Structure including metal-ceramic bonded substrate and manufacturing method thereof

Abstract

To provide a structure including a metal-ceramic bonded substrate which can be easily manufactured by bonding a metal base plate and a cooling jacket with satisfactory bearing without the occurrence of corrosion or plastic deformation of a metal, and a manufacturing method thereof.SOLUTION: A manufacturing method of a structure including a metal-ceramic bonded substrate includes: storing a metal-ceramic bonded substrate, which includes a metal base plate consisting of aluminum or an aluminum alloy, on at least one face of a ceramic substrate in a storage section which is formed in a cooling jacket; and integrating the metal base plate and the cooling jacket by laser welding.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a structure including a metal-ceramic bonding substrate and a manufacturing method thereof, and more particularly to a structure including a metal-ceramic bonding substrate in which a metal plate (metal circuit plate) for mounting electronic components is formed on one surface of a ceramic substrate and a metal base plate for heat dissipation is formed on the other surface, and a manufacturing method thereof. [Background technology]

[0002] Conventionally, in a metal-ceramic bonding substrate used as an insulating substrate for a power module, a metal circuit plate is bonded to one surface of a ceramic substrate, a heat dissipating metal base plate is bonded to the other surface, and a semiconductor chip or the like is mounted on the metal circuit plate. In order to dissipate heat from heat generating elements such as the semiconductor chip to the outside, a cooling jacket is attached to the back surface of the heat dissipating metal base plate by fastening with screws or bolts through through holes formed in the peripheral portion of the metal base plate.

[0003] As an example of such a metal-ceramic bonding substrate, for example, Patent Document 1 discloses a metal-ceramic bonding substrate in which a metal plate is bonded to one surface of a ceramic substrate and a metal base plate is bonded to the other surface, and a side surface of a plate-shaped reinforcing member made of a metal having strength greater than that of the metal base plate is bonded to the side surface of the metal base plate, and the reinforcing member is fastened to a cooling jacket via a through hole provided in the reinforcing member.

[0004] Furthermore, for example, Patent Document 2 discloses a joint structure in which a heat dissipating base plate (second member) is placed on a cooling jacket (first member) having a stepped portion, and a joint is formed by friction stir welding the overlapping portion of the two, with an insulating sealant formed to cover the joint.

[0005] Furthermore, for example, Patent Document 3 discloses a semiconductor cooling device equipped with a liquid-cooling type cooler in which a flange of a heat dissipation substrate is abutted against the upper surface of a jacket, and the abutting surface between the flange and the jacket is kept watertight by brazing or a sealing structure using an O-ring. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2022-157171 A [Patent Document 2] JP 2022-34138 A [Patent Document 3] Patent Publication No. 2021-82702 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the technology disclosed in the above Patent Document 1, when the metal part of the metal-ceramic bonding substrate is made of aluminum, there is a risk of galvanic corrosion if the stainless steel or carbon steel used as the reinforcing member is exposed. Although it is also disclosed that the surface of the reinforcing member is coated with pure aluminum to suppress galvanic corrosion, if the surface of the reinforcing member is coated with pure aluminum, when the reinforcing member is fastened to a heat dissipation member or the like through a through hole with a screw or bolt, the fastening must be performed with a surface pressure that does not peel off the coated pure aluminum, and there is a risk of the reliability of fastening being impaired. In addition, since the reinforcing member needs to be placed in a mold, there is a problem that the mold structure becomes complicated and the manufacturing of the substrate is difficult.

[0008] Furthermore, when the friction stir welding technique disclosed in Patent Document 2, in which a rotating welding tool is pressed against the joint to join, is applied to a metal-ceramic bonded substrate in which the heat-dissipating metal base plate is made of aluminum, it is necessary to press the tool against the joint and apply a high load to stir and plastically deform the joint while performing joining, which may result in deformation of the metal-ceramic bonded substrate and the generation of cracks in the ceramic substrate.

[0009] Furthermore, when the technology disclosed in Patent Document 3 is applied to a metal-ceramic bonding substrate in which the metal part is made of aluminum, the entire substrate needs to be heated to a high temperature of, for example, 400°C or higher for brazing, which may lengthen the manufacturing time. Furthermore, if the entire substrate is heated to a high temperature of, for example, 400°C or higher for a long period of time, the metal-ceramic bonding substrate may be thermally warped, which may cause cracks in the ceramic substrate. In order to prevent thermal warping of the metal-ceramic bonding substrate, it is conceivable to use a jig or a press machine to constantly apply a load to the metal-ceramic bonding substrate and the jacket during bonding, so that the bonding is performed while they are constantly in contact with each other, but this may complicate the manufacturing method.

[0010] In view of the above circumstances, an object of the present invention is to provide a structure including a metal-ceramic bonding substrate that can be easily manufactured by preventing metal corrosion and suppressing the occurrence of cracks in the ceramic substrate due to plastic deformation or heat input during the manufacturing process, and a method for manufacturing the same. [Means for solving the problem]

[0011] In order to achieve the above-mentioned object, the present invention provides a method for producing a structure including a metal-ceramic bonding substrate, the method comprising the steps of: accommodating a metal-ceramic bonding substrate having a metal base plate made of aluminum or an aluminum alloy on at least one surface of a ceramic substrate in a housing portion formed in a cooling jacket; and integrating the metal base plate and the cooling jacket by laser welding.

