containing Ag, Cu, and at least one active metal selected from Ti and Zr, and Sn as a low-melting-point metal. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-91673 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the manufacturing method of a metal-ceramic bonded substrate described in Patent Document 1, in which a ceramic substrate and a metal plate are bonded using a brazing filler metal containing Ag, Cu, an active metal, and Sn as a low-melting-point metal, there are cases in which many unbonded portions that become bond defects between the metal plate and the ceramic substrate occur. When many unbonded portions occur between the ceramic substrate and the metal plate, it is difficult to obtain the desired bond strength between the ceramic substrate and the metal plate, and cracks tend to occur in the metal-ceramic bonded portion when the metal-ceramic bonded substrate is subjected to repeated heat cycles.

[0007] The present invention has been made under the above circumstances, and an object of the present invention is to provide a method for manufacturing a metal-ceramic bonding substrate that hardly generates unbonded portions between a ceramic substrate and a metal plate. [Means for solving the problem]

[0008] The first invention for solving the above-mentioned problems is: A method for manufacturing a metal-ceramic bonding substrate, comprising: A laminate is formed on at least one surface of a ceramic substrate, in which a first brazing filler metal containing at least one active metal selected from Ti, Zr, Hf, and Nb, a second brazing filler metal containing a metal consisting of Ag, Cu, and Sn, and a metal plate are arranged in the stated order; This is a method for producing a metal-ceramic bonding substrate, characterized in that a metal plate is bonded to a ceramic substrate by heating the laminate while applying a load in the thickness direction of the laminate. The second invention is: A method for manufacturing a metal-ceramic bonding substrate, comprising: A first brazing filler metal containing at least one active metal selected from Ti, Zr, Hf, and Nb is disposed on at least one surface of a ceramic substrate; A second brazing filler metal containing Ag, Cu, and Sn is placed on one surface of the metal plate; forming a laminate by laminating the ceramic substrate and the metal plate such that the first brazing filler metal and the second brazing filler metal are in contact with each other; This is a method for producing a metal-ceramic bonding substrate, characterized in that a metal plate is bonded to a ceramic substrate by heating the laminate while applying a load in the thickness direction of the laminate. The third invention is In the ceramic substrate of the laminate, the amount of the active metal in the first brazing filler metal per unit area is 0.1 mg / cm 2 More than 0.5mg / cm 2 The method for producing a metal / ceramic bonding substrate according to the first or second invention is characterized in that: The fourth invention is In the ceramic substrate of the laminate, the total amount of the active metal in the first and second brazing filler metals per unit area and the amount of the metal consisting of Ag, Cu, and Sn per unit area is 10 mg / cm 2 More than 20mg / cm 2 The method for producing a metal / ceramic bonding substrate according to the first or second invention is characterized in that: The fifth invention is In the ceramic substrate of the laminate, The method for producing a metal-ceramic bonding substrate according to the first or second invention is characterized in that an active metal amount ratio, which is the ratio of the amount of active metal arranged per unit area in the first brazing filler metal to the sum of the amount of active metal arranged per unit area in the first and second brazing filler metals and the amount of metal consisting of Ag, Cu and Sn arranged per unit area, is 0.5% or more and 5% or less. The sixth invention is The method for producing a metal-ceramic bonding substrate according to the first or second invention is characterized in that the first brazing filler metal contains only at least one active metal selected from Ti, Zr, Hf, and Nb. The seventh invention is The method for producing a metal / ceramic bonding substrate according to the first or second invention is characterized in that the first brazing filler metal contains only Ti as a metal. The eighth invention is In the ceramic substrate of the laminate before heating, the first brazing filler metal contains, as a metal, at least one active metal selected from Ti, Zr, Hf, and Nb, and a metal consisting of Ag and Cu, the amount of Ag is such that, when the total mass of Ag, Cu, and Sn in the first brazing filler metal and the second brazing filler metal is 100 parts by mass, the total mass of the amounts of Ag in the first brazing filler metal and the second brazing filler metal is 15 parts by mass or more and 85 parts by mass or less; The method for producing a metal-ceramic bonding substrate according to the first or second invention is characterized in that the amount of Cu is such that, when the total mass of Ag, Cu, and Sn in the first brazing filler metal and the second brazing filler metal is 100 parts by mass, the total mass of the amounts of Cu in the first brazing filler metal and the second brazing filler metal is 5 parts by mass or more and 60 parts by mass or less. The ninth invention is 0.005 kgf / cm in the thickness direction of the laminate 2 More than 0.5kgf / cm 2 A method for producing a metal-ceramic bonding substrate according to the first or second invention, characterized in that the metal plate is bonded to the ceramic substrate by heating while applying the following load: [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a method for producing a metal-ceramic bonding substrate in which the brazing filler metal is sufficiently wetted and spread, and there is almost no occurrence of unbonded portions between the ceramic substrate and the metal plate. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view schematically showing a laminate of a metal plate and a ceramic substrate used in a method for producing a metal-ceramic bonding substrate according to the present invention. [Figure 2]1 is a cross-sectional view schematically showing a laminate of a metal plate and a ceramic substrate in a step of applying a load in a method for manufacturing a metal-ceramic bonding substrate according to the present invention. [Figure 3] FIG. 3 is a cross-sectional view illustrating a step of placing a first brazing filler metal on a ceramic substrate in the embodiment of the method for manufacturing a metal / ceramic bonding substrate according to the present invention. [Figure 4] FIG. 3 is a cross-sectional view illustrating a step of arranging a second brazing filler metal on a metal plate in the embodiment of the method for manufacturing a metal / ceramic bonding substrate according to the present invention. [Figure 5] 1 is a schematic cross-sectional view of a metal / ceramic bonding substrate according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] A method for producing a metal / ceramic bonding substrate according to the present invention will be described with reference to the drawings.

