WO2023058667A1 - Metal base substrate - Google Patents

Metal base substrate Download PDF

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Publication number
WO2023058667A1
WO2023058667A1 PCT/JP2022/037198 JP2022037198W WO2023058667A1 WO 2023058667 A1 WO2023058667 A1 WO 2023058667A1 JP 2022037198 W JP2022037198 W JP 2022037198W WO 2023058667 A1 WO2023058667 A1 WO 2023058667A1
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WIPO (PCT)
Prior art keywords
insulating layer
layer
metal
metal base
substrate
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PCT/JP2022/037198
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French (fr)
Japanese (ja)
Inventor
史朗 石川
慎太郎 原
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三菱マテリアル株式会社
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Publication of WO2023058667A1 publication Critical patent/WO2023058667A1/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
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/03—Use of materials for the substrate
    • H05K1/05—Insulated conductive substrates, e.g. insulated metal substrate

Definitions

  • the present invention relates to metal base substrates.
  • This application claims priority based on Japanese Patent Application No. 2021-164296 filed in Japan on October 5, 2021, the content of which is incorporated herein.
  • a metal base substrate is known as one of the substrates for mounting electronic components such as semiconductor elements and LEDs.
  • a metal base substrate is a laminate in which a metal substrate, an insulating layer, and a circuit layer are laminated in this order.
  • the insulating layer of the metal base substrate is generally formed from an insulating composition containing a resin having excellent insulating properties and voltage resistance and an inorganic filler having excellent thermal conductivity.
  • the thickness of the metal substrate is 1 to 5 mm
  • the thickness of the circuit layer is 100 to 500 ⁇ m
  • the insulating layer is made of two or more insulating resin layers
  • the two or more insulating resin layers are The layer has at least a layer containing a thermoplastic insulating resin and a layer containing a non-thermoplastic insulating resin, and at least one of the two or more insulating resin layers is an insulating resin layer.
  • the thickness of the base metal has been increased to improve heat dissipation.
  • the metal substrate of the metal base substrate has a high coefficient of thermal expansion and is easily expanded and contracted by heat to change its volume.
  • many electronic parts are based on ceramics and have a low coefficient of thermal expansion. For this reason, in a module in which electronic components are mounted on the circuit layer of a metal base substrate via solder, the stress applied to the solder fluctuates due to the switching on/off of the electronic components and temperature changes in the external environment. Cracks may occur in the solder, reducing reliability.
  • the film thickness of the insulating layer so that the insulating layer absorbs the volume change of the metal substrate.
  • the thickness of the insulating layer is increased, the heat generated by the electronic component is less likely to be transferred to the metal substrate through the insulating layer, and the heat dissipation performance of the metal base substrate may deteriorate. In other words, it is difficult to satisfy both the heat radiation property and the reliability of the metal base substrate.
  • the present invention has been made in view of the circumstances described above, and its object is to provide a metal base substrate that is excellent in heat dissipation and reliability.
  • a metal base substrate is a metal base substrate in which a metal substrate, at least one insulating layer, and a circuit layer are laminated in this order,
  • the plate thickness T M of the metal substrate is in the range of 0.5 mm or more and 1.1 mm or less, and the cube value of the plate thickness T M (unit: mm) of the metal substrate and the elasticity of the metal substrate at 25 ° C.
  • the product TM 3 ⁇ EM with the modulus EM (unit: GPa) is in the range of 10 or more and 1000 or less, and the elastic modulus ER (unit: GPa) of each layer constituting the insulating layer at 100 ° C.
  • the sum of the ratios TR / ER of the film thickness TR (unit: ⁇ m) is in the range of 30 or more and 1000 or less, and the thermal conductivity CR (unit: W/mK) of each layer constituting the insulating layer It is characterized in that the sum of the ratios T R /C R of the film thicknesses T R (unit: ⁇ m) is in the range of 2 or more and 40 or less.
  • the metal base substrate configured as described above, since the plate thickness TM of the metal substrate is in the range of 0.5 mm or more and 1.1 mm or less, the electronic component can be joined onto the metal base substrate by soldering. , the thermal stress applied to the solder can be suppressed even when the temperature of the electronic component changes. Further, the product TM 3 ⁇ EM of the cube value of the plate thickness TM ( unit : mm) and the elastic modulus EM (unit: GPa ) at 25°C of the metal substrate is in the range of 10 or more and 1000 or less. Therefore, it is possible to suppress warping of the metal base substrate after mounting the electronic component.
  • the sum of the ratios T R /E R of the film thickness T R (unit: ⁇ m) to the elastic modulus E R (unit: GPa) at 100° C. of each layer constituting the insulating layer is in the range of 30 or more and 1000 or less. Therefore, the ability of the circuit layer to relax stress is enhanced, and when an electronic component is mounted on the circuit layer via solder, the stress applied to the solder can be reduced. Further, the sum of the ratios T R /C R of the film thickness T R (unit: ⁇ m) to the thermal conductivity C R (unit: W/mK) of each layer constituting the insulating layer is in the range of 2 or more and 40 or less. Therefore, when an electronic component is mounted on the circuit layer via solder, the heat generated by the electronic component can be efficiently transferred to the metal substrate. Therefore, the metal base substrate configured as described above is excellent in heat dissipation and reliability.
  • the metal substrate may contain at least one metal selected from the group consisting of aluminum, copper and iron.
  • the metal substrate since the metal substrate has high thermal conductivity and heat resistance, the heat dissipation and reliability of the metal base substrate are further improved.
  • the insulating layer is a single-layer body, and the single-layer body has a filler content of 30% by volume or more and 85% by volume or less.
  • the structure which is a resin composition may be sufficient.
  • the insulating layer is a two-layer laminate having a first insulating layer formed on a metal layer and a second insulating layer laminated on the first insulating layer, wherein the first insulating layer One of the layer and the second insulating layer is a layer of a resin composition having a filler content in the range of 50% by volume or more and 85% by volume or less, and the other layer contains a resin or a filler.
  • a layer of a resin composition having a rate of 1% by volume or less may be used.
  • the thermal conductivity and stress relieving ability of the insulating layer are further improved, so that the heat dissipation and reliability of the metal base substrate are further improved.
  • the thickness of the insulating layer may be 100 ⁇ m or less.
  • the film thickness of the insulating layer is thin, when an electronic component is mounted on the circuit layer via solder, the heat generated by the electronic component can be efficiently transferred to the metal substrate.
  • the film thickness of the circuit layer may be 80 ⁇ m or less.
  • the film thickness of the circuit layer is thin, when an electronic component is mounted on the circuit layer through solder, the thermal stress applied from the circuit layer to the solder is reduced, thereby improving the reliability of the metal base substrate. is further improved.
  • FIG. 1 is a schematic cross-sectional view of a metal base substrate according to one embodiment of the present invention.
  • FIG. 1 is a schematic cross-sectional view of a metal base substrate according to one embodiment of the present invention.
  • the metal base substrate 10 is a laminate in which a metal substrate 20, an insulating layer 30, and a circuit layer 40 are laminated in this order. Electrode terminals 61 of an electronic component 60 are connected to the circuit layer 40 of the metal base substrate 10 via solder 50 to form a module.
  • the metal substrate 20 is a member that serves as the base of the metal base substrate 10 .
  • the metal substrate 20 has a plate thickness TM within the range of 0.5 mm or more and 1.1 mm or less.
  • the plate thickness TM is 0.5 mm or more, the strength of the metal substrate 20 is increased, so deformation such as warping due to heat can be suppressed.
  • the plate thickness TM is 1.1 mm or less, the amount of volumetric change of the metal substrate 20 due to heat is small.
  • the plate thickness TM is preferably 0.8 mm or more.
  • the plate thickness TM is preferably 1.0 mm or less.
  • the product TM3 ⁇ EM of the cube of the plate thickness TM (unit: mm) of the metal substrate 20 and the elastic modulus EM (unit: GPa) of the metal substrate 20 at 25°C is 10 or more and 1000 or less. Within range.
  • T M 3 ⁇ E M is 10 or more, deformation such as warping of the metal substrate 20 due to heat can be suppressed.
  • T M 3 ⁇ E M is preferably 30 or more, and preferably 300 or less.
  • the elastic modulus (tensile elastic modulus) of the metal substrate 20 at 25° C. can be measured by a tensile test (JIS Z2241:2011 Metal material tensile test method).
  • the metal substrate 20 preferably contains at least one metal selected from the group consisting of aluminum, copper and iron. More preferably, the metal substrate 20 is a copper substrate, an aluminum substrate, or an iron substrate.
  • the copper substrate is made of copper or copper alloy.
  • a copper alloy is an alloy containing the largest amount of copper among the constituent elements.
  • the aluminum substrate is made of aluminum or an aluminum alloy.
  • Aluminum alloys are alloys containing the largest amount of aluminum among the constituent elements.
  • the iron substrate consists of iron or an iron alloy. Iron alloys are alloys containing the largest amount of iron among the constituent elements.
  • Ferrous alloys include carbon steel.
  • the insulating layer 30 is a layer for insulating the metal substrate 20 and the circuit layer 40 .
  • the insulating layer 30 has a heat transfer function to transfer the heat generated in the electronic component 60 to the metal substrate 20, and a stress relaxation function to absorb the volume change of the metal substrate 20 due to heat and relax the stress applied to the solder 50. have a function.
  • the insulating layer 30 has a ratio T R / E R of a film thickness T R (unit: ⁇ m) to an elastic modulus E R (unit: GPa) at 100° C. within a range of 30 or more and 1000 or less. When T R /E R is 1000 or less, the stress relaxation function of the insulating layer 30 is improved, and the stress applied to the solder 50 can be reduced.
  • T R /E R is preferably 30 or more, more preferably 100 or more. Moreover, T R /E R is preferably 300 or less, particularly preferably 200 or less.
  • the elastic modulus of the insulating layer 30 at 100° C. can be measured, for example, as follows. The metal substrate 20 and the circuit layer 40 of the metal base substrate 10 are removed by etching to isolate the insulating layer 30 . The elastic modulus (tensile elastic modulus) of the obtained insulating layer 30 is measured by dynamic viscoelasticity measurement (DMA).
  • DMA dynamic viscoelasticity measurement
  • the insulating layer 30 has a ratio T R /C R of the film thickness T R (unit: ⁇ m) to the thermal conductivity C R (unit: W/mK ) within a range of 2 or more and 40 or less.
  • T R /C R is 2 or more, the film thickness of the insulating layer 30 does not become too thin, and the insulating property is ensured.
  • T R /C R is 40 or less, the heat transfer function of the insulating layer 30 is improved, and the heat generated in the electronic component 60 can be efficiently transferred to the metal substrate 20 .
  • T R /C R is preferably 3 or more, more preferably 5 or more.
  • T R /C R is preferably 30 or less, particularly preferably 20 or less.
  • the thermal conductivity of the insulating layer 30 can be measured, for example, as follows.
  • the metal substrate 20 and the circuit layer 40 of the metal base substrate 10 are removed by etching to isolate the insulating layer 30 .
  • the thermal conductivity of the obtained insulating layer 30 is measured by a laser flash method.
  • the insulating layer 30 is at least one layer.
  • the insulating layer 30 of the present embodiment is a single layer made of an insulating resin composition containing an insulating resin 31 and an inorganic filler 32 (also referred to as a filler).
  • an insulating resin composition containing an insulating resin 31 with high insulating properties and an inorganic filler 32 with high thermal conductivity thermal conductivity is improved while maintaining insulating properties. can be done.
  • the insulating resin 31 for example, a polyimide resin, a polyamideimide resin, or a mixture thereof can be used. These resins are excellent in properties such as insulation, withstand voltage, chemical resistance and mechanical properties, so that these properties of the metal base substrate 10 are improved.
  • the inorganic filler 32 examples include alumina (Al 2 O 3 ) particles, alumina hydrate particles, aluminum nitride (AlN) particles, silica (SiO 2 ) particles, silicon carbide (SiC) particles, and titanium oxide (TiO 2 ). particles, boron nitride (BN) particles, and the like can be used.
  • the average particle size of the inorganic filler 32 is preferably in the range of 0.1 ⁇ m or more and 20 ⁇ m or less.
  • the content of the inorganic filler 32 in the insulating layer 30 is preferably in the range of 30% by volume or more and 85% by volume or less.
  • the thermal conductivity of the insulating layer 30 is improved.
  • the content of the inorganic filler 32 is 85% by volume or less, the insulating properties of the insulating layer 30 are improved.
  • the content of the inorganic filler 32 is more preferably 50% by volume or more, and particularly preferably 80% by volume or less.
  • the film thickness of the insulating layer 30 is preferably 100 ⁇ m or less. When the film thickness of the insulating layer 30 is 100 ⁇ m or less, the heat transfer function of the insulating layer 30 is improved, and the heat generated in the electronic component 60 can be efficiently transferred to the metal substrate 20 .
  • the film thickness of the insulating layer 30 is not particularly limited as long as the dielectric breakdown voltage is within a practical range, but is preferably 30 ⁇ m or more. When the thickness of the insulating layer 30 is 30 ⁇ m or more, the metal substrate 20 and the circuit layer 40 can be reliably insulated, the stress relaxation function of the insulating layer 30 is improved, and the stress applied to the solder 50 is reduced. can be reduced.