[0012] A side surface of the metal base plate and an inner side surface of the accommodation portion of the cooling jacket may be laser welded to integrate the metal base plate and the cooling jacket.

[0013] The laser welding on the side surface of the metal base plate may be performed over the entire periphery of the side surface of the metal base plate.

[0014] The metal base plate may have heat dissipation fins.

[0015] The metal base plate may be formed on the peripheral portion and side surfaces of one surface of the ceramic substrate and on the entire surface of the other surface.

[0016] A fiber laser may be used for the laser welding.

[0017] Furthermore, according to the present invention, there is provided a method for manufacturing a structure including a metal-ceramic bonding substrate, characterized in that at least a part of a metal-ceramic bonding substrate having a metal base plate made of aluminum or an aluminum alloy on at least one surface of a ceramic substrate is accommodated in an accommodation portion formed in a cooling jacket, and a top plate attached to the cooling jacket, an inner surface of the accommodation portion formed on the top plate, and a side surface of the metal base plate are laser welded to the top plate, so that the accommodation portion of the cooling jacket and the accommodation portion of the top plate are integrated.

[0018] The top plate may be attached to the cooling jacket by laser welding.

[0019] The top plate may be attached to the cooling jacket by fastening, and a sealing member may be provided on a joint surface between the metal base plate and the cooling jacket or on a joint surface between the top plate and the cooling jacket.

[0020] According to another aspect of the present invention, there is provided a structure including a metal-ceramic bonding substrate, characterized in that a metal-ceramic bonding substrate having a metal base plate made of aluminum or an aluminum alloy on at least one surface of a ceramic substrate is accommodated in a housing portion formed in a cooling jacket, and the metal base plate and the cooling jacket are integrated by laser welding.

[0021] A side surface of the metal base plate and an inner side surface of the accommodation portion of the cooling jacket may be laser welded to integrate the metal base plate and the cooling jacket.

[0022] The laser welding on the side surface of the metal base plate may be performed over the entire periphery of the side surface of the metal base plate.

[0023] The metal base plate may have heat dissipation fins.

[0024] The metal base plate may be formed on the peripheral portion and side surfaces of one surface of the ceramic substrate and on the entire surface of the other surface.

[0025] The cooling jacket may be made of a material having a greater strength than the metal base plate.

[0026] Furthermore, according to the present invention, there is provided a structure including a metal-ceramic bonding substrate, characterized in that at least a part of a metal-ceramic bonding substrate having a metal base plate made of aluminum or an aluminum alloy on at least one surface of a ceramic substrate is accommodated in an accommodation portion formed in a cooling jacket, and a top plate attached to the cooling jacket, an inner surface of the accommodation portion formed on the top plate and a side surface of the metal base plate are laser welded to the top plate, and the top plate is attached to the cooling jacket such that the accommodation portion of the cooling jacket and the accommodation portion of the top plate are integrated.

[0027] The top plate may be attached to the cooling jacket by laser welding.

[0028] The cooling jacket may include a fastening member for attaching the top plate to the cooling jacket, and a sealing member may be provided on a joint surface between the metal base plate and the cooling jacket or on a joint surface between the top plate and the cooling jacket.

[0029] The cooling jacket and the top plate may be made of a material having a greater strength than the metal base plate.

[0030] Furthermore, according to the present invention, there is provided a structure including a metal-ceramic bonding substrate, characterized in that a metal-ceramic bonding substrate having a metal base plate made of aluminum or an aluminum alloy on at least one surface of a ceramic substrate is accommodated in a housing portion formed in a cooling jacket, and a side surface of the metal base plate and an inner side surface of the housing portion of the cooling jacket are integrated by welding.

[0031] Furthermore, according to the present invention, there is provided a structure including a metal-ceramic bonding substrate, the structure including a metal-ceramic bonding substrate having a metal base plate made of aluminum or an aluminum alloy on at least one surface of a ceramic substrate, and a top plate attached to a cooling jacket, the metal-ceramic bonding substrate having a side surface of the metal base plate and an inner surface of a housing portion formed in the top plate integrated by welding, the top plate being attached to the cooling jacket. Effect of the Invention

[0032] According to the present invention, it is possible to provide a structure including a metal-ceramic bonding substrate that can be easily manufactured while preventing metal corrosion and suppressing the occurrence of cracks in the ceramic substrate due to plastic deformation and heat input during the manufacturing process, and a method for manufacturing the same. [Brief description of the drawings]

[0033] [Figure 1] FIG. 1 is a schematic explanatory diagram of a metal-ceramic bonding substrate. [Diagram 2]FIG. 1 is a schematic explanatory view of a structure including a metal / ceramic bonding substrate according to a first embodiment. [Diagram 3] FIG. 11 is a schematic explanatory view of a structure including a metal / ceramic bonding substrate according to a second embodiment. [Figure 4] FIG. 11 is a schematic explanatory view of a structure including a metal / ceramic bonding substrate according to a third embodiment. [Diagram 5] FIG. 11 is a schematic explanatory view of a structure including a metal / ceramic bonding substrate according to a fourth embodiment. [Figure 6] FIG. 13 is a schematic explanatory view of a structure including a metal / ceramic bonding substrate according to a fifth embodiment. [Figure 7] FIG. 2 is a schematic explanatory diagram of a structure according to an embodiment. [Figure 8] FIG. 1 is a schematic explanatory diagram of a reference example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] <First embodiment> Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this specification and the drawings, components having substantially the same functional configurations are denoted by the same reference numerals, and duplicated explanations will be omitted. Hereinafter, a first embodiment of the present invention will be described.

