WO2016060079A1 - Substrate with cooler for power modules and method for producing same - Google Patents

Substrate with cooler for power modules and method for producing same Download PDF

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Publication number
WO2016060079A1
WO2016060079A1 PCT/JP2015/078765 JP2015078765W WO2016060079A1 WO 2016060079 A1 WO2016060079 A1 WO 2016060079A1 JP 2015078765 W JP2015078765 W JP 2015078765W WO 2016060079 A1 WO2016060079 A1 WO 2016060079A1
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WIPO (PCT)
Prior art keywords
metal layer
cooler
aluminum
layer
copper
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PCT/JP2015/078765
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French (fr)
Japanese (ja)
Inventor
宗太郎 大井
智哉 大開
丈嗣 北原
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三菱マテリアル株式会社
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Application filed by 三菱マテリアル株式会社 filed Critical 三菱マテリアル株式会社
Priority to KR1020177012925A priority Critical patent/KR20170073618A/en
Priority to CN201580050213.8A priority patent/CN107112298A/en
Priority to EP15851276.4A priority patent/EP3208839B1/en
Priority to US15/518,347 priority patent/US10211068B2/en
Priority claimed from JP2015200784A external-priority patent/JP6048558B2/en
Publication of WO2016060079A1 publication Critical patent/WO2016060079A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/12—Mountings, e.g. non-detachable insulating substrates
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
    • H01L23/36—Selection of materials, or shaping, to facilitate cooling or heating, e.g. heatsinks
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/0001—Technical content checked by a classifier
    • H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Definitions

  • the present invention relates to a substrate for a power module with a cooler used in a semiconductor device that controls a large current and a high voltage, and a method for manufacturing the same.
  • a conventional power module substrate in which a circuit layer is bonded to one surface of a ceramic substrate serving as an insulating layer, and a metal layer for heat dissipation is bonded to the other surface. Further, a power module substrate with a cooler is configured by bonding a cooler to the metal layer of the power module substrate. Then, a semiconductor element such as a power element is mounted on the circuit layer via a solder material to form a power module.
  • a power module substrate with a cooler that uses copper or a copper alloy having excellent thermal and electrical characteristics for the circuit layer and a cooler made of an aluminum alloy is used. It is becoming popular.
  • Patent Document 1 discloses that silicon nitride, aluminum nitride, aluminum oxide or the like is used as a ceramic substrate, and a metal layer is bonded to the ceramic substrate by a direct bonding method or an active metal method. It is described that it is preferable to use copper as the metal layer. It also describes that a heat sink is joined to the power module substrate with solder.
  • the solder layer that joins the metal layer and the heat sink has a large thermal resistance, hinders heat transfer from the semiconductor element to the heat sink, and there is a risk that the solder layer may crack due to thermal expansion and contraction and break the solder layer. is there. For this reason, brazing joints with low thermal resistance and high joint reliability have attracted attention.
  • an aluminum cooler having a cooling channel formed therein as a heat sink When joining to a power module substrate by brazing, the aluminum cooler may be deformed by the applied pressure.
  • the present invention has been made in view of such circumstances, prevents deformation when brazing a metal layer made of copper or a copper alloy to an aluminum cooler, has low thermal resistance, and has high bonding reliability. It aims at providing the board
  • a circuit layer is formed by bonding a metal plate made of copper or a copper alloy to one surface of a ceramic substrate, and copper is formed on the other surface of the ceramic substrate.
  • a first joining step of joining a metal plate made of a copper alloy to form a first metal layer and solid phase diffusion joining of the metal plate made of aluminum or aluminum alloy, or nickel or nickel alloy, and the first metal layer.
  • a first metal layer made of copper or a copper alloy is joined to a second metal layer made of aluminum or an aluminum alloy, or nickel or a nickel alloy by solid phase diffusion bonding, thereby cooling the aluminum alloy. It is possible to braze and join the vessel using an Mg-containing Al-based brazing material. This brazing can be performed with a low load (for example, 0.001 MPa to 0.5 MPa) in an atmosphere such as nitrogen or argon, and even a low-rigidity aluminum cooler can be reliably bonded without being deformed.
  • a low load for example, 0.001 MPa to 0.5 MPa
  • a titanium foil is interposed between the first metal layer and the second metal layer, and the first metal layer, the titanium foil, the second metal layer, and the titanium foil are Solid phase diffusion bonding may be performed, and in the third bonding step, the second metal layer and the cooler may be brazed using an Al—Si—Mg-based brazing material.
  • first metal layer and the second metal layer By joining the first metal layer and the second metal layer by solid phase diffusion bonding through the titanium foil, the titanium atoms are diffused in both metal layers, and the aluminum atoms and the copper atoms are diffused in the titanium foil. These first metal layer, titanium foil, and second metal layer can be reliably bonded.
  • the titanium foil preferably has a larger area than the first metal layer. In this case, contact between the copper of the first metal layer made of copper or a copper alloy and the aluminum of the Mg-containing Al-based brazing material joining the cooler can be prevented more reliably.
  • the brazing material joining the cooler contains Mg having low wettability with respect to the aluminum oxide film.
  • the molten Mg-containing Al-based brazing material is repelled by the oxide film on the side surface of the second metal layer made of aluminum or aluminum alloy, and does not reach the first metal layer. Thereby, it does not contact the 1st metal layer which consists of copper or a copper alloy, and does not deform the 1st metal layer.
  • the first joining step and the second joining step may be performed simultaneously.
  • the first joining step and the second joining step can be performed simultaneously.
  • brazing joining using an Ag—Cu—Ti brazing material can be employed.
  • the second metal layer made of nickel or a nickel alloy has a larger area than the first metal layer
  • the copper of the first metal layer made of copper or a copper alloy and aluminum as a brazing material for joining the cooler This is preferable because the contact can be prevented more reliably.
  • an aluminum plate is stacked on the second metal layer, and the first metal layer, the second metal layer, the second metal layer, and the aluminum plate are respectively solid phase diffusion bonded. May be joined together.
  • the substrate for a power module with a cooler includes a ceramic substrate, a circuit layer made of copper or a copper alloy bonded to one surface of the ceramic substrate, and copper bonded to the other surface of the ceramic substrate or A first metal layer made of a copper alloy, an aluminum or aluminum alloy joined to the first metal layer, or a second metal layer made of nickel or a nickel alloy, and an aluminum alloy joined to the second metal layer A cooler, wherein metal atoms in a member bonded to the surface of the first metal layer are present in a diffused state, and bonded to the surface of the second metal layer.
  • the metal atoms in the member exist in a diffused state.
  • a titanium layer interposed between the first metal layer and the second metal layer is further included, and titanium in the titanium layer is diffused in the first metal layer and the second metal layer. It is preferable that it exists in a state.
  • the titanium layer preferably has a larger area than the first metal layer.
  • the second metal layer is preferably made of aluminum or an aluminum alloy.
  • the second metal layer is preferably made of nickel or a nickel alloy.
  • the second metal layer made of nickel or a nickel alloy preferably has a larger area than the first metal layer.
  • an aluminum layer interposed between the second metal layer made of nickel or a nickel alloy and the cooler may be further included.
  • a cooler made of an aluminum alloy can be brazed with a low load in a nitrogen or argon atmosphere to the first metal layer made of copper or a copper alloy of a power module substrate. It is possible to join without fail.
  • the molten Mg-containing Al-based brazing material is made of copper or a copper alloy due to the second metal layer interposed between the cooling device and the cooler. There is no contact with the first metal layer, and there is no deformation of the first metal layer. And since it is brazing, the board
  • FIG. 3 is a front view showing an example of a pressure device used in the manufacturing method of FIGS. 2A to 2C.
  • the power module substrate 10 with a cooler shown in FIG. 1 includes a ceramic substrate 11, a circuit layer 12 bonded to one surface of the ceramic substrate 11, and a first metal bonded to the other surface of the ceramic substrate 11.
  • Reference numeral 48 in FIG. 1 denotes a bonding layer described later.
  • the semiconductor element 30 is joined on the circuit layer 12 with the solder material as shown by the dashed-two dotted line of FIG. 1, and a power module is comprised.
  • the ceramic substrate 11 prevents electrical connection between the circuit layer 12 and the first metal layer 13, and includes aluminum nitride (AlN), silicon nitride (Si 3 N 4 ), aluminum oxide (Al 2 O). 3 ) and the like can be used, among which silicon nitride is preferable because of its high strength.
  • the thickness of the ceramic substrate 11 is set within a range of 0.2 mm or more and 1.5 mm or less.
  • the circuit layer 12 is made of copper or a copper alloy having excellent electrical characteristics.
  • the first metal layer 13 is also made of copper or a copper alloy.
  • the circuit layer 12 and the first metal layer 13 are formed, for example, by brazing and joining an oxygen-free copper plate having a purity of 99.96% by mass or more to the ceramic substrate 11 with an active metal brazing material, for example.
  • the thicknesses of the circuit layer 12 and the first metal layer 13 are set in the range of 0.1 mm to 1.0 mm.
  • the first metal layer 13 is formed by bonding a metal plate 13 ′ made of copper or a copper alloy to the ceramic substrate 11. In the first metal layer 13, the metal atoms in the member bonded to the surface thereof are present in a diffused state.
  • the second metal layer 14 is formed by joining a metal plate 14 'made of aluminum or an aluminum alloy, or nickel or a nickel alloy (in this embodiment, aluminum) to the first metal layer 13 by solid phase diffusion bonding. .
  • the thickness of the metal plate 14 ′ is set within a range of 0.1 mm to 1.0 mm when the material is aluminum or an aluminum alloy, and is set to 50 ⁇ m or more when the material is nickel or a nickel alloy.
  • the metal atoms in the member bonded to the surface thereof are present in a diffused state.
  • the cooler 20 is for dissipating the heat of the semiconductor element 30.
  • the cooler 20 has a plurality of partitions that divide an internal flow path 22 in a flat cylinder 21 through which a cooling medium such as water flows.
  • the partition wall 23 is formed along the thickness direction of the flat cylindrical body 21.
  • the cooler 20 is formed by, for example, extrusion molding of an aluminum alloy (for example, A3003, A6063, etc.).
  • the top plate 21a located above the cylinder 21 of the cooler 20 is fixed to the second metal layer 14 of the power module substrate 10 by brazing.
  • the semiconductor element 30 is an electronic component including a semiconductor, and IGBTs (Insulated Gate Bipolar Transistors), MOSFETs (Metal Oxide Semiconductor Field Effect Transistors), FWDs (FreDW, etc.) of FWD (FreeWh, etc.) depending on required functions.
  • IGBTs Insulated Gate Bipolar Transistors
  • MOSFETs Metal Oxide Semiconductor Field Effect Transistors
  • FWDs FreDW, etc.
  • FreeWh FreeWh, etc.
