JP2018022738A - Method for producing insulating substrate and insulating substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an insulating substrate, capable of satisfactorily joining an insulating layer made of ceramic and a layer arranged to be laminated to the insulating layer, and an insulating substrate.SOLUTION: An insulating substrate includes a first constituent layer and a second constituent layer 2 arranged on at least one side of both sides of the first constituent layer in a thickness direction to be laminated to the first constituent layer. The first constituent layer is an insulating layer 3 made of ceramic. The second constituent layer 2 is made of an aluminum-based composite material containing carbon particles as particles that are composited with aluminum. The insulating layer 3 and the second constituent layer 2 are joined to each other by brazing with a brazing sheet 10 interposed therebetween.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an insulating substrate on which a heat generating element such as an electronic element is mounted and a method for manufacturing the same.

  In the present specification and claims, the term “aluminum” is used to include both pure aluminum and an aluminum alloy unless otherwise specified, and the term “plate” is specifically indicated. Except in some cases, “foil” is used to mean.

  Further, although the vertical direction of the insulating substrate according to the present invention is not limited, in this specification and the claims, in order to facilitate understanding of the configuration of the insulating substrate, the insulating substrate on which the heat generating element is mounted. Is defined as the upper side of the insulating substrate, and the opposite side is defined as the lower side of the insulating substrate.

  Regarding the conventional method of manufacturing an insulating substrate on which an exothermic element such as an electronic element is mounted, a wiring layer (also referred to as a circuit layer) is arranged in a laminated form on a ceramic insulating layer via a brazing material plate. In addition, it is known that the insulating layer and the wiring layer are joined to each other by brazing (for example, Patent Documents 1 and 2).

  In the insulating substrate, the heat generating element is mounted on the mounting surface composed of the upper surface of the wiring layer by, for example, soldering. In general, the insulating substrate is bonded onto a cooling member (including a heat radiating member) in order to cool the heat generating element that generates heat as the heat generating element operates.

  In general, an insulating substrate is required to have high reliability (eg, bonding reliability) with respect to a thermal cycle load.

No. 8-10202 JP 2011-66387 A (paragraph [0002])

  In recent years, the stress acting on the insulating layer tends to increase due to an increase in the amount of heat generated from the heat generating element and the thinning of the insulating layer of the insulating substrate. High reliability is required. In order to satisfy this requirement, it is necessary to satisfactorily bond an insulating layer and a layer (for example, a wiring layer, a buffer layer) arranged in a laminated form with respect to the insulating layer.

  The present invention has been made in view of the above-described technical background, and an object of the present invention is to provide an insulating substrate that can satisfactorily bond a ceramic insulating layer and a layer arranged in a laminated manner to the insulating layer. An object of the present invention is to provide a manufacturing method, and to provide an insulating substrate in which a ceramic insulating layer and a layer arranged in a laminated form with respect to the insulating layer are well bonded.

  The present invention provides the following means.

[1] An insulating substrate comprising: a first constituent layer; and a second constituent layer disposed on at least one side of the first constituent layer in a thickness direction with respect to the first constituent layer. A manufacturing method of
The first constituent layer is a ceramic insulating layer,
The second constituent layer is made of an aluminum-based composite material containing carbon particles as particles to be composited with aluminum,
A method of manufacturing an insulating substrate, wherein the insulating layer and the second constituent layer are joined to each other by brazing via a brazing sheet.

  [2] The preceding item in which the insulating layer and the second constituent layer are joined so that an average crystal grain size of the brazing sheet is 10 μm or more and 300 μm or less after the insulating layer and the second constituent layer are joined. 2. A method for producing an insulating substrate according to 1.

  [3] The preceding item 1 or 2, wherein the insulating layer and the second constituent layer are joined such that the brazing sheet has a thickness of 60 μm or more and 500 μm or less after the insulating layer and the second constituent layer are joined. 3. A method for producing an insulating substrate according to 2.

[4] The second constituent layer is disposed on both sides in the thickness direction of the first constituent layer,
The insulating layer and one of the second constituent layers are joined to each other by brazing through the first brazing sheet, and at the same time, the insulating layer and the other second constituent layer are joined to each other by brazing through the second brazing sheet. The method for manufacturing an insulating substrate according to any one of the preceding items 1 to 3.

[5] Insulating substrate comprising: a first component layer; and a second component layer disposed on at least one side of both sides of the first component layer in the thickness direction with respect to the first component layer. Because
The first constituent layer is a ceramic insulating layer,
The second constituent layer is made of an aluminum-based composite material containing carbon particles as particles to be composited with aluminum,
An insulating substrate in which the insulating layer and the second constituent layer are joined to each other by brazing via a brazing sheet.

  [6] The insulating substrate according to item 5 above, wherein an average crystal grain size of the brazing sheet is 10 μm or more and 300 μm or less.

  [7] The insulating substrate according to item 5 or 6 above, wherein the thickness of the brazing sheet is 60 μm or more and 500 μm or less.

[8] The second constituent layer is disposed on both sides in the thickness direction of the first constituent layer,
The insulating layer and one of the second constituent layers are joined together by brazing via a first brazing heat, and the insulating layer and the other second constituent layer are joined by brazing via a second brazing sheet. The insulating substrate according to any one of the preceding items 5 to 7, which are bonded to each other.

  The present invention has the following effects.