[0012] In the method for manufacturing a metal-ceramic bonding substrate according to the present invention, as shown in FIG. 1, which is a cross-sectional view schematically illustrating a laminate of a metal plate and a ceramic substrate, a laminate 17 is formed on at least one surface of a ceramic substrate 10 (on both surfaces of the ceramic substrate 10 in the embodiment shown in FIG. 1), in which a first brazing filler metal 12 containing at least one active metal selected from Ti, Zr, Hf, and Nb, a second brazing filler metal 14 containing a metal consisting of Ag, Cu, and Sn, and a metal plate 16 are arranged in the stated order.

[0013] 2, which is a cross-sectional view schematically illustrating a laminate of a metal plate and a ceramic substrate in the load application step in the method for producing a metal-ceramic bonding substrate according to the present invention, the formed laminate 17 is placed on one spacer (lower spacer) 18 of a pair of spacers 18, and then the other spacer (upper spacer) 18 is placed on this laminate 17. Thereafter, by heating the laminate 17 while applying a load from the upper spacer 18 side in the thickness direction of the laminate, the ceramic substrate 10 and the metal plate 16 are bonded via the bonding layer, and a metal-ceramic bonding substrate 32 is obtained as shown in FIG. 5, which is a schematic cross-sectional view of a metal-ceramic bonding substrate according to the present invention.

[0014] The method for manufacturing a metal / ceramic bonding substrate according to the present invention will be described below in the order of [1] a first embodiment and [2] a different embodiment.

[0015] [1] First embodiment The first embodiment of the method for manufacturing a metal-ceramic bonding substrate according to the present invention will be described in the following order: (1) ceramic substrate, (2) first brazing filler metal, (3) metal plate, (4) second brazing filler metal, (5) formation of a laminate, (6) load on the laminate, and heat treatment.

[0016] (1) Ceramic substrate The ceramic substrate 10 used in the present invention may be a ceramic substrate made of alumina, aluminum nitride, silicon nitride, silicon carbide, or the like. The ceramic substrate 10 may have a length of 5 to 200 mm, a width of 5 to 200 mm, and a thickness of 0.25 to 3.0 mm, for example.

[0017] (2) First brazing filler metal The first brazing filler metal 12 according to the present invention contains an active metal consisting of at least one metal selected from Ti, Zr, Hf, and Nb or its hydrogen compound. This is believed to be because the inclusion of the active metal in the first brazing filler metal 12 disposed on the surface of the ceramic substrate shortens the physical distance between the ceramic substrate and the active metal, promoting chemical reactions between the active metal and the ceramic substrate and improving the wetting and spreading of the brazing filler metal. Furthermore, by increasing the physical distance between the active metal contained in the first brazing filler metal and the Sn contained in the second brazing filler metal (described later), it is believed that the formation of an intermetallic compound between the active metal and the Sn, which inhibits the chemical reaction between the active metal and the ceramic substrate, is suppressed, thereby improving the wetting and spreading of the brazing filler metal. It is believed that this suppresses the occurrence of unjoined portions between the ceramic substrate and the metal plate.

[0018] Here, it is preferable that the first brazing filler metal 12 contains only at least one active metal selected from Ti, Zr, Hf, and Nb as the metal, from the viewpoint of promoting the reaction between the active metal and the ceramics. Moreover, the active metal contained in the first brazing filler metal 12 is preferably Ti from the viewpoint of cost.

[0019] The first brazing material 12 is preferably in paste form so that the desired film thickness and amount can be easily set, and can be prepared by a known method of kneading an active metal powder with a vehicle consisting of a binder and an organic solvent. In the present invention, the term "placement amount" is the same concept as the so-called "application amount." However, in the present invention, the method for applying the paste to the substrate is not limited to the application method, and therefore the term "placement amount" is used instead of the "application amount."

[0020] The binder contained in the vehicle in the first brazing filler metal 12 is not particularly limited and can be appropriately selected depending on the purpose. Examples include acrylic resin, ethyl cellulose, ethylhydroxyethyl cellulose, nitrocellulose, etc. Two or more of these binders may be used in combination.

[0021] The organic solvent contained in the vehicle in the first brazing filler metal 12 is not particularly limited and can be appropriately selected depending on the purpose. Examples include toluene, methyl ethyl ketone, methyl isobutyl ketone, tetradecane, tetralin, propyl alcohol, isopropyl alcohol, terpineol, ethyl carbitol, butyl carbitol, ethyl carbitol acetate, butyl carbitol acetate, and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate. Two or more of these organic solvents may be used in combination.

[0022] When the metal in the first brazing filler metal 12 is only active metal, when the mass of the active metal in the first brazing filler metal 12 is 100 parts by mass, the amount of binder in the first brazing filler metal 12 is preferably 150 parts by mass or more and 350 parts by mass or less, more preferably 200 parts by mass or more and 300 parts by mass or less, and even more preferably 230 parts by mass or more and 270 parts by mass or less.

[0023] When the metal in the first brazing filler metal 12 is only an active metal, when the mass of the active metal in the first brazing filler metal 12 is 100 parts by mass, the amount of organic solvent in the first brazing filler metal 12 is preferably 450 parts by mass or more and 750 parts by mass or less, more preferably 500 parts by mass or more and 700 parts by mass or less, and even more preferably 550 parts by mass or more and 650 parts by mass or less.

[0024] In addition, in order to adjust the printability of the first brazing filler metal 12, the adhesiveness of the dried coating film, the abrasion resistance, and the like, a dispersant, a viscosity adjuster, a plasticizer, and the like may be added as appropriate.

[0025] (3) Metal plate The metal plate 16 is preferably made of a material with excellent thermal conductivity, such as Cu, Al, or an alloy thereof. Furthermore, it is preferable to use a Cu plate or a Cu alloy plate, which has high thermal conductivity and electrical conductivity, as the metal plate 16. The metal plate 16 may have a length of 10 to 200 mm, a width of 10 to 200 mm, and a thickness of 0.1 to 1.0 mm, for example.