[0035] <Metal-ceramic bonded substrate> Fig. 1 is a schematic diagram of a metal-ceramic bonding substrate 1 according to this embodiment, where (a) is a plan view and (b) is a side view. As shown in Fig. 1, the metal-ceramic bonding substrate 1 includes an electrically insulating ceramic substrate 3 having a substantially rectangular shape in a plan view, a metal base plate 5 having a substantially rectangular shape in a plan view bonded to the periphery and side of one surface (the upper surface in Fig. 1(b)) of the ceramic substrate 3 and the entire surface of the other surface (the lower surface in Fig. 1(b)), and one or more metal plates 7 for circuit patterns directly bonded to one surface (the upper surface in Fig. 1(b)) of the ceramic substrate 3.

[0036] 1(b), heat dissipation fins 5a as heat dissipation members consisting of a plurality of fin members protruding downward may be formed on the lower surface of the metal base plate 5. Electronic components such as semiconductor elements mounted on the metal plate 7 are heat generating bodies, and are cooled by dissipating the heat to the heat dissipation fins 5a via the metal base plate 5.

[0037] The ceramic substrate 3 has a function of maintaining insulation between the metal plates 7 for circuit patterns when there are multiple metal plates 7, and between the metal plates 7 and the metal base plate 5. The ceramic substrate 3 is preferably made of one or more selected from alumina, aluminum nitride, silicon nitride, and silicon carbide, and in the case of the metal-ceramic bonding substrate 1 used as an insulating substrate for a power module, it is preferably made of aluminum nitride or silicon nitride from the viewpoint of reliability and heat dissipation. Here, the ceramic substrate 3 may contain unavoidable impurities and sintering aids. The thickness of the ceramic substrate 3 may be 0.1 mm to 1.0 mm, and the total thickness of the metal-ceramic bonding substrate 1 may be 1.0 mm to 5.0 mm. The shape of the ceramic substrate 3 is not particularly limited, but it may be approximately rectangular in plan view.

[0038] The metal base plate 5 is preferably directly bonded to the ceramic substrate 3. The metal base plate 5 may be formed on the periphery and side of one surface (upper surface) and the entire surface of the other surface (lower surface) of the ceramic substrate 3 as shown in FIG. 2 described later, or may be formed on the entire surface of the other surface (lower surface) of the ceramic substrate 3 as shown in FIG. 3 described later. The metal base plate 5 is preferably made of aluminum or an aluminum alloy. It is desirable for the metal base plate 5 to have a certain degree of hardness as a constituent member as well as thermal conductivity, and therefore, for example, the metal base plate 5 preferably has a tensile strength of about 70 to 130 MPa (more preferably 75 to 120 MPa).

[0039] The metal plate 7 for the circuit pattern is preferably bonded to the ceramic substrate 3. The metal plate 7 is preferably made of aluminum or an aluminum alloy. Since chip members such as semiconductor elements are mounted on the metal plate 7, the metal plate 7 is preferably made of a metal having excellent electrical conductivity and thermal conductivity, and is preferably made of aluminum or an aluminum alloy containing, for example, 99.7% by mass or more of aluminum, and more preferably 99.9% by mass or more of aluminum.

[0040] The manufacturing method of the metal-ceramic bonding substrate 1 is arbitrary, and for example, a general molten metal bonding method such as that described in JP 2017-228551 A or JP 2022-157171 A may be used. A heat dissipation member such as a water-cooling jacket is further attached to the metal-ceramic bonding substrate 1 configured as shown in FIG. 1, and they are integrated to form a single structure. The structure including the integrated metal-ceramic bonding substrate will be described below.

[0041] <Structures including metal-ceramic bonded substrates> 2 is a schematic explanatory diagram of a structure 10 including a metal-ceramic bonding substrate 1 according to this embodiment, and is a schematic diagram of a side cross-sectional view of the structure 10. As shown in FIG. 2, the structure 10 is configured by housing the above-mentioned metal-ceramic bonding substrate 1 in a housing portion (a recess on the upper surface side in the figure) 21 formed in a cooling jacket 20. The structure 10 configured as shown in FIG. 2 employs a structure in which the metal-ceramic bonding substrate 1 is housed in the housing portion 21, and the overall height of the structure 10 can be kept low. This allows the structure 10 to be low-profile when used as a power module.

[0042] The cooling jacket 20 is preferably made of an aluminum alloy (e.g., an A2000 series alloy, an A5000 series alloy, or an A6000 series alloy). The cooling jacket 20 is required to have machinability for forming the housing portion 21, bondability with the metal-ceramic bonding substrate 1, and high strength (high hardness) for restraining the metal-ceramic bonding substrate 1 when it is warped. When bonding to the metal-ceramic bonding substrate 1, the occurrence of galvanic corrosion is suppressed because the metal base plate 5 is made of aluminum or an aluminum alloy and the cooling jacket 20 is made of an aluminum alloy.