  • the film thickness of the insulating layer 30 is preferably 70 ⁇ m or less, particularly preferably 50 ⁇ m or less, from the viewpoint of improving the heat transfer function. Moreover, it is particularly preferable that the film thickness of the insulating layer 30 is 40 ⁇ m or more from the viewpoint of improving the insulating properties.
  • the circuit layer 40 is formed in a circuit pattern. Electrode terminals 61 of an electronic component 60 are bonded via solder 50 or the like onto the circuit layer 40 formed in the shape of a circuit pattern.
  • As a material for the circuit layer 40 metals such as copper, aluminum, and gold can be used.
  • Circuit layer 40 is preferably made of copper foil. The film thickness of the circuit layer 40 is preferably in the range of 2 ⁇ m or more and 200 ⁇ m or less.
  • the film thickness of the circuit layer 40 is 80 ⁇ m or less. Since the film thickness of the circuit layer 40 is 80 ⁇ m or less, the thermal stress generated in the circuit layer 40 is reduced, and the thermal stress applied to the solder 50 is reduced. From the viewpoint of reducing thermal stress, the film thickness of the circuit layer 40 is preferably 75 ⁇ m or less, particularly preferably 50 ⁇ m or less.
  • the film thickness of the circuit layer 40 is not particularly limited as long as it has a sufficiently low resistance to the current used, but is preferably 2 ⁇ m or more. When the film thickness of the circuit layer 40 is 2 ⁇ m or more, the electric resistance of the circuit layer 40 is lowered, and the internal resistance of the module can be reduced.
  • the film thickness of the circuit layer 40 is preferably 5 ⁇ m or more, particularly preferably 20 ⁇ m or more, from the viewpoint of reducing electrical resistance.
  • Examples of the electronic component 60 mounted on the metal base substrate 10 of this embodiment are not particularly limited, and include semiconductor elements, resistors, capacitors, crystal oscillators, and the like.
  • semiconductor elements include MOSFET (Metal-oxide-semiconductor field effect transistor), IGBT (Insulated Gate Bipolar Transistor), LSI (Large Scale Integration), LED (light emitting diode), LED chip, LED-CSP (LED-Chip Size Package).
  • solder 50 for example, Sn--Ag-based, Sn--Cu-based, Sn--In-based, Sn--Ag--Cu-based solder materials (so-called lead-free solder materials) can be used.
  • the metal base substrate 10 of this embodiment can be manufactured, for example, by a method including an insulating layer forming step and a circuit layer pressure bonding step.
  • the insulating layer 30 is formed on the metal substrate 20 to obtain a metal substrate with an insulating layer.
  • a coating method or an electrodeposition method can be used as a method for forming the insulating layer 30, a coating method or an electrodeposition method.
  • the coating method is a method in which a coating liquid containing a solvent, an insulating resin 31, and an inorganic filler 32 is coated on the metal substrate 20 to form a coating layer, and then the coating layer is heated to obtain the insulating layer 30.
  • an inorganic filler-dispersed resin material solution containing a resin material solution in which the insulating resin 31 is dissolved and the inorganic filler 32 dispersed in the resin material solution can be used.
  • Spin coating, bar coating, knife coating, roll coating, blade coating, die coating, gravure coating, dip coating, and the like can be used as methods for applying the coating liquid to the surface of the substrate.
  • the metal substrate 20 is immersed in an electrodeposition liquid containing insulating resin particles and inorganic fillers 32, and the insulating resin particles and inorganic fillers 32 are electrodeposited on the surface of the substrate to form an electrodeposited film, Then, the obtained electrodeposited film is heated to form the insulating layer 30 .
  • the electrodeposition liquid a poor solvent for the insulating resin is added to the inorganic filler dispersed insulating resin solution containing the insulating resin solution and the inorganic filler 32 dispersed in the insulating resin solution to deposit the insulating resin 31 as particles. It is possible to use those prepared by
  • a metal foil is laminated on the insulating layer 30 of the metal substrate with an insulating layer, and the obtained laminated body is pressed while being heated to form the circuit layer 40, thereby forming the metal base substrate 10.
  • the heating temperature of the laminate is, for example, 200° C. or higher, and more preferably 250° C. or higher.
  • the upper limit of the heating temperature is lower than the thermal decomposition temperature of the insulating resin, preferably lower than the thermal temperature by 30°C.
  • the pressure applied during crimping is, for example, within the range of 1 MPa or more and 30 MPa or less, and more preferably within the range of 3 MPa or more and 25 MPa or less.
  • the crimping time varies depending on the heating temperature and pressure, but is generally 60 minutes or more and 180 minutes or less.
  • the plate thickness TM of the metal substrate 20 is within the range of 0.5 mm or more and 1.1 mm or less.
  • the change in shape can be suppressed, and the amount of change in volume can be reduced.
  • the product TM 3 ⁇ EM of the cube value of the plate thickness TM ( unit : mm) and the elastic modulus EM (unit: GPa ) at 25°C of the metal substrate is in the range of 10 or more and 1000 or less. Therefore, deformation of the metal substrate 20 due to heat can be further suppressed.
  • the ratio T R /E R of the thickness T R (unit: ⁇ m) to the elastic modulus E R (unit: GPa) of the insulating layer 30 at 100° C. is in the range of 30 or more and 1000 or less, The applied stress can be reduced.
  • the total ratio T R /C R of the film thickness T R (unit: ⁇ m) to the thermal conductivity C R ( unit: W/mK) of the insulating layer 30 is within the range of 2 or more and 40 or less, electron Heat generated in the component 60 can be efficiently transferred to the metal substrate 20 . Therefore, the metal base substrate 10 of this embodiment is excellent in heat dissipation and reliability.
  • the metal substrate 20 contains at least one metal selected from the group consisting of aluminum, copper and iron, the thermal conductivity and heat resistance of the metal substrate 20 are increased. Therefore, the heat dissipation and reliability of the metal base substrate 10 are further improved.
  • the insulating layer 30 is a resin composition having a filler content in the range of 30% by volume or more and 85% by volume or less, the thermal conductivity of the insulating layer 30 and the stress Since the relaxation capability is increased, the heat dissipation and reliability of the metal base substrate 10 are further improved.
  • the metal base substrate 10 of the present embodiment when the thickness of the insulating layer 30 is as thin as 100 ⁇ m or less, the heat generated in the electronic component 60 can be efficiently transferred to the metal substrate 20 .
  • the film thickness of the circuit layer 40 when the film thickness of the circuit layer 40 is as thin as 80 ⁇ m or less, the thermal stress applied from the circuit layer 40 to the solder 50 is reduced, so the reliability of the metal base substrate 10 is further enhanced. improves.
  • the insulating layer 30 is a single layer in this embodiment, the insulating layer 30 may be a laminate.
  • TR / ER is the ratio TR of the film thickness TR (unit: ⁇ m) to the elastic modulus ER (unit: GPa) at 100° C. of each layer constituting the insulating layer 30 .
  • /E is the sum of R.
  • the insulating layer 30 is a two-layer laminate having a first insulating layer formed on the metal substrate 20 and a second insulating layer laminated on the first insulating layer
  • the insulating layer 30 T R /E R is the ratio T R1 /E R1 of the thickness T R1 (unit: ⁇ m) to the elastic modulus E R1 (unit: GPa) of the first insulating layer at 100° C. and the ratio T R1 /E R1 of the second insulating layer at 100° C. It is the total value of the ratio T R2 / E R2 of the film thickness T R2 (unit: ⁇ m) to the elastic modulus E R2 (unit: GPa).
  • TR / CR is the ratio of the film thickness TR (unit: ⁇ m) to the thermal conductivity CR (unit: W/mK) of each layer constituting the insulating layer 30. It is the sum of T R /C R.
  • the T R /C R of the insulating layer 30 is the first The ratio T R1 /C R1 of the film thickness T R1 ( unit: ⁇ m) to the thermal conductivity C R (unit: W/mK) of the insulating layer and the thermal conductivity C R ( unit: W/mK) of the second insulating layer ) and the ratio T R2 /C R2 of the film thickness T R2 (unit: ⁇ m).
  • insulating layer 30 is a two-layer laminate having a first insulating layer formed on the metal substrate 20 side and a second insulating layer laminated on the first insulating layer, the first insulating layer and One layer of the second insulating layer is a layer of a resin composition (first resin composition layer) having a filler content in the range of 50% by volume or more and 85% by volume or less, and the other layer is A layer (second resin composition layer) of a resin composition having a filler content of 0% by volume or more and 1% by volume or less is preferable.
  • first resin composition layer having a filler content in the range of 50% by volume or more and 85% by volume or less
  • the thermal conductivity and stress relieving ability of the insulating layer 30 are enhanced, so that the heat dissipation and reliability of the metal base substrate 10 are further improved.
  • the first insulating layer is the first resin composition layer
  • the second insulating layer is the second resin composition layer.
  • the film thickness of the first insulating layer is preferably 10 ⁇ m or more and 100 ⁇ m or less.
  • the film thickness of the second insulating layer is preferably 1 ⁇ m or more and 5 ⁇ m or less.
  • the number of layers of the laminate is preferably two to three, more preferably two.
  • the elastic modulus of metal means the elastic modulus at 25°C
  • the elastic modulus of resin means the elastic modulus at 100°C.
  • a polyimide resin solution and an alumina particle dispersion were mixed at a ratio such that the alumina concentration was 60% by volume.
  • the obtained mixture was subjected to dispersion treatment by repeating high pressure injection treatment at a pressure of 50 MPa 10 times using Star Burst manufactured by Sugino Machine Co., Ltd. to prepare an alumina particle-dispersed polyimide resin solution.
  • the alumina concentration is the content of alumina particles in the solid produced when the alumina particle-dispersed polyimide resin solution is heated and dried.
  • an aluminum substrate (length: 30 mm, width: 20 mm) having a plate thickness TM of 0.7 mm and an elastic modulus EM of 74 GPa was prepared.
  • the alumina particle-dispersed polyimide resin solution prepared above was applied by a bar coating method to form a coating film.
  • the aluminum substrate on which the coating film was formed was placed on a hot plate, heated from room temperature to 60°C at a rate of 3°C/min, heated at 60°C for 100 minutes, and further heated to 120°C at a rate of 1°C/min. The temperature was raised and heated at 120° C. for 100 minutes to dry the coating layer.
  • an insulating layer having a film thickness TR of 30 ⁇ m and made of a polyimide resin in which alumina particles were dispersed was formed on the surface of the aluminum substrate to obtain an aluminum substrate with an insulating layer.
  • a copper foil (thickness: 70 ⁇ m, modulus of elasticity: 118 GPa) was laminated as a circuit layer on the insulating layer of the obtained aluminum substrate with an insulating layer.
  • the obtained laminate was heated in a vacuum at a pressure bonding temperature of 300° C. for 120 minutes while applying a pressure of 5 MPa using a carbon jig to bond the insulating layer and the copper foil.
  • a metal base substrate was produced in which the aluminum substrate, the insulating layer and the copper foil were laminated in this order.
  • a metal base substrate was produced in the same manner as in Inventive Example 1, except that an aluminum substrate having a thickness TM shown in Table 1 below was used as the metal substrate.
  • a metal base substrate was produced in the same manner as in Invention Example 3, except that the polyimide resin A was changed to the polyimide resin B in the preparation of the alumina particle-dispersed polyimide solution.
  • the polyimide resin B one having an elastic modulus of 0.32 GPa at 100° C. when mixed with alumina was selected.
  • a metal base substrate was produced in the same manner as in Inventive Example 3, except that the polyimide resin A was changed to the polyimide resin C in the preparation of the alumina particle-dispersed polyimide solution.
  • the polyimide resin C one having an elastic modulus of 1.01 GPa at 100° C. when mixed with alumina was selected.
  • Inventive Example 1 and Example 1 were used, except that a copper substrate having a plate thickness TM as shown in Table 1 below and an elastic modulus EM as an elastic modulus shown in Table 1 below was used as the metal substrate.
  • a metal base substrate was produced in the same manner.
  • Inventive Example 1 and Example 1 were used, except that, as the metal substrate, carbon steel having a plate thickness TM shown in Table 1 below and an elastic modulus EM shown in Table 1 below was used. A metal base substrate was produced in the same manner.
  • the elastic modulus ER of the insulating layer was measured by the method described above, and the ratio TR / ER of the film thickness TR (unit: ⁇ m) to the elastic modulus ER (unit: GPa) was calculated.
  • the thermal conductivity CR of the insulating layer was measured by the method described above, and the ratio TR / CR of the film thickness TR (unit: ⁇ m) to the thermal conductivity CR (unit: W/mK) was calculated. The results are shown in Table 1 below.
  • a heating element (TO-3P) was placed on the copper foil of the metal base substrate to which the copper foil was adhered via a heat dissipation sheet (BFG-30A: manufactured by Denka Co., Ltd.).
  • the metal base substrate on which the heating element was placed was pressed in the stacking direction from above the heating element with a screw having a torque of 40 Ncm.
  • T3Ster manufactured by Siemens
  • the heat generation conditions of the heating element were 10 A and 30 seconds, and the thermal resistance measurement conditions were 0.01 A and measurement time of 60 seconds.