[0026] (4) Second brazing filler metal The second brazing filler metal 14 according to the present invention does not contain the above-mentioned active metal, but contains a metal composed of Ag, Cu, and Sn. The metals in the second brazing filler metal 14 are Ag, Cu, and the low-melting-point metal Sn, which lowers the melting point of the second brazing filler metal 14 itself. The lower melting point of the second brazing filler metal 14 itself allows the second brazing filler metal 14 to sufficiently wet and spread during heat treatment of the laminate, as described below, and can prevent the occurrence of unjoined portions between the ceramic substrate 10 and the metal plate 16.

[0027] The second brazing filler metal 14 is preferably in a paste form so that the desired film thickness and amount can be easily set, and can be prepared by a known method of kneading metal powders of Ag, Cu, and Sn with a vehicle consisting of a binder and an organic solvent.

[0028] The mass ratio of Ag to the metals in the second brazing filler metal 14 is preferably 15 parts by mass or more and 85 parts by mass or less, and more preferably 20 parts by mass or more and 70 parts by mass or less, from the viewpoint of electrical conductivity and thermal conductivity, assuming that the total mass of the metals in the second brazing filler metal 14 is 100 parts by mass. Also, from the viewpoint of cost, in order to avoid an increase in cost due to an increase in the amount of Ag used, which is a precious metal, it is preferably 40 parts by mass or less.

[0029] The mass proportion of Cu in the metal in the second brazing filler metal 14 is preferably 5 parts by mass or more and 60 parts by mass or less, and more preferably 10 parts by mass or more and 55 parts by mass or less, from the viewpoint of electrical conductivity and thermal conductivity, assuming that the total mass of the metal in the second brazing filler metal 14 is 100 parts by mass.

[0030] The mass proportion of Sn in the metal in the second brazing filler metal 14 is preferably 3 parts by mass or more and 30 parts by mass or less, more preferably 5 parts by mass or more, and even more preferably 15 parts by mass or more, from the viewpoint of ensuring the wetting and spreading of the second brazing filler metal 14, assuming that the total mass of the metal in the second brazing filler metal 14 is 100 parts by mass.

[0031] The binder contained in the vehicle in the second brazing filler material 14 is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include acrylic resin, ethyl cellulose, ethylhydroxyethyl cellulose, nitrocellulose, etc. These binders may be used alone or in combination of two or more.

[0032] When the amount of metal in the second brazing filler metal 14 is 100 parts by mass, the amount of binder in the second brazing filler metal 14 is in the range of 0.4 parts by mass or more and 1.6 parts by mass or less, preferably in the range of 0.6 parts by mass or more and 1.4 parts by mass or less, and more preferably in the range of 0.8 parts by mass or more and 1.2 parts by mass or less.

[0033] The organic solvent contained in the vehicle in the second brazing filler metal 14 is not particularly limited and can be appropriately selected depending on the purpose. Examples include toluene, methyl ethyl ketone, methyl isobutyl ketone, tetradecane, tetralin, propyl alcohol, isopropyl alcohol, terpineol, ethyl carbitol, butyl carbitol, ethyl carbitol acetate, butyl carbitol acetate, and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate. These organic solvents may be used alone or in combination of two or more.

[0034] When the amount of metal in the second brazing filler metal 14 is 100 parts by mass, the amount of organic solvent in the second brazing filler metal 14 is in the range of 7 parts by mass or more and 19 parts by mass or less, preferably in the range of 9 parts by mass or more and 17 parts by mass or less, and more preferably in the range of 11 parts by mass or more and 15 parts by mass or less.

[0035] In addition, in order to adjust the printability of the second brazing filler metal 14, the adhesiveness of the dried coating film, the abrasion resistance, and the like, a dispersant, a viscosity adjuster, a plasticizer, and the like may be added to the second brazing filler metal 14 as appropriate.

[0036] (5) Formation of laminate There is no particular limitation on the method for forming the laminate shown in Fig. 1. For example, as shown in Fig. 3, which is a cross-sectional view illustrating the process of arranging a first brazing filler metal 12 on a ceramic substrate, the first brazing filler metal 12 is applied to at least one surface (both surfaces in the illustrated embodiment) of the ceramic substrate 10, and dried to obtain a ceramic substrate 30 on which the first brazing filler metal is arranged.

[0037] At this time, the first brazing filler metal 12 is preferably disposed so that the film thickness on the ceramic substrate 10 is 10 μm or more and 20 μm or less. The first brazing filler metal 12 can be disposed on one or both surfaces of the ceramic substrate 10 by disposing it on the surface of the ceramic substrate 10 by, for example, screen printing.

[0038] Then, a second brazing filler metal 14 may be applied to the first brazing filler metal 12 placed on the ceramic substrate 10 so as to have the same shape as the first brazing filler metal, dried, and placed thereon, and a metal plate 16 may be placed on the second brazing filler metal 14 to form a laminate 17.

[0039] However, when the second brazing filler metal 14 is applied onto the first brazing filler metal 12, the first brazing filler metal 12 may peel off from the ceramic substrate 10. To avoid such a situation, as shown in FIG. 4, which is a cross-sectional view illustrating the process of disposing the second brazing filler metal 14 on the metal plate, the second brazing filler metal 14 is applied to one side of the metal plate 16 in advance and dried to obtain a metal plate 31 on which the second brazing filler metal 14 is disposed. Then, the ceramic substrate 30 on which the first brazing filler metal 12 is disposed and the metal plate 31 on which the second brazing filler metal 14 is disposed are stacked so that the first brazing filler metal 12 and the second brazing filler metal 14 abut against each other to form a laminate 17. In this manner, by disposing the second brazing filler metal 14 on the first brazing filler metal 12, it is preferable to prevent the first brazing filler metal 12 from peeling off from the ceramic substrate 30 on which the first brazing filler metal 12 is disposed.