  In the preceding paragraph 1, since the second constituent layer is made of an aluminum-based composite material containing carbon particles as particles to be composited with aluminum, the linear expansion coefficient of the second constituent layer is reduced. The difference between the linear expansion coefficient and the linear expansion coefficient of the second constituent layer can be reduced. Thereby, the stress resulting from the difference in linear expansion coefficient between the insulating layer and the second constituent layer can be reduced.

  Furthermore, the insulating layer and the second constituent layer can be favorably joined by joining the insulating layer and the second constituent layer to each other by brazing via a brazing sheet.

  By these actions, the reliability of the insulating substrate with respect to the thermal cycle load can be enhanced.

  In the preceding item 2, the brazing sheet is brazed between the second component layer and the brazing sheet when the thermal cycle is applied, because the average crystal grain size of the brazing sheet is 10 μm or more and 300 μm or less after the insulating layer and the second component layer are joined. The stress generated in the part can be surely relieved. Thereby, the reliability with respect to the cooling cycle load of an insulated substrate can further be improved.

  In the previous item 3, the thickness of the brazing sheet is 60 μm or more and 500 μm or less after the insulating layer and the second constituent layer are joined, so that the insulating layer and the second constituent layer can be joined better. Moreover, the breakage of the insulating layer due to the stress acting on the insulating layer from the brazing sheet can be reliably suppressed. Thereby, the reliability with respect to the cooling cycle load of an insulated substrate can further be improved.

  In the preceding item 4, since the insulating layer and one second constituent layer are joined simultaneously with the insulating layer and the other second constituent layer, the manufacturing time of the insulating substrate can be shortened.

  In the preceding item 5, it is possible to improve the reliability of the insulating substrate with respect to the thermal cycle load.

  In the preceding items 6 to 8, the reliability of the insulating substrate with respect to the cooling cycle load can be further improved.

FIG. 1 is a schematic front view of an insulating substrate according to the first embodiment of the present invention. FIG. 2 is a schematic front view showing the insulating substrate in a state of being manufactured. FIG. 3 is a schematic front view showing the insulating substrate according to the second embodiment of the present invention in the middle of manufacturing. FIG. 4 is a schematic front view of an insulating substrate according to a reference embodiment (comparative example) of the present invention. FIG. 5 is an enlarged view of a portion A in FIG. FIG. 6 is a schematic front view showing the insulating substrate in a state of being manufactured.

  Next, several embodiments of the present invention will be described below with reference to the drawings.

  1 and 2 are diagrams for explaining a first embodiment of the present invention.

  As shown in FIG. 1, the insulating substrate 1 of the first embodiment includes a plurality of constituent layers constituting the insulating substrate 1, and the plurality of constituent layers are joined and integrated in a laminated form by brazing. It is formed by.

  The plurality of constituent layers include a wiring layer 2, an insulating layer 3, and a buffer layer 4. The buffer layer 4, the insulating layer 3, the brazing sheet 10, and the wiring layer 2 are joined and integrated by brazing in order from the bottom to the top, thereby forming the insulating substrate 1. Yes.

  Further, the buffer layer 4 and the cooling member 5 disposed below the buffer layer 4 are joined to each other by brazing, whereby the insulating substrate 1 is joined onto the cooling member 5. Therefore, the insulating substrate 1 of the first embodiment is provided with the cooling member 5 in detail. Such an insulating substrate 1 with the cooling member 5 is also called a cooler.

  In the insulating substrate 1 of the first embodiment, the insulating layer 3 and the wiring layer 2 correspond to the “first constituent layer” and the “second constituent layer” recited in the claims, respectively.

The insulating layer (first constituent layer) 3 is made of ceramic and has electrical insulation. Specifically, the insulating layer 3 is formed of a ceramic plate such as an AlN (aluminum nitride) plate, an Al ₂ O ₃ (alumina) plate, or a Si ₃ N ₄ (silicon nitride) plate.

  The wiring layer (second constituent layer) 2 is also called a circuit layer and is made of an aluminum-based composite material containing carbon particles as particles to be combined with aluminum. Details of this composite material will be described later.

  The wiring layer 2 has a mounting surface 2a composed of the flat upper surface. A heat generating element 20 (indicated by a two-dot chain line in FIG. 1) is mounted on the mounting surface 2a by a predetermined bonding means (eg, soldering). The exothermic element 20 generates heat with the operation of the exothermic element 20, and is, for example, an electronic element (including a semiconductor chip).

  The buffer layer 4 is a layer for relaxing stress such as thermal stress generated in the insulating substrate 1. In the first embodiment, the buffer layer 4 is formed of an aluminum plate. More specifically, for example, the buffer layer 4 is formed of a high-purity aluminum plate. The purity of the high purity aluminum plate is, for example, 4N or more.

  The shapes of the wiring layer 2, the insulating layer 3, and the buffer layer 4 are, for example, substantially rectangular shapes in plan view. The length of one side of the insulating layer 3 is set to be larger than the length of one side of the wiring layer 2 and further set to be longer than the length of one side of the buffer layer 4.

  The cooling member 5 is for cooling the exothermic element 20, and is made of metal such as aluminum. In the first embodiment, the cooling member 5 is, for example, a heat radiating member (such as a heat sink).