[0043] With the metal-ceramic bonding substrate 1 accommodated in the accommodation portion 21, the structure 10 is integrated by joining the side surface of the metal base plate 5 to the inner side surface of the accommodation portion 21. As shown in the figure, the side surface of the metal base plate 5 and the inner side surface of the accommodation portion 21 are integrated by laser welding at positions where they face each other, which are welded portions 23 (see the dashed line in the figure). This laser welding may be performed around the entire periphery of the side surface of the metal base plate 5.

[0044] Here, the distance (shortest distance L1) between the welded portion 23 and the ceramic substrate 3 is designed to be such that the influence of heat input accompanying laser welding does not significantly affect the ceramic substrate 3. For example, the distance L1 may be designed to be 1 mm to 15 mm. When the metal base plate 5 is made of aluminum and the cooling jacket 20 is made of an aluminum alloy, an additive element (e.g., Mg) contained in the aluminum alloy diffuses into the aluminum through the welded portion 23 during heat input. The diffusion distance of the additive element at this time can be confirmed by external observation of the cross section or observation with an electron microscope (e.g., EDS mapping). Since the diffusion distance is kept small and the diffusion of the additive element does not reach the ceramic substrate 3, it can be determined that the influence of heat input due to laser welding on the ceramic substrate 3 is small, and it is presumed that cracks in the ceramic substrate 3 can be suppressed. In addition, in the structure 10, the optimal weld thickness of laser welding (target weld thickness in the thickness direction of the structure 10) may be the total thickness of the cooling jacket 20 and the metal base plate 5, and varies depending on the laser output, the type of aluminum alloy, and the like, and can be determined experimentally.

[0045] The accommodation section 21 may be composed of two stages (first accommodation section 21a and second accommodation section 21b) having different widths in side view, and a step may be formed by forming the upper first accommodation section 21a wider than the second accommodation section 21b. When the metal-ceramic bonding substrate 1 is accommodated in the accommodation section 21, the peripheral portion of the metal base plate 5 may be placed on the step between the first accommodation section 21a and the second accommodation section 21b, and the heat dissipation fins 5a may be accommodated in the second accommodation section 21b.

[0046] <Laser welding> The laser welding for joining the above-mentioned metal base plate 5 and the cooling jacket 20 will be described. In order to perform deep welding instantaneously in a short time in laser welding, it is preferable to use a laser beam with a low wavelength and high energy absorption rate. In particular, in the welding of aluminum-based materials, it is preferable to use a semiconductor laser, a fiber laser, or a YAG laser. From the viewpoints of maintenance costs and high output for obtaining a deep weld, a fiber laser is particularly preferable.

[0047] The preferred conditions for using a fiber laser are as follows. The laser output is preferably 200 to 2700 W for a welding thickness of 0.5 mm to 4 mm. The slower the laser scanning speed, the deeper the weld that can be obtained, and the faster the speed, the shorter the production time. From this viewpoint, the laser scanning speed is preferably 40 mm / s or less. The laser irradiation direction may be parallel to the side surface of the metal base plate 5 to be welded (i.e., vertical direction, taper angle 0°), or the angle between the laser irradiation direction and the side surface of the metal base plate 5 (laser irradiation angle: taper angle) may be 0° to 10°.

[0048] During laser welding, in order to prevent oxidation and suppress scattering caused by laser welding, it is preferable to use an inert gas as a shielding gas or to use a wobble function. Helium or argon is preferably used as the inert gas. As the flow method of the shielding gas, for example, a coaxial nozzle or a side nozzle may be used.

[0049] <Action and effect> In the structure 10 including the metal-ceramic bonding substrate 1 according to this embodiment, as described above, the side surface of the metal base plate 5 and the inner surface of the housing portion 21 are integrated by laser welding at the opposing positions as the joints 23. Therefore, plastic deformation can be suppressed without applying a heavy load to the metal-ceramic bonding substrate 1 during the manufacturing process, and cracks in the ceramic substrate 3 can be prevented.

[0050] In addition, the metal base plate 5 and the cooling jacket 20 of the metal-ceramic bonding substrate 1 are integrated using laser welding, and welding is performed with localized heat input. It is presumed that this can suppress cracking of the ceramic substrate 3 that would occur due to high-temperature heating of 400°C or more as in the conventional technology.

[0051] Furthermore, since the metal base plate 5 is made of aluminum or an aluminum alloy and the cooling jacket 20 is made of an aluminum alloy, the occurrence of galvanic corrosion is suppressed. Moreover, when integrating the metal-ceramic bonding substrate 1 and the cooling jacket 20, there is no need to constantly apply a load using a device such as a jig or a press machine, so that the structure 10 can be easily manufactured.

[0052] In the structure 10 including the metal-ceramic bonding substrate 1 according to this embodiment, the metal base plate 5 is directly bonded to the ceramic substrate 3, and there is a particular concern about the influence of heat input to the ceramic substrate 3 at the bonded portion between the metal-ceramic bonding substrate 1 and the cooling jacket 20. Depending on the heat input to the ceramic substrate 3, cracks may occur. Therefore, by designing the distance between the welded portion 23 and the ceramic substrate 3 to a distance that does not significantly affect the ceramic substrate 3 due to the heat input caused by laser welding, and by locally inputting heat, it is possible to prevent cracks in the ceramic substrate 3 and manufacture the structure 10 with high productivity.