  • the semiconductor element 30 is joined to the circuit layer 12 by soldering, and the solder material is, for example, Sn—Sb, Sn—Ag, Sn—Cu, Sn—In, or Sn—Ag—Cu solder.
  • a material so-called lead-free solder material is used.
  • a metal plate 12 ′ made of copper or a copper alloy is bonded to one surface of the ceramic substrate 11 to form the circuit layer 12, and a metal plate 13 ′ made of copper or a copper alloy is formed on the other surface of the ceramic substrate 11.
  • a silver titanium (Ag—Ti) -based or silver copper titanium (Ag—Cu—Ti) -based active metal brazing material such as Ag-27.4% by mass Cu is formed on both surfaces of the ceramic substrate 11.
  • a copper plate (metal plate) that forms a brazing filler metal coating layer 40 by applying a paste of a brazing filler metal of ⁇ 2.0 mass% Ti and forms the circuit layer 12 and the first metal layer 13 on the brazing filler metal coating layer 40 12 'and 13' are laminated respectively.
  • the pressure device 110 includes a base plate 111, guide posts 112 vertically attached to the four corners of the upper surface of the base plate 111, a fixed plate 113 fixed to the upper ends of the guide posts 112, and the base plates 111.
  • a pressing plate 114 supported by a guide post 112 so as to freely move up and down between the fixing plate 113 and a spring provided between the fixing plate 113 and the pressing plate 114 to urge the pressing plate 114 downward.
  • urging means 115 is provided by a guide post 112 so as to freely move up and down between the fixing plate 113 and a spring provided between the fixing plate 113 and the pressing plate 114 to urge the pressing plate 114 downward.
  • the fixing plate 113 and the pressing plate 114 are arranged in parallel to the base plate 111, and the above-described laminate S is arranged between the base plate 111 and the pressing plate 114.
  • Cushion sheets 116 are disposed on both surfaces of the laminate S to make the pressure uniform.
  • the cushion sheet 116 is formed of a laminate of a carbon sheet and a graphite sheet.
  • the pressurizing device 110 and the pressurizing device 110 are installed in a heating furnace (not shown), heated to a bonding temperature in a vacuum atmosphere, and then the copper plate 12 '(circuit) Layer 12) and copper plate 13 '(first metal layer 13) are brazed.
  • the joining conditions in this case are, for example, heating for 1 minute to 60 minutes at a joining temperature of 800 ° C. to 930 ° C. with a pressure of 0.05 MPa to 1.0 MPa.
  • This brazing is an active metal brazing method in which Ti, which is an active metal in the brazing material, preferentially diffuses into the ceramic substrate 11 to form titanium nitride (TiN), and a silver-copper (Ag—Cu) alloy.
  • Ti titanium nitride
  • Au—Cu silver-copper
  • the metal plate 14 ′ made of aluminum or aluminum alloy, or nickel or nickel alloy, and the first metal layer 13 are joined by solid phase diffusion bonding to form the second metal layer 14. That is, the second metal layer 14 is formed on the surface of the first metal layer 13 opposite to the ceramic substrate 11.
  • a metal plate 14 ′ of aluminum or aluminum alloy or nickel or nickel alloy (aluminum in this embodiment) to be the second metal layer 14 is laminated on the first metal layer 13, and these laminates are the same as described above.
  • the pressure device 110 pressurizes in the stacking direction and heats to a predetermined bonding temperature in a vacuum atmosphere to form the second metal layer 14 bonded to the first metal layer 13 by solid phase diffusion bonding.
  • FIG. 2B shows a case where a metal plate 14 ′ made of aluminum or an aluminum alloy, nickel or a nickel alloy (aluminum in the present embodiment) is used as the second metal layer 14, and the metal plate 14 ′ and the first metal are used.
  • Solid phase diffusion bonding is performed with a titanium foil 41 interposed between the layer 13 and the layer 13.
  • the titanium foil 41 is set to a thickness of 3 ⁇ m or more and 40 ⁇ m or less. And it pressurizes to 0.1 MPa or more and 3.4 MPa or less, and it heats for 1 minute or more and 120 minutes or less to the joining temperature of 580 degreeC or more and 640 degrees C or less in a vacuum atmosphere.
  • a titanium layer 42 is formed between the first metal layer 13 and the second metal layer 14.
  • the metal plate 14 made of aluminum or an aluminum alloy, for example, pure aluminum having a purity of 99% or more, a purity of 99.9% or more, and a purity of 99.99% or more, or an aluminum alloy such as A3003 or A6063 is used. Can do.
  • the first metal layer 13 and the metal plate 14 ′ are bonded by solid phase diffusion bonding via the titanium foil 41, and as a result, bonded to the surface of the first metal layer 13.
  • the Ti in the titanium layer 42 exists in a diffused state, and the Ti in the titanium layer 42 bonded to the surface of the second metal layer 14 also exists in a diffused state.
  • a cooler 20 made of an aluminum alloy is brazed to the second metal layer 14 using an Mg-containing Al brazing material.
  • Mg-containing Al-based brazing material Al—Si—Mg foil, Al—Cu—Mg foil, Al—Ge—Cu—Si—Mg foil, or the like can be used.
  • a double-sided brazing clad material 45 in which Mg-containing Al-based brazing material is provided on both sides of the core material can also be used.
  • the double-sided brazing clad material 45 of the present embodiment is a clad material in which an Al—Si—Mg based brazing material layer 47 is formed on both sides of a core material 46 made of an aluminum alloy (for example, A3003 material). It is formed by rolling a brazing material on both sides.
  • the thickness of the core material 46 is 0.05 mm or more and 0.6 mm or less, and the brazing filler metal layers 47 on both sides have a thickness of 5 ⁇ m or more and 100 ⁇ m or less.
  • the double-sided brazing clad material 45 is interposed between the second metal layer 14 and the cooler 20 and stacked, and is pressed in the stacking direction using the pressurizing device 110 similar to FIG.
  • the pressure device 110 is brazed by heating in a nitrogen atmosphere or an argon atmosphere.
  • the applied pressure is, for example, 0.001 MPa or more and 0.5 MPa or less, and the bonding temperature is 580 ° C. or more and 630 ° C. or less higher than the eutectic temperature of Al and Cu.
  • the brazing bonding temperature is higher than the eutectic temperature of Al and Cu. Therefore, if the molten brazing material containing Al comes into contact with the first metal layer 13 made of copper or a copper alloy, copper or The first metal layer 13 made of a copper alloy is eroded and deformation of the first metal layer 13 occurs.
  • a molten Mg-containing Al-based brazing material in this embodiment, an Al—Si—Mg-based alloy.
  • the brazing material does not contact the first metal layer 13 beyond the side surface of the second metal layer 14 and does not deform the first metal layer 13.
  • the bonding temperature in the third bonding step in which the cooler 20 is brazed to the second metal layer 14 is higher than the eutectic temperature of aluminum and copper. Since the titanium layer 42 is present at the interface portion with the metal layer 13, the liquid phase is present between the aluminum of the second metal layer 14 and the copper of the first metal layer 13 even during brazing in the third bonding step. It does not occur and the first metal layer 13 is prevented from melting.
  • a bonding layer 48 made of an aluminum alloy that is the core material 46 of the double-sided brazing clad material 45 is thinly interposed.
  • the power module substrate 10 with a cooler manufactured as described above has the circuit layer 12 and the first metal layer 13 formed on both surfaces of the ceramic substrate 11, and the first metal layer 13 is made of aluminum or an aluminum alloy. Since the cooler 20 made of an aluminum alloy is brazed through the second metal layer 14, it can be brazed with a low load using an Mg-containing Al-based brazing material. In addition, the cooler 20 is brazed using the Mg-containing Al brazing material, but the molten Mg-containing Al brazing material is repelled on the side surface of the second metal layer 14, and thus is made of copper or a copper alloy. There is no contact with the first metal layer 13, and the first metal layer 13 is not deformed. Since this cooler 20 is made of an aluminum alloy and has a flow path 22 inside, the cooler 20 has relatively low rigidity. However, since this brazing has a low load, the cooler 20 can be reliably joined without being deformed.
  • the titanium layer 42 is interposed between the first metal layer 13 and the second metal layer 14.
  • an Mg-containing Al-based brazing material having a melting point lower than the eutectic temperature of Al and Cu for example, Al-15Ge-12Si-5Cu-1Mg, melting point 540 ° C.
  • a titanium layer is interposed.
  • the first metal layer 13 and the second metal layer 14 can be directly solid phase diffusion bonded. In this case, the metal atoms in the joined second metal layer exist in the first metal layer 13 in a diffused state, and the metal atoms in the first metal layer diffuse in the second metal layer. Exists.
  • the cooler is not limited to the above-described structure, and a flat plate material may be used.
  • the material is not limited to an aluminum alloy, and an Al-based or Mg-based low thermal expansion material (for example, AlSiC) can be used.
  • a power module substrate 210 with a cooler includes a ceramic substrate 211 and a circuit layer made of copper or a copper alloy bonded to one surface of the ceramic substrate 211. 212, a first metal layer 213 made of copper or a copper alloy joined to the other surface of the ceramic substrate 211, a second metal layer 214 made of nickel or a nickel alloy joined to the first metal layer 213, And a cooler 20 made of an aluminum alloy joined to the two metal layers 214.
  • a part of the double-sided clad material used for brazing the cooler 20 remains as the bonding layer 48 between the second metal layer 214 and the cooler 20. ing.
  • Ni in the second metal layer 214 bonded to the surface thereof is present in the first metal layer 213 in a diffused state, and in the second metal layer 214.
  • Cu in the first metal layer 213 bonded to the surface thereof is present in a diffused state.
  • the second metal layer 214 has a larger area than the first metal layer 213. This prevents the brazing material melted when joining the cooler 20 from reaching the first metal layer 213.
  • the cooler-equipped power module substrate 210 is manufactured by the same manufacturing method as in the first embodiment described above. However, since the second metal layer 214 is nickel, the first bonding step and the second bonding step are performed. It is possible to do it at the same time.
  • each metal plate to be the circuit layer 212 and the first metal layer 211 is made of an active metal brazing material of silver titanium (Ag—Ti) or silver copper titanium (Ag—Cu—Ti) based on the ceramic substrate 211. Simultaneously with the brazing and joining, the metal plate to be the second metal layer 214 is bonded to the metal plate to be the first metal layer 211 by solid phase diffusion joining.
  • a power module substrate 310 with a cooler includes a ceramic substrate 311 and a circuit layer made of copper or a copper alloy bonded to one surface of the ceramic substrate 311. 312, a first metal layer 313 made of copper or a copper alloy joined to the other surface of the ceramic substrate 311, a second metal layer 314 made of nickel or a nickel alloy joined to the first metal layer 313, A cooler 20 made of an aluminum alloy joined to the two metal layers 314, and an aluminum layer 315 interposed between the second metal layer 314 and the cooler 20. Further, as in the above embodiments, a part of the double-sided clad material used for brazing the cooler 20 remains as the bonding layer 48 between the aluminum layer 315 and the cooler 20. .