  However, in the present invention, the cooling member 5 is not limited to being a heat radiating member. In addition, for example, as in the cooling member 105 of the second embodiment shown in FIG. It may be a cooling member provided with a channel 105a through which (example: cooling liquid) flows.

  The insulating layer 3 and the wiring layer 2 are joined to each other by brazing via the brazing sheet 10. The insulating layer 3 and the buffer layer 4 are joined to each other by brazing. The buffer layer 4 and the cooling member 5 are joined together by brazing.

  Therefore, the insulating substrate 1 includes a brazing part (first brazing part) 1a in which the insulating layer 3 and the brazing sheet 10 are joined, and a brazing part (second brazing part) in which the wiring layer 2 and the brazing sheet 10 are joined. 1b, a brazing part (third brazing part) 1c in which the insulating layer 3 and the buffer layer 4 are joined, and a brazing part (fourth brazing part) 1d in which the buffer layer 4 and the cooling member 5 are joined. ing.

  In FIG. 1, the wiring layer 2 and the brazing sheet 10 are shown in cross section for easy understanding of the respective configurations, and hatching such as oblique lines attached to the cross section of the wiring layer 2 and the cross section of the brazing sheet 10. Are omitted.

  Next, the configuration of the wiring layer 2 will be described below.

  The wiring layer 2 is made of an aluminum-based composite material containing carbon particles as particles that are combined with aluminum as described above. Hereinafter, this composite material is also referred to as “aluminum-based carbon particle composite material”.

  The type of the composite material is not limited. Desirably, the composite material is obtained by sintering and integrating a plurality of coated foils obtained by coating a carbon particle layer on an aluminum foil in a laminated state (hereinafter referred to as “laminated sintered composite material”). Or a mixture of aluminum particles (eg, aluminum powder) and carbon particles (eg, carbon powder) sintered (this composite material is hereinafter referred to as “particle-sintered composite material”). It is good to be. All of these composite materials use aluminum as a matrix and contain carbon particles as particles to be combined with the aluminum.

  Reference numeral “7” in FIG. 1 indicates carbon particles of the composite material, and reference numeral “8” in FIG. 1 indicates a matrix of the composite material. The matrix 8 is made of aluminum as described above.

  The kind of aluminum is not limited. In particular, it is desirable that aluminum has a high thermal conductivity such as high-purity aluminum.

  The kind of carbon particle 7 is not limited. In particular, it is desirable that the carbon particles 7 have a high thermal conductivity and can be easily combined with aluminum. Specifically, the carbon particles 7 are one type of carbon particles selected from the group consisting of carbon fibers, carbon nanotubes, graphene, natural graphite particles, and artificial graphite particles, or mixed carbon particles in which two or more types of carbon particles are mixed. It is desirable that the carbon particle, carbon nanotube, graphene, and natural graphite particles are selected from one type of carbon particles or a mixture of two or more types of carbon particles.

  As the carbon fiber, pitch-based carbon fiber, PAN-based carbon fiber, or the like is preferably used.

  As the carbon nanotubes, single-walled carbon nanotubes, multi-walled carbon nanotubes, vapor-grown carbon fibers (including VGCF (registered trademark)) and the like are preferably used.

  As graphene, single layer graphene, multilayer graphene, or the like is preferably used.

  As natural graphite particles, scaly graphite particles and the like are preferably used.

  As the artificial graphite particles, anisotropic graphite particles, pyrolytic graphite particles and the like are preferably used.

  The size of the carbon particles 7 is not limited. However, when the carbon particles 7 are carbon fibers, short carbon fibers are preferably used, and in particular, short carbon fibers having an average fiber length of 10 μm or more and 2 mm or less are preferably used. When the carbon particles 7 are carbon nanotubes, carbon nanotubes having an average length of 1 μm or more and 10 μm or less are particularly preferably used. When the carbon particles 7 are natural graphite particles and artificial graphite particles, natural graphite particles and artificial graphite particles having an average particle diameter of 10 μm or more and 3 mm or less are particularly preferably used.

  Next, a method for manufacturing the insulating substrate 1 according to the first embodiment will be described below.

  As shown in FIG. 2, the wiring layer 2, the insulating layer 3, the buffer layer 4, the cooling member 5, and the brazing sheet 10 are prepared.

  The brazing sheet 10 is for joining the wiring layer 2 and the insulating layer 3 to each other by brazing. As shown in FIG. 2, the skin material 12 made of brazing material is formed on the upper and lower surfaces of the core material 11 by rolling or the like. It is formed by being clad. That is, the brazing sheet 10 is a double-sided brazing sheet in detail. In the present embodiment, the skin material 12 provided on the upper surface of the brazing sheet 10 is referred to as the epithelial material 12a of the brazing sheet 10, and the skin material 12 provided on the lower surface of the brazing sheet 10 is referred to as the lower skin material 12b of the brazing sheet 10. .

  It is desirable that the brazing sheet 10 has an average crystal grain size of 10 μm or more and 300 μm or less after the insulating layer 3 and the wiring layer 2 are joined. The reason is as follows. That is, the strength of the brazing sheet 10 increases as the crystal grains contained in the brazing sheet 10 (see FIG. 1, reference numeral “9”) become finer. Thereby, the strength of the brazing sheet 10 approaches the strength of the wiring layer 2 (that is, the strength of the above-described aluminum-based carbon particle composite material that is the material of the wiring layer 2). As a result, the stress generated in the brazed portion (second brazed portion) 1b between the wiring layer 2 and the brazing sheet 10 during a cold cycle load can be reliably relaxed. A particularly desirable lower limit of the average crystal grain size is 30 μm, and a particularly desirable upper limit is 200 μm.