[0053] Although an example of the embodiment of the present invention has been described above, the present invention is not limited to the illustrated embodiment. It is clear that a person skilled in the art can conceive of various modified or revised examples within the scope of the ideas described in the claims, and it is understood that these also naturally belong to the technical scope of the present invention. Hereinafter, the second to fifth embodiments of the present invention will be described with reference to the drawings as other embodiments of the present invention.

[0054] Second embodiment of the present invention In the first embodiment, the metal-ceramic bonding substrate 1 is configured such that the metal base plate 5 is formed on the periphery and side surfaces of one surface (upper surface) and the entire surface of the other surface (lower surface) of the ceramic substrate 3 (see FIG. 2). However, the configuration of the metal base plate 5 is not limited to this.

[0055] 3 is a schematic explanatory diagram of a structure 10a including a metal-ceramic bonding substrate 1a according to the second embodiment, and is a schematic diagram of a side cross-sectional view of the structure 10a. Note that components having the same functional configuration as those in the above embodiment are shown with the same reference numerals, and their description may be omitted.

[0056] As shown in Fig. 3, in the metal-ceramic bonding substrate 1a according to the second embodiment, a ceramic substrate 3 is bonded to the upper surface of a metal base plate 5, and the side and upper surfaces of the ceramic substrate 3 are not covered by the metal base plate 5. A structure 10a including such a metal-ceramic bonding substrate 1a has a simpler structure, and therefore the structure 10a can be easily manufactured. Note that when the structure 10 is used as a power module, it is more preferable to use the structure described in the first embodiment above, from the viewpoint of the desirability of a low height.

[0057] <Third embodiment of the present invention> In the first embodiment, the structure 10 including the metal-ceramic bonding substrate 1 has a configuration in which the metal-ceramic bonding substrate 1 and the cooling jacket 20 are bonded and integrated together (see FIG. 2). However, the configuration of the structure 10 is not limited to this.

[0058] 4 is a schematic explanatory diagram of a structure 10b including a metal-ceramic bonding substrate 1b according to the third embodiment, and is a schematic diagram of a side cross-sectional view of the structure 10b. Note that components having the same functional configuration as those in the above embodiment are shown with the same reference numerals, and their description may be omitted.

[0059] 4, a structure 10b including a metal-ceramic bonding substrate 1b according to the third embodiment includes a top plate 30 attached to a cooling jacket 20. The top plate 30 is formed with a housing portion 31 for housing the metal base plate 5, and may be attached so as to cover the peripheral edge of the metal base plate 5. The top plate 30 is preferably made of an aluminum alloy (e.g., an A2000 series alloy, an A5000 series alloy, or an A6000 series alloy).

[0060] In the structure 10b according to this embodiment, as shown in the figure, a part of the metal-ceramic bonding substrate 1b (heat dissipation fins 5a) may be accommodated in the accommodation portion 21 formed in the cooling jacket 20, and a part of the metal-ceramic bonding substrate 1b may be accommodated in the accommodation portion 31, thereby forming an integrated structure 10b. That is, the accommodation portion 21 formed in the cooling jacket 20 and the accommodation portion 31 formed in the top plate 30 may be integrated, and the metal-ceramic bonding substrate 1b may be accommodated therein.

[0061] In this structure 10b, the side surface of the metal base plate 5 and the inner surface of the storage section 31 of the top plate 30 are joined by laser welding at a position where they face each other, which serves as a first joint 33 (see the dashed line in the figure). Also, the joint surfaces between the metal base plate 5 and the cooling jacket 20 and the joint surfaces between the top plate 30 and the cooling jacket 20 are joined by laser welding, which serves as second joints 34 (see the dashed line in the figure).

[0062] Here, when manufacturing the structure 10b including the metal-ceramic bonding substrate 1b according to the third embodiment, a part of the metal-ceramic bonding substrate 1b may be accommodated in the accommodation portion 31 of the top plate 30, and in this state, welding is performed at the first bonding portion 33 to previously integrate the top plate 30 and the metal-ceramic bonding substrate 1b, and then the integrated top plate 30 and the metal-ceramic bonding substrate 1b are integrated with the cooling jacket 20 by welding at the second bonding portion 34. By adopting such a process, it is possible to prepare and attach the top plate 30 in accordance with the size of the cooling jacket 20 without designing the metal-ceramic bonding substrate 1b in accordance with the size of the cooling jacket 20 as in the conventional method, thereby improving the degree of freedom in designing the metal-ceramic bonding substrate 1b.

[0063] Furthermore, according to the structure 10b of this embodiment, in addition to the same advantageous effects as those of the first embodiment, by adopting a configuration using the top plate 30, it is possible to further strengthen the bonding between the metal-ceramic bonding substrate 1b and the cooling jacket 20.

[0064] <Fourth embodiment of the present invention> In the configuration of the above-mentioned third embodiment, the joint surfaces between the metal base plate 5 and the cooling jacket 20, and the joint surface between the top plate 30 and the cooling jacket 20 are described as being joined by laser welding as the second joint 34, but a sealing member 40 such as an O-ring may be provided between the metal base plate 5 and the cooling jacket 20.