  • Ni in the second metal layer 314 bonded to the surface of the first metal layer 313 is present in a diffused state, and in the second metal layer 314.
  • Cu in the first metal layer 313 bonded to one surface thereof and Al in the aluminum layer 315 bonded to the other surface are present in a diffused state.
  • a power module substrate 410 with a cooler includes a ceramic substrate 411 and a circuit layer made of copper or a copper alloy bonded to one surface of the ceramic substrate 411. 412, a first metal layer 413 made of copper or a copper alloy joined to the other surface of the ceramic substrate 411, and a second metal made of aluminum or an aluminum alloy joined to the first metal layer 413, or nickel or a nickel alloy. It has a metal layer 414 and a cooler 20 made of an aluminum alloy joined to the second metal layer 414, and further includes a titanium layer 415 interposed between the first metal layer 413 and the second metal layer 414. As in the above embodiments, a part of the double-sided clad material used for brazing the cooler 20 remains as the bonding layer 48 between the second metal layer 414 and the cooler 20. ing.
  • Ti in the titanium layer 415 bonded to the surface of the first metal layer 413 and the second metal layer 414 is present in a diffused state.
  • At least one of the second metal layer 414 and the titanium layer 415 has a larger area than the first metal layer 413. This prevents the brazing material melted when the cooler 20 is joined from reaching the first metal layer 413.
  • a power module substrate with a cooler that prevents the occurrence of deformation when a metal layer made of copper or a copper alloy is brazed to an aluminum cooler, has low thermal resistance, and has high bonding reliability.

Abstract

Provided is a substrate with a cooler for power modules, which is prevented from the occurrence of deformation during brazing of a metal layer that is formed from copper or a copper alloy to a cooler that is formed from aluminum, and which has low thermal resistance and high bonding reliability. A circuit layer that is formed from copper or a copper alloy is bonded to one surface of a ceramic substrate, while bonding a metal layer that is formed from copper or a copper alloy to the other surface of the ceramic substrate. A second metal layer that is formed from aluminum or an aluminum alloy is bonded to the metal layer by solid-phase diffusion, and a cooler that is formed form an aluminum alloy is joined to the second metal layer by brazing with use of an Mg-containing Al-based brazing filler material.

Description

冷却器付パワーモジュール用基板及びその製造方法Substrate for power module with cooler and method for manufacturing the same
　本発明は、大電流、高電圧を制御する半導体装置に用いられる冷却器付パワーモジュール用基板及びその製造方法に関する。
　本願は、２０１４年１０月１６日に出願された特願２０１４－２１１５２９号、および２０１５年１０月０９日に出願された特願２０１５－２００７８４号に基づき優先権を主張し、その内容をここに援用する。 The present invention relates to a substrate for a power module with a cooler used in a semiconductor device that controls a large current and a high voltage, and a method for manufacturing the same.
This application claims priority based on Japanese Patent Application No. 2014-2111529 filed on October 16, 2014 and Japanese Patent Application No. 2015-200784 filed on October 09, 2015, the contents of which are incorporated herein by reference. Incorporate.
　従来のパワーモジュール用基板として、絶縁層となるセラミックス基板の一方の面に回路層が接合されるとともに、他方の面に放熱のための金属層が接合された構成のものが知られている。また、このパワーモジュール用基板の金属層に冷却器が接合されることで、冷却器付パワーモジュール用基板が構成される。そして、回路層上にはんだ材を介してパワー素子等の半導体素子が搭載され、パワーモジュールとなる。 A conventional power module substrate is known in which a circuit layer is bonded to one surface of a ceramic substrate serving as an insulating layer, and a metal layer for heat dissipation is bonded to the other surface. Further, a power module substrate with a cooler is configured by bonding a cooler to the metal layer of the power module substrate. Then, a semiconductor element such as a power element is mounted on the circuit layer via a solder material to form a power module.
　この種のパワーモジュール用基板において、回路層に熱的特性、電気的特性に優れる銅又は銅合金を用い、冷却器にはアルミニウム合金からなる構造のものを用いた冷却器付パワーモジュール用基板が普及しつつある。 In this type of power module substrate, a power module substrate with a cooler that uses copper or a copper alloy having excellent thermal and electrical characteristics for the circuit layer and a cooler made of an aluminum alloy is used. It is becoming popular.
　そのようなパワーモジュール用基板として、特許文献１に、セラミックス基板として窒化ケイ素、窒化アルミニウム、酸化アルミニウム等を用い、このセラミックス基板に、金属層を直接接合法や活性金属法によって接合することが開示されており、その金属層として、銅を用いるのが好ましいと記載されている。また、そのパワーモジュール用基板に、ヒートシンクをはんだにより接合することも記載されている。 As such a power module substrate, Patent Document 1 discloses that silicon nitride, aluminum nitride, aluminum oxide or the like is used as a ceramic substrate, and a metal layer is bonded to the ceramic substrate by a direct bonding method or an active metal method. It is described that it is preferable to use copper as the metal layer. It also describes that a heat sink is joined to the power module substrate with solder.
特開２００６‐２４５４３７号公報JP 2006-245437 A
　ところで、金属層とヒートシンクとを接合しているはんだ層は熱抵抗が大きく、半導体素子からヒートシンクへの熱伝達を妨げ、また、熱伸縮によりはんだ層にクラックが入ってはんだ層が破壊するおそれがある。このため、熱抵抗が小さく、接合信頼性も高いろう付け接合が注目されている。 By the way, the solder layer that joins the metal layer and the heat sink has a large thermal resistance, hinders heat transfer from the semiconductor element to the heat sink, and there is a risk that the solder layer may crack due to thermal expansion and contraction and break the solder layer. is there. For this reason, brazing joints with low thermal resistance and high joint reliability have attracted attention.
　しかしながら、ろう付け工程は、ろう材を介して積層した金属板どうしを積層方向に加圧して加熱することにより行われるものであるため、ヒートシンクとして、内部に冷却流路を形成したアルミニウム製冷却器をろう付けによりパワーモジュール用基板に接合する場合、その加圧力によってアルミニウム製冷却器が変形するおそれがある。 However, since the brazing process is performed by pressurizing and heating the metal plates laminated via the brazing material in the laminating direction, an aluminum cooler having a cooling channel formed therein as a heat sink When joining to a power module substrate by brazing, the aluminum cooler may be deformed by the applied pressure.
　本発明は、このような事情に鑑みてなされたもので、銅又は銅合金からなる金属層をアルミニウム製冷却器にろう付けする際の変形の発生を防止し、熱抵抗が小さく、接合信頼性の高い冷却器付パワーモジュール用基板を提供することを目的とする。 The present invention has been made in view of such circumstances, prevents deformation when brazing a metal layer made of copper or a copper alloy to an aluminum cooler, has low thermal resistance, and has high bonding reliability. It aims at providing the board | substrate for power modules with a cooler with high.
　本発明の冷却器付パワーモジュール用基板の製造方法は、セラミックス基板の一方の面に銅又は銅合金からなる金属板を接合して回路層を形成するとともに、前記セラミックス基板の他方の面に銅又は銅合金からなる金属板を接合して第１金属層を形成する第１接合工程と、アルミニウム又はアルミニウム合金，あるいはニッケル又はニッケル合金からなる金属板と前記第１金属層とを固相拡散接合により接合して第２金属層を形成する第２接合工程と、前記第２金属層にアルミニウム合金からなる冷却器をＭｇ含有Ａｌ系ろう材を用いてろう付け接合する第３接合工程とを有する。 In the method for manufacturing a power module substrate with a cooler according to the present invention, a circuit layer is formed by bonding a metal plate made of copper or a copper alloy to one surface of a ceramic substrate, and copper is formed on the other surface of the ceramic substrate. Alternatively, a first joining step of joining a metal plate made of a copper alloy to form a first metal layer, and solid phase diffusion joining of the metal plate made of aluminum or aluminum alloy, or nickel or nickel alloy, and the first metal layer. A second bonding step of forming a second metal layer by bonding, and a third bonding step of brazing and bonding a cooler made of an aluminum alloy to the second metal layer using an Mg-containing Al-based brazing material. .
　本発明の製造方法は、銅又は銅合金からなる第１金属層にアルミニウム又はアルミニウム合金，あるいはニッケル又はニッケル合金からなる第２金属層を固相拡散接合によって接合することにより、アルミニウム合金からなる冷却器をＭｇ含有Ａｌ系ろう材を用いてろう付け接合することが可能である。このろう付けは、窒素又はアルゴン等の雰囲気中で低荷重（例えば０．００１ＭＰａ～０．５ＭＰａ）で行うことができ、剛性の低いアルミニウム製冷却器でも変形させることなく確実に接合できる。 In the manufacturing method of the present invention, a first metal layer made of copper or a copper alloy is joined to a second metal layer made of aluminum or an aluminum alloy, or nickel or a nickel alloy by solid phase diffusion bonding, thereby cooling the aluminum alloy. It is possible to braze and join the vessel using an Mg-containing Al-based brazing material. This brazing can be performed with a low load (for example, 0.001 MPa to 0.5 MPa) in an atmosphere such as nitrogen or argon, and even a low-rigidity aluminum cooler can be reliably bonded without being deformed.
　さらに、前記第２接合工程において、前記第１金属層と前記第２金属層との間にチタン箔を介在させ、前記第１金属層と前記チタン箔および前記第２金属層と前記チタン箔をそれぞれ固相拡散接合し、前記第３接合工程において、前記第２金属層と前記冷却器とをＡｌ－Ｓｉ－Ｍｇ系ろう材を用いてろう付け接合するとよい。 Further, in the second bonding step, a titanium foil is interposed between the first metal layer and the second metal layer, and the first metal layer, the titanium foil, the second metal layer, and the titanium foil are Solid phase diffusion bonding may be performed, and in the third bonding step, the second metal layer and the cooler may be brazed using an Al—Si—Mg-based brazing material.
　チタン箔を介して第１金属層と第２金属層とを固相拡散接合により接合することにより、両金属層にチタン原子を拡散させるとともに、チタン箔にアルミニウム原子及び銅原子を拡散させて、これら第１金属層、チタン箔、第２金属層を確実に接合できる。 By joining the first metal layer and the second metal layer by solid phase diffusion bonding through the titanium foil, the titanium atoms are diffused in both metal layers, and the aluminum atoms and the copper atoms are diffused in the titanium foil. These first metal layer, titanium foil, and second metal layer can be reliably bonded.
　この場合、第２金属層を接合した後、冷却器をろう付けする際に加熱されるが、チタン箔が介在しているので、このろう付けの際にアルミニウムと銅とに拡散が生じることが防止される。 In this case, after joining the second metal layer, it is heated when brazing the cooler, but since titanium foil is interposed, diffusion may occur between aluminum and copper during this brazing. Is prevented.