  • a similar measurement was performed on a single copper substrate on which no insulating film was formed, and the thermal resistance (K/W) was obtained by subtracting the thermal resistance from the measured value of the metal base substrate.
  • a metal base substrate was cut into a size of 50 mm long ⁇ 50 mm wide.
  • Sn--Ag--Cu solder is applied to the copper foil of the cut metal base substrate to form a solder layer of 25 mm long x 25 mm wide x 100 ⁇ m thick, and a 25 mm square Si chip is placed on the solder layer. It was mounted and a test body was produced.
  • the prepared specimen was subjected to 3000 cycles of cooling/heating cycles of -30°C for 30 minutes to 105°C for 30 minutes. After applying thermal cycles, the specimen was embedded in resin, and the cross section was observed using a polished specimen to measure the length (mm) of cracks occurring in the solder layer.
  • a value calculated from the following formula based on the length of one side of the solder layer and the measured crack length was taken as the crack resistance rate.
  • a high crack resistance rate means that cracks are less likely to occur, that is, high reliability.
  • Crack resistance rate (%) ⁇ (solder layer side length (25 mm) - 2 x crack length)/bonding layer side length (25 mm) ⁇ x 100
  • warp After measuring the crack resistance rate, the warpage of the sample was measured with a feeler gauge. The sample was placed on a flat plate, and the gap between the flat plate and the edge of the sample was measured as warpage. A was assigned to the case where the largest warp was 50 ⁇ m or less, B was assigned to the case where the warp was greater than 50 ⁇ m and 70 ⁇ m or less, and C was assigned to the case where the warp was greater than 70 ⁇ m.
  • the metal base substrates obtained in Examples 1 to 11 of the present invention in which T M , T M 3 ⁇ E M , T R /E R and T R /C R are all within the scope of the present invention. was excellent in heat resistance, crack resistance and warpage.
  • the metal base substrates obtained in Examples 2 to 7 and 9 to 11 of the present invention having T M 3 ⁇ E M of 30 or more exhibited improved warpage.
  • the metal base substrates obtained in Examples 1 to 5 and 8 to 11 of the present invention having a T R /E R of 100 or more had improved crack resistance.
  • the metal base substrates obtained in Examples 1 to 4 and 6 to 11 of the present invention having a T R /C R of 30 or less had a lower thermal resistance.
  • the metal base substrate obtained in Comparative Example 1 in which TM 3 ⁇ TM is lower than the range of the present invention and TM is thinner than the range of the present invention, and TM 3 ⁇ EM is the thickness of the present invention.
  • the metal base substrate obtained in Comparative Example 8 which is lower than the range of , had large warpage.
  • the crack resistance rate of the metal base substrates obtained in Comparative Examples 2 to 6, in which the TM was larger than the range of the present invention was lowered.
  • the metal base substrates obtained in Comparative Examples 5 to 7, in which T R /C R was larger than the range of the present invention had large thermal resistance.
  • alumina particle-dispersed polyimide solution was prepared in the same manner as in Invention Example 1, except that polyimide resin A was changed to polyimide resin D.
  • polyimide resin D a mixture with alumina having an elastic modulus of 2.15 GPa at 100° C. was selected.
  • a polyimide resin having a modulus of elasticity at 100° C. of 0.01 GPa was mixed with NMP, and the polyimide resin was dissolved to prepare a polyimide resin solution having a polyimide resin concentration of 10% by mass.
  • an aluminum substrate (length: 30 mm, width: 20 mm) having a plate thickness TM of 1.0 mm and an elastic modulus EM of 74 GPa was prepared.
  • the alumina particle-dispersed polyimide resin solution prepared above was applied by a bar coating method to form a coating film.
  • the aluminum substrate on which the coating film was formed was placed on a hot plate, heated from room temperature to 60°C at a rate of 3°C/min, heated at 60°C for 100 minutes, and further heated to 120°C at a rate of 1°C/min. The temperature was raised and heated at 120° C. for 100 minutes to dry the coating layer.
  • the aluminum substrate was heated at 250° C. for 1 minute and then at 400° C. for 1 minute.
  • a first insulating layer made of polyimide resin in which alumina particles were dispersed and having a film thickness TR1 of 10 ⁇ m was formed on the surface of the aluminum substrate to obtain an aluminum substrate with a first insulating layer.
  • the polyimide resin solution prepared above was applied by a bar coating method to form a coating film.
  • the formed coating film was dried by heating at 300° C. to form a second insulating layer made of polyimide resin and having a film thickness TR2 of 1.0 ⁇ m. In this way, an aluminum substrate with an insulating layer composed of the first insulating layer and the second insulating layer was obtained.
  • a copper foil was crimped as a circuit layer in the same manner as in Example 1 of the present invention.
  • a metal base substrate was produced in which the aluminum substrate, the insulating layer and the copper foil were laminated in this order.
  • a metal base substrate was fabricated in the same manner as in Inventive Example 12, except that the film thickness TR1 of the first insulating layer was set to 30 ⁇ m and the second insulating layer was not formed.
  • TR / ER TR1 / ER1 + TR2 / ER2
  • TR/ CR TR1 / CR1 + TR2 / CR2
  • the metal base substrate of the present invention is excellent in heat dissipation and reliability. Therefore, it is suitable as a substrate for mounting electronic components such as semiconductor elements and LEDs.

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Abstract

This metal base substrate (10) is characterized in that: a metal substrate (20), one or more insulation layers (30), and a circuit layer (40) are laminated in the stated order; the plate thickness TM of the metal substrate (20) is in a range of 0.5-1.1 mm; a product TM 3×EM of a cube value of the plate thickness TM (unit: mm) of the metal substrate (20) and the elastic modulus EM (unit: GPa) at 25°C of the metal substrate (20) is in a range of 10-1000; the total of ratios TR/ER of the film thicknesses TR (unit: μm) with respect to the elastic moduli ER(unit: GPa) at 100°C of the layers that constitute each of the one or more insulation layers (30) is in a range of 30-1000; and the total of ratios TR/CR of the film thicknesses TR (unit: μm) with respect to the thermal conductivities CR (unit: W/mK) of layers constituting the insulation layers (30) is in a range of 2-40.

Description

金属ベース基板metal base substrate
　本発明は、金属ベース基板に関する。
　本願は、２０２１年１０月５日に、日本に出願された特願２０２１－１６４２９６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 metal base substrates.
This application claims priority based on Japanese Patent Application No. 2021-164296 filed in Japan on October 5, 2021, the content of which is incorporated herein.
　半導体素子やＬＥＤなどの電子部品を実装するための基板の一つとして、金属ベース基板が知られている。金属ベース基板は、金属基板と、絶縁層と、回路層とがこの順で積層された積層体である。金属ベース基板の回路層の上にはんだを介して電子部品を実装したモジュールでは、電子部品にて発生した熱は、絶縁層を介して金属基板に伝達され、金属基板から外部に放熱される。このため、金属ベース基板の絶縁層は、一般に、絶縁性や耐電圧性に優れる樹脂と、熱伝導性に優れる無機物フィラーとを含む絶縁性組成物から形成されている。 A metal base substrate is known as one of the substrates for mounting electronic components such as semiconductor elements and LEDs. A metal base substrate is a laminate in which a metal substrate, an insulating layer, and a circuit layer are laminated in this order. In a module in which electronic components are mounted on a circuit layer of a metal base substrate via solder, heat generated by the electronic components is transferred to the metal substrate through the insulating layer and radiated from the metal substrate to the outside. For this reason, the insulating layer of the metal base substrate is generally formed from an insulating composition containing a resin having excellent insulating properties and voltage resistance and an inorganic filler having excellent thermal conductivity.
　金属ベース基板としては、例えば、金属基板の厚みが１～５ｍｍ、回路層の厚みが１００～５００μｍであり、絶縁層を２層以上の絶縁性樹脂層からなり、その２層以上の絶縁性樹脂層は、少なくとも熱可塑性絶縁性樹脂を含む層と非熱可塑性絶縁性樹脂を含む層とを有し、２層以上の絶縁性樹脂層のうち少なくとも一層の絶縁性樹脂層は、絶縁性樹脂層を構成する絶縁性樹脂よりも熱伝導率が高いフィラーを含む構成のものが知られている（特許文献１）。 As the metal base substrate, for example, the thickness of the metal substrate is 1 to 5 mm, the thickness of the circuit layer is 100 to 500 μm, the insulating layer is made of two or more insulating resin layers, and the two or more insulating resin layers are The layer has at least a layer containing a thermoplastic insulating resin and a layer containing a non-thermoplastic insulating resin, and at least one of the two or more insulating resin layers is an insulating resin layer. (Patent Document 1).
特開２０１５－４３４１７号公報JP 2015-43417 A
　金属ベース基板の開発においては、放熱性を重要視するため、ベース金属の厚みを大きくすることで放熱性を上げるということが行われてきた。しかしながら、金属ベース基板の金属基板は熱膨張係数が高く、熱によって膨張・収縮して体積変化しやすい。一方、電子部品はセラミックを基体としたものが多く、熱膨張係数が低い。このため、金属ベース基板の回路層の上にはんだを介して電子部品を実装したモジュールでは、電子部品のオン／オフや外部環境の温度変化によって、はんだに付与される応力が変動することにより、はんだにクラックが発生するなど信頼性が低下することがある。はんだに付与される応力の変動を軽減するために、絶縁層の膜厚を厚くして、金属基板の体積変化を絶縁層に吸収させることは有効である。しかしながら、絶縁層の膜厚を厚くすると、電子部品にて発生した熱を、絶縁層を介して金属基板に伝達しにくくなり、金属ベース基板の放熱性が低下するおそれがある。つまり金属ベース基板の放熱性と信頼性を十分に両立させることは難しい。 　In the development of metal base substrates, heat dissipation has been emphasized, so the thickness of the base metal has been increased to improve heat dissipation. However, the metal substrate of the metal base substrate has a high coefficient of thermal expansion and is easily expanded and contracted by heat to change its volume. On the other hand, many electronic parts are based on ceramics and have a low coefficient of thermal expansion. For this reason, in a module in which electronic components are mounted on the circuit layer of a metal base substrate via solder, the stress applied to the solder fluctuates due to the switching on/off of the electronic components and temperature changes in the external environment. Cracks may occur in the solder, reducing reliability. In order to reduce variations in the stress applied to the solder, it is effective to increase the film thickness of the insulating layer so that the insulating layer absorbs the volume change of the metal substrate. However, if the thickness of the insulating layer is increased, the heat generated by the electronic component is less likely to be transferred to the metal substrate through the insulating layer, and the heat dissipation performance of the metal base substrate may deteriorate. In other words, it is difficult to satisfy both the heat radiation property and the reliability of the metal base substrate.
　この発明は、前述した事情に鑑みてなされたものであって、その目的は、放熱性と信頼性とに優れる金属ベース基板を提供することにある。 The present invention has been made in view of the circumstances described above, and its object is to provide a metal base substrate that is excellent in heat dissipation and reliability.
　上記の課題を解決するために、本発明の一態様に係る金属ベース基板は、金属基板と、少なくとも１層の絶縁層と、回路層とがこの順で積層された金属ベース基板であって、前記金属基板の板厚ＴＭが０．５ｍｍ以上１．１ｍｍ以下の範囲内にあり、前記金属基板の板厚ＴＭ（単位：ｍｍ）の３乗値と、前記金属基板の２５℃における弾性率ＥＭ（単位：ＧＰａ）との積ＴＭ ３×ＥＭが１０以上１０００以下の範囲内にあって、前記絶縁層を構成する各層の１００℃における弾性率ＥＲ（単位：ＧＰａ）に対する膜厚ＴＲ（単位：μｍ）の比ＴＲ／ＥＲの合計が３０以上１０００以下の範囲内にあり、前記絶縁層を構成する各層の熱伝導度ＣＲ（単位：Ｗ/ｍＫ）に対する膜厚ＴＲ（単位：μｍ）の比ＴＲ／ＣＲの合計が２以上４０以下の範囲内にあることを特徴としている。 In order to solve the above problems, a metal base substrate according to one aspect of the present invention is a metal base substrate in which a metal substrate, at least one insulating layer, and a circuit layer are laminated in this order, The plate thickness T M of the metal substrate is in the range of 0.5 mm or more and 1.1 mm or less, and the cube value of the plate thickness T M (unit: mm) of the metal substrate and the elasticity of the metal substrate at 25 ° C. The product TM 3 × EM with the modulus EM (unit: GPa) is in the range of 10 or more and 1000 or less, and the elastic modulus ER (unit: GPa) of each layer constituting the insulating layer at 100 ° C. The sum of the ratios TR / ER of the film thickness TR (unit: μm) is in the range of 30 or more and 1000 or less, and the thermal conductivity CR (unit: W/mK) of each layer constituting the insulating layer It is characterized in that the sum of the ratios T R /C R of the film thicknesses T R (unit: μm) is in the range of 2 or more and 40 or less.