  The kind of the core material 11 of the brazing sheet 10 is not limited. The core material 11 is made of, for example, aluminum, and is particularly preferably made of an Al—Mn-based aluminum alloy (eg, A3003). The reason is that the average crystal grain size of the brazing sheet 10 can be reliably in the above-described desirable range after the insulating layer 3 and the wiring layer 2 are joined.

  The kind of each skin material 12 (12a, 12b) of the brazing sheet 10 is not limited. Each skin material 12 is made of, for example, a brazing material of an aluminum alloy, and particularly preferably made of a brazing material of an Al—Si—Mg-based aluminum alloy. The reason is that the insulating layer 3 and the wiring layer 2 can be satisfactorily bonded when the bonding between the insulating layer 3 and the wiring layer 2 is performed by vacuum brazing. Further, each skin material 12 may be made of an aluminum alloy brazing material to which Bi is added. In this case, the fluidity of each skin material (brazing material) 12 at the time of joining (ie, brazing). Is desirable in terms of improvement.

  Furthermore, it is desirable that the brazing sheet 10 has a thickness of 60 μm or more and 500 μm or less after the insulating layer 3 and the wiring layer 2 are joined. The reason is as follows. That is, the occurrence of erosion of the brazing sheet 10 due to the brazing sheet 10 being too thin can be reliably suppressed, so that the insulating layer 3 and the wiring layer 2 can be reliably bonded to each other. Furthermore, the problem that the insulating layer 3 breaks due to a large stress acting on the insulating layer 3 when the brazing sheet 10 is too thick can be reliably suppressed. A particularly desirable lower limit of the thickness is 80 μm, and a particularly desirable upper limit is 300 μm.

  Brazing material layers 4 a and 4 b are clad by rolling or the like on both surfaces in the thickness direction of the buffer layer 4, respectively, whereby brazing material layers 4 a and 4 b are provided on both surfaces of the buffer layer 4, respectively.

  The brazing material layer 4a on one surface in the thickness direction of the buffer layer 4 (that is, the upper surface of the buffer layer 4) is for joining the insulating layer 3 and the buffer layer 4 by brazing. The brazing material layer 4b on the other side in the thickness direction of the buffer layer 4 (that is, the lower surface of the buffer layer 4) is for joining the buffer layer 4 and the cooling member 5 by brazing. The kind of each brazing filler metal layer 4a, 4b is not limited. For example, each brazing material layer 4a, 4b is made of, for example, an aluminum alloy brazing material, and more specifically, is made of the same kind of brazing material as the brazing material of the skin material 12 of the brazing sheet 10 described above.

  Next, as shown in FIG. 2, the wiring layer 2, the brazing sheet 10, the insulating layer 3, the buffer layer 4, and the cooling member 5 are arranged in this order to form a laminated body. Then, by heating the laminated body in a predetermined brazing atmosphere with a predetermined brazing temperature and a predetermined brazing time in a state where a compressive load in the laminating direction is applied as a brazing load to the laminated body, The brazing sheet 10, the insulating layer 3, the buffer layer 4 and the cooling member 5 are joined and integrated together by brazing (eg, vacuum brazing). That is, the wiring layer 2 and the insulating layer 3 are joined to each other by brazing via the brazing sheet 10, and at the same time, the insulating layer 3 and the buffer layer 4 are joined to each other by brazing, and at the same time, the buffer layer 4 and the cooling member 5 are brazed. Are joined together. As a result, the above-described insulating substrate 1 (specifically, the insulating substrate 1 with the cooling member 5) of the first embodiment is obtained.

  The joining condition by brazing described above, that is, the brazing condition is not limited. Desirable brazing load is 0.01-1 MPa, desirable brazing atmosphere is vacuum, non-oxidizing gas atmosphere (eg, argon gas atmosphere, nitrogen gas atmosphere), and desirable brazing temperature is 590-620 ° C. The desirable brazing time (ie, the brazing temperature holding time) is 1 to 60 min. By joining and integrating the wiring layer 2, the brazing sheet 10, the insulating layer 3, the buffer layer 4, and the cooling member 5 under these desirable brazing conditions, the brazing sheet 10 in a state after the insulating layer 3 and the wiring layer 2 are joined. The average crystal grain size and thickness of each can be reliably set within the desired ranges described above.

  In the insulating substrate 1, the insulating layer 3 and the brazing sheet 10 are joined by a brazing material of a base material 12 b of the brazing sheet 10, and the wiring layer 2 and the brazing sheet 10 are joined by a brazing material of an epithelial material 12 a of the brazing sheet. The insulating layer 3 and the buffer layer 4 are joined by the brazing material of the brazing material layer 4 a on the upper surface of the buffer layer 4, and the buffer layer 4 and the cooling member 5 are brazed on the brazing material layer 4 b on the lower surface of the buffer layer 4. Joined with materials.

  In order to improve the solderability of the mounting surface 2a on the mounting surface 2a of the wiring layer 2 of the insulating substrate 1, a nickel layer such as nickel plating is bonded before the exothermic element 20 is joined to the mounting surface 2a by soldering. May be formed.