　この製造方法において、前記チタン箔は前記第１金属層よりも面積が大きいことが好ましい。この場合、銅又は銅合金からなる第１金属層の銅と、冷却器を接合するＭｇ含有Ａｌ系ろう材のアルミニウムとの接触を、より確実に防止できる。 In this manufacturing method, the titanium foil preferably has a larger area than the first metal layer. In this case, contact between the copper of the first metal layer made of copper or a copper alloy and the aluminum of the Mg-containing Al-based brazing material joining the cooler can be prevented more reliably.
　この製造方法において、前記第２金属層をアルミニウムまたはアルミニウム合金からなる前記金属板を用いて形成する場合、冷却器を接合するろう材にアルミニウム酸化膜に対する濡れ性の低いＭｇが含有されているので、溶融したＭｇ含有Ａｌ系ろう材が、アルミニウムまたはアルミニウム合金からなる第２金属層の側面の酸化膜に弾かれ、第１金属層まで到達しない。これにより、銅又は銅合金からなる第１金属層と接触せず、第１金属層を変形させることが無い。 In this manufacturing method, when the second metal layer is formed using the metal plate made of aluminum or an aluminum alloy, the brazing material joining the cooler contains Mg having low wettability with respect to the aluminum oxide film. The molten Mg-containing Al-based brazing material is repelled by the oxide film on the side surface of the second metal layer made of aluminum or aluminum alloy, and does not reach the first metal layer. Thereby, it does not contact the 1st metal layer which consists of copper or a copper alloy, and does not deform the 1st metal layer.
　あるいはこの製造方法において、前記第２金属層をニッケル又はニッケル合金からなる前記金属板を用いて形成する場合、前記第１接合工程および前記第２接合工程を同時に行ってもよい。この場合、第２金属層がニッケル又はニッケル合金であることにより、第１接合工程と第２接合工程とを同時に行うことができる。第１接合工程には、例えばＡｇ－Ｃｕ－Ｔｉ系ろう材を用いたろう付け接合が採用できる。 Alternatively, in this manufacturing method, when the second metal layer is formed using the metal plate made of nickel or a nickel alloy, the first joining step and the second joining step may be performed simultaneously. In this case, since the second metal layer is nickel or a nickel alloy, the first joining step and the second joining step can be performed simultaneously. For the first joining step, for example, brazing joining using an Ag—Cu—Ti brazing material can be employed.
　この場合、ニッケル又はニッケル合金からなる前記第２金属層が前記第１金属層よりも面積が大きいと、銅又は銅合金からなる第１金属層の銅と冷却器を接合するろう材のアルミニウムとの接触をより確実に防止できるので好ましい。 In this case, when the second metal layer made of nickel or a nickel alloy has a larger area than the first metal layer, the copper of the first metal layer made of copper or a copper alloy and aluminum as a brazing material for joining the cooler, This is preferable because the contact can be prevented more reliably.
　さらにこの場合、前記第２接合工程において、前記第２金属層にアルミニウム板を積層して前記第１金属層と前記第２金属層および前記第２金属層と前記アルミニウム板をそれぞれ固相拡散接合により接合してもよい。 Further, in this case, in the second bonding step, an aluminum plate is stacked on the second metal layer, and the first metal layer, the second metal layer, the second metal layer, and the aluminum plate are respectively solid phase diffusion bonded. May be joined together.
　本発明の冷却器付パワーモジュール用基板は、セラミックス基板と、前記セラミックス基板の一方の面に接合された銅又は銅合金からなる回路層と、前記セラミックス基板の他方の面に接合された銅又は銅合金からなる第１金属層と、前記第１金属層に接合されたアルミニウム又はアルミニウム合金，あるいはニッケル又はニッケル合金からなる第２金属層と、前記第２金属層に接合されたアルミニウム合金からなる冷却器とを備え、前記第１金属層中に、その表面に接合された部材中の金属原子が拡散した状態で存在しているとともに、前記第２金属層中に、その表面に接合された部材中の金属原子が拡散した状態で存在している。 The substrate for a power module with a cooler according to the present invention includes a ceramic substrate, a circuit layer made of copper or a copper alloy bonded to one surface of the ceramic substrate, and copper bonded to the other surface of the ceramic substrate or A first metal layer made of a copper alloy, an aluminum or aluminum alloy joined to the first metal layer, or a second metal layer made of nickel or a nickel alloy, and an aluminum alloy joined to the second metal layer A cooler, wherein metal atoms in a member bonded to the surface of the first metal layer are present in a diffused state, and bonded to the surface of the second metal layer. The metal atoms in the member exist in a diffused state.
　また、前記第１金属層と前記第２金属層との間に介在するチタン層をさらに有し、前記第１金属層中および前記第２金属層中に、前記チタン層中のチタンが拡散した状態で存在していることが好ましい。 Further, a titanium layer interposed between the first metal layer and the second metal layer is further included, and titanium in the titanium layer is diffused in the first metal layer and the second metal layer. It is preferable that it exists in a state.
　この場合、前記チタン層は前記第１金属層よりも面積が大きいことが好ましい。 In this case, the titanium layer preferably has a larger area than the first metal layer.
　この冷却器付パワーモジュール用基板において、前記第２金属層はアルミニウム又はアルミニウム合金からなることが好ましい。 In the power module substrate with a cooler, the second metal layer is preferably made of aluminum or an aluminum alloy.
　あるいは、この冷却器付パワーモジュール用基板において、前記第２金属層はニッケル又はニッケル合金からなることが好ましい。 Alternatively, in the power module substrate with a cooler, the second metal layer is preferably made of nickel or a nickel alloy.
　この場合、ニッケル又はニッケル合金からなる前記第２金属層は前記第１金属層よりも面積が大きいことが好ましい。 In this case, the second metal layer made of nickel or a nickel alloy preferably has a larger area than the first metal layer.
　また、ニッケル又はニッケル合金からなる前記第２金属層と前記冷却器との間に介在するアルミニウム層をさらに有してもよい。 Further, an aluminum layer interposed between the second metal layer made of nickel or a nickel alloy and the cooler may be further included.
　本発明によれば、パワーモジュール用基板の銅又は銅合金からなる第１金属層に、アルミニウム合金からなる冷却器を窒素又はアルゴン雰囲気で低荷重でろう付けでき、剛性の低い冷却器でも、変形させることなく確実に接合できる。また、Ｍｇ含有Ａｌ系ろう材を用いてろう付けを行っているが、冷却器との間に第２金属層が介在することにより、溶融したＭｇ含有Ａｌ系ろう材が銅又は銅合金からなる第１金属層と接触することが無く、第１金属層を変形させることが無い。しかも、ろう付けであるので、熱抵抗が小さく、接合信頼性の高い冷却器付パワーモジュール用基板を得ることができる。 According to the present invention, a cooler made of an aluminum alloy can be brazed with a low load in a nitrogen or argon atmosphere to the first metal layer made of copper or a copper alloy of a power module substrate. It is possible to join without fail. In addition, although brazing is performed using an Mg-containing Al-based brazing material, the molten Mg-containing Al-based brazing material is made of copper or a copper alloy due to the second metal layer interposed between the cooling device and the cooler. There is no contact with the first metal layer, and there is no deformation of the first metal layer. And since it is brazing, the board | substrate for power modules with a cooler with low thermal resistance and high joining reliability can be obtained.
本発明の第一実施形態の冷却器付パワーモジュール用基板の縦断面図である。It is a longitudinal cross-sectional view of the board | substrate for power modules with a cooler of 1st embodiment of this invention. 図１の冷却器付パワーモジュール用基板の製造方法における第１接合工程を示した縦断面図である。It is the longitudinal cross-sectional view which showed the 1st joining process in the manufacturing method of the board | substrate for power modules with a cooler of FIG. 図１の冷却器付パワーモジュール用基板の製造方法における第２接合工程を示した縦断面図である。It is the longitudinal cross-sectional view which showed the 2nd joining process in the manufacturing method of the board | substrate for power modules with a cooler of FIG. 図１の冷却器付パワーモジュール用基板の製造方法における第３接合工程を示した縦断面図である。It is the longitudinal cross-sectional view which showed the 3rd joining process in the manufacturing method of the board | substrate for power modules with a cooler of FIG. 図２Ａ～２Ｃの製造方法で用いられる加圧装置の例を示す正面図である。FIG. 3 is a front view showing an example of a pressure device used in the manufacturing method of FIGS. 2A to 2C. 本発明の第２実施形態に係る冷却器付パワーモジュール用基板の縦断面図である。It is a longitudinal cross-sectional view of the board | substrate for power modules with a cooler which concerns on 2nd Embodiment of this invention. 本発明の第３実施形態に係る冷却器付パワーモジュール用基板の縦断面図である。It is a longitudinal cross-sectional view of the board | substrate for power modules with a cooler which concerns on 3rd Embodiment of this invention. 本発明の第４実施形態に係る冷却器付パワーモジュール用基板の縦断面図である。It is a longitudinal cross-sectional view of the board | substrate for power modules with a cooler which concerns on 4th Embodiment of this invention.
　以下、本発明に係る冷却器付パワーモジュール用基板及びその製造方法の各実施形態について説明する。 Hereinafter, each embodiment of the board | substrate for power modules with a cooler which concerns on this invention, and its manufacturing method is demonstrated.
（第１実施形態）
　図１に示す冷却器付パワーモジュール用基板１０は、セラミックス基板１１と、そのセラミックス基板１１の一方の面に接合された回路層１２と、セラミックス基板１１の他方の面に接合された第１金属層１３と、この第１金属層１３のセラミックス基板１１とは反対側の面に接合された第２金属層１４と、この第２金属層１４に接合された冷却器２０と、第１金属層１３と第２金属層１４との間に介在するチタン層４２とを有している。図１中符号４８は後述する接合層である。そして、回路層１２の上に図１の二点鎖線で示すように半導体素子３０がはんだ材により接合されて、パワーモジュールを構成する。 (First embodiment)
The power module substrate 10 with a cooler shown in FIG. 1 includes a ceramic substrate 11, a circuit layer 12 bonded to one surface of the ceramic substrate 11, and a first metal bonded to the other surface of the ceramic substrate 11. A layer 13, a second metal layer 14 bonded to the surface of the first metal layer 13 opposite to the ceramic substrate 11, a cooler 20 bonded to the second metal layer 14, and a first metal layer And a titanium layer 42 interposed between the second metal layer 14 and the second metal layer 14. Reference numeral 48 in FIG. 1 denotes a bonding layer described later. And the semiconductor element 30 is joined on the circuit layer 12 with the solder material as shown by the dashed-two dotted line of FIG. 1, and a power module is comprised.