　上記のような構成とされた金属ベース基板によれば、金属基板の板厚ＴＭが０．５ｍｍ以上１．１ｍｍ以下の範囲内にあるので、金属ベース基板上にはんだによって電子部品を接合し、電子部品が温度変化した場合であっても、はんだにかかる熱応力を抑えることができる。また、板厚ＴＭ（単位：ｍｍ）の３乗値と、金属基板の２５℃における弾性率ＥＭ（単位：ＧＰａ）との積ＴＭ ３×ＥＭが１０以上１０００以下の範囲内にあるので、電子部品実装後の金属ベース基板の反りを抑えることができる。また、絶縁層を構成する各層の１００℃における弾性率ＥＲ（単位：ＧＰａ）に対する膜厚ＴＲ（単位：μｍ）の比ＴＲ／ＥＲの合計が３０以上１０００以下の範囲内にあるので、回路層の応力の緩和能力が高くなり、回路層の上にはんだを介して電子部品を実装した場合は、はんだに付与される応力を低減させることができる。さらに、絶縁層を構成する各層の熱伝導度ＣＲ（単位：Ｗ/ｍＫ）に対する膜厚ＴＲ（単位：μｍ）の比ＴＲ／ＣＲの合計が２以上４０以下の範囲内にあるので、回路層の上にはんだを介して電子部品を実装した場合は、電子部品にて発生した熱を金属基板に効率よく伝えることができる。したがって、上記のような構成とされた金属ベース基板は放熱性と信頼性とに優れる。 According to the metal base substrate configured as described above, since the plate thickness TM of the metal substrate is in the range of 0.5 mm or more and 1.1 mm or less, the electronic component can be joined onto the metal base substrate by soldering. , the thermal stress applied to the solder can be suppressed even when the temperature of the electronic component changes. Further, the product TM 3 × EM of the cube value of the plate thickness TM ( unit : mm) and the elastic modulus EM (unit: GPa ) at 25°C of the metal substrate is in the range of 10 or more and 1000 or less. Therefore, it is possible to suppress warping of the metal base substrate after mounting the electronic component. In addition, the sum of the ratios T R /E R of the film thickness T R (unit: μm) to the elastic modulus E R (unit: GPa) at 100° C. of each layer constituting the insulating layer is in the range of 30 or more and 1000 or less. Therefore, the ability of the circuit layer to relax stress is enhanced, and when an electronic component is mounted on the circuit layer via solder, the stress applied to the solder can be reduced. Further, the sum of the ratios T R /C R of the film thickness T R (unit: μm) to the thermal conductivity C R (unit: W/mK) of each layer constituting the insulating layer is in the range of 2 or more and 40 or less. Therefore, when an electronic component is mounted on the circuit layer via solder, the heat generated by the electronic component can be efficiently transferred to the metal substrate. Therefore, the metal base substrate configured as described above is excellent in heat dissipation and reliability.
　ここで、本発明の一態様に係る金属ベース基板においては、前記金属基板が、アルミニウム、銅および鉄からなる群より選ばれる少なくとも１種の金属を含む構成であってもよい。
　この場合、金属基板の熱伝導性と耐熱性とが高いので、金属ベース基板の放熱性と信頼性とがより向上する。 Here, in the metal base substrate according to one aspect of the present invention, the metal substrate may contain at least one metal selected from the group consisting of aluminum, copper and iron.
In this case, since the metal substrate has high thermal conductivity and heat resistance, the heat dissipation and reliability of the metal base substrate are further improved.
　また、本発明の一態様に係る金属ベース基板においては、前記絶縁層が単層体であって、前記単層体は、フィラーの含有率が３０体積％以上８５体積％以下の範囲内にある樹脂組成物である構成であってもよい。あるいは、前記絶縁層が金属層の上に形成された第１絶縁層と前記第１絶縁層の上に積層された第２絶縁層とを有する２層の積層体であって、前記第１絶縁層および前記第２絶縁層の一方の層は、フィラーの含有率が５０体積％以上８５体積％以下の範囲内にある樹脂組成物の層であって、他方の層は、樹脂もしくはフィラーの含有率が１体積％以下の樹脂組成物の層である構成であってもよい。
　この場合、絶縁層の熱伝導性と応力の緩和能力とがより高くなるので、金属ベース基板の放熱性と信頼性とがさらに向上する。 Further, in the metal base substrate according to one aspect of the present invention, the insulating layer is a single-layer body, and the single-layer body has a filler content of 30% by volume or more and 85% by volume or less. The structure which is a resin composition may be sufficient. Alternatively, the insulating layer is a two-layer laminate having a first insulating layer formed on a metal layer and a second insulating layer laminated on the first insulating layer, wherein the first insulating layer One of the layer and the second insulating layer is a layer of a resin composition having a filler content in the range of 50% by volume or more and 85% by volume or less, and the other layer contains a resin or a filler. A layer of a resin composition having a rate of 1% by volume or less may be used.
In this case, the thermal conductivity and stress relieving ability of the insulating layer are further improved, so that the heat dissipation and reliability of the metal base substrate are further improved.
　また、本発明の一態様に係る金属ベース基板においては、前記絶縁層の膜厚が１００μｍ以下である構成であってもよい。
　この場合、絶縁層の膜厚が薄いので、回路層の上にはんだを介して電子部品を実装したときは、電子部品にて発生した熱を金属基板により効率よく伝えることができる。 Further, in the metal base substrate according to one embodiment of the present invention, the thickness of the insulating layer may be 100 μm or less.
In this case, since the film thickness of the insulating layer is thin, when an electronic component is mounted on the circuit layer via solder, the heat generated by the electronic component can be efficiently transferred to the metal substrate.
　また、本発明の一態様に係る金属ベース基板においては、前記回路層の膜厚が８０μｍ以下である構成であってもよい。
　この場合、回路層の膜厚が薄いので、回路層の上にはんだを介して電子部品を実装したときは、回路層からはんだに付与される熱応力が低減するので、金属ベース基板の信頼性がさらに向上する。 Further, in the metal base substrate according to one aspect of the present invention, the film thickness of the circuit layer may be 80 μm or less.
In this case, since the film thickness of the circuit layer is thin, when an electronic component is mounted on the circuit layer through solder, the thermal stress applied from the circuit layer to the solder is reduced, thereby improving the reliability of the metal base substrate. is further improved.
　本発明の上記態様によれば、放熱性と信頼性とに優れる金属ベース基板を提供することが可能となる。 According to the above aspect of the present invention, it is possible to provide a metal base substrate that is excellent in heat dissipation and reliability.
本発明の一実施形態に係る金属ベース基板の概略断面図である。1 is a schematic cross-sectional view of a metal base substrate according to one embodiment of the present invention; FIG.
　以下に、本発明の一実施形態について添付した図面を参照して説明する。
　図１は、本発明の一実施形態に係る金属ベース基板の概略断面図である。
　図１において、金属ベース基板１０は、金属基板２０と、絶縁層３０と、回路層４０とがこの順で積層された積層体である。金属ベース基板１０の回路層４０の上には、はんだ５０を介して、電子部品６０の電極端子６１が接続されていて、モジュールが形成されている。 An embodiment of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a schematic cross-sectional view of a metal base substrate according to one embodiment of the present invention.
In FIG. 1, the metal base substrate 10 is a laminate in which a metal substrate 20, an insulating layer 30, and a circuit layer 40 are laminated in this order. Electrode terminals 61 of an electronic component 60 are connected to the circuit layer 40 of the metal base substrate 10 via solder 50 to form a module.
　金属基板２０は、金属ベース基板１０のベースとなる部材である。
　金属基板２０は、板厚ＴＭが０．５ｍｍ以上１．１ｍｍ以下の範囲内にある。板厚ＴＭが０．５ｍｍ以上であることによって、金属基板２０の強度が高くなるので、熱による反りなどの変形を抑えることができる。また、板厚ＴＭが１．１ｍｍ以下であることによって、金属基板２０の熱による体積変化量が小さくなる。金属基板２０の熱による変形を抑える観点から板厚ＴＭは０．８ｍｍ以上であることが好ましい。金属基板２０の熱による体積変化量を小さくする観点から、板厚ＴＭは１．０ｍｍ以下であることが好ましい。 The metal substrate 20 is a member that serves as the base of the metal base substrate 10 .
The metal substrate 20 has a plate thickness TM within the range of 0.5 mm or more and 1.1 mm or less. When the plate thickness TM is 0.5 mm or more, the strength of the metal substrate 20 is increased, so deformation such as warping due to heat can be suppressed. Further, since the plate thickness TM is 1.1 mm or less, the amount of volumetric change of the metal substrate 20 due to heat is small. From the viewpoint of suppressing thermal deformation of the metal substrate 20, the plate thickness TM is preferably 0.8 mm or more. From the viewpoint of reducing the volume change amount of the metal substrate 20 due to heat, the plate thickness TM is preferably 1.0 mm or less.
　金属基板２０の板厚ＴＭ（単位：ｍｍ）の３乗値と、金属基板２０の２５℃における弾性率ＥＭ（単位：ＧＰａ）との積ＴＭ ３×ＥＭが１０以上１０００以下の範囲内にある。ＴＭ ３×ＥＭが１０以上であることによって、金属基板２０の熱による反りなどの変形を抑えることができる。また、ＴＭ ３×ＥＭが１０００以下であることによって、金属基板２０が厚くなりすぎない。ＴＭ ３×ＥＭは３０以上であることが好ましく、３００以下であることが好ましい。金属基板２０の２５℃における弾性率（引張弾性率）は、引張試験（ＪＩＳ　Ｚ２２４１：２０１１　金属材料引張試験方法）によって測定することができる。 The product TM3×EM of the cube of the plate thickness TM (unit: mm) of the metal substrate 20 and the elastic modulus EM (unit: GPa) of the metal substrate 20 at 25°C is 10 or more and 1000 or less. Within range. When T M 3 ×E M is 10 or more, deformation such as warping of the metal substrate 20 due to heat can be suppressed. Also, by setting T M 3 ×E M to 1000 or less, the metal substrate 20 does not become too thick. T M 3 ×E M is preferably 30 or more, and preferably 300 or less. The elastic modulus (tensile elastic modulus) of the metal substrate 20 at 25° C. can be measured by a tensile test (JIS Z2241:2011 Metal material tensile test method).
　金属基板２０は、アルミニウム、銅、鉄からなる群より選ばれる少なくとも１種の金属を含むことが好ましい。金属基板２０は、銅基板、アルミニウム基板または鉄基板であることがより好ましい。銅基板は、銅または銅合金からなる。銅合金は構成元素のうち銅が最も多く含まれる合金である。アルミニウム基板は、アルミニウムもしくはアルミニウム合金からなる。アルミニウム合金は構成元素のうちアルミニウムが最も多く含まれる合金である。鉄基板は、鉄もしくは鉄合金からなる。鉄合金は構成元素のうち鉄が最も多く含まれる合金である。鉄合金は、炭素鋼を含む。 The metal substrate 20 preferably contains at least one metal selected from the group consisting of aluminum, copper and iron. More preferably, the metal substrate 20 is a copper substrate, an aluminum substrate, or an iron substrate. The copper substrate is made of copper or copper alloy. A copper alloy is an alloy containing the largest amount of copper among the constituent elements. The aluminum substrate is made of aluminum or an aluminum alloy. Aluminum alloys are alloys containing the largest amount of aluminum among the constituent elements. The iron substrate consists of iron or an iron alloy. Iron alloys are alloys containing the largest amount of iron among the constituent elements. Ferrous alloys include carbon steel.
　絶縁層３０は、金属基板２０と回路層４０とを絶縁するための層である。また、絶縁層３０は、電子部品６０にて発生した熱を金属基板２０に伝える伝熱機能と、熱による金属基板２０の体積変化を吸収し、はんだ５０に付与される応力を緩和する応力緩和機能を有する。
　絶縁層３０は、１００℃における弾性率ＥＲ（単位：ＧＰａ）に対する膜厚ＴＲ（単位：μｍ）の比ＴＲ／ＥＲが３０以上１０００以下の範囲内にある。ＴＲ／ＥＲが１０００以下であることによって、絶縁層３０の応力緩和機能が向上し、はんだ５０に付与される応力を低減させることができる。ＴＲ／ＥＲは、３０以上であることが好ましく、１００以上であることがさらに好ましい。また、ＴＲ／ＥＲは、３００以下であることが好ましく、２００以下であることが特に好ましい。絶縁層３０の１００℃における弾性率は、例えば、次のようにして測定することができる。金属ベース基板１０の金属基板２０と回路層４０をエッチングによって除去し、絶縁層３０を単離する。得られた絶縁層３０について、動的粘弾性測定（ＤＭＡ）によって弾性率（引張弾性率）を測定する。 The insulating layer 30 is a layer for insulating the metal substrate 20 and the circuit layer 40 . In addition, the insulating layer 30 has a heat transfer function to transfer the heat generated in the electronic component 60 to the metal substrate 20, and a stress relaxation function to absorb the volume change of the metal substrate 20 due to heat and relax the stress applied to the solder 50. have a function.
The insulating layer 30 has a ratio T R / E R of a film thickness T R (unit: μm) to an elastic modulus E R (unit: GPa) at 100° C. within a range of 30 or more and 1000 or less. When T R /E R is 1000 or less, the stress relaxation function of the insulating layer 30 is improved, and the stress applied to the solder 50 can be reduced. T R /E R is preferably 30 or more, more preferably 100 or more. Moreover, T R /E R is preferably 300 or less, particularly preferably 200 or less. The elastic modulus of the insulating layer 30 at 100° C. can be measured, for example, as follows. The metal substrate 20 and the circuit layer 40 of the metal base substrate 10 are removed by etching to isolate the insulating layer 30 . The elastic modulus (tensile elastic modulus) of the obtained insulating layer 30 is measured by dynamic viscoelasticity measurement (DMA).