  In the insulating substrate 1 of the first embodiment, since the wiring layer 2 is made of an aluminum-based carbon particle composite material, the linear expansion coefficient of the wiring layer 2 is reduced. Therefore, the linear expansion coefficient and the wiring of the ceramic insulating layer 3 are reduced. The difference from the linear expansion coefficient of the layer 2 can be reduced. Thereby, the stress resulting from the difference in coefficient of linear expansion between the insulating layer 3 and the wiring layer 2 can be reduced.

  Furthermore, the insulating layer 3 and the wiring layer 2 can be favorably bonded by bonding the insulating layer 3 and the wiring layer 2 to each other by brazing via the brazing sheet 10.

  By these actions, the reliability (especially the bonding reliability) of the insulating substrate 1 with respect to the thermal cycle load can be improved.

  FIG. 3 is a diagram for explaining a second embodiment of the present invention. In the figure, elements having the same action as the elements of the insulating substrate 1 of the first embodiment are given reference numerals obtained by adding 100 to the reference numerals. The insulating substrate 101 and the manufacturing method thereof according to the second embodiment will be described below with a focus on differences from the insulating substrate 1 according to the first embodiment and the manufacturing method thereof.

  In the insulating substrate 101 of the second embodiment, the insulating layer 103 corresponds to the “first constituent layer” described in the claims, and the wiring layer 102 and the buffer layer 104 are described in the claims. It corresponds to “one second constituent layer” and “the other second constituent layer”.

  In the manufacturing method of the insulating substrate 101 of the second embodiment, as shown in the figure, the wiring layer 102, the insulating layer 103, the buffer layer 104, the cooling member 105, the first brazing sheet 110, the second brazing sheet 120, and the first Three brazing sheets 130 are prepared.

  The first brazing sheet 110 is for joining the wiring layer 102 and the insulating layer 103 together by brazing, and the core materials 111 are clad by rolling or the like with the skin materials 112a and 112b made of brazing material, respectively. Is formed. That is, the first brazing sheet 110 is a double-sided brazing sheet in detail.

  The second brazing sheet 120 is for joining the insulating layer 103 and the buffer layer 104 to each other by brazing, and the skin materials 122a and 122b made of brazing material are clad by rolling or the like on both surfaces of the core material 121, respectively. Is formed. That is, in detail, the second brazing sheet 120 is a double-sided brazing sheet.

  The third brazing sheet 130 is for joining the buffer layer 104 and the cooling member 105 to each other by brazing, and the skin materials 132a and 132b made of brazing material are clad by rolling or the like on both surfaces of the core material 131, respectively. Is formed. That is, the third brazing sheet 130 is a double-sided brazing sheet in detail.

  It is desirable that the first brazing sheet 110 has an average crystal grain size of 10 μm or more and 300 μm or less after the wiring layer 102 and the insulating layer 103 are joined. The reason is the same as that of the brazing sheet 10 of the first embodiment described above. A particularly desirable lower limit of the average crystal grain size is 30 μm, and a particularly desirable upper limit is 200 μm.

  As for the 2nd brazing sheet 120, it is desirable for the average crystal grain size of the 2nd brazing sheet 120 to become 10 micrometers or more and 300 micrometers or less after the insulating layer 103 and the buffer layer 104 are joined. The reason is the same as that of the brazing sheet 10 of the first embodiment described above. A particularly desirable lower limit of the average crystal grain size is 30 μm, and a particularly desirable upper limit is 200 μm.

  As for the 3rd brazing sheet 130, it is desirable for the average crystal grain size of the 3rd brazing sheet 130 to become 10 micrometers or more and 300 micrometers or less after the buffer layer 104 and the cooling member 105 are joined. The reason is the same as that of the brazing sheet 10 of the first embodiment described above. A particularly desirable lower limit of the average crystal grain size is 30 μm, and a particularly desirable upper limit is 200 μm.

  The types of the core materials 111, 121, and 131 of the first to third brazing sheets 110, 120, and 130 are not limited. The cores 111, 121, and 131 are made of, for example, aluminum, and are particularly preferably made of an Al—Mn-based aluminum alloy (eg, A3003). The reason is the same as the reason for the core material 11 of the brazing sheet 10 of the first embodiment described above.

  The types of the skin materials 112, 122, 132 of the first to third brazing sheets 110, 120, 130 are not limited. Each of the skin materials 112, 122, 132 is made of, for example, a brazing material of an aluminum alloy, and particularly preferably made of a brazing material of an Al—Si—Mg-based aluminum alloy. The reason is the same as the reason for the skin 12 of the brazing sheet 10 of the first embodiment described above. Each skin material 12 may be made of an aluminum alloy brazing material to which Bi is added.

  It is preferable that the first brazing sheet 110 has a thickness of 60 μm or more and 500 μm or less after the wiring layer 102 and the insulating layer 103 are joined. The reason is the same as the reason for the thickness of the brazing sheet 10 of the first embodiment described above. A particularly desirable lower limit of the thickness is 80 μm, and a particularly desirable upper limit is 300 μm.

  As for the 2nd brazing sheet 120, it is desirable for the thickness of the 2nd brazing sheet 120 to be 60 micrometers or more and 500 micrometers or less after the insulating layer 103 and the buffer layer 104 are joined. The reason is the same as the reason for the thickness of the brazing sheet 10 of the first embodiment described above. A particularly desirable lower limit of the thickness is 80 μm, and a particularly desirable upper limit is 300 μm.