　セラミックス基板１１は、回路層１２と第１金属層１３との間の電気的接続を防止するものであって、窒化アルミニウム（ＡｌＮ），窒化ケイ素（Ｓｉ３Ｎ４），酸化アルミニウム（Ａｌ２Ｏ３）等を用いることができるが、そのうち、窒化ケイ素が高強度であるため、好適である。このセラミックス基板１１の厚みは０．２ｍｍ以上１．５ｍｍ以下の範囲内に設定される。 The ceramic substrate 11 prevents electrical connection between the circuit layer 12 and the first metal layer 13, and includes aluminum nitride (AlN), silicon nitride (Si 3 N 4 ), aluminum oxide (Al 2 O). 3 ) and the like can be used, among which silicon nitride is preferable because of its high strength. The thickness of the ceramic substrate 11 is set within a range of 0.2 mm or more and 1.5 mm or less.
　回路層１２は、電気特性に優れる銅又は銅合金から構成される。また、第１金属層１３も銅又は銅合金から構成される。これら回路層１２及び第１金属層１３は、例えば、純度９９．９６質量％以上の無酸素銅の銅板がセラミックス基板１１に例えば活性金属ろう材にてろう付け接合されることにより形成される。この回路層１２及び第１金属層１３の厚みは０．１ｍｍ～１．０ｍｍの範囲内に設定される。 The circuit layer 12 is made of copper or a copper alloy having excellent electrical characteristics. The first metal layer 13 is also made of copper or a copper alloy. The circuit layer 12 and the first metal layer 13 are formed, for example, by brazing and joining an oxygen-free copper plate having a purity of 99.96% by mass or more to the ceramic substrate 11 with an active metal brazing material, for example. The thicknesses of the circuit layer 12 and the first metal layer 13 are set in the range of 0.1 mm to 1.0 mm.
　第１金属層１３は、銅又は銅合金からなる金属板１３′がセラミックス基板１１に接合されることにより形成されている。この第１金属層１３中には、その表面に接合された部材中の金属原子が拡散した状態で存在している。 The first metal layer 13 is formed by bonding a metal plate 13 ′ made of copper or a copper alloy to the ceramic substrate 11. In the first metal layer 13, the metal atoms in the member bonded to the surface thereof are present in a diffused state.
　第２金属層１４は、アルミニウム又はアルミニウム合金，あるいはニッケル又はニッケル合金（本実施形態ではアルミニウム）からなる金属板１４′が第１金属層１３に固相拡散接合により接合されることにより形成される。金属板１４′の厚みは、材質がアルミニウム又はアルミニウム合金の場合は０．１ｍｍ～１．０ｍｍの範囲内、ニッケル又はニッケル合金の場合は５０μｍ以上に設定される。この第２金属層１４中には、その表面に接合された部材中の金属原子が拡散した状態で存在している。 The second metal layer 14 is formed by joining a metal plate 14 'made of aluminum or an aluminum alloy, or nickel or a nickel alloy (in this embodiment, aluminum) to the first metal layer 13 by solid phase diffusion bonding. . The thickness of the metal plate 14 ′ is set within a range of 0.1 mm to 1.0 mm when the material is aluminum or an aluminum alloy, and is set to 50 μm or more when the material is nickel or a nickel alloy. In the second metal layer 14, the metal atoms in the member bonded to the surface thereof are present in a diffused state.
　冷却器２０は、半導体素子３０の熱を放散するためのものであり、本実施形態では、水等の冷却媒体が流通する偏平な筒体２１内に、内部の流路２２を区画する複数の仕切り壁２３が偏平な筒体２１の厚さ方向に沿って形成されている。この冷却器２０は例えばアルミニウム合金（例えばＡ３００３、Ａ６０６３等）の押出成形によって形成される。そして、パワーモジュール用基板１０の第２金属層１４に、冷却器２０の筒体２１の上側に位置する天板２１ａがろう付け接合により固定されている。 The cooler 20 is for dissipating the heat of the semiconductor element 30. In this embodiment, the cooler 20 has a plurality of partitions that divide an internal flow path 22 in a flat cylinder 21 through which a cooling medium such as water flows. The partition wall 23 is formed along the thickness direction of the flat cylindrical body 21. The cooler 20 is formed by, for example, extrusion molding of an aluminum alloy (for example, A3003, A6063, etc.). And the top plate 21a located above the cylinder 21 of the cooler 20 is fixed to the second metal layer 14 of the power module substrate 10 by brazing.
　半導体素子３０は、半導体を備えた電子部品であり、必要とされる機能に応じてＩＧＢＴ（Ｉｎｓｕｌａｔｅｄ　Ｇａｔｅ　Ｂｉｐｏｌａｒ　Ｔｒａｎｓｉｓｔｏｒ）、ＭＯＳＦＥＴ（Ｍｅｔａｌ　Ｏｘｉｄｅ　Ｓｅｍｉｃｏｎｄｕｃｔｏｒ　Ｆｉｅｌｄ　Ｅｆｆｅｃｔ　Ｔｒａｎｓｉｓｔｏｒ）、ＦＷＤ（Ｆｒｅｅ　Ｗｈｅｅｌｉｎｇ　Ｄｉｏｄｅ）等の種々の半導体素子が選択される。 The semiconductor element 30 is an electronic component including a semiconductor, and IGBTs (Insulated Gate Bipolar Transistors), MOSFETs (Metal Oxide Semiconductor Field Effect Transistors), FWDs (FreDW, etc.) of FWD (FreeWh, etc.) depending on required functions. A semiconductor element is selected.
　この半導体素子３０は回路層１２にはんだ付けにより接合され、そのはんだ材は、例えばＳｎ‐Ｓｂ系、Ｓｎ‐Ａｇ系、Ｓｎ‐Ｃｕ系、Ｓｎ‐Ｉｎ系、もしくはＳｎ‐Ａｇ‐Ｃｕ系のはんだ材（いわゆる鉛フリーはんだ材）が用いられる。 The semiconductor element 30 is joined to the circuit layer 12 by soldering, and the solder material is, for example, Sn—Sb, Sn—Ag, Sn—Cu, Sn—In, or Sn—Ag—Cu solder. A material (so-called lead-free solder material) is used.
　このように構成される冷却器付パワーモジュール用基板１０の製造方法について図２Ａ～図２Ｃを参照しながら説明する。 A method of manufacturing the power module substrate 10 with a cooler configured as described above will be described with reference to FIGS. 2A to 2C.
（第１接合工程）
　まず、セラミックス基板１１の一方の面に銅又は銅合金からなる金属板１２′を接合して回路層１２を形成するとともに、セラミックス基板１１の他方の面に銅又は銅合金からなる金属板１３′を接合して第１金属層１３を形成する。すなわち、図２Ａに示すように、セラミックス基板１１の両面に銀チタン（Ａｇ－Ｔｉ）系又は銀銅チタン（Ａｇ－Ｃｕ－Ｔｉ）系の活性金属ろう材、例えばＡｇ－２７．４質量％Ｃｕ－２．０質量％Ｔｉのろう材のペーストを塗布してろう材塗布層４０を形成し、これらろう材塗布層４０の上に回路層１２及び第１金属層１３となる銅板（金属板）１２′、１３′をそれぞれ積層する。 (First joining process)
First, a metal plate 12 ′ made of copper or a copper alloy is bonded to one surface of the ceramic substrate 11 to form the circuit layer 12, and a metal plate 13 ′ made of copper or a copper alloy is formed on the other surface of the ceramic substrate 11. Are joined to form the first metal layer 13. That is, as shown in FIG. 2A, a silver titanium (Ag—Ti) -based or silver copper titanium (Ag—Cu—Ti) -based active metal brazing material such as Ag-27.4% by mass Cu is formed on both surfaces of the ceramic substrate 11. A copper plate (metal plate) that forms a brazing filler metal coating layer 40 by applying a paste of a brazing filler metal of −2.0 mass% Ti and forms the circuit layer 12 and the first metal layer 13 on the brazing filler metal coating layer 40 12 'and 13' are laminated respectively.
　そして、その積層体Ｓを図３に示す加圧装置１１０によって積層方向に加圧した状態とする。 Then, the stacked body S is pressed in the stacking direction by the pressurizing device 110 shown in FIG.
　この加圧装置１１０は、ベース板１１１と、ベース板１１１の上面の四隅に垂直に取り付けられたガイドポスト１１２と、これらガイドポスト１１２の上端部に固定された固定板１１３と、これらベース板１１１と固定板１１３との間で上下移動自在にガイドポスト１１２に支持された押圧板１１４と、固定板１１３と押圧板１１４との間に設けられて押圧板１１４を下方に付勢するばね等の付勢手段１１５とを備えている。 The pressure device 110 includes a base plate 111, guide posts 112 vertically attached to the four corners of the upper surface of the base plate 111, a fixed plate 113 fixed to the upper ends of the guide posts 112, and the base plates 111. A pressing plate 114 supported by a guide post 112 so as to freely move up and down between the fixing plate 113 and a spring provided between the fixing plate 113 and the pressing plate 114 to urge the pressing plate 114 downward. And urging means 115.
　固定板１１３および押圧板１１４は、ベース板１１１に対して平行に配置されており、ベース板１１１と押圧板１１４との間に前述の積層体Ｓが配置される。積層体Ｓの両面には加圧を均一にするためにクッションシート１１６が配設される。クッションシート１１６は、カーボンシートとグラファイトシートの積層板で形成されている。 The fixing plate 113 and the pressing plate 114 are arranged in parallel to the base plate 111, and the above-described laminate S is arranged between the base plate 111 and the pressing plate 114. Cushion sheets 116 are disposed on both surfaces of the laminate S to make the pressure uniform. The cushion sheet 116 is formed of a laminate of a carbon sheet and a graphite sheet.
　この加圧装置１１０により積層体Ｓを加圧した状態で、加圧装置１１０ごと図示略の加熱炉内に設置し、真空雰囲気下で接合温度に加熱してセラミックス板１１に銅板１２′（回路層１２）と銅板１３′（第１金属層１３）をろう付け接合する。この場合の接合条件としては、例えば０．０５ＭＰａ以上１．０ＭＰａ以下の加圧力で、８００℃以上９３０℃以下の接合温度で、１分～６０分の加熱とする。 In a state where the laminate S is pressurized by the pressurizing device 110, the pressurizing device 110 and the pressurizing device 110 are installed in a heating furnace (not shown), heated to a bonding temperature in a vacuum atmosphere, and then the copper plate 12 '(circuit) Layer 12) and copper plate 13 '(first metal layer 13) are brazed. The joining conditions in this case are, for example, heating for 1 minute to 60 minutes at a joining temperature of 800 ° C. to 930 ° C. with a pressure of 0.05 MPa to 1.0 MPa.
　このろう付けは、活性金属ろう付け法であり、ろう材中の活性金属であるＴｉがセラミックス基板１１に優先的に拡散して窒化チタン（ＴｉＮ）を形成し、銀銅（Ａｇ－Ｃｕ）合金を介して銅板１２′，１３′とセラミックス基板１１とを接合する。これにより、セラミックス基板１１の両面に回路層１２及び第１金属層１３を形成する。 This brazing is an active metal brazing method in which Ti, which is an active metal in the brazing material, preferentially diffuses into the ceramic substrate 11 to form titanium nitride (TiN), and a silver-copper (Ag—Cu) alloy. The copper plates 12 ′ and 13 ′ and the ceramic substrate 11 are joined via Thereby, the circuit layer 12 and the first metal layer 13 are formed on both surfaces of the ceramic substrate 11.