　また、絶縁層３０は、熱伝導度ＣＲ（単位：Ｗ/ｍＫ）に対する膜厚ＴＲ（単位：μｍ）の比ＴＲ／ＣＲが２以上４０以下の範囲内にある。ＴＲ／ＣＲが２以上であることによって、絶縁層３０の膜厚が薄くなりすぎず、絶縁性が担保される。また、ＴＲ／ＣＲが４０以下であることによって、絶縁層３０の伝熱機能が向上し、電子部品６０にて発生した熱を金属基板２０に効率よく伝えることができる。ＴＲ／ＣＲは、３以上であることが好ましく、５以上であることがさらに好ましい。また、ＴＲ／ＣＲは、３０以下であることが好ましく、２０以下であることが特に好ましい。絶縁層３０の熱伝導度は、例えば、次のようにして測定することができる。金属ベース基板１０の金属基板２０と回路層４０をエッチングによって除去し、絶縁層３０を単離する。得られた絶縁層３０について、レーザーフラッシュ法によって熱伝導度を測定する。 Moreover, the insulating layer 30 has a ratio T R /C R of the film thickness T R (unit: μm) to the thermal conductivity C R (unit: W/mK ) within a range of 2 or more and 40 or less. When T R /C R is 2 or more, the film thickness of the insulating layer 30 does not become too thin, and the insulating property is ensured. Further, when T R /C R is 40 or less, the heat transfer function of the insulating layer 30 is improved, and the heat generated in the electronic component 60 can be efficiently transferred to the metal substrate 20 . T R /C R is preferably 3 or more, more preferably 5 or more. Moreover, T R /C R is preferably 30 or less, particularly preferably 20 or less. The thermal conductivity of the insulating layer 30 can be measured, for example, as follows. The metal substrate 20 and the circuit layer 40 of the metal base substrate 10 are removed by etching to isolate the insulating layer 30 . The thermal conductivity of the obtained insulating layer 30 is measured by a laser flash method.
　絶縁層３０は、少なくとも１層以上である。本実施形態の絶縁層３０は、絶縁樹脂３１と無機物フィラー３２（フィラーともいう）とを含む絶縁性樹脂組成物からなる単層体とされている。絶縁層３０を、絶縁性が高い絶縁樹脂３１と、熱伝導度が高い無機物フィラー３２とを含む絶縁性樹脂組成物から形成することによって、絶縁性を維持しつつ、熱伝導性を向上させることができる。 The insulating layer 30 is at least one layer. The insulating layer 30 of the present embodiment is a single layer made of an insulating resin composition containing an insulating resin 31 and an inorganic filler 32 (also referred to as a filler). By forming the insulating layer 30 from an insulating resin composition containing an insulating resin 31 with high insulating properties and an inorganic filler 32 with high thermal conductivity, thermal conductivity is improved while maintaining insulating properties. can be done.
　絶縁樹脂３１としては、例えば、ポリイミド樹脂、ポリアミドイミド樹脂、またはこれらの混合物を用いることができる。これらの樹脂は、絶縁性、耐電圧性、化学的耐性及び機械特性などの特性に優れるので、金属ベース基板１０のこれらの特性が向上する。 As the insulating resin 31, for example, a polyimide resin, a polyamideimide resin, or a mixture thereof can be used. These resins are excellent in properties such as insulation, withstand voltage, chemical resistance and mechanical properties, so that these properties of the metal base substrate 10 are improved.
　無機物フィラー３２としては、例えば、アルミナ（Ａｌ２Ｏ３）粒子、アルミナ水和物粒子、窒化アルミニウム（ＡｌＮ）粒子、シリカ（ＳｉＯ２）粒子、炭化珪素（ＳｉＣ）粒子、酸化チタン（ＴｉＯ２）粒子、窒化硼素（ＢＮ）粒子などを用いることができる。無機物フィラー３２の平均粒子径は、０．１μｍ以上２０μｍ以下の範囲内にあることが好ましい。 Examples of the inorganic filler 32 include alumina (Al 2 O 3 ) particles, alumina hydrate particles, aluminum nitride (AlN) particles, silica (SiO 2 ) particles, silicon carbide (SiC) particles, and titanium oxide (TiO 2 ). particles, boron nitride (BN) particles, and the like can be used. The average particle size of the inorganic filler 32 is preferably in the range of 0.1 μm or more and 20 μm or less.
　絶縁層３０の無機物フィラー３２の含有量は、３０体積％以上８５体積％以下の範囲内にあることが好ましい。無機物フィラー３２の含有量が３０体積％以上であることによって、絶縁層３０の熱伝導性が向上する。一方、無機物フィラー３２の含有量が８５体積％以下であることによって、絶縁層３０の絶縁性が向上する。絶縁層３０の熱伝導性を向上させる観点では、無機物フィラー３２の含有量は、５０体積％以上であることがさらに好ましく、８０体積％以下であることが特に好ましい。 The content of the inorganic filler 32 in the insulating layer 30 is preferably in the range of 30% by volume or more and 85% by volume or less. When the content of the inorganic filler 32 is 30% by volume or more, the thermal conductivity of the insulating layer 30 is improved. On the other hand, when the content of the inorganic filler 32 is 85% by volume or less, the insulating properties of the insulating layer 30 are improved. From the viewpoint of improving the thermal conductivity of the insulating layer 30, the content of the inorganic filler 32 is more preferably 50% by volume or more, and particularly preferably 80% by volume or less.
　絶縁層３０の膜厚は１００μｍ以下であることが好ましい。絶縁層３０の膜厚が１００μｍ以下であることによって、絶縁層３０の伝熱機能が向上し、電子部品６０にて発生した熱を金属基板２０に効率よく伝えることができる。絶縁層３０の膜厚は、絶縁耐圧が実用的な範囲であれば特に制限はないが、３０μｍ以上であることが好ましい。絶縁層３０の膜厚が３０μｍ以上であることによって、金属基板２０と回路層４０とを確実に絶縁することができ、絶縁層３０の応力緩和機能が向上し、はんだ５０に付与される応力を低減させることができる。絶縁層３０の膜厚は、伝熱機能向上の観点からは、７０μｍ以下であることが好ましく、５０μｍ以下であることが特に好ましい。また、絶縁層３０の膜厚は、絶縁性向上の観点からは、４０μｍ以上であることが特に好ましい。 The film thickness of the insulating layer 30 is preferably 100 μm or less. When the film thickness of the insulating layer 30 is 100 μm or less, the heat transfer function of the insulating layer 30 is improved, and the heat generated in the electronic component 60 can be efficiently transferred to the metal substrate 20 . The film thickness of the insulating layer 30 is not particularly limited as long as the dielectric breakdown voltage is within a practical range, but is preferably 30 μm or more. When the thickness of the insulating layer 30 is 30 μm or more, the metal substrate 20 and the circuit layer 40 can be reliably insulated, the stress relaxation function of the insulating layer 30 is improved, and the stress applied to the solder 50 is reduced. can be reduced. The film thickness of the insulating layer 30 is preferably 70 μm or less, particularly preferably 50 μm or less, from the viewpoint of improving the heat transfer function. Moreover, it is particularly preferable that the film thickness of the insulating layer 30 is 40 μm or more from the viewpoint of improving the insulating properties.
　回路層４０は、回路パターン状に形成される。その回路パターン状に形成された回路層４０の上に、電子部品６０の電極端子６１がはんだ５０等を介して接合される。回路層４０の材料としては、銅、アルミニウム、金などの金属を用いることができる。回路層４０は銅箔からなることが好ましい。回路層４０の膜厚は、２μｍ以上２００μｍ以下の範囲内にあることが好ましい。 The circuit layer 40 is formed in a circuit pattern. Electrode terminals 61 of an electronic component 60 are bonded via solder 50 or the like onto the circuit layer 40 formed in the shape of a circuit pattern. As a material for the circuit layer 40, metals such as copper, aluminum, and gold can be used. Circuit layer 40 is preferably made of copper foil. The film thickness of the circuit layer 40 is preferably in the range of 2 μm or more and 200 μm or less.
　回路層４０の膜厚は８０μｍ以下であることが特に好ましい。回路層４０の膜厚が８０μｍ以下であることによって、回路層４０で発生する熱応力が少なくなり、はんだ５０に付与される熱応力が低減する。また、回路層４０の膜厚は、熱応力を低減させる観点からは、７５μｍ以下であることが好ましく、５０μｍ以下であることが特に好ましい。回路層４０の膜厚は、利用する際の電流に対して十分に低抵抗であれば特に制限はないが、２μｍ以上であることが好ましい。回路層４０の膜厚が２μｍ以上であることによって、回路層４０の電気抵抗が低くなり、モジュールの内部抵抗を低減させることができる。回路層４０の膜厚は、電気抵抗を小さくするという観点からは、５μｍ以上であることが好ましく、２０μｍ以上であることが特に好ましい。 It is particularly preferable that the film thickness of the circuit layer 40 is 80 μm or less. Since the film thickness of the circuit layer 40 is 80 μm or less, the thermal stress generated in the circuit layer 40 is reduced, and the thermal stress applied to the solder 50 is reduced. From the viewpoint of reducing thermal stress, the film thickness of the circuit layer 40 is preferably 75 μm or less, particularly preferably 50 μm or less. The film thickness of the circuit layer 40 is not particularly limited as long as it has a sufficiently low resistance to the current used, but is preferably 2 μm or more. When the film thickness of the circuit layer 40 is 2 μm or more, the electric resistance of the circuit layer 40 is lowered, and the internal resistance of the module can be reduced. The film thickness of the circuit layer 40 is preferably 5 μm or more, particularly preferably 20 μm or more, from the viewpoint of reducing electrical resistance.
　本実施形態の金属ベース基板１０に実装される電子部品６０の例としては、特に制限はなく、半導体素子、抵抗、キャパシタ、水晶発振器などが挙げられる。半導体素子の例としては、ＭＯＳＦＥＴ（Ｍｅｔａｌ－ｏｘｉｄｅ－ｓｅｍｉｃｏｎｄｕｃｔｏｒ　ｆｉｅｌｄ　ｅｆｆｅｃｔ　ｔｒａｎｓｉｓｔｏｒ）、ＩＧＢＴ（Ｉｎｓｕｌａｔｅｄ　Ｇａｔｅ　Ｂｉｐｏｌａｒ　Ｔｒａｎｓｉｓｔｏｒ）、ＬＳＩ（Ｌａｒｇｅ　Ｓｃａｌｅ　Ｉｎｔｅｇｒａｔｉｏｎ）、ＬＥＤ（発光ダイオード）、ＬＥＤチップ、ＬＥＤ－ＣＳＰ（ＬＥＤ－Ｃｈｉｐ　Ｓｉｚｅ　Ｐａｃｋａｇｅ）が挙げられる。 Examples of the electronic component 60 mounted on the metal base substrate 10 of this embodiment are not particularly limited, and include semiconductor elements, resistors, capacitors, crystal oscillators, and the like. Examples of semiconductor elements include MOSFET (Metal-oxide-semiconductor field effect transistor), IGBT (Insulated Gate Bipolar Transistor), LSI (Large Scale Integration), LED (light emitting diode), LED chip, LED-CSP (LED-Chip Size Package).
　はんだ５０としては、例えば、Ｓｎ－Ａｇ系、Ｓｎ－Ｃｕ系、Ｓｎ－Ｉｎ系およびＳｎ－Ａｇ－Ｃｕ系などのはんだ材（いわゆる鉛フリーはんだ材）を用いることができる。 As the solder 50, for example, Sn--Ag-based, Sn--Cu-based, Sn--In-based, Sn--Ag--Cu-based solder materials (so-called lead-free solder materials) can be used.
　本実施形態の金属ベース基板１０は、例えば、絶縁層形成工程と、回路層圧着工程とを含む方法によって製造することができる。 The metal base substrate 10 of this embodiment can be manufactured, for example, by a method including an insulating layer forming step and a circuit layer pressure bonding step.
　絶縁層形成工程では、金属基板２０の上に絶縁層３０を形成して、絶縁層付き金属基板を得る。絶縁層３０の形成方法としては、塗布法または電着法を用いることができる。
　塗布法は、溶媒と絶縁樹脂３１と無機物フィラー３２とを含む塗布液を、金属基板２０の上に塗布して塗布層を形成し、次いで塗布層を加熱して絶縁層３０を得る方法である。塗布液は、絶縁樹脂３１が溶解した樹脂材料溶液と、その樹脂材料溶液に分散されている無機物フィラー３２とを含む無機物フィラー分散樹脂材料溶液を用いることができる。塗布液を基板の表面に塗布する方法としては、スピンコート法、バーコート法、ナイフコート法、ロールコート法、ブレードコート法、ダイコート法、グラビアコート法、ディップコート法などを用いることができる。 In the insulating layer forming step, the insulating layer 30 is formed on the metal substrate 20 to obtain a metal substrate with an insulating layer. As a method for forming the insulating layer 30, a coating method or an electrodeposition method can be used.