  As for the 3rd brazing sheet 130, it is desirable for the thickness of the 3rd brazing sheet 130 to become 60 micrometers or more and 500 micrometers or less in the state after joining the buffer layer 104 and the cooling member 105. FIG. The reason is the same as the reason for the thickness of the brazing sheet 10 of the first embodiment described above. A particularly desirable lower limit of the thickness is 80 μm, and a particularly desirable upper limit is 300 μm.

  The buffer layer 104 is made of an aluminum-based carbon particle composite material. The type of the composite material is not limited. For example, the composite material may be the same as or different from the aluminum-based carbon particle composite material that is the material of the wiring layer 2 of the first embodiment described above.

  Further, the brazing material layer is not provided on both surfaces of the buffer layer 104 in the thickness direction.

  The cooling member 105 is provided with a flow path 105a through which a cooling fluid (for example, cooling liquid) flows. In FIG. 3, in order to facilitate understanding of the internal structure of the cooling member 105, the cooling member 105 is shown in cross section, and hatching such as oblique lines attached to the cross section of the cooling member 105 is omitted.

  Next, as shown in the figure, the wiring layer 102, the first brazing sheet 110, the insulating layer 103, the second brazing sheet 120, the buffer layer 104, the third brazing sheet 130, and the cooling member 105 are arranged in this order. These laminates are formed. Then, by heating the laminated body in a predetermined brazing atmosphere with a predetermined brazing temperature and a predetermined brazing time in a state where a compressive load in the laminating direction is applied as a brazing load to the laminated body, The first brazing sheet 110, the insulating layer 103, the second brazing sheet 120, the buffer layer 104, the third brazing sheet 130, and the cooling member 105 are joined and integrated together by brazing (eg, vacuum brazing). That is, the wiring layer 102 and the insulating layer 103 are joined to each other by brazing via the first brazing sheet 110, and at the same time, the insulating layer 103 and the buffer layer 104 are joined to each other by brazing via the second brazing sheet 120. The buffer layer 104 and the cooling member 105 are joined to each other by brazing via the third brazing sheet 130. As a result, the insulating substrate 101 of the second embodiment (more specifically, the insulating substrate 101 with the cooling member 105) is obtained.

  The joining condition by brazing described above, that is, the brazing condition is not limited, and is the same as, for example, the brazing condition of the first embodiment described above.

  In the insulating substrate 101, the insulating layer 103 and the first brazing sheet 110 are joined by the brazing material of the base material 112 b of the first brazing sheet 110, and the wiring layer 102 and the first brazing sheet 110 are the epithelial material of the first brazing sheet 110. 112 a brazing material, the insulating layer 103 and the second brazing sheet 120 are joined by the epithelial material 122 a brazing material of the second brazing sheet 120, and the buffer layer 104 and the second brazing sheet 120 are joined by the second brazing sheet 120. The brazing material of the lower skin material 122b is joined, the buffer layer 104 and the third brazing sheet 130 are joined by the brazing material of the epithelial material 132a of the third brazing sheet 130, and the cooling member 105 and the third brazing sheet 130 are joined by the third brazing. Contact with the brazing material of the base material 132b of the sheet 130 It is.

  Therefore, the insulating substrate 101 includes a brazing portion (first brazing portion) where the insulating layer 103 and the first brazing sheet 110 are joined, and a brazing portion (second brazing portion) where the wiring layer 102 and the first brazing sheet 110 are joined. Brazing part), a brazing part (third brazing part) in which the insulating layer 103 and the second brazing sheet 120 are joined, and a brazing part (fourth brazing part) in which the buffer layer 104 and the second brazing sheet 120 are joined. ), A brazing part (fifth brazing part) in which the buffer layer 104 and the third brazing sheet 130 are joined, and a brazing part (sixth brazing part) in which the cooling member 105 and the third brazing sheet 130 are joined. It has.

  In the manufacturing method of the insulating substrate 101 of the second embodiment, the insulating layer 103 and the wiring layer 102 are joined to each other by brazing via the first brazing sheet 110, and at the same time, the insulating layer 103 and the buffer layer 104 are bonded to the second brazing sheet 120. Since the buffer layer 104 and the cooling member 105 are joined to each other by brazing via the third brazing sheet 130, the manufacturing time of the insulating substrate 101 can be greatly shortened. Can do.

  Furthermore, since not only the wiring layer 102 but also the buffer layer 104 is made of an aluminum-based carbon particle composite material, not only the stress caused by the difference in the linear expansion coefficient between the insulating layer 103 and the wiring layer 102 but also the insulating layer 103 and the buffer layer 104. The stress caused by the difference in linear expansion coefficient between the layer 104 and the insulating layer 103 and the buffer layer 104 can be favorably bonded. Therefore, the reliability (especially the bonding reliability) of the insulating substrate 101 with respect to the thermal cycle load can be greatly increased.

  4-6 is a figure explaining the reference form of this invention. In the drawing, elements having the same action as the elements of the insulating substrate 1 of the first embodiment are given reference numerals obtained by adding 200 to the reference numerals. The insulating substrate 201 and its manufacturing method of the present embodiment will be described below with a focus on differences from the insulating substrate 1 of the first embodiment and its manufacturing method.