[0040] The first brazing filler metal 12 is arranged in a ceramic substrate 10 of the laminate such that the amount of the active metal in the first brazing filler metal 12 per unit area is 0.1 mg / cm 2 More than 0.5mg / cm 2 It is preferable to arrange it so that it is 0.15 mg / cm or less, and more preferably 0.15 mg / cm 2 More than 0.4mg / cm 2 or less, more preferably 0.2 mg / cm 2 More than 0.3mg / cm 2 The following is the result.

[0041] This is because the amount of active metal in the first brazing filler metal per unit area in the ceramic substrate 10 of the laminate is 0.1 mg / cm 2 By setting the above, it is considered that when heat treatment is performed while applying a load between the ceramic substrate and the metal plate, as described later in "(6) Load on the laminate and heat treatment", the reaction between the active metal and the ceramic substrate can be promoted, and the wetting and spreading of the brazing filler metal can be improved. Meanwhile, in the ceramic substrate 10 of the laminate, the amount of the active metal arranged per unit area in the first brazing filler metal is set to 0.5 mg / cm. 2 By setting the following, it is believed that the formation of intermetallic compounds with Sn in the second brazing filler metal 14 described above is suppressed, and the phenomenon of inhibiting the chemical reaction between the active metal and the ceramic substrate is suppressed, thereby improving the wetting and spreading of the brazing filler metal.

[0042] The second brazing filler metal 14 is arranged such that the amount of Ag per unit area in the second brazing filler metal 14 is 2 mg / cm 2 in the ceramic substrate 10 of the laminate. 2 More than 11mg / cm 2 It is preferable to arrange it so that it is equal to or less than 3 mg / cm, and more preferably 3 mg / cm 2 Over 9mg / cm 2 The following is the result.

[0043] The second brazing filler metal 14 is arranged such that the amount of Cu arranged per unit area in the second brazing filler metal 14 is 0.5 mg / cm 2 in the ceramic substrate 10 of the laminate. 2 More than 10mg / cm 2It is preferable to arrange it so that it is equal to or less than 1 mg / cm, and more preferably 1 mg / cm 2 More than 7mg / cm 2 The following is the result.

[0044] The second brazing filler metal 14 has a Sn content per unit area of ​​0.5 mg / cm in the ceramic substrate 10 of the laminate. 2 More than 5mg / cm 2 It is preferable to arrange it so that it is 2 mg / cm or less, and more preferably 2 mg / cm 2 More than 4mg / cm 2 The following is the result.

[0045] In the ceramic substrate 10 of the laminate, the total amount of the metal components arranged, which is the sum of the amount of the active metal arranged per unit area in the first and second brazing filler metals and the amount of Ag, Cu, and Sn arranged per unit area, is 10 mg / cm 2 More than 20mg / cm 2 It is preferable to arrange it so that it is 11 mg / cm or less, and more preferably 11 mg / cm 2 More than 18mg / cm 2 or less, more preferably 12 mg / cm 2 More than 16mg / cm 2 The following is the result.

[0046] Furthermore, it is preferable to stack the first brazing filler metal 12 and the second brazing filler metal 14 on the ceramic substrate 10 so that the active metal amount ratio, which is the ratio of the amount of active metal in the first brazing filler metal 12 per unit area to the total amount of metal components arranged per unit area in the ceramic substrate 10 of the laminate, is 0.5% or more and 5% or less, more preferably 1.0% or more and 4.0% or less, and even more preferably 1.5% or more and 3.0% or less.

[0047] For convenience, the "active metal amount ratio" according to the present invention can be expressed by the following formula: Active metal amount ratio (%) = (amount of active metal arranged per unit area in the first brazing filler metal) / (total amount of the amount of active metal arranged per unit area and the amount of metal consisting of Ag, Cu, and Sn arranged per unit area in the first and second brazing filler metals) × 100

[0048] (6) Loading and heat treatment of laminate The laminate 17 shown in FIG. 1 is placed on one spacer (lower spacer) 18 of a pair of spacers 18, as shown in FIG. 2, and the other spacer (upper spacer) 18 is placed on the laminate 17. After that, a load is applied between the ceramic substrate and the metal plate from the upper spacer 18 side, and they are bonded by heat treatment.

[0049] The load applied to the laminate 17 in the thickness direction of the laminate is 0.005 kgf / cm 2 More than 0.5kgf / cm 2 Preferably, it is less than 0.01 kgf / cm. More preferably, it is less than 0.01 kgf / cm. 2 More than 0.2kgf / cm 2 The heating temperature during the heat treatment is preferably 780°C or higher and 890°C or lower, more preferably 800 to 850°C. The atmosphere for the heat treatment is preferably 8.0 × 10 -2 It is preferable to carry out the process in a vacuum of 5.0×10 Pa or less. -2 The heat treatment time is not particularly limited, but is preferably 30 minutes or more. From the viewpoint of production efficiency, it is preferably 1 hour or less.

[0050] Then, by applying a load to the laminate and performing a heat treatment, the metal-ceramic bonding substrate according to the present invention is obtained as shown in Fig. 5. By performing the heat treatment while applying the load, the first brazing filler metal becomes first bonding layer 22, and the second brazing filler metal becomes second bonding layer 24, thereby bonding ceramic substrate 10 and metal plate 16 with almost no unbonded portions.

[0051] [2] Different embodiments Different embodiments of the method for manufacturing a metal-ceramic bonding substrate according to the present invention will be described in the following order: (1) ceramic substrate, (2) first brazing filler metal, (3) metal plate, (4) second brazing filler metal, (5) formation of a laminate, (6) load on the laminate, and heat treatment.

[0052] (1) ceramic substrate, The ceramic substrate 10 used in the different embodiments is the same as that in the first embodiment described above.

[0053] (2) First brazing filler metal As explained in the first embodiment, the first brazing filler metal 12 according to the present invention preferably contains only active metal as the metal. However, the first brazing filler metal 12 is also allowed to contain Ag and Cu, which are metals contained in the second brazing filler metal 14, as long as the amount is within a range that does not inhibit the progress of the reaction between the active metal and the ceramics.