The coating method is a method in which a coating liquid containing a solvent, an insulating resin 31, and an inorganic filler 32 is coated on the metal substrate 20 to form a coating layer, and then the coating layer is heated to obtain the insulating layer 30. . As the coating liquid, an inorganic filler-dispersed resin material solution containing a resin material solution in which the insulating resin 31 is dissolved and the inorganic filler 32 dispersed in the resin material solution can be used. Spin coating, bar coating, knife coating, roll coating, blade coating, die coating, gravure coating, dip coating, and the like can be used as methods for applying the coating liquid to the surface of the substrate.
　電着法は、絶縁樹脂粒子と無機物フィラー３２とを含む電着液に金属基板２０を浸漬して、基板の表面に絶縁樹脂粒子と無機物フィラー３２を電着させて電着膜を形成し、次いで得られた電着膜を加熱して絶縁層３０を形成する方法である。電着液としては、絶縁樹脂溶液と、その絶縁樹脂溶液に分散されている無機物フィラー３２とを含む無機物フィラー分散絶縁樹脂溶液に、絶縁樹脂の貧溶媒を加えて絶縁樹脂３１を粒子として析出させることによって調製したものを用いることができる。 In the electrodeposition method, the metal substrate 20 is immersed in an electrodeposition liquid containing insulating resin particles and inorganic fillers 32, and the insulating resin particles and inorganic fillers 32 are electrodeposited on the surface of the substrate to form an electrodeposited film, Then, the obtained electrodeposited film is heated to form the insulating layer 30 . As the electrodeposition liquid, a poor solvent for the insulating resin is added to the inorganic filler dispersed insulating resin solution containing the insulating resin solution and the inorganic filler 32 dispersed in the insulating resin solution to deposit the insulating resin 31 as particles. It is possible to use those prepared by
　回路層圧着工程では、絶縁層付き金属基板の絶縁層３０の上に金属箔を積層し、得られた積層体を加熱しながら加圧することによって回路層４０を形成して、金属ベース基板１０を得る。積層体の加熱温度は、例えば、２００℃以上であり、２５０℃以上であることがより好ましい。加熱温度の上限は、絶縁樹脂の熱分解温度未満であり、好ましくは熱分温度よりも３０℃低い温度以下である。圧着時に加える圧力は、例えば、１ＭＰａ以上３０ＭＰａ以下の範囲内であり、３ＭＰａ以上２５ＭＰａ以下の範囲内であることがより好ましい。圧着時間は、加熱温度や圧力によって異なるが、一般に６０分間以上１８０分間以下である。 In the circuit layer crimping step, a metal foil is laminated on the insulating layer 30 of the metal substrate with an insulating layer, and the obtained laminated body is pressed while being heated to form the circuit layer 40, thereby forming the metal base substrate 10. obtain. The heating temperature of the laminate is, for example, 200° C. or higher, and more preferably 250° C. or higher. The upper limit of the heating temperature is lower than the thermal decomposition temperature of the insulating resin, preferably lower than the thermal temperature by 30°C. The pressure applied during crimping is, for example, within the range of 1 MPa or more and 30 MPa or less, and more preferably within the range of 3 MPa or more and 25 MPa or less. The crimping time varies depending on the heating temperature and pressure, but is generally 60 minutes or more and 180 minutes or less.
　以上のような構成とされた本実施形態の金属ベース基板１０によれば、金属基板２０の板厚ＴＭが０．５ｍｍ以上１．１ｍｍ以下の範囲内にあるので、金属基板２０の熱による形状の変化を抑えることができ、かつ体積変化量を小さくできる。また、板厚ＴＭ（単位：ｍｍ）の３乗値と、金属基板の２５℃における弾性率ＥＭ（単位：ＧＰａ）との積ＴＭ ３×ＥＭが１０以上１０００以下の範囲内にあるので、金属基板２０の熱による変形をより抑えることができる。また、絶縁層３０の１００℃における弾性率ＥＲ（単位：ＧＰａ）に対する膜厚ＴＲ（単位：μｍ）の比ＴＲ／ＥＲが３０以上１０００以下の範囲内にあるので、はんだ５０に付与される応力を低減させることができる。さらに、絶縁層３０の熱伝導度ＣＲ（単位：Ｗ/ｍＫ）に対する膜厚ＴＲ（単位：μｍ）の比ＴＲ／ＣＲの合計が２以上４０以下の範囲内にあるので、電子部品６０にて発生した熱を金属基板２０に効率よく伝えることができる。したがって、本実施形態の金属ベース基板１０は放熱性と信頼性とに優れる。 According to the metal base substrate 10 of the present embodiment configured as described above, the plate thickness TM of the metal substrate 20 is within the range of 0.5 mm or more and 1.1 mm or less. The change in shape can be suppressed, and the amount of change in volume can be reduced. Further, the product TM 3 × EM of the cube value of the plate thickness TM ( unit : mm) and the elastic modulus EM (unit: GPa ) at 25°C of the metal substrate is in the range of 10 or more and 1000 or less. Therefore, deformation of the metal substrate 20 due to heat can be further suppressed. In addition, since the ratio T R /E R of the thickness T R (unit: μm) to the elastic modulus E R (unit: GPa) of the insulating layer 30 at 100° C. is in the range of 30 or more and 1000 or less, The applied stress can be reduced. Furthermore, since the total ratio T R /C R of the film thickness T R (unit: μm) to the thermal conductivity C R ( unit: W/mK) of the insulating layer 30 is within the range of 2 or more and 40 or less, electron Heat generated in the component 60 can be efficiently transferred to the metal substrate 20 . Therefore, the metal base substrate 10 of this embodiment is excellent in heat dissipation and reliability.
　本実施形態の金属ベース基板１０において、金属基板２０が、アルミニウム、銅および鉄からなる群より選ばれる少なくとも１種の金属を含む場合は、金属基板２０の熱伝導性と耐熱性とが高くなるので、金属ベース基板１０の放熱性と信頼性とがより向上する。 In the metal base substrate 10 of the present embodiment, when the metal substrate 20 contains at least one metal selected from the group consisting of aluminum, copper and iron, the thermal conductivity and heat resistance of the metal substrate 20 are increased. Therefore, the heat dissipation and reliability of the metal base substrate 10 are further improved.
　本実施形態の金属ベース基板１０において、絶縁層３０のフィラーの含有率が３０体積％以上８５体積％以下の範囲内にある樹脂組成物である場合は、絶縁層３０の熱伝導性と応力の緩和能力とが高くなるので、金属ベース基板１０の放熱性と信頼性とがさらに向上する。 In the metal base substrate 10 of the present embodiment, when the insulating layer 30 is a resin composition having a filler content in the range of 30% by volume or more and 85% by volume or less, the thermal conductivity of the insulating layer 30 and the stress Since the relaxation capability is increased, the heat dissipation and reliability of the metal base substrate 10 are further improved.
　本実施形態の金属ベース基板１０において、絶縁層３０の膜厚が１００μｍ以下と薄い場合は、電子部品６０にて発生した熱を金属基板２０により効率よく伝えることができる。
　本実施形態の金属ベース基板１０において、回路層４０の膜厚が８０μｍ以下と薄い場合は、回路層４０からはんだ５０に付与される熱応力が低減するので、金属ベース基板１０の信頼性がさらに向上する。 In the metal base substrate 10 of the present embodiment, when the thickness of the insulating layer 30 is as thin as 100 μm or less, the heat generated in the electronic component 60 can be efficiently transferred to the metal substrate 20 .
In the metal base substrate 10 of the present embodiment, when the film thickness of the circuit layer 40 is as thin as 80 μm or less, the thermal stress applied from the circuit layer 40 to the solder 50 is reduced, so the reliability of the metal base substrate 10 is further enhanced. improves.
　以上、本発明の実施形態について説明したが、本発明はこれに限定されることはなく、その発明の技術的思想を逸脱しない範囲で適宜変更可能である。
　例えば、本実施形態においては、絶縁層３０は単層体であるが、絶縁層３０は積層体であってもよい。絶縁層３０が積層体である場合、ＴＲ／ＥＲは絶縁層３０を構成する各層の１００℃における弾性率ＥＲ（単位：ＧＰａ）に対する膜厚ＴＲ（単位：μｍ）の比ＴＲ／ＥＲの合計である。例えば、絶縁層３０が金属基板２０の上に形成された第１絶縁層と第１絶縁層の上に積層された第２絶縁層とを有する２層の積層体である場合、絶縁層３０のＴＲ／ＥＲは、第１絶縁層の１００℃における弾性率ＥＲ１（単位：ＧＰａ）に対する膜厚ＴＲ１（単位：μｍ）の比ＴＲ１／ＥＲ１と、第２絶縁層の１００℃における弾性率ＥＲ２（単位：ＧＰａ）に対する膜厚ＴＲ２（単位：μｍ）の比ＴＲ２／ＥＲ２との合計値である。
　また、絶縁層３０が積層体である場合、ＴＲ／ＣＲは絶縁層３０を構成する各層の熱伝導度ＣＲ（単位：Ｗ/ｍＫ）に対する膜厚ＴＲ（単位：μｍ）の比ＴＲ／ＣＲの合計である。例えば、絶縁層３０が金属基板２０側の第１絶縁層と回路層４０側の第２絶縁層とからなる２層の積層体である場合、絶縁層３０のＴＲ／ＣＲは、第１絶縁層の熱伝導度ＣＲ（単位：Ｗ/ｍＫ）に対する膜厚ＴＲ１（単位：μｍ）の比ＴＲ１／ＣＲ１と、第２絶縁層の熱伝導度ＣＲ（単位：Ｗ/ｍＫ）に対する膜厚ＴＲ２（単位：μｍ）の比ＴＲ２／ＣＲ２との合計値である。 Although the embodiment of the present invention has been described above, the present invention is not limited to this, and can be modified as appropriate without departing from the technical idea of the invention.
For example, although the insulating layer 30 is a single layer in this embodiment, the insulating layer 30 may be a laminate. When the insulating layer 30 is a laminate, TR / ER is the ratio TR of the film thickness TR (unit: μm) to the elastic modulus ER (unit: GPa) at 100° C. of each layer constituting the insulating layer 30 . /E is the sum of R. For example, when the insulating layer 30 is a two-layer laminate having a first insulating layer formed on the metal substrate 20 and a second insulating layer laminated on the first insulating layer, the insulating layer 30 T R /E R is the ratio T R1 /E R1 of the thickness T R1 (unit: μm) to the elastic modulus E R1 (unit: GPa) of the first insulating layer at 100° C. and the ratio T R1 /E R1 of the second insulating layer at 100° C. It is the total value of the ratio T R2 / E R2 of the film thickness T R2 (unit: μm) to the elastic modulus E R2 (unit: GPa).
Further, when the insulating layer 30 is a laminate, TR / CR is the ratio of the film thickness TR (unit: μm) to the thermal conductivity CR (unit: W/mK) of each layer constituting the insulating layer 30. It is the sum of T R /C R. For example, when the insulating layer 30 is a two-layer laminate consisting of a first insulating layer on the metal substrate 20 side and a second insulating layer on the circuit layer 40 side, the T R /C R of the insulating layer 30 is the first The ratio T R1 /C R1 of the film thickness T R1 ( unit: μm) to the thermal conductivity C R (unit: W/mK) of the insulating layer and the thermal conductivity C R ( unit: W/mK) of the second insulating layer ) and the ratio T R2 /C R2 of the film thickness T R2 (unit: μm).
　絶縁層３０が金属基板２０側の上に形成された第１絶縁層と第１絶縁層の上に積層された第２絶縁層とを有する２層の積層体である場合、第１絶縁層および第２絶縁層の一方の層は、フィラーの含有率が５０体積％以上８５体積％以下の範囲内にある樹脂組成物の層（第１樹脂組成物層）であって、他方の層は、フィラーの含有率が０体積％以上１体積％以下の樹脂組成物の層（第２樹脂組成物層）であることが好ましい。この場合、絶縁層３０の熱伝導性と応力の緩和能力とが高くなるので、金属ベース基板１０の放熱性と信頼性とがさらに向上する。第１絶縁層が第１樹脂組成物層であって、第２絶縁層が第２樹脂組成物層であることがより好ましい。
　第１絶縁層の膜厚は１０μｍ以上１００μｍ以下であることが好ましい。第２絶縁層の膜厚は１μｍ以上５μｍ以下であることが好ましい。
　絶縁層３０が積層体である場合、積層体の層数は、２層以上３層以下であることが好ましく、２層であることがより好ましい。 When insulating layer 30 is a two-layer laminate having a first insulating layer formed on the metal substrate 20 side and a second insulating layer laminated on the first insulating layer, the first insulating layer and One layer of the second insulating layer is a layer of a resin composition (first resin composition layer) having a filler content in the range of 50% by volume or more and 85% by volume or less, and the other layer is A layer (second resin composition layer) of a resin composition having a filler content of 0% by volume or more and 1% by volume or less is preferable. In this case, the thermal conductivity and stress relieving ability of the insulating layer 30 are enhanced, so that the heat dissipation and reliability of the metal base substrate 10 are further improved. More preferably, the first insulating layer is the first resin composition layer, and the second insulating layer is the second resin composition layer.
The film thickness of the first insulating layer is preferably 10 μm or more and 100 μm or less. The film thickness of the second insulating layer is preferably 1 μm or more and 5 μm or less.