  As shown in FIG. 4, in the insulating substrate 201 of this embodiment, the insulating layer 203 and the wiring layer 202 are directly joined to each other by brazing without using a brazing sheet.

  In the method for manufacturing the insulating substrate 201 according to this embodiment, as shown in FIG. 6, a wiring layer 202, an insulating layer 203, a buffer layer 204, a cooling member 205 and a brazing material plate 15 are prepared.

  The wiring layer 202 is made of an aluminum-based carbon particle composite material, like the wiring layer 2 of the first embodiment.

  The brazing material plate 15 is for joining the wiring layer 202 and the insulating layer 203, and is made of, for example, a brazing material of an Al—Si—Mg based aluminum alloy.

  The insulating layer 203 is made of ceramic like the insulating layer 3 of the first embodiment.

  The buffer layer 204 is formed of an aluminum plate in the same manner as the buffer layer 4 of the first embodiment. More specifically, the buffer layer 204 is formed of, for example, a high-purity aluminum plate. Further, brazing material layers 204a and 204b are clad by rolling or the like on both surfaces in the thickness direction of the buffer layer 204, as in the buffer layer 4 of the first embodiment, whereby the both surfaces of the buffer layer 4 are brazed. Material layers 204a and 204b are provided.

  The cooling member 205 is made of a metal such as aluminum, like the cooling member 5 of the first embodiment.

  Next, as shown in FIG. 6, the wiring layer 202, the brazing material plate 15, the insulating layer 203, the buffer layer 204, and the cooling member 205 are arranged in this order to form a laminated body. Then, the wiring body 202 is heated by a predetermined brazing temperature and a predetermined brazing time in a predetermined brazing atmosphere in a state where a compressive load in the stacking direction is applied as a brazing load to the laminated body. The insulating layer 203, the buffer layer 204, and the cooling member 205 are joined and integrated together by brazing (eg, vacuum brazing). That is, the wiring layer 202 and the insulating layer 203 are joined together by brazing, and at the same time, the insulating layer 203 and the buffer layer 204 are joined together by brazing, and at the same time, the buffer layer 204 and the cooling member 205 are joined together by brazing. As a result, the insulating substrate 201 of this embodiment shown in FIG. 4 (more specifically, the insulating substrate 201 with the cooling member 205) is obtained.

  In the insulating substrate 201 of this reference embodiment, the insulating layer 203 and the wiring layer 202 are joined to each other by brazing without using a brazing sheet as described above. That is, the insulating layer 203 and the wiring layer 202 are joined by the brazing material of the brazing material plate 15. In this case, as shown in FIG. 5, the brazed portion 201 e where the insulating layer 203 and the wiring layer 202 are joined is hardly joined at the contact portion 207 a of the carbon particles 207 included in the wiring layer 202 with the insulating layer 203. Therefore, the bonding rate between the insulating layer 203 and the wiring layer 202 is low, and the bonding state between the insulating layer 203 and the wiring layer 202 is not very good. As a result, the reliability (particularly the bonding reliability) of the insulating substrate 201 with respect to the cooling / heating cycle load is reduced.

  Although several embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications can be made without departing from the scope of the present invention.

  For example, in the insulating substrate 1 of the first embodiment described above, the wiring layer 2 is made of an aluminum-based carbon particle composite material among the plurality of constituent layers constituting the insulating substrate 1, and in the insulating substrate 101 of the second embodiment described above. The wiring layer 2 and the buffer layer 4 are each made of an aluminum-based carbon particle composite material. However, in the insulating substrate according to the present invention, for example, only the buffer layer 4 may be made of an aluminum-based carbon particle composite material. .

  Next, specific examples and comparative examples of the present invention are shown below. However, the present invention is not limited to the following examples.

<Example>
In this example, the insulating substrate of the first embodiment shown in FIGS. 1 and 2 was manufactured by the following method.

  A wiring layer 2, a brazing sheet 10, an insulating layer 3, a buffer layer 4, and a heat sink 5 as a cooling member were prepared.

  The wiring layer 2 is made of an aluminum-based carbon particle composite material. More specifically, the wiring layer 2 is made of the above-described laminated sintered composite material. The thickness of the wiring layer 2 is 0.4 mm.

  The insulating layer 3 is formed of an AlN plate as a ceramic plate.

  The brazing sheet 10 is a double-sided aluminum brazing sheet having a thickness of 200 μm and a cladding rate of 10%. The core material 11 of the brazing sheet 10 is made of A3003. Each skin material 12 (12a, 12b) of the brazing sheet 10 is made of a brazing material of an aluminum alloy of Al-10 mass% Si-1 mass% Mg-0.1 mass% Bi.

  The buffer layer 4 is formed of a high purity aluminum plate having a purity of 4N. The thickness of the buffer layer 4 is 1.6 mm. Furthermore, brazing material layers 4a and 4b are clad by rolling on both surfaces in the thickness direction of the buffer layer 4, respectively. Each brazing filler metal layer 4a, 4b consists of a brazing material of an aluminum alloy of Al-10 mass% Si-1 mass% Mg-0.1 mass% Bi. The thickness of each brazing material layer 4a, 4b is 30 μm.

  The heat sink 5 is made of aluminum.