[0054] Even if the first brazing filler metal 12 contains Ag and Cu, the amount is kept below a predetermined amount, which allows the first and second brazing filler metals 14 to wet and spread sufficiently, and makes it possible to almost completely prevent the occurrence of unjoined areas between the ceramic substrate and the metal plate.

[0055] When the first brazing filler metal 12 contains Ag, from the viewpoint of promoting the reaction between the active metal and the ceramic, the amount of Ag arranged per unit area in the ceramic substrate 10 of the laminate is set to, for example, 0.1 mg / cm 2 so as not to hinder the progress of the reaction. 2 More than 0.15mg / cm 2 It is acceptable if it is less than 0.07 mg / cm 2 More than 0.2mg / cm 2 Even if it is less than 0.05 mg / cm 2 More than 0.25mg / cm 2 The following is acceptable:

[0056] When the first brazing filler metal 12 contains Cu, from the viewpoint of promoting the reaction between the active metal and the ceramic, the amount of Cu arranged per unit area in the ceramic substrate 10 of the laminate is set to, for example, 0.1 mg / cm 2 so as not to hinder the progress of the reaction. 2 More than 0.15mg / cm 2 It is acceptable if it is less than 0.07 mg / cm 2 More than 0.2mg / cm 2 Even if it is less than 0.05 mg / cm 2 More than 0.25mg / cm 2 The following is acceptable:

[0057] (3) Metal plate The metal plate 16 used in the different embodiments is the same as that in the first embodiment described above.

[0058] (4) Second brazing filler metal When the first brazing filler metal 12 contains Ag, the mass proportion of Ag in the metal in the second brazing filler metal 14 will be described. From the viewpoint of electrical conductivity and thermal conductivity, when the total mass of Ag, Cu, and Sn in the first brazing filler metal 12 and the second brazing filler metal 14 is taken as 100 parts by mass, the total mass of the amount of Ag arranged in the first brazing filler metal 12 and the second brazing filler metal 14 is preferably 15 parts by mass or more and 85 parts by mass or less, and more preferably 20 parts by mass or more and 70 parts by mass or less. Furthermore, from the viewpoint of avoiding an increase in cost due to an increase in the amount of Ag used, which is a precious metal, the total mass is appropriately adjusted to 40 parts by mass or less.

[0059] When the first brazing filler metal 12 contains Cu, the mass proportion of Cu in the metal in the second brazing filler metal 14 will be described. From the viewpoint of electrical conductivity and thermal conductivity, when the total mass of Ag, Cu, and Sn in the first brazing filler metal 12 and the second brazing filler metal 14 is taken as 100 parts by mass, the total mass of the amount of Cu arranged in the first brazing filler metal 12 and the second brazing filler metal 14 is suitably adjusted to be preferably 5 parts by mass or more and 60 parts by mass or less, more preferably 10 parts by mass or more and 55 parts by mass or less.

[0060] When the first brazing filler metal 12 contains Ag and Cu, when the mass of the metal in the first brazing filler metal 12 is 100 parts by mass, the amount of binder in the first brazing filler metal 12 is preferably 100 parts by mass or more and 200 parts by mass or less, more preferably 110 parts by mass or more and 175 parts by mass or less, and even more preferably 120 parts by mass or more and 150 parts by mass or less.

[0061] When the first brazing filler metal 12 contains Ag and Cu, when the mass of the metal in the first brazing filler metal 12 is 100 parts by mass, the amount of organic solvent in the first brazing filler metal 12 is preferably 350 parts by mass or more and 450 parts by mass or less, more preferably 300 parts by mass or more and 400 parts by mass or less, and even more preferably 250 parts by mass or more and 350 parts by mass or less.

[0062] The amounts of binder and organic solvent in the second brazing filler metal 14 may be the same as those in the first embodiment.

[0063] (5) Formation of laminate (5) Formation of a laminate carried out in the different embodiment is the same as in the first embodiment described above.

[0064] (6) Loading and heat treatment of laminate (6) Loading and heat treatment on the laminated body carried out in the different embodiment is the same as in the first embodiment described above. [Example]

[0065] The method for producing a metal / ceramic bonding substrate according to the present invention will be described in detail below with reference to examples.

[0066] [Example 1] An aluminum nitride plate measuring 68 mm long, 68 mm wide, and 0.635 mm thick was prepared as the ceramic substrate. A paste was prepared as the first brazing filler metal by kneading Ti powder with a vehicle consisting of an acrylic binder and an organic solvent. The first brazing filler metal consisted solely of Ti, the active metal, and was formulated so that, based on 100 parts by mass (standard) of Ti, the amount of organic solvent was 610 parts by mass and the amount of binder was 248 parts by mass.

[0067] Next, the first brazing filler metal was applied to both sides of the prepared aluminum nitride plate by screen printing. At this time, the first brazing filler metal was applied in a pattern of four approximately squares measuring 33 mm in length, 33 mm in width, and 15 μm in thickness, and the amount of Ti arranged per unit area was 0.2 mg / cm. 2 After that, it was dried in the air.

[0068] Next, two oxygen-free Cu plates measuring 70 mm long, 70 mm wide, and 0.25 mm thick were prepared as metal plates. A paste was then prepared as the second brazing filler metal by kneading Ag powder, Cu powder, Sn powder, and a vehicle consisting of an acrylic binder and an organic solvent. The second brazing filler metal consisted of Ag, Cu, and Sn.

[0069] When the total amount of metal components in the second brazing filler metal was 100 parts by mass (standard), the amounts of Ag were 84.6 parts by mass, Cu was 10.3 parts by mass, Sn was 5.1 parts by mass, organic solvent was 12.7 parts by mass, and binder was 1.01 parts by mass.