（第２接合工程）
　次に、アルミニウム又はアルミニウム合金，あるいはニッケル又はニッケル合金からなる金属板１４′と第１金属層１３とを固相拡散接合により接合して第２金属層１４を形成する。すなわち、第１金属層１３のセラミックス基板１１とは反対側の面に第２金属層１４を形成する。 (Second joining process)
Next, the metal plate 14 ′ made of aluminum or aluminum alloy, or nickel or nickel alloy, and the first metal layer 13 are joined by solid phase diffusion bonding to form the second metal layer 14. That is, the second metal layer 14 is formed on the surface of the first metal layer 13 opposite to the ceramic substrate 11.
　この場合、第２金属層１４となるアルミニウム又はアルミニウム合金，あるいはニッケル又はニッケル合金（本実施形態ではアルミニウム）の金属板１４′を第１金属層１３に積層し、これらの積層体を前述と同様の加圧装置１１０により積層方向に加圧し、真空雰囲気下で所定の接合温度に加熱し、第１金属層１３に固相拡散接合により接合された第２金属層１４を形成する。 In this case, a metal plate 14 ′ of aluminum or aluminum alloy or nickel or nickel alloy (aluminum in this embodiment) to be the second metal layer 14 is laminated on the first metal layer 13, and these laminates are the same as described above. The pressure device 110 pressurizes in the stacking direction and heats to a predetermined bonding temperature in a vacuum atmosphere to form the second metal layer 14 bonded to the first metal layer 13 by solid phase diffusion bonding.
　図２Ｂは、第２金属層１４としてアルミニウム又はアルミニウム合金，あるいはニッケル又はニッケル合金（本実施形態ではアルミニウム）からなる金属板１４′を用いる場合を示しており、その金属板１４′と第１金属層１３との間にチタン箔４１を介在させて固相拡散接合する。このチタン箔４１は３μｍ以上４０μｍ以下の厚みに設定される。そして、０．１ＭＰａ以上３．４ＭＰａ以下に加圧し、真空雰囲気下で接合温度５８０℃以上６４０℃以下に１分以上１２０分以下加熱する。これにより、チタン箔４１と第１金属層１３との間、及びチタン箔４１と第２金属層１４との間でそれぞれ拡散接合される。そして、第１金属層１３と第２金属層１４との間にはチタン層４２が形成される。なお、アルミニウム又はアルミニウム合金からなる金属板１４′には、例えば、純度９９％以上、純度９９．９％以上、純度９９．９９％以上の純アルミニウムや、Ａ３００３、Ａ６０６３等のアルミニウム合金を用いることができる。 FIG. 2B shows a case where a metal plate 14 ′ made of aluminum or an aluminum alloy, nickel or a nickel alloy (aluminum in the present embodiment) is used as the second metal layer 14, and the metal plate 14 ′ and the first metal are used. Solid phase diffusion bonding is performed with a titanium foil 41 interposed between the layer 13 and the layer 13. The titanium foil 41 is set to a thickness of 3 μm or more and 40 μm or less. And it pressurizes to 0.1 MPa or more and 3.4 MPa or less, and it heats for 1 minute or more and 120 minutes or less to the joining temperature of 580 degreeC or more and 640 degrees C or less in a vacuum atmosphere. Thus, diffusion bonding is performed between the titanium foil 41 and the first metal layer 13 and between the titanium foil 41 and the second metal layer 14. A titanium layer 42 is formed between the first metal layer 13 and the second metal layer 14. For the metal plate 14 'made of aluminum or an aluminum alloy, for example, pure aluminum having a purity of 99% or more, a purity of 99.9% or more, and a purity of 99.99% or more, or an aluminum alloy such as A3003 or A6063 is used. Can do.
　この工程において第１金属層１３と金属板１４′（第２金属層１４）とがチタン箔４１を介して固相拡散接合により接合された結果、第１金属層１３中にはその表面に接合されたチタン層４２中のＴｉが拡散した状態で存在するとともに、第２金属層１４中にもその表面に接合されたチタン層４２中のＴｉが拡散した状態で存在する。 In this step, the first metal layer 13 and the metal plate 14 ′ (second metal layer 14) are bonded by solid phase diffusion bonding via the titanium foil 41, and as a result, bonded to the surface of the first metal layer 13. The Ti in the titanium layer 42 exists in a diffused state, and the Ti in the titanium layer 42 bonded to the surface of the second metal layer 14 also exists in a diffused state.
（第３接合工程）
　次に、第２金属層１４にアルミニウム合金からなる冷却器２０をＭｇ含有Ａｌ系ろう材を用いてろう付け接合する。 (Third joining step)
Next, a cooler 20 made of an aluminum alloy is brazed to the second metal layer 14 using an Mg-containing Al brazing material.
　このＭｇ含有Ａｌ系ろう材としては、Ａｌ－Ｓｉ－Ｍｇ箔、Ａｌ－Ｃｕ－Ｍｇ箔やＡｌ－Ｇｅ－Ｃｕ－Ｓｉ－Ｍｇ箔等を用いることができる。また、図２Ｃに示すように、芯材の両面にＭｇ含有Ａｌ系ろう材が設けられた両面ろうクラッド材４５を用いることもできる。 As the Mg-containing Al-based brazing material, Al—Si—Mg foil, Al—Cu—Mg foil, Al—Ge—Cu—Si—Mg foil, or the like can be used. Moreover, as shown in FIG. 2C, a double-sided brazing clad material 45 in which Mg-containing Al-based brazing material is provided on both sides of the core material can also be used.
　本実施形態の両面ろうクラッド材４５は、アルミニウム合金（例えばＡ３００３材）からなる芯材４６の両面にＡｌ－Ｓｉ－Ｍｇ系のろう材層４７が形成されたクラッド材であり、芯材４６の両面にろう材を重ねて圧延することにより形成される。芯材４６の厚みは０．０５ｍｍ以上０．６ｍｍ以下であり、両面のろう材層４７は５μｍ以上１００μｍ以下の厚みである。 The double-sided brazing clad material 45 of the present embodiment is a clad material in which an Al—Si—Mg based brazing material layer 47 is formed on both sides of a core material 46 made of an aluminum alloy (for example, A3003 material). It is formed by rolling a brazing material on both sides. The thickness of the core material 46 is 0.05 mm or more and 0.6 mm or less, and the brazing filler metal layers 47 on both sides have a thickness of 5 μm or more and 100 μm or less.
　この両面ろうクラッド材４５を第２金属層１４と冷却器２０との間に介在させてこれらを積層し、図３と同様の加圧装置１１０を用いて積層方向に加圧した状態で、加圧装置１１０ごと窒素雰囲気又はアルゴン雰囲気下で加熱してろう付けする。加圧力としては、例えば０．００１ＭＰａ以上０．５ＭＰａ以下とされ、接合温度としてはＡｌとＣｕの共晶温度よりも高い５８０℃以上６３０℃以下とされる。 The double-sided brazing clad material 45 is interposed between the second metal layer 14 and the cooler 20 and stacked, and is pressed in the stacking direction using the pressurizing device 110 similar to FIG. The pressure device 110 is brazed by heating in a nitrogen atmosphere or an argon atmosphere. The applied pressure is, for example, 0.001 MPa or more and 0.5 MPa or less, and the bonding temperature is 580 ° C. or more and 630 ° C. or less higher than the eutectic temperature of Al and Cu.
　この第３接合工程ではろう付けの接合温度がＡｌとＣｕの共晶温度よりも高いので、もしもＡｌを含んだ溶融ろう材が銅又は銅合金からなる第１金属層１３と接触すると、銅又は銅合金からなる第１金属層１３が浸食され、第１金属層１３の変形等が生じる。 In this third bonding step, the brazing bonding temperature is higher than the eutectic temperature of Al and Cu. Therefore, if the molten brazing material containing Al comes into contact with the first metal layer 13 made of copper or a copper alloy, copper or The first metal layer 13 made of a copper alloy is eroded and deformation of the first metal layer 13 occurs.
　しかしながら本実施形態では、アルミニウムからなる第２金属層１４の側面にろう材に濡れにくいアルミ酸化物が存在するため、溶融したＭｇ含有Ａｌ系ろう材（本実施形態においてはＡｌ－Ｓｉ－Ｍｇ系のろう材）はこの第２金属層１４の側面を越えて第１金属層１３と接触することが無く、第１金属層１３を変形させることが無い。 However, in the present embodiment, there is an aluminum oxide that is difficult to wet the brazing filler metal on the side surface of the second metal layer 14 made of aluminum. Therefore, a molten Mg-containing Al-based brazing material (in this embodiment, an Al—Si—Mg-based alloy). The brazing material) does not contact the first metal layer 13 beyond the side surface of the second metal layer 14 and does not deform the first metal layer 13.
　これは、溶融したＭｇ含有Ａｌ系ろう材が第２金属層１４及び第１金属層１３へ這い上がろうとした際に、第２金属層１４の側面に存在する酸化物がろう材をはじくバリアとしての効果が生じるためである。 This is a barrier that the oxide present on the side surface of the second metal layer 14 repels the brazing material when the molten Mg-containing Al-based brazing material tries to climb up to the second metal layer 14 and the first metal layer 13. This is because the effect is produced.
　また、本実施形態では、第２金属層１４に冷却器２０をろう付けする第３接合工程時の接合温度がアルミニウムと銅との共晶温度よりも高いが、第２金属層１４と第１金属層１３との界面部分にはチタン層４２が介在しているので、第３接合工程のろう付け時にも第２金属層１４のアルミニウムと第１金属層１３の銅との間で液相が生じず、第１金属層１３が溶融することが防止される。 In the present embodiment, the bonding temperature in the third bonding step in which the cooler 20 is brazed to the second metal layer 14 is higher than the eutectic temperature of aluminum and copper. Since the titanium layer 42 is present at the interface portion with the metal layer 13, the liquid phase is present between the aluminum of the second metal layer 14 and the copper of the first metal layer 13 even during brazing in the third bonding step. It does not occur and the first metal layer 13 is prevented from melting.
　なお、このろう付けの後、第２金属層１４と冷却器２０との間には、両面ろうクラッド材４５の芯材４６であったアルミニウム合金からなる接合層４８が薄く介在する。 In addition, after this brazing, between the second metal layer 14 and the cooler 20, a bonding layer 48 made of an aluminum alloy that is the core material 46 of the double-sided brazing clad material 45 is thinly interposed.