  Then, the wiring layer 2, the brazing sheet 10, the insulating layer 3, the buffer layer 4 and the heat sink 5 were arranged in this order in a laminated form to form these laminated bodies. Next, by heating the laminated body in a vacuum as a brazing atmosphere in a state where a compressive load in the laminating direction of 0.1 MPa is applied as a brazing load to the laminated body, wiring is performed by brazing temperature 610 ° C. and brazing time 20 minutes. The layer 2, the brazing sheet 10, the insulating layer 3, the buffer layer 4 and the heat sink 5 were joined and integrated together by vacuum brazing. The insulating substrate 1 (specifically, the insulating substrate 1 with the heat sink 5) was obtained by the above procedure.

  In the insulating substrate 1, the average crystal grain size of the brazing sheet 10 was 50 μm, and the thickness of the brazing sheet 10 was 170 μm.

  Further, when the bonding interface between the insulating layer 3 of the insulating substrate 1 and the brazing sheet 10 was confirmed by an ultrasonic flaw detector, the insulating layer 3 and the brazing sheet 10 were bonded at a bonding rate of almost 100%. Therefore, the bonding state between the insulating layer 3 and the brazing sheet 10 was good.

<Comparative example>
In this comparative example, the insulating substrate 201 of the above reference embodiment shown in FIGS. 4 to 6 was manufactured by the following method.

  A wiring layer 202, a brazing material plate 15, an insulating layer 203, a buffer layer 204, and a heat sink 205 as a cooling member were prepared.

  The wiring layer 202, the insulating layer 203, the buffer layer 204, and the heat sink 205 are the same as those in the first embodiment.

  The brazing material plate 15 is made of an aluminum alloy brazing material of Al-10 mass% Si-1 mass% Mg-0.1 mass% Bi. The thickness of the brazing material plate 15 is 20 μm.

  Then, the wiring layer 202, the brazing material plate 15, the insulating layer 203, the buffer layer 204, and the heat sink 205 were arranged in this order in a laminated form, and these were laminated. Next, by heating the laminated body, the wiring layer 202, the insulating layer 203, the buffer layer 204, and the heat sink 205 were joined and integrated together by brazing. The brazing conditions (brazing load, brazing atmosphere, brazing temperature, brazing time) applied at this time are the same as the brazing conditions in Example 1. Through the above procedure, an insulating substrate 201 (specifically, an insulating substrate 201 with a heat sink 205) was obtained.

  When the bonding interface between the insulating layer 203 and the wiring layer 202 of the insulating substrate 201 was confirmed with an ultrasonic flaw detector, the insulating layer 203 and the wiring layer 202 were bonded at a bonding rate of 95%. Therefore, the bonding state between the insulating layer 203 and the wiring layer 202 was not very good.

  INDUSTRIAL APPLICABILITY The present invention can be used for an insulating substrate manufacturing method and an insulating substrate on which a heat generating element such as an electronic element is mounted.

1: Insulating substrate 2: Wiring layer (second component layer)
3: Insulating layer (first component layer)
4: Buffer layer (second component layer)
5: Cooling member 7: Carbon particle 10: Brazing sheet 20: Exothermic element

Claims (8)

A method of manufacturing an insulating substrate, comprising: a first component layer; and a second component layer disposed on at least one side of the first component layer in a thickness direction with respect to the first component layer. Because
The first constituent layer is a ceramic insulating layer,
The second constituent layer is made of an aluminum-based composite material containing carbon particles as particles to be composited with aluminum,
A method of manufacturing an insulating substrate, wherein the insulating layer and the second constituent layer are joined to each other by brazing via a brazing sheet.   The said insulating layer and the said 2nd structural layer are joined so that the average crystal grain diameter of the said brazing sheet may be 10 micrometers or more and 300 micrometers or less in the state after joining the said insulating layer and the said 2nd structural layer. Method for manufacturing an insulating substrate.   The said insulating layer and the said 2nd structural layer are joined so that the thickness of the said brazing sheet may be 60 micrometers or more and 500 micrometers or less in the state after joining the said insulating layer and the said 2nd structural layer. Method for manufacturing an insulating substrate. The second constituent layer is disposed on both sides in the thickness direction of the first constituent layer,
The insulating layer and one of the second constituent layers are joined to each other by brazing through the first brazing sheet, and at the same time, the insulating layer and the other second constituent layer are joined to each other by brazing through the second brazing sheet. The manufacturing method of the insulated substrate in any one of Claims 1-3 to do. An insulating substrate comprising: a first component layer; and a second component layer disposed on at least one side of both sides of the first component layer in the thickness direction with respect to the first component layer. ,
The first constituent layer is a ceramic insulating layer,
The second constituent layer is made of an aluminum-based composite material containing carbon particles as particles to be composited with aluminum,
An insulating substrate in which the insulating layer and the second constituent layer are joined to each other by brazing via a brazing sheet.   The insulating substrate according to claim 5, wherein an average crystal grain size of the brazing sheet is 10 μm or more and 300 μm or less.   The insulating substrate according to claim 5 or 6, wherein a thickness of the brazing sheet is 60 µm or more and 500 µm or less. The second constituent layer is disposed on both sides in the thickness direction of the first constituent layer, respectively.
The insulating layer and one of the second constituent layers are joined together by brazing via a first brazing heat, and the insulating layer and the other second constituent layer are joined by brazing via a second brazing sheet. The insulating substrate according to claim 5, which is bonded to each other.

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