[0070] The second brazing filler metal was then applied to one surface of each of the prepared metal plates by screen printing. At this time, the second brazing filler metal was applied in a pattern of four approximately squares measuring 33 mm in length, 33 mm in width, and 15 μm in thickness, and the total amount of the metal components, which was the sum of the amounts of Ag, Cu, and Sn arranged per unit area, was 12.3 mg / cm. 2 After that, it was dried in the air.

[0071] Next, metal plates were placed on both sides of the ceramic substrate so that the first brazing filler metal placed on the ceramic substrate and the second brazing filler metal placed on the metal plate were in contact with each other, and a laminate was formed in which the first brazing filler metal, the second brazing filler metal, and the Cu plate were stacked in the order listed on both sides of the ceramic substrate. As a result, the total amount of metal components arranged per unit area, which is the sum of the amount of Ti arranged per unit area and the amounts of Ag, Cu, and Sn arranged per unit area, was 12.5 mg / cm 2 This is what happened. In addition, the value of the active metal amount ratio, which is the ratio of the amount of Ti arranged per unit area to the total amount of metal components arranged per unit area, was 1.8%.

[0072] The formed laminate was placed on one spacer (lower spacer) of a pair of spacers made of alumina plates measuring 90 mm × 75 mm × 0.6 mm, and the other spacer (upper spacer) was placed on the laminate. Then, a pressure of 0.007 kgf / cm was applied to the laminate in the thickness direction of the laminate. 2 While applying a load of 4.0 x 10 -2 The metal plate and the ceramic substrate were bonded together by heating at 835° C. for 45 minutes in a vacuum atmosphere of 100 Pa, to obtain a metal-ceramic bonding substrate according to Example 1.

[0073] The obtained metal-ceramic bonding substrate has a laminated structure in which a first bonding layer made of Ti as a metal, a second bonding layer made of Ag, Cu, and Sn, and a metal plate are laminated in the order listed on at least one surface of a ceramic substrate.

[0074] [Example 2] The amount of the organic solvent was 612 parts by mass and the amount of the binder was 249 parts by mass when the amount of Ti, which is the active metal in the first brazing filler metal, was taken as 100 parts by mass (reference).

[0075] Next, the first brazing filler metal was applied to both sides of the prepared aluminum nitride plate by screen printing. At this time, the first brazing filler metal was applied in a pattern of four approximately squares measuring 33 mm in length, 33 mm in width, and 15 μm in thickness, and the amount of Ti arranged per unit area was 0.2 mg / cm. 2 After that, it was dried in the air.

[0076] Next, two oxygen-free Cu plates measuring 70 mm long, 70 mm wide, and 0.25 mm thick were prepared as metal plates. A paste was then prepared as the second brazing filler metal by kneading Ag powder, Cu powder, Sn powder, and a vehicle consisting of an acrylic binder and an organic solvent. The second brazing filler metal consisted of Ag, Cu, and Sn.

[0077] When the total amount of metal components in the second brazing filler metal was 100 parts by mass (standard), the amounts of Ag were 65.0 parts by mass, Cu was 10.0 parts by mass, Sn was 25.0 parts by mass, organic solvent was 12.7 parts by mass, and binder was 1.01 parts by mass.

[0078] Next, the amount of the metal component in the second brazing filler metal per unit area on one side of each metal plate was 12.4 mg / cm 2 The coating was applied by screen printing so that the thickness became 1 / 2 mm, and the coating was dried in the air and then placed.

[0079] Next, metal plates were placed on both sides of the ceramic substrate so that the first brazing filler metal placed on the ceramic substrate and the second brazing filler metal placed on the metal plate were in contact with each other, and a laminate was formed in which the first brazing filler metal, the second brazing filler metal, and the Cu plate were stacked in the order listed on both sides of the ceramic substrate. As a result, the total amount of metal components arranged per unit area, which is the sum of the amount of Ti arranged per unit area and the amounts of Ag, Cu, and Sn arranged per unit area, was 12.6 mg / cm 2 This is what happened. In addition, the value of the active metal amount ratio, which is the ratio of the amount of Ti arranged per unit area to the total amount of metal components arranged per unit area, was 1.8%.

[0080] The resulting laminate was subjected to the same operation as in Example 1, to obtain a metal / ceramic bonding substrate according to Example 2.

[0081] [Example 3] The amount of the organic solvent was 611 parts by mass and the amount of the binder was 249 parts by mass when the amount of Ti, which is the active metal in the first brazing filler metal, was taken as 100 parts by mass (reference).

[0082] Next, the first brazing filler metal was applied to both sides of the prepared aluminum nitride plate by screen printing. At this time, the first brazing filler metal was applied in a pattern of four approximately squares measuring 33 mm in length, 33 mm in width, and 15 μm in thickness, and the amount of Ti arranged per unit area was 0.2 mg / cm. 2 After that, it was dried in the air.

[0083] Next, two oxygen-free Cu plates measuring 70 mm long, 70 mm wide, and 0.25 mm thick were prepared as metal plates. A paste was then prepared as the second brazing filler metal by kneading Ag powder, Cu powder, Sn powder, and a vehicle consisting of an acrylic binder and an organic solvent. The second brazing filler metal consisted of Ag, Cu, and Sn.

[0084] When the total amount of metal components in the second brazing filler metal was 100 parts by mass (standard), the components were blended so that Ag was 24.2 parts by mass, Cu was 50.8 parts by mass, Sn was 25.0 parts by mass, organic solvent was 12.7 parts by mass, and binder was 1.01 parts by mass.

[0085] Next, the amount of the metal component in the second brazing filler metal per unit area on one side of each metal plate was 12.4 mg / cm 2 The coating was applied by screen printing so that the thickness became 1 / 2 mm, and the coating was dried in the air and then placed.