[0065] 5 is a schematic explanatory diagram of a structure 10c including a metal-ceramic bonding substrate 1c according to the fourth embodiment, and is a schematic diagram of a side cross-sectional view of the structure 10c. Note that components having the same functional configuration as those in the third embodiment are shown with the same reference numerals, and their description may be omitted.

[0066] 5, in the structure 10c according to this embodiment, a sealing member 40 such as an O-ring is provided on the joint surface between the metal base plate 5 and the cooling jacket 20. In the illustrated configuration, the sealing member 40 is provided on the joint surface between the metal base plate 5 and the cooling jacket 20, but the sealing member 40 may be provided on the joint surface between the top plate 30 and the cooling jacket 20.

[0067] According to the structure 10b of this embodiment, in addition to the same effects as those of the third embodiment, it is possible to improve the sealing performance between the metal-ceramic bonding substrate 1c or the top plate 30 and the cooling jacket 20. Furthermore, by shortening the welding depth of the laser welding at the second bonding portion, thermal warping of the substrate due to heat input can be suppressed, and the influence of heat input to the ceramic substrate 3 can be suppressed.

[0068] Fifth embodiment of the present invention In the configurations according to the third and fourth embodiments, the joining surfaces of the top plate 30 and the cooling jacket 20 are described as the second joint 34 and joined by laser welding, but the joining means is not limited to this. That is, the top plate 30 and the cooling jacket 20 may be joined by fastening using a fastening member.

[0069] 6 is a schematic explanatory diagram of a structure 10d including a metal-ceramic bonding substrate 1d according to the fifth embodiment, and is a schematic diagram of a side cross-sectional view of the structure 10d. Note that components having the same functional configurations as those in the third and fourth embodiments are shown with the same reference numerals, and their description may be omitted.

[0070] 6, in the structure 10d according to this embodiment, the joint surfaces between the top plate 30 and the cooling jacket 20 are fastened with fastening members 50 such as bolts or screws. That is, at a first joint portion 33 where the side surface of the metal base plate 5 and the inner surface of the accommodation portion 31 of the top plate 30 face each other, joining is performed by laser welding, and the top plate 30 and the cooling jacket 20 are joined by fastening. Note that, in the structure 10d according to this embodiment, it is preferable that a sealing member 40 such as an O-ring is provided on the joint surface between the metal base plate 5 and the cooling jacket 20, as in the above-mentioned fourth embodiment.

[0071] In the structure 10d according to this embodiment, the top plate 30 and the cooling jacket 20 are joined using the fastening members 50, so there is a high degree of freedom in designing the sealing parts (fastening parts), and the structure 10d can be manufactured easily. In addition, both the cooling jacket 20 and the top plate 30 are preferably made of a high-hardness aluminum alloy (e.g., A2000 series alloy, A5000 series alloy, A6000 series alloy), in which case buckling or the like does not occur when the fastening members 50 are used, and reliable sealing is ensured. EXAMPLES

[0072] <Example> As Examples 1 and 2 of the present invention, structures including a metal-ceramic bonding substrate having a configuration similar to that of the structure 10 according to the first embodiment were manufactured by laser welding using a fiber laser, and their performance was evaluated. An example of a method for manufacturing the structures according to Examples 1 and 2 will be described below.

[0073] FIG. 7 is a schematic diagram of a structure according to an embodiment, showing the dimensions of a portion of the structure. First, a silicon nitride plate as a rectangular ceramic substrate measuring 42 mm long x 41 mm wide x 0.32 mm thick was placed in a mold, and then the mold was heated in a nitrogen atmosphere. Molten high-purity aluminum containing 99.9% by mass or more of aluminum was poured into the mold while removing the oxide film on the surface. The mold was then cooled to solidify the molten aluminum, and a metal-ceramic bonded substrate integrated with a metal base plate was obtained. The obtained metal-ceramic bonded substrate had a metal base plate made of aluminum integrally formed on the periphery (a portion covered with aluminum from the periphery to a width of 1 mm) of one side of the ceramic substrate, the side surface, and the entire surface of the other side. This metal base plate was rectangular, measuring 46 mm long and 45 mm wide when viewed from the other side. The thickness of the metal base plate was 1.4 mm.

[0074] An aluminum plate (metal plate) for circuit patterns, 36 mm long x 35 mm wide x 0.6 mm thick, was formed on one side of this metal base plate, 2 mm away from the portion formed on the periphery of one side of the ceramic substrate, and 105 columnar projections (heat dissipation pins) 3 mm high and 2.5 mm in diameter were formed on the opposite side of the metal base plate, spaced 3.5 mm apart to produce a base-integrated metal-ceramic bonding substrate. The width of the metal base plate formed on the side of the ceramic substrate (the distance from the side of the ceramic substrate to the side of the metal base plate) was 2.0 mm, and the thickness of the metal base plate was 0.5 mm.