When the insulating layer 30 is a laminate, the number of layers of the laminate is preferably two to three, more preferably two.
　以下、本発明を実施例により説明する。なお、本実施例において、金属の弾性率は、２５℃における弾性率、樹脂の弾性率は、１００℃における弾性率を意味する。 The present invention will be described below with reference to examples. In this embodiment, the elastic modulus of metal means the elastic modulus at 25°C, and the elastic modulus of resin means the elastic modulus at 100°C.
［本発明例１］
（アルミナ粒子分散ポリイミド溶液の調製）
　ポリイミド樹脂ＡとＮＭＰ（Ｎ－メチル－２－ピロリドン）とを混合し、ポリイミド樹脂を溶解させることによって、ポリイミド樹脂濃度が１０質量％のポリイミド樹脂溶液を調製した。ポリイミド樹脂Ａはアルミナとの混合物の１００℃における弾性率が０．２７ＧＰａとなるものを選んだ。また、アルミナ粉末（平均粒子径：０．３μｍ）とＮＭＰとを混合し、３０分間超音波処理を行なうことによって、α－アルミナ粒子濃度が１０質量％のα－アルミナ粒子分散液を調製した。ポリイミド樹脂溶液とアルミナ粒子分散液とを、アルミナ濃度が６０体積％となる割合で混合した。得られた混合物を、株式会社スギノマシン社製スターバーストを用い、圧力５０ＭＰａの高圧噴射処理を１０回繰り返すことにより分散処理を行なって、アルミナ粒子分散ポリイミド樹脂溶液を調製した。なお、アルミナ濃度は、アルミナ粒子分散ポリイミド樹脂溶液を加熱して乾燥したときに生成する固形物中のアルミナ粒子の含有量である。 [Invention Example 1]
(Preparation of alumina particle-dispersed polyimide solution)
Polyimide resin A and NMP (N-methyl-2-pyrrolidone) were mixed to dissolve the polyimide resin, thereby preparing a polyimide resin solution having a polyimide resin concentration of 10% by mass. As the polyimide resin A, one having an elastic modulus of 0.27 GPa at 100° C. when mixed with alumina was selected. Further, an α-alumina particle dispersion having an α-alumina particle concentration of 10% by mass was prepared by mixing alumina powder (average particle size: 0.3 μm) and NMP and subjecting the mixture to ultrasonic treatment for 30 minutes. A polyimide resin solution and an alumina particle dispersion were mixed at a ratio such that the alumina concentration was 60% by volume. The obtained mixture was subjected to dispersion treatment by repeating high pressure injection treatment at a pressure of 50 MPa 10 times using Star Burst manufactured by Sugino Machine Co., Ltd. to prepare an alumina particle-dispersed polyimide resin solution. Incidentally, the alumina concentration is the content of alumina particles in the solid produced when the alumina particle-dispersed polyimide resin solution is heated and dried.
（金属ベース基板の作製）
　金属基板として、板厚ＴＭが０．７ｍｍで、弾性率ＥＭが７４ＧＰａのアルミニウム基板（縦：３０ｍｍ、横：２０ｍｍ）を用意した。このアルミニウム基板の上に、上記で調製したアルミナ粒子分散ポリイミド樹脂溶液を、バーコート法により塗布して塗布膜を形成した。次いで、塗布膜を形成したアルミニウム基板をホットプレート上に配置して、室温から３℃／分で６０℃まで昇温し、６０℃で１００分間加熱した後、さらに１℃／分で１２０℃まで昇温し、１２０℃で１００分間加熱して、塗布層を乾燥させた。次いで、アルミニウム基板を２５０℃で１分間加熱した後、４００℃で１分間加熱した。こうして、アルミニウム基板の表面に、アルミナ粒子が分散されたポリイミド樹脂からなる膜厚ＴＲが３０μｍの絶縁層を形成して、絶縁層付きアルミニウム基板を得た。 (Preparation of metal base substrate)
As a metal substrate, an aluminum substrate (length: 30 mm, width: 20 mm) having a plate thickness TM of 0.7 mm and an elastic modulus EM of 74 GPa was prepared. On this aluminum substrate, the alumina particle-dispersed polyimide resin solution prepared above was applied by a bar coating method to form a coating film. Next, the aluminum substrate on which the coating film was formed was placed on a hot plate, heated from room temperature to 60°C at a rate of 3°C/min, heated at 60°C for 100 minutes, and further heated to 120°C at a rate of 1°C/min. The temperature was raised and heated at 120° C. for 100 minutes to dry the coating layer. Then, the aluminum substrate was heated at 250° C. for 1 minute and then at 400° C. for 1 minute. Thus, an insulating layer having a film thickness TR of 30 μm and made of a polyimide resin in which alumina particles were dispersed was formed on the surface of the aluminum substrate to obtain an aluminum substrate with an insulating layer.
　得られた絶縁層付きアルミニウム基板の絶縁層の上に、回路層として銅箔（厚み：７０μｍ、弾性率：１１８ＧＰａ）を重ね合わせて積層した。次いで、得られた積層体を、カーボン治具を用いて５ＭＰａの圧力を付与しながら、真空中にて３００℃の圧着温度で１２０分間加熱して、絶縁層と銅箔とを圧着した。こうして、アルミニウム基板と絶縁層と銅箔とがこの順で積層された金属ベース基板を作製した。 A copper foil (thickness: 70 μm, modulus of elasticity: 118 GPa) was laminated as a circuit layer on the insulating layer of the obtained aluminum substrate with an insulating layer. Next, the obtained laminate was heated in a vacuum at a pressure bonding temperature of 300° C. for 120 minutes while applying a pressure of 5 MPa using a carbon jig to bond the insulating layer and the copper foil. Thus, a metal base substrate was produced in which the aluminum substrate, the insulating layer and the copper foil were laminated in this order.
［本発明例２～３］
　金属基板として、板厚ＴＭが下記の表１に記載の板厚であるアルミニウム基板を用いたこと以外は、本発明例１と同様にして金属ベース基板を作製した。 [Invention Examples 2 and 3]
A metal base substrate was produced in the same manner as in Inventive Example 1, except that an aluminum substrate having a thickness TM shown in Table 1 below was used as the metal substrate.
［本発明例４～５］
　絶縁層の膜厚ＴＲを下記の表１に記載の膜厚としたこと以外は、本発明例３と同様にして金属ベース基板を作製した。 [Invention Examples 4-5]
A metal base substrate was produced in the same manner as in Invention Example 3, except that the film thickness TR of the insulating layer was set to the film thickness shown in Table 1 below.
［本発明例６］
　アルミナ粒子分散ポリイミド溶液の調製において、ポリイミド樹脂Ａをポリイミド樹脂Ｂに変えたこと以外は、本発明例３と同様にして金属ベース基板を作製した。ポリイミド樹脂Ｂはアルミナとの混合物の１００℃における弾性率が０．３２ＧＰａとなるものを選んだ。 [Invention Example 6]
A metal base substrate was produced in the same manner as in Invention Example 3, except that the polyimide resin A was changed to the polyimide resin B in the preparation of the alumina particle-dispersed polyimide solution. As the polyimide resin B, one having an elastic modulus of 0.32 GPa at 100° C. when mixed with alumina was selected.
［本発明例７］
　アルミナ粒子分散ポリイミド溶液の調製において、ポリイミド樹脂Ａをポリイミド樹脂Ｃに変えたこと以外は、本発明例３と同様にして金属ベース基板を作製した。ポリイミド樹脂Ｃはアルミナとの混合物の１００℃における弾性率が１．０１ＧＰａとなるものを選んだ。 [Invention Example 7]
A metal base substrate was produced in the same manner as in Inventive Example 3, except that the polyimide resin A was changed to the polyimide resin C in the preparation of the alumina particle-dispersed polyimide solution. As the polyimide resin C, one having an elastic modulus of 1.01 GPa at 100° C. when mixed with alumina was selected.
［本発明例８～１０］
　金属基板として、板厚ＴＭが下記の表１に記載の板厚で、弾性率ＥＭが下記の表１に記載の弾性率である銅基板を用いたこと以外は、本発明例１と同様にして金属ベース基板を作製した。 [Invention Examples 8 to 10]
Inventive Example 1 and Example 1 were used, except that a copper substrate having a plate thickness TM as shown in Table 1 below and an elastic modulus EM as an elastic modulus shown in Table 1 below was used as the metal substrate. A metal base substrate was produced in the same manner.
［本発明例１１］
　金属基板として、板厚ＴＭが下記の表１に記載の板厚で、弾性率ＥＭが下記の表１に記載の弾性率である炭素鋼を用いたこと以外は、本発明例１と同様にして金属ベース基板を作製した。 [Invention Example 11]
Inventive Example 1 and Example 1 were used, except that, as the metal substrate, carbon steel having a plate thickness TM shown in Table 1 below and an elastic modulus EM shown in Table 1 below was used. A metal base substrate was produced in the same manner.
［比較例１～８］
　金属基板として、材質、板厚ＴＭ、弾性率ＥＭが下記の表１に記載のものを用い、絶縁層の膜厚ＴＲを下記の表１に記載の膜厚としたこと以外は、本発明例１と同様にして金属ベース基板を作製した。 [Comparative Examples 1 to 8]
As the metal substrate, the material, plate thickness T M , and elastic modulus E M shown in Table 1 below were used, and the film thickness T R of the insulating layer was set to the film thickness shown in Table 1 below. A metal base substrate was produced in the same manner as in Example 1 of the present invention.
［評価］
（金属基板のＴＭ ３×ＥＭ）
　金属基板の板厚ＴＭ（単位：ｍｍ）の３乗値と、金属基板の弾性率ＥＭ（単位：ＧＰａ）との積ＴＭ ３×ＥＭを算出した。その結果を、下記の表１に示す。 [evaluation]
( TM 3 × EM of metal substrate)
The product TM 3 × EM of the cube of the plate thickness TM (unit: mm) of the metal substrate and the elastic modulus EM (unit: GPa) of the metal substrate was calculated. The results are shown in Table 1 below.
（絶縁層のＴＲ／ＥＲ及びＴＲ／ＣＲ）
　絶縁層の弾性率ＥＲを上述の方法により測定し、弾性率ＥＲ（単位：ＧＰａ）に対する膜厚ＴＲ（単位：μｍ）の比ＴＲ／ＥＲを算出した。絶縁層の熱伝導度ＣＲを上述の方法により測定し、熱伝導度ＣＲ（単位：Ｗ/ｍＫ）に対する膜厚ＴＲ（単位：μｍ）の比ＴＲ／ＣＲを算出した。その結果を、下記の表１に示す。 (T R /E R and T R /C R of insulating layer)
The elastic modulus ER of the insulating layer was measured by the method described above, and the ratio TR / ER of the film thickness TR (unit: μm) to the elastic modulus ER (unit: GPa) was calculated. The thermal conductivity CR of the insulating layer was measured by the method described above, and the ratio TR / CR of the film thickness TR (unit: μm) to the thermal conductivity CR (unit: W/mK) was calculated. The results are shown in Table 1 below.
（熱抵抗）
　銅箔を張り付けた金属ベース基板の銅箔上に、放熱シート（ＢＦＧ－３０Ａ：デンカ株式会社製）を介して発熱体（ＴＯ－３Ｐ）を載置した。発熱体を載置した金属ベース基板を、発熱体の上部からトルク４０Ｎｃｍのねじによって積層方向に加圧した。そして、Ｔ３Ｓｔｅｒ（シーメンス社製）を用いて、発熱体から銅基板までの熱抵抗を測定した。発熱体の発熱条件は１０Ａ、３０秒とし、熱抵抗の測定条件は、０．０１Ａ、測定時間６０秒とした。同様の測定を、絶縁膜を形成していない銅基板単体に対して行い、その熱抵抗を金属ベース基板の測定値から減じた値を、熱抵抗（Ｋ／Ｗ）とした。 (Thermal resistance)
A heating element (TO-3P) was placed on the copper foil of the metal base substrate to which the copper foil was adhered via a heat dissipation sheet (BFG-30A: manufactured by Denka Co., Ltd.). The metal base substrate on which the heating element was placed was pressed in the stacking direction from above the heating element with a screw having a torque of 40 Ncm. Then, using T3Ster (manufactured by Siemens), the thermal resistance from the heating element to the copper substrate was measured. The heat generation conditions of the heating element were 10 A and 30 seconds, and the thermal resistance measurement conditions were 0.01 A and measurement time of 60 seconds. A similar measurement was performed on a single copper substrate on which no insulating film was formed, and the thermal resistance (K/W) was obtained by subtracting the thermal resistance from the measured value of the metal base substrate.