[0086] Next, metal plates were placed on both sides of the ceramic substrate so that the first brazing filler metal placed on the ceramic substrate and the second brazing filler metal placed on the metal plate were in contact with each other, and a laminate was formed in which the first brazing filler metal, the second brazing filler metal, and the Cu plate were stacked in the order listed on both sides of the ceramic substrate. As a result, the total amount of metal components arranged per unit area, which is the sum of the amount of Ti arranged per unit area and the amounts of Ag, Cu, and Sn arranged per unit area, was 12.6 mg / cm 2 This is what happened. In addition, the value of the active metal amount ratio, which is the ratio of the amount of Ti arranged per unit area to the total amount of metal components arranged per unit area, was 1.8%.

[0087] The resulting laminate was subjected to the same operation as in Example 1, to obtain a metal / ceramic bonding substrate according to Example 3.

[0088] [Comparative Example 1] An aluminum nitride plate measuring 68 mm long, 68 mm wide, and 0.635 mm thick was prepared as the ceramic substrate. Instead of using the first and second brazing filler metals, a paste was prepared as the third brazing filler metal by kneading Ag powder, Cu powder, Sn powder, Ti powder, and TiO powder as an oxide, with a vehicle consisting of an acrylic binder and an organic solvent.

[0089] When the total amount of Ag, Cu, Sn, Ti, and TiO2 in the third brazing filler metal is 100 parts by mass (standard), the components are blended so that Ag is 82.6 parts by mass, Cu is 10.0 parts by mass, Sn is 5.0 parts by mass, Ti is 1.9 parts by mass, TiO2 is 0.5 parts by mass, organic solvent is 12.7 parts by mass, and binder is 1.01 parts by mass.

[0090] Next, the third brazing filler metal according to Comparative Example 1 was applied to both sides of the prepared aluminum nitride plate by screen printing. At this time, the third brazing filler metal was applied in a shape of four substantially square patterns measuring 33 mm in length, 33 mm in width, and 15 μm in thickness, and the total amount of metal components arranged per unit area was 12.1 mg / cm. 2 After that, it was dried in the air.

[0091] Next, two oxygen-free Cu plates measuring 70 mm in length, 70 mm in width, and 0.25 mm in thickness were prepared as metal plates.

[0092] Next, two oxygen-free Cu plates were placed facing the third brazing filler metal of Comparative Example 1, and a laminate was formed in which the third brazing filler metal of Comparative Example 1 and the Cu plates were stacked in the order listed on both sides of the ceramic substrate.

[0093] The formed laminate was placed on one spacer (lower spacer) of a pair of spacers made of alumina plates measuring 90 mm × 75 mm × 0.6 mm, and the other spacer (upper spacer) was placed on the laminate. Then, a pressure of 0.007 kgf / cm was applied to the laminate in the thickness direction of the laminate. 2 While applying a load of 4.0 x 10 -2 The metal plate and the ceramic substrate were bonded together by heating at 835° C. for 45 minutes in a vacuum atmosphere of 100 Pa, to obtain a metal-ceramic bonding substrate according to Comparative Example 1.

[0094] Comparative Example 2 Without using the first brazing filler metal and the second brazing filler metal, a paste was prepared as a fourth brazing filler metal by kneading Ag powder, Cu powder, Sn powder, Ti powder with a vehicle made of an acrylic binder and an organic solvent. First, when the total amount of metal components in the brazing filler metal was 100 parts by mass (standard), Ag was mixed at 63.8 parts by mass, Cu at 9.8 parts by mass, Sn at 24.5 parts by mass, Ti at 1.9 parts by mass, organic solvent at 12.7 parts by mass, and binder at 1.01 parts by mass to obtain a fourth brazing filler metal according to Comparative Example 2.

[0095] Next, the fourth brazing filler metal according to Comparative Example 2 was applied to both sides of the prepared aluminum nitride plate by screen printing. At this time, the fourth brazing filler metal was applied in a shape of four approximately square patterns of 33 mm in length × 33 mm in width × 15 μm in thickness to the aluminum nitride plate, and the total amount of metal components arranged per unit area was 12.5 mg / cm. 2 After that, it was dried in the air. Other than this, the same procedure as in Comparative Example 1 was carried out to obtain a metal / ceramic bonding substrate according to Comparative Example 2.

[0096] [Measuring the bonding rate] In the metal-ceramic bonded substrates obtained in Examples 1 to 3 and Comparative Examples 1 and 2, the bonded portion between one surface (back surface) of the ceramic substrate and the Cu plate was subjected to ultrasonic flaw detection using an ultrasonic flaw detector (Fine SAT FS100II: manufactured by Hitachi Power Solutions Co., Ltd.), and ultrasonic flaw detection images were obtained. The obtained ultrasonic flaw detection images were binarized using analysis software attached to the ultrasonic flaw detector, and the area of ​​the bonded region free of defects such as unbonded portions was calculated. The ratio of the area of ​​the bonded region free of defects such as unbonded portions to the area coated with the brazing filler metal was then determined, and this ratio was taken as the bonding rate (%). The results for Examples 1 to 3 are shown in Table 1, and the results for Comparative Examples 1 and 2 are shown in Table 2.

[0097] [Table 1] [Table 2]

[0098] [Consideration] The bonding rates of the metal-ceramic bonding substrates according to Examples 1 to 3 were higher than those of Comparative Examples 1 and 2. This indicates that the methods for manufacturing metal-ceramic bonding substrates according to Examples 1 to 3 are methods for manufacturing metal-ceramic bonding substrates with good wetting and spreading of the brazing filler metal and few unbonded portions. In particular, in Example 2, the brazing filler metal spread over an area wider than the area where the brazing filler metal was initially applied, achieving a bonding rate of more than 100%, and no unbonded portions were observed. In contrast to this, in Comparative Examples 1 and 2, the bonding rate was about 94 to 96%, and defects occurred in which 4 to 6% of the bonding layer was unbonded.