[0075] Next, a cooling jacket made of A5052 aluminum alloy was prepared. A storage section was formed in the center of the cooling jacket (see FIG. 2). The storage section is composed of two storage sections (first storage section, second storage section) as described in the first embodiment above, and the upper first storage section is formed wider than the lower second storage section. The metal-ceramic bonding substrate was arranged so that the metal base plate was placed on the step section, and the lower heat dissipation fin was accommodated in the second storage section. In this state, laser welding was performed using a fiber laser under the conditions shown in Table 1 below, and the side surface of the metal base plate and the entire circumference of the inner side surface of the storage section of the cooling jacket were joined and integrated. Here, the laser irradiation angle in the laser welding was set to 0°, and welding was performed using a wobble function. In this manner, structures including the metal-ceramic bonding substrates of Examples 1 and 2 were obtained.

[0076] In addition, as Examples 3 and 4, a structure including a metal-ceramic bonding substrate having the configuration of the structure 10b according to the third embodiment was manufactured by laser welding using a fiber laser, and the performance of the structure was evaluated. An example of a manufacturing method for the structures according to Examples 3 and 4 will be described below.

[0077] First, a metal-ceramic bonding substrate was prepared in the same manner as in Examples 1 and 2 above. Next, a top plate made of an A5052 aluminum alloy was prepared. A housing section capable of housing the metal base plate so as to cover the peripheral portion of the metal base plate was formed in the center of the top plate (see FIG. 4). A step was formed in this housing section to accommodate the peripheral portion of the metal base plate, and the metal base plate was placed on this step, and laser welding was performed using a fiber laser under the conditions shown in Table 1 below. The side surface of the metal base plate and the entire periphery of the inner surface of the housing section were joined together to form an integrated structure.

[0078] Next, a cooling jacket made of A5052 aluminum alloy was prepared, in which a housing was formed in the center, and the heat dissipation fins on the lower side of the metal-ceramic bonding substrate were enclosed in the housing, thereby obtaining a structure including the metal-ceramic bonding substrate of Examples 3 and 4.

[0079] Cross-sectional observation samples were prepared for the structures containing the metal-ceramic bonded substrates obtained in this way, and the presence or absence of voids (spaces) at the laser welded parts was evaluated by cross-sectional observation using a scanning electron microscope (SEM) with a highly sensitive detector (UVD). In addition, the presence or absence of cracks in the ceramic substrate was visually observed and evaluated by cross-sectional observation of the structures containing the metal-ceramic bonded substrates. In addition, element mapping was performed by energy dispersive X-ray analysis (EDS) using a scanning electron microscope (SEM) with a highly sensitive detector (UVD).

[0080] The following Table 1 shows the welding conditions and the materials of the respective members in Examples 1 to 4. In the table, "3N Al" refers to high-purity aluminum containing 99.9% by mass or more of aluminum, and "A5052" refers to the A5052 aluminum alloy. [Table 1]

[0081] As shown in Table 1, for the structures including the metal-ceramic bonding substrates of Examples 1 to 4, no voids (spaces) were found within 2 mm of the laser welding point in any of the cross-sectional observation samples. In addition, the diffusion distance during welding was kept sufficiently small, and no cracks in the ceramic substrate due to heat input were confirmed using an electron microscope, indicating good bonding.

[0082] <Reference example> As reference examples of the present invention, high purity aluminum (3N Al) and various aluminum alloys (A5052, A6061, A2017, A7204) were laser welded using a fiber laser under the conditions of Reference Examples 1 to 4, and the weld strength was evaluated by a tensile test. The tensile test was performed using a Shimadzu Corporation AG-I 100kN material strength testing machine at a test speed of 1mm / min.

[0083] Fig. 8 is a schematic diagram of a reference example. As a sample of the reference example, high purity aluminum (3N Al) as member 1 and various aluminum alloys (A5052, A6061, A2017, A7204) as member 2 were used as plates of length 35 mm x width 15 mm x thickness 4 mm, and the ends were butted together and laser welded. Laser irradiation in the laser welding was performed only on one side (top surface in the figure) of the part where member 1 and member 2 were butted together. Table 2 below shows the welding conditions for reference examples 1 to 4. [Table 2]

[0084] As shown in Table 2, in all of Reference Examples 1 to 4, the tensile test results showed no fracture at the welded portion, but fracture was confirmed in the high purity aluminum (3N Al), confirming that good weld strength was achieved. From the results of Reference Examples 1 to 4, it was confirmed that sufficient weld strength was ensured even when thick high purity aluminum (3N Al) and an aluminum alloy were welded by laser welding using a fiber laser. [Industrial Applicability]

[0085] The present invention relates to a structure including a metal-ceramic bonding substrate and a manufacturing method thereof, and is particularly applicable to a structure including a metal-ceramic bonding substrate in which a metal plate (metal circuit plate) for mounting electronic components is formed on one surface of a ceramic substrate and a metal base plate for heat dissipation is formed on the other surface, and a manufacturing method thereof. [Explanation of symbols]

[0086] 1...Metal-ceramic bonded substrate 3…Ceramics substrate 5…Metal base plate 5a…Heat dissipation fin 7...Metal plate 10...Structure 20…Cooling jacket 21...(cooling jacket) housing 21a...First storage section 21b...Second storage section 23…Welded section 30…Tabletop 31...(Tabletop) storage area 40...Sealing member 50...Fastening member

Claims

1. A metal-ceramic bonding substrate having a metal base plate made of aluminum or an aluminum alloy on at least one surface of a ceramic substrate is accommodated in an accommodating portion formed in a cooling jacket; A method for producing a structure including a metal / ceramic bonding substrate, characterized in that the metal base plate and the cooling jacket are integrated by laser welding.