　以上のように製造される冷却器付パワーモジュール用基板１０は、セラミックス基板１１の両面に回路層１２、第１金属層１３を形成して、その第１金属層１３にアルミニウム又はアルミニウム合金からなる第２金属層１４を介してアルミニウム合金製の冷却器２０をろう付けするので、Ｍｇ含有Ａｌ系ろう材を用いて低荷重でろう付けできる。また、Ｍｇ含有Ａｌ系ろう材を用いて冷却器２０のろう付けを行っているが、溶融したＭｇ含有Ａｌ系ろう材は第２金属層１４の側面で弾かれるので、銅又は銅合金からなる第１金属層１３と接触することが無く、第１金属層１３を変形させることが無い。この冷却器２０は、アルミニウム合金製で内部に流路２２を有するため、比較的剛性が低いが、このろう付けが低荷重であるので、冷却器２０を変形させることなく確実に接合できる。 The power module substrate 10 with a cooler manufactured as described above has the circuit layer 12 and the first metal layer 13 formed on both surfaces of the ceramic substrate 11, and the first metal layer 13 is made of aluminum or an aluminum alloy. Since the cooler 20 made of an aluminum alloy is brazed through the second metal layer 14, it can be brazed with a low load using an Mg-containing Al-based brazing material. In addition, the cooler 20 is brazed using the Mg-containing Al brazing material, but the molten Mg-containing Al brazing material is repelled on the side surface of the second metal layer 14, and thus is made of copper or a copper alloy. There is no contact with the first metal layer 13, and the first metal layer 13 is not deformed. Since this cooler 20 is made of an aluminum alloy and has a flow path 22 inside, the cooler 20 has relatively low rigidity. However, since this brazing has a low load, the cooler 20 can be reliably joined without being deformed.
　なお、本発明は、上記実施形態の構成のものに限定されるものではなく、細部構成においては、本発明の趣旨を逸脱しない範囲において種々の変更を加えることが可能である。 The present invention is not limited to the configuration of the above-described embodiment, and various modifications can be made in the detailed configuration without departing from the spirit of the present invention.
　上記実施形態では、ＡｌとＣｕの共晶温度以上の融点を持つＡｌ－Ｓｉ－Ｍｇろう材を用いているために第１金属層１３と第２金属層１４との間にチタン層４２が介在する構造としたが、ＡｌとＣｕの共晶温度未満の融点を持つＭｇ含有Ａｌ系ろう材（例えばＡｌ－１５Ｇｅ－１２Ｓｉ－５Ｃｕ－１Ｍｇ：融点５４０℃）を用いる場合、チタン層を介在させることなく第１金属層１３と第２金属層１４とを直接固相拡散接合することも可能である。この場合、第１金属層１３中には接合された第２金属層中の金属原子が拡散した状態で存在するとともに、第２金属層中には第１金属層中の金属原子が拡散した状態で存在する。 In the above embodiment, since the Al—Si—Mg brazing material having a melting point equal to or higher than the eutectic temperature of Al and Cu is used, the titanium layer 42 is interposed between the first metal layer 13 and the second metal layer 14. When using an Mg-containing Al-based brazing material having a melting point lower than the eutectic temperature of Al and Cu (for example, Al-15Ge-12Si-5Cu-1Mg, melting point 540 ° C.), a titanium layer is interposed. Alternatively, the first metal layer 13 and the second metal layer 14 can be directly solid phase diffusion bonded. In this case, the metal atoms in the joined second metal layer exist in the first metal layer 13 in a diffused state, and the metal atoms in the first metal layer diffuse in the second metal layer. Exists.
　また、この場合、第２金属層１４に冷却器２０をろう付けする時の温度がＡｌとＣｕの共晶温度未満となるので、第２金属層１４のアルミニウムと第１金属層１３の銅との間で液相が生じず、第１金属層１３が変形することが防止される。 In this case, since the temperature when brazing the cooler 20 to the second metal layer 14 is lower than the eutectic temperature of Al and Cu, the aluminum of the second metal layer 14 and the copper of the first metal layer 13 A liquid phase is not generated between the first metal layer 13 and the first metal layer 13 is prevented from being deformed.
　冷却器としては、上述のような構造に限らず平板材を用いてもよく、材質はアルミニウム合金に限らずＡｌ系またはＭｇ系の低熱線膨張材（例えばＡｌＳｉＣ等）を用いることができる。 The cooler is not limited to the above-described structure, and a flat plate material may be used. The material is not limited to an aluminum alloy, and an Al-based or Mg-based low thermal expansion material (for example, AlSiC) can be used.
（第２実施形態）
　本発明の第２実施形態に係る冷却器付パワーモジュール用基板２１０は、図４に示すように、セラミックス基板２１１と、セラミックス基板２１１の一方の面に接合された銅又は銅合金からなる回路層２１２と、セラミックス基板２１１の他方の面に接合された銅又は銅合金からなる第１金属層２１３と、第１金属層２１３に接合されたニッケル又はニッケル合金からなる第２金属層２１４と、第２金属層２１４に接合されたアルミニウム合金からなる冷却器２０とを備える。また、第１実施形態と同様に、冷却器２０をろう付け接合するのに用いられた両面クラッド材の一部が、接合層４８として第２金属層２１４と冷却器２０との間に残存している。 (Second Embodiment)
As shown in FIG. 4, a power module substrate 210 with a cooler according to a second embodiment of the present invention includes a ceramic substrate 211 and a circuit layer made of copper or a copper alloy bonded to one surface of the ceramic substrate 211. 212, a first metal layer 213 made of copper or a copper alloy joined to the other surface of the ceramic substrate 211, a second metal layer 214 made of nickel or a nickel alloy joined to the first metal layer 213, And a cooler 20 made of an aluminum alloy joined to the two metal layers 214. As in the first embodiment, a part of the double-sided clad material used for brazing the cooler 20 remains as the bonding layer 48 between the second metal layer 214 and the cooler 20. ing.
　この冷却器付パワーモジュール用基板２１０では、第１金属層２１３中に、その表面に接合された第２金属層２１４中のＮｉが拡散した状態で存在しているとともに、第２金属層２１４中に、その表面に接合された第１金属層２１３中のＣｕが拡散した状態で存在している。 In the power module substrate 210 with a cooler, Ni in the second metal layer 214 bonded to the surface thereof is present in the first metal layer 213 in a diffused state, and in the second metal layer 214. In addition, Cu in the first metal layer 213 bonded to the surface thereof is present in a diffused state.
　また、この冷却器付パワーモジュール用基板２１０では、第２金属層２１４は第１金属層２１３よりも面積が大きい。これにより、冷却器２０を接合する際に溶融したろう材が第１金属層２１３に到達するのが防止されている。 In the power module substrate 210 with a cooler, the second metal layer 214 has a larger area than the first metal layer 213. This prevents the brazing material melted when joining the cooler 20 from reaching the first metal layer 213.
　この冷却器付パワーモジュール用基板２１０は、上述した第１実施形態と同様の製造方法により製造されるが、第２金属層２１４がニッケルであることにより、第１接合工程および第２接合工程を同時に行うことが可能である。この場合、回路層２１２および第１金属層２１１となる各金属板をセラミックス基板２１１に、銀チタン（Ａｇ－Ｔｉ）系又は銀銅チタン（Ａｇ－Ｃｕ－Ｔｉ）系の活性金属ろう材を用いてろう付け接合するのと同時に、第１金属層２１１となる金属板に第２金属層２１４となる金属板を固相拡散接合する。 The cooler-equipped power module substrate 210 is manufactured by the same manufacturing method as in the first embodiment described above. However, since the second metal layer 214 is nickel, the first bonding step and the second bonding step are performed. It is possible to do it at the same time. In this case, each metal plate to be the circuit layer 212 and the first metal layer 211 is made of an active metal brazing material of silver titanium (Ag—Ti) or silver copper titanium (Ag—Cu—Ti) based on the ceramic substrate 211. Simultaneously with the brazing and joining, the metal plate to be the second metal layer 214 is bonded to the metal plate to be the first metal layer 211 by solid phase diffusion joining.
（第３実施形態）
　本発明の第３実施形態に係る冷却器付パワーモジュール用基板３１０は、図５に示すように、セラミックス基板３１１と、セラミックス基板３１１の一方の面に接合された銅又は銅合金からなる回路層３１２と、セラミックス基板３１１の他方の面に接合された銅又は銅合金からなる第１金属層３１３と、第１金属層３１３に接合されたニッケル又はニッケル合金からなる第２金属層３１４と、第２金属層３１４に接合されたアルミニウム合金からなる冷却器２０とを備え、さらに、第２金属層３１４と冷却器２０との間に介在するアルミニウム層３１５を有する。また、上記各実施形態と同様に、冷却器２０をろう付け接合するのに用いられた両面クラッド材の一部が、接合層４８としてアルミニウム層３１５と冷却器２０との間に残存している。 (Third embodiment)
As shown in FIG. 5, a power module substrate 310 with a cooler according to a third embodiment of the present invention includes a ceramic substrate 311 and a circuit layer made of copper or a copper alloy bonded to one surface of the ceramic substrate 311. 312, a first metal layer 313 made of copper or a copper alloy joined to the other surface of the ceramic substrate 311, a second metal layer 314 made of nickel or a nickel alloy joined to the first metal layer 313, A cooler 20 made of an aluminum alloy joined to the two metal layers 314, and an aluminum layer 315 interposed between the second metal layer 314 and the cooler 20. Further, as in the above embodiments, a part of the double-sided clad material used for brazing the cooler 20 remains as the bonding layer 48 between the aluminum layer 315 and the cooler 20. .
　この冷却器付パワーモジュール用基板３１０では、第１金属層３１３中に、その表面に接合された第２金属層３１４中のＮｉが拡散した状態で存在しているとともに、第２金属層３１４中に、その一方の表面に接合された第１金属層３１３中のＣｕと、他方の表面に接合されたアルミニウム層３１５中のＡｌが拡散した状態で存在している。 In the power module substrate 310 with a cooler, Ni in the second metal layer 314 bonded to the surface of the first metal layer 313 is present in a diffused state, and in the second metal layer 314. In addition, Cu in the first metal layer 313 bonded to one surface thereof and Al in the aluminum layer 315 bonded to the other surface are present in a diffused state.