[0099] This is thought to be because the brazing filler metals of Examples 1 to 3 have a short physical distance between the active metal in the brazing filler metal placed on the surface of the ceramic substrate and the ceramic substrate, thereby accelerating the chemical reaction between the active metal and the ceramic substrate and improving the wetting and spreading of the brazing filler metal. Furthermore, by increasing the physical distance between the active metal contained in the first brazing filler metal and the Sn contained in the second brazing filler metal, it is thought that the active metal and Sn form an intermetallic compound, which inhibits the chemical reaction between the active metal and the ceramic substrate, thereby improving the wetting and spreading of the brazing filler metal. As a result, it is thought that the occurrence of unjoined portions between the ceramic substrate and the metal plate can be suppressed.

[0100] On the other hand, the brazing filler metals of Comparative Examples 1 and 2 contain Ag, Cu, Sn, etc. in addition to the active metal Ti, which causes a physical distance between the active metal and the ceramic substrate, preventing the chemical reaction between the active metal and the ceramic substrate and thus preventing the brazing filler metal from wetting and spreading. Also, the Sn contained in the brazing filler metals of Comparative Examples 1 and 2 and the active metal Ti form an intermetallic compound, which inhibits the chemical reaction between the active metal and the ceramic substrate and therefore prevents the brazing filler metal from wetting and spreading.

[0101] In the present invention, a first brazing filler metal, whose metallic component is an active metal, is disposed on at least one surface of a ceramic substrate, and a second brazing filler metal, whose metallic component does not include the above-mentioned active metal and is composed of Ag, Cu, and Sn, is disposed on at least one surface of a copper plate. A manufacturing method is then implemented in which the first brazing filler metal and the second brazing filler metal are brought into contact with each other to form a laminate of a ceramic substrate and a copper plate, which is then heated while applying a load. By implementing this manufacturing method, the active metal and the ceramic substrate are physically closer to each other, promoting a chemical reaction between the active metal and the ceramic substrate and suppressing a reaction between Sn and the active metal. This is thought to ensure sufficient wettability of the brazing filler metal and reduce non-bonding defects. [Explanation of symbols]

[0102] 10 Ceramic substrate 12 First brazing filler metal 14 Second brazing filler metal 16 metal plate 18 spacer 22 First bonding layer 24 Second bonding layer 30 Ceramic substrate on which first brazing material is arranged 31 Metal plate on which second brazing material is placed 32 Metal-ceramic bonded substrate

Claims

1. A method for manufacturing a metal-ceramic bonding substrate, comprising: A laminate is formed on at least one surface of a ceramic substrate, in which a first brazing filler metal containing at least one active metal selected from Ti, Zr, Hf, and Nb, a second brazing filler metal containing a metal consisting of Ag, Cu, and Sn, and a metal plate are arranged in the stated order; A method for producing a metal-ceramic bonding substrate, characterized in that a metal plate is bonded to a ceramic substrate by heating a laminate while applying a load in the thickness direction of the laminate.

2. A method for manufacturing a metal-ceramic bonding substrate, comprising: A first brazing filler metal containing at least one active metal selected from Ti, Zr, Hf, and Nb is disposed on at least one surface of a ceramic substrate; A second brazing filler metal containing Ag, Cu, and Sn is disposed on one surface of the metal plate; forming a laminate by laminating the ceramic substrate and the metal plate such that the first brazing filler metal and the second brazing filler metal are in contact with each other; A method for producing a metal-ceramic bonding substrate, characterized in that a metal plate is bonded to a ceramic substrate by heating a laminate while applying a load in the thickness direction of the laminate.

3. In the ceramic substrate of the laminate, the amount of the active metal in the first brazing filler metal per unit area is 0.1 mg / cm ２ 0.5mg / cm or more ２ 3. The method for producing a metal / ceramic bonding substrate according to claim 1, wherein the following is performed:

4. In the ceramic substrate of the laminate, the total amount of the active metal in the first and second brazing filler metals per unit area and the amount of the metal consisting of Ag, Cu, and Sn per unit area is 10 mg / cm ２ 20mg / cm or more ２ 3. The method for producing a metal / ceramic bonding substrate according to claim 1, wherein the following is performed:

5. In the ceramic substrate of the laminate, 3. The method for producing a metal-ceramic bonding substrate according to claim 1, wherein an active metal amount ratio, which is a ratio of the amount of the active metal arranged per unit area in the first brazing filler metal to the sum of the amount of the active metal arranged per unit area in the first and second brazing filler metals and the amount of the metal consisting of Ag, Cu, and Sn arranged per unit area, is 0.5% or more and 5% or less.

6. 3. The method for producing a metal / ceramic bonding substrate according to claim 1, wherein the first brazing filler metal contains only at least one active metal selected from the group consisting of Ti, Zr, Hf, and Nb.

7. 3. The method for producing a metal / ceramic bonding substrate according to claim 1, wherein the first brazing filler metal contains only Ti as a metal.

8. In the ceramic substrate of the laminate before heating, the first brazing filler metal contains, as metals, at least one active metal selected from Ti, Zr, Hf, and Nb, and a metal consisting of Ag and Cu, the amount of Ag is such that, when the total mass of Ag, Cu, and Sn in the first brazing filler metal and the second brazing filler metal is 100 parts by mass, the total mass of the amounts of Ag in the first brazing filler metal and the second brazing filler metal is 15 parts by mass or more and 85 parts by mass or less; 3. The method for manufacturing a metal-ceramic bonding substrate according to claim 1 or 2, wherein the amount of Cu is such that, when the total mass of Ag, Cu, and Sn in the first brazing filler metal and the second brazing filler metal is 100 parts by mass, the total mass of the amount of Cu in the first brazing filler metal and the second brazing filler metal is 5 parts by mass or more and 60 parts by mass or less.

9. 0.005 kgf / cm in the thickness direction of the laminate ２ More than 0.5kgf / cm ２ 3. The method for producing a metal / ceramic bonding substrate according to claim 1, wherein the metal plate is bonded to the ceramic substrate by heating while applying the following load:

Images