2. 2. The method for manufacturing a structure including a metal-ceramic bonding substrate according to claim 1, wherein a side surface of the metal base plate and an inner side surface of the housing part of the cooling jacket are laser welded to integrate the metal base plate and the cooling jacket.

3. 3. The method for producing a structure including a metal / ceramic bonding substrate according to claim 2, wherein the laser welding on the side surface of the metal base plate is performed over the entire periphery of the side surface of the metal base plate.

4. 4. The method for manufacturing a structure including a metal / ceramic bonding substrate according to claim 1, wherein the metal base plate has heat dissipation fins.

5. The method for manufacturing a structure including a metal-ceramic bonding substrate according to any one of claims 1 to 3, wherein the metal base plate is formed on a peripheral portion and a side surface of one surface of the ceramic substrate, and on the entire surface of the other surface.

6. 4. The method for producing a structure including a metal / ceramic bonding substrate according to claim 1, wherein a fiber laser is used for the laser welding.

7. At least a part of a metal-ceramic bonding substrate having a metal base plate made of aluminum or an aluminum alloy on at least one surface of a ceramic substrate is accommodated in an accommodation portion formed in a cooling jacket, and a top plate attached to the cooling jacket is laser-welded to an inner surface of the accommodation portion formed on the top plate and a side surface of the metal base plate; A method for manufacturing a structure including a metal / ceramic bonding substrate, characterized in that the top plate is attached to the cooling jacket so that an accommodation portion of the cooling jacket and an accommodation portion of the top plate are integrated.

8. 8. The method for producing a structure including a metal / ceramic bonding substrate according to claim 7, wherein said top plate is attached to said cooling jacket by laser welding.

9. The top plate is attached to the cooling jacket by fastening; 8. The method for manufacturing a structure including a metal-ceramic bonding substrate according to claim 7, wherein a sealing member is provided on a bonding surface between the metal base plate and the cooling jacket, or on a bonding surface between the top plate and the cooling jacket.

10. A metal-ceramic bonding substrate having a metal base plate made of aluminum or an aluminum alloy on at least one surface of a ceramic substrate is accommodated in an accommodating portion formed in a cooling jacket; A structure including a metal / ceramic bonding substrate, wherein the metal base plate and the cooling jacket are integrated by laser welding.

11. 11. The structure including the metal-ceramic bonding substrate according to claim 10, wherein a side surface of the metal base plate and an inner side surface of the housing portion of the cooling jacket are laser welded to integrate the metal base plate and the cooling jacket.

12. 12. The structure including a metal / ceramic bonding substrate according to claim 11, wherein the laser welding on the side surface of the metal base plate is performed over the entire periphery of the side surface of the metal base plate.

13. 13. A structure including a metal / ceramic bonding substrate according to claim 10, wherein the metal base plate has heat dissipation fins.

14. The structure including the metal-ceramic bonding substrate according to any one of claims 10 to 12, characterized in that the metal base plate is formed on the peripheral portion and side surface of one surface of the ceramic substrate, and on the entire surface of the other surface.

15. 13. The structure including a metal / ceramic bonding substrate according to claim 10, wherein the cooling jacket is made of a material having a strength higher than that of the metal base plate.

16. At least a part of a metal-ceramic bonding substrate having a metal base plate made of aluminum or an aluminum alloy on at least one surface of a ceramic substrate is accommodated in an accommodation portion formed in a cooling jacket, and a top plate attached to the cooling jacket is laser-welded to an inner surface of the accommodation portion formed on the top plate and a side surface of the metal base plate; A structure including a metal / ceramic bonding substrate, characterized in that the top plate is attached to the cooling jacket such that an accommodation portion of the cooling jacket and an accommodation portion of the top plate are integrated.

17. 17. The structure including a metal / ceramic bonding substrate according to claim 16, wherein said top plate is attached to said cooling jacket by laser welding.

18. a fastening member for attaching the top plate to the cooling jacket; 17. The structure including a metal / ceramic bonding substrate according to claim 16, wherein a sealing member is provided on a bonding surface between said metal base plate and said cooling jacket, or on a bonding surface between said top plate and said cooling jacket.

19. 19. A structure including a metal / ceramic bonding substrate according to claim 16, wherein the cooling jacket and the top plate are made of a material having a higher strength than the metal base plate.

20. A metal-ceramic bonding substrate having a metal base plate made of aluminum or an aluminum alloy on at least one surface of a ceramic substrate is accommodated in an accommodating portion formed in a cooling jacket; A structure including a metal / ceramic bonding substrate, characterized in that a side surface of the metal base plate and an inner side surface of the housing portion of the cooling jacket are integrated by welding.

21. a metal-ceramic bonding substrate having a metal base plate made of aluminum or an aluminum alloy on at least one surface of a ceramic substrate; a top plate attached to the cooling jacket; a metal-ceramic bonding substrate in which a side surface of the metal base plate and an inner side surface of the housing portion formed in the top plate are integrated by welding; A structure including a metal / ceramic bonding substrate, characterized in that the top plate is attached to the cooling jacket.

Images