（第４実施形態）
　本発明の第４実施形態に係る冷却器付パワーモジュール用基板４１０は、図６に示すように、セラミックス基板４１１と、セラミックス基板４１１の一方の面に接合された銅又は銅合金からなる回路層４１２と、セラミックス基板４１１の他方の面に接合された銅又は銅合金からなる第１金属層４１３と、第１金属層４１３に接合されたアルミニウムまたはアルミニウム合金、あるいはニッケル又はニッケル合金からなる第２金属層４１４と、第２金属層４１４に接合されたアルミニウム合金からなる冷却器２０とを備え、さらに、第１金属層４１３と第２金属層４１４との間に介在するチタン層４１５を有する。また、上記各実施形態と同様に、冷却器２０をろう付け接合するのに用いられた両面クラッド材の一部が、接合層４８として第２金属層４１４と冷却器２０との間に残存している。 (Fourth embodiment)
As shown in FIG. 6, a power module substrate 410 with a cooler according to a fourth embodiment of the present invention includes a ceramic substrate 411 and a circuit layer made of copper or a copper alloy bonded to one surface of the ceramic substrate 411. 412, a first metal layer 413 made of copper or a copper alloy joined to the other surface of the ceramic substrate 411, and a second metal made of aluminum or an aluminum alloy joined to the first metal layer 413, or nickel or a nickel alloy. It has a metal layer 414 and a cooler 20 made of an aluminum alloy joined to the second metal layer 414, and further includes a titanium layer 415 interposed between the first metal layer 413 and the second metal layer 414. As in the above embodiments, a part of the double-sided clad material used for brazing the cooler 20 remains as the bonding layer 48 between the second metal layer 414 and the cooler 20. ing.
　この冷却器付パワーモジュール用基板４１０では、第１金属層４１３および第２金属層４１４中に、その表面に接合されたチタン層４１５中のＴｉが拡散した状態で存在している。 In the cooler-equipped power module substrate 410, Ti in the titanium layer 415 bonded to the surface of the first metal layer 413 and the second metal layer 414 is present in a diffused state.
　また、この冷却器付パワーモジュール用基板４１０では、第２金属層４１４およびチタン層４１５の少なくともいずれかが、第１金属層４１３よりも面積が大きい。これにより、冷却器２０を接合する際に溶融したろう材が第１金属層４１３に到達するのが防止されている。 In the power module substrate 410 with a cooler, at least one of the second metal layer 414 and the titanium layer 415 has a larger area than the first metal layer 413. This prevents the brazing material melted when the cooler 20 is joined from reaching the first metal layer 413.
　銅又は銅合金からなる金属層をアルミニウム製冷却器にろう付けする際の変形の発生を防止し、熱抵抗が小さく、接合信頼性の高い冷却器付パワーモジュール用基板を提供できる。 It is possible to provide a power module substrate with a cooler that prevents the occurrence of deformation when a metal layer made of copper or a copper alloy is brazed to an aluminum cooler, has low thermal resistance, and has high bonding reliability.
１０，２１０，３１０，４１０　冷却器付パワーモジュール用基板
１１，２１１，３１１，４１１　セラミックス基板
１２，２１２，３１２，４１２　回路層
１３，２１３，３１３，４１３　第１金属層
１４，２１４，３１４，４１４　第２金属層
１２′，１３′　銅板（金属板）
１４′　金属板
２０　冷却器
２１　筒体
２１ａ　天板
２２　流路
２３　仕切り壁
３０　半導体素子
４０　ろう材塗布層
４１　チタン箔
４２，４１５　チタン層
４５　両面ろうクラッド材（Ｍｇ含有Ａｌ系ろう材）
４６　芯材
４７　ろう層
４８　接合層
３１５　アルミニウム層 10, 210, 310, 410 Substrate for power module with cooler 11, 211, 311, 411 Ceramic substrate 12, 212, 312, 412 Circuit layer 13, 213, 313, 413 First metal layer 14, 214, 314, 414 Second metal layer 12 ', 13' Copper plate (metal plate)
14 'metal plate 20 cooler 21 cylinder 21a top plate 22 flow path 23 partition wall 30 semiconductor element 40 brazing material coating layer 41 titanium foil 42,415 titanium layer 45 double-sided brazing clad material (Mg-containing Al-based brazing material)
46 Core material 47 Brazing layer 48 Bonding layer 315 Aluminum layer

Claims (14)

  1. 　セラミックス基板の一方の面に銅又は銅合金からなる金属板を接合して回路層を形成するとともに、前記セラミックス基板の他方の面に銅又は銅合金からなる金属板を接合して第１金属層を形成する第１接合工程と、
    　アルミニウム又はアルミニウム合金，あるいはニッケル又はニッケル合金からなる金属板と前記第１金属層とを固相拡散接合により接合して第２金属層を形成する第２接合工程と、
    　前記第２金属層にアルミニウム合金からなる冷却器をＭｇ含有Ａｌ系ろう材を用いてろう付け接合する第３接合工程と
    を有することを特徴とする冷却器付パワーモジュール用基板の製造方法。     A metal plate made of copper or a copper alloy is joined to one surface of the ceramic substrate to form a circuit layer, and a metal plate made of copper or a copper alloy is joined to the other surface of the ceramic substrate to make a first metal layer Forming a first joining step;
    A second joining step of joining the metal plate made of aluminum or aluminum alloy, or nickel or nickel alloy, and the first metal layer by solid phase diffusion joining to form a second metal layer;
    And a third joining step of brazing a cooler made of an aluminum alloy to the second metal layer using an Mg-containing Al-based brazing material.
  2. 　前記第２接合工程において、前記第１金属層と前記第２金属層との間にチタン箔を介在させ、前記第１金属層と前記チタン箔および前記第２金属層と前記チタン箔をそれぞれ固相拡散接合し、
    　前記第３接合工程において、前記第２金属層と前記冷却器とをＡｌ－Ｓｉ－Ｍｇ系ろう材を用いてろう付け接合することを特徴とする請求項１記載の冷却器付パワーモジュール用基板の製造方法。     In the second bonding step, a titanium foil is interposed between the first metal layer and the second metal layer, and the first metal layer, the titanium foil, the second metal layer, and the titanium foil are fixed. Phase diffusion bonding,
    2. The substrate for a power module with a cooler according to claim 1, wherein, in the third joining step, the second metal layer and the cooler are brazed and joined using an Al—Si—Mg based brazing material. Manufacturing method.
  3. 　前記チタン箔は前記第１金属層よりも面積が大きいことを特徴とする請求項２記載の冷却器付パワーモジュール用基板の製造方法。 3. The method for manufacturing a power module substrate with a cooler according to claim 2, wherein the titanium foil has a larger area than the first metal layer.
  4. 　前記第２接合工程において、前記第２金属層は、アルミニウムまたはアルミニウム合金からなる前記金属板を用いて形成することを特徴とする請求項１記載の冷却器付パワーモジュール用基板の製造方法。 The method for manufacturing a power module substrate with a cooler according to claim 1, wherein, in the second bonding step, the second metal layer is formed using the metal plate made of aluminum or an aluminum alloy.
  5. 　前記第２接合工程において、前記第２金属層は、ニッケル又はニッケル合金からなる前記金属板を用いて形成し、
    　前記第１接合工程および前記第２接合工程を同時に行うことを特徴とする請求項１記載の冷却器付パワーモジュール用基板の製造方法。     In the second joining step, the second metal layer is formed using the metal plate made of nickel or a nickel alloy,
    The method for manufacturing a power module substrate with a cooler according to claim 1, wherein the first bonding step and the second bonding step are performed simultaneously.
  6. 　前記第２金属層は前記第１金属層よりも面積が大きいことを特徴とする請求項５記載の冷却器付パワーモジュール用基板の製造方法。 6. The method for manufacturing a power module substrate with a cooler according to claim 5, wherein the second metal layer has a larger area than the first metal layer.
  7. 　前記第２接合工程において、前記第２金属層にアルミニウム板をさらに積層して前記第１金属層と前記第２金属層および前記第２金属層と前記アルミニウム板をそれぞれ固相拡散接合により接合する
    ことを特徴とする請求項５記載の冷却器付パワーモジュール用基板の製造方法。     In the second bonding step, an aluminum plate is further laminated on the second metal layer, and the first metal layer, the second metal layer, the second metal layer, and the aluminum plate are bonded by solid phase diffusion bonding. The method for producing a substrate for a power module with a cooler according to claim 5.
  8. 　セラミックス基板と、
    　前記セラミックス基板の一方の面に接合された銅又は銅合金からなる回路層と、
    　前記セラミックス基板の他方の面に接合された銅又は銅合金からなる第１金属層と、
    　前記第１金属層に接合されたアルミニウム又はアルミニウム合金，あるいはニッケル又はニッケル合金からなる第２金属層と、
    　前記第２金属層に接合されたアルミニウム合金からなる冷却器と
    を備え、
    　前記第１金属層中に、その表面に接合された部材中の金属原子が拡散した状態で存在しているとともに、
    　前記第２金属層中に、その表面に接合された部材中の金属原子が拡散した状態で存在している
    ことを特徴とする冷却器付パワーモジュール用基板。     A ceramic substrate;
    A circuit layer made of copper or a copper alloy bonded to one surface of the ceramic substrate;
    A first metal layer made of copper or a copper alloy bonded to the other surface of the ceramic substrate;
    A second metal layer made of aluminum or an aluminum alloy or nickel or a nickel alloy joined to the first metal layer;
    A cooler made of an aluminum alloy joined to the second metal layer,
    In the first metal layer, the metal atom in the member bonded to the surface is present in a diffused state,
    A substrate for a power module with a cooler, wherein metal atoms in a member bonded to the surface of the second metal layer are present in a diffused state.
  9. 　前記第１金属層と前記第２金属層との間に介在するチタン層をさらに有し、
    　前記第１金属層中および前記第２金属層中に、前記チタン層中のチタンが拡散した状態で存在していることを特徴とする請求項８記載の冷却器付パワーモジュール用基板。     A titanium layer interposed between the first metal layer and the second metal layer;
    9. The power module substrate with a cooler according to claim 8, wherein titanium in the titanium layer is present in a diffused state in the first metal layer and in the second metal layer.
  10. 　前記チタン層は前記第１金属層よりも面積が大きいことを特徴とする請求項９記載の冷却器付パワーモジュール用基板。 The power module substrate with a cooler according to claim 9, wherein the titanium layer has a larger area than the first metal layer.
  11. 　前記第２金属層はアルミニウム又はアルミニウム合金からなることを特徴とする請求項８に記載の冷却器付パワーモジュール用基板。 The power module substrate with a cooler according to claim 8, wherein the second metal layer is made of aluminum or an aluminum alloy.
  12. 　前記第２金属層はニッケル又はニッケル合金からなることを特徴とする請求項８記載の冷却器付パワーモジュール用基板。 The power module substrate with a cooler according to claim 8, wherein the second metal layer is made of nickel or a nickel alloy.
  13. 　前記第２金属層は前記第１金属層よりも面積が大きいことを特徴とする請求項１２記載の冷却器付パワーモジュール用基板。 The power module substrate with a cooler according to claim 12, wherein the second metal layer has a larger area than the first metal layer.
  14. 　前記第２金属層と前記冷却器との間に介在するアルミニウム層をさらに有することを特徴とする請求項１２に記載の冷却器付パワーモジュール用基板。 The power module substrate with a cooler according to claim 12, further comprising an aluminum layer interposed between the second metal layer and the cooler.
PCT/JP2015/078765 2014-10-16 2015-10-09 Substrate with cooler for power modules and method for producing same WO2016060079A1 (en)

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