（耐クラック率）
　金属ベース基板を縦５０ｍｍ×横５０ｍｍのサイズに切断した。切断した金属ベース基板の銅箔上に、Ｓｎ－Ａｇ－Ｃｕはんだを塗布して、縦２５ｍｍ×横２５ｍｍ×厚み１００μｍのはんだ層を形成し、そのはんだ層の上に、２５ｍｍ角のＳｉチップを搭載して、試験体を作製した。作製した試験体に、１サイクルが－３０℃×３０分間～１０５℃×３０分間の冷熱サイクルを３０００サイクル付与した。冷熱サイクル付与後の試験体を、樹脂埋めし、断面を研磨によって出した試料を用いて観察し、はんだ層に生じたクラックの長さ（ｍｍ）を測定した。はんだ層の一辺の長さと、測定したクラックの長さとから下記式より算出した値を、耐クラック率とした。耐クラック率が高いことは、クラックが発生しにくいこと、すなわち信頼性が高いことを意味する。
　耐クラック率（％）＝｛（はんだ層の一辺の長さ（２５ｍｍ）－２×クラックの長さ）／接合層の一辺の長さ（２５ｍｍ）｝×１００ (Crack resistance rate)
A metal base substrate was cut into a size of 50 mm long×50 mm wide. Sn--Ag--Cu solder is applied to the copper foil of the cut metal base substrate to form a solder layer of 25 mm long x 25 mm wide x 100 μm thick, and a 25 mm square Si chip is placed on the solder layer. It was mounted and a test body was produced. The prepared specimen was subjected to 3000 cycles of cooling/heating cycles of -30°C for 30 minutes to 105°C for 30 minutes. After applying thermal cycles, the specimen was embedded in resin, and the cross section was observed using a polished specimen to measure the length (mm) of cracks occurring in the solder layer. A value calculated from the following formula based on the length of one side of the solder layer and the measured crack length was taken as the crack resistance rate. A high crack resistance rate means that cracks are less likely to occur, that is, high reliability.
Crack resistance rate (%) = {(solder layer side length (25 mm) - 2 x crack length)/bonding layer side length (25 mm)} x 100
（反り）
　耐クラック率の測定後のサンプルの反りを隙間ゲージによって測定した。サンプルを平板上に配置して、平板とサンプルの端部の隙間を反りとして計測した。最も大きな反りが５０μｍ以下であったものをＡとし、反りが５０μｍより大きく７０μｍ以下であったものをＢとし、反りが７０μｍより大きいものをＣとした。 (warp)
After measuring the crack resistance rate, the warpage of the sample was measured with a feeler gauge. The sample was placed on a flat plate, and the gap between the flat plate and the edge of the sample was measured as warpage. A was assigned to the case where the largest warp was 50 μm or less, B was assigned to the case where the warp was greater than 50 μm and 70 μm or less, and C was assigned to the case where the warp was greater than 70 μm.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１の結果から、ＴＭ、ＴＭ ３×ＥＭ、ＴＲ／ＥＲ及びＴＲ／ＣＲの全てが本発明の範囲内にある本発明例１～１１で得られた金属ベース基板は、熱抵抗、耐クラック率、反りのいずれも優れていた。特に、ＴＭ ３×ＥＭが３０以上の本発明例２～７、９～１１で得られた金属ベース基板は、反りがより向上した。また、ＴＲ／ＥＲが１００以上の本発明例１～５、８～１１で得られた金属ベース基板は、耐クラック率がより向上した。また、ＴＲ／ＣＲが３０以下の本発明例１～４、６～１１で得られた金属ベース基板は、熱抵抗がより低くなった。 From the results in Table 1, the metal base substrates obtained in Examples 1 to 11 of the present invention in which T M , T M 3 ×E M , T R /E R and T R /C R are all within the scope of the present invention. was excellent in heat resistance, crack resistance and warpage. In particular, the metal base substrates obtained in Examples 2 to 7 and 9 to 11 of the present invention having T M 3 ×E M of 30 or more exhibited improved warpage. In addition, the metal base substrates obtained in Examples 1 to 5 and 8 to 11 of the present invention having a T R /E R of 100 or more had improved crack resistance. In addition, the metal base substrates obtained in Examples 1 to 4 and 6 to 11 of the present invention having a T R /C R of 30 or less had a lower thermal resistance.
　これに対して、ＴＭ ３×ＴＭが本発明の範囲よりも低い比較例１で得られた金属ベース基板およびＴＭが本発明の範囲よりも薄く、ＴＭ ３×ＥＭが本発明の範囲よりも低い比較例８で得られた金属ベース基板は、反りが大きくなった。また、ＴＭが本発明の範囲よりも大きい比較例２～６で得られた金属ベース基板は、耐クラック率が低下した。また、ＴＲ／ＣＲが本発明の範囲よりも大きい比較例５～７で得られた金属ベース基板は、熱抵抗が大きくなった。 In contrast, the metal base substrate obtained in Comparative Example 1, in which TM 3 × TM is lower than the range of the present invention and TM is thinner than the range of the present invention, and TM 3 × EM is the thickness of the present invention. The metal base substrate obtained in Comparative Example 8, which is lower than the range of , had large warpage. Moreover, the crack resistance rate of the metal base substrates obtained in Comparative Examples 2 to 6, in which the TM was larger than the range of the present invention, was lowered. In addition, the metal base substrates obtained in Comparative Examples 5 to 7, in which T R /C R was larger than the range of the present invention, had large thermal resistance.
［本発明例１２］
（アルミナ粒子分散ポリイミド溶液の調製）
　ポリイミド樹脂Ａをポリイミド樹脂Ｄに変えたこと以外は、本発明例１と同様にしてアルミナ粒子分散ポリイミド溶液を調製した。なお、ポリイミド樹脂Ｄはアルミナとの混合物の１００℃における弾性率が２．１５ＧＰａとなるものを選んだ。 [Invention Example 12]
(Preparation of alumina particle-dispersed polyimide solution)
An alumina particle-dispersed polyimide solution was prepared in the same manner as in Invention Example 1, except that polyimide resin A was changed to polyimide resin D. As the polyimide resin D, a mixture with alumina having an elastic modulus of 2.15 GPa at 100° C. was selected.
（ポリイミド樹脂溶液の調製）
　１００℃における弾性率が０．０１ＧＰａのポリイミド樹脂とＮＭＰとを混合し、ポリイミド樹脂を溶解させて、ポリイミド樹脂濃度が１０質量％のポリイミド樹脂溶液を調製した。 (Preparation of polyimide resin solution)
A polyimide resin having a modulus of elasticity at 100° C. of 0.01 GPa was mixed with NMP, and the polyimide resin was dissolved to prepare a polyimide resin solution having a polyimide resin concentration of 10% by mass.
（金属ベース基板の作製）
　金属基板として、板厚ＴＭが１．０ｍｍで、弾性率ＥＭが７４ＧＰａのアルミニウム基板（縦：３０ｍｍ、横：２０ｍｍ）を用意した。このアルミニウム基板の上に、上記で調製したアルミナ粒子分散ポリイミド樹脂溶液を、バーコート法により塗布して塗布膜を形成した。次いで、塗布膜を形成したアルミニウム基板をホットプレート上に配置して、室温から３℃／分で６０℃まで昇温し、６０℃で１００分間加熱した後、さらに１℃／分で１２０℃まで昇温し、１２０℃で１００分間加熱して、塗布層を乾燥させた。次いで、アルミニウム基板を２５０℃で１分間加熱した後、４００℃で１分間加熱した。こうして、アルミニウム基板の表面に、アルミナ粒子が分散されたポリイミド樹脂からなる膜厚ＴＲ１が１０μｍの第１絶縁層を形成して、第１絶縁層付きアルミニウム基板を得た。 (Preparation of metal base substrate)
As a metal substrate, an aluminum substrate (length: 30 mm, width: 20 mm) having a plate thickness TM of 1.0 mm and an elastic modulus EM of 74 GPa was prepared. On this aluminum substrate, the alumina particle-dispersed polyimide resin solution prepared above was applied by a bar coating method to form a coating film. Next, the aluminum substrate on which the coating film was formed was placed on a hot plate, heated from room temperature to 60°C at a rate of 3°C/min, heated at 60°C for 100 minutes, and further heated to 120°C at a rate of 1°C/min. The temperature was raised and heated at 120° C. for 100 minutes to dry the coating layer. Then, the aluminum substrate was heated at 250° C. for 1 minute and then at 400° C. for 1 minute. In this way, a first insulating layer made of polyimide resin in which alumina particles were dispersed and having a film thickness TR1 of 10 μm was formed on the surface of the aluminum substrate to obtain an aluminum substrate with a first insulating layer.
　次いで、第１絶縁層付きアルミニウム基板の第１絶縁層の上に、上記で調製したポリイミド樹脂溶液を、バーコート法により塗布して塗布膜を形成した。形成した塗布膜を、３００℃で加熱乾燥して、ポリイミド樹脂からなる膜厚ＴＲ２が１．０μｍの第２絶縁層を形成した。こうして第１絶縁層と第２絶縁層とからなる絶縁層付きアルミニウム基板を得た。 Next, on the first insulating layer of the aluminum substrate with the first insulating layer, the polyimide resin solution prepared above was applied by a bar coating method to form a coating film. The formed coating film was dried by heating at 300° C. to form a second insulating layer made of polyimide resin and having a film thickness TR2 of 1.0 μm. In this way, an aluminum substrate with an insulating layer composed of the first insulating layer and the second insulating layer was obtained.
　得られた絶縁層付きアルミニウム基板の絶縁層の上に、本発明例１と同様に回路層として銅箔を圧着した。こうして、アルミニウム基板と絶縁層と銅箔とがこの順で積層された金属ベース基板を作製した。 On the insulating layer of the obtained aluminum substrate with an insulating layer, a copper foil was crimped as a circuit layer in the same manner as in Example 1 of the present invention. Thus, a metal base substrate was produced in which the aluminum substrate, the insulating layer and the copper foil were laminated in this order.
［比較例９］
　第１絶縁層の膜厚ＴＲ１を３０μｍとし、第２絶縁層を形成しなかったこと以外は、本発明例１２と同様にして金属ベース基板を作製した。 [Comparative Example 9]
A metal base substrate was fabricated in the same manner as in Inventive Example 12, except that the film thickness TR1 of the first insulating layer was set to 30 μm and the second insulating layer was not formed.
［評価］
　金属基板のＴＭ ３×ＥＭ、絶縁層のＴＲ／ＥＲ（＝ＴＲ１／ＥＲ１＋ＴＲ２／ＥＲ２）及びＴＲ／ＣＲ（＝ＴＲ１／ＣＲ１＋ＴＲ２／ＣＲ２）を上記の方法により算出した。また熱抵抗、耐クラック率、反りを上記の方法により測定した。その結果を下記の表２に示す。 [evaluation]
TM3 × EM of the metal substrate, TR / ER (= TR1 / ER1 + TR2 / ER2 ) and TR/ CR (= TR1 / CR1 + TR2 / CR2 ) of the insulating layer was calculated by the method described above. Also, thermal resistance, crack resistance and warpage were measured by the above methods. The results are shown in Table 2 below.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表１の結果から、ＴＭ、ＴＭ ３×ＥＭ、ＴＲ／ＥＲ及びＴＲ／ＣＲの全てが本発明の範囲内にある本発明例１２で得られた金属ベース基板は、熱抵抗、耐クラック率、反りのいずれも優れていた。これに対して、ＴＲ／ＥＲが本発明の範囲よりも低い比較例９で得られた金属ベース基板は、耐クラック率が低下した。また、本発明例１２と比較例９の結果から、絶縁層を第１絶縁層と第２絶縁層とを組み合わせた積層体とすることによって、単層体の場合と比較して膜厚を薄くしても、熱抵抗、耐クラック率および反りに優れる金属ベース基板を得ることが可能となることがわかる。 From the results in Table 1, it can be seen that the metal base substrate obtained in Example 12 of the present invention, in which all of T M , T M 3 ×E M , T R /E R and T R /C R are within the scope of the present invention, All of the heat resistance, crack resistance rate, and warpage were excellent. In contrast, the metal base substrate obtained in Comparative Example 9, in which TR / ER was lower than the range of the present invention, had a decreased crack resistance rate. In addition, from the results of Inventive Example 12 and Comparative Example 9, it was found that by forming the insulating layer into a laminate in which the first insulating layer and the second insulating layer are combined, the film thickness can be reduced as compared with the case of a single layer. However, it is possible to obtain a metal base substrate excellent in thermal resistance, crack resistance and warpage.
　本発明の金属ベース基板は、放熱性と信頼性とに優れる。このため、半導体素子やＬＥＤなどの電子部品を実装するための基板として好適である。 The metal base substrate of the present invention is excellent in heat dissipation and reliability. Therefore, it is suitable as a substrate for mounting electronic components such as semiconductor elements and LEDs.
　１０　金属ベース基板
　２０　金属基板
　３０　絶縁層
　３１　絶縁樹脂
　３２　無機物フィラー
　４０　回路層
　５０　はんだ
　６０　電子部品
　６１　電極端子 REFERENCE SIGNS LIST 10 metal base substrate 20 metal substrate 30 insulating layer 31 insulating resin 32 inorganic filler 40 circuit layer 50 solder 60 electronic component 61 electrode terminal

Claims (7)

  1. 　金属基板と、少なくとも１層の絶縁層と、回路層とがこの順で積層された金属ベース基板であって、
    　前記金属基板の板厚ＴＭが０．５ｍｍ以上１．１ｍｍ以下の範囲内にあり、
    　前記金属基板の板厚ＴＭ（単位：ｍｍ）の３乗値と、前記金属基板の２５℃における弾性率ＥＭ（単位：ＧＰａ）との積ＴＭ ３×ＥＭが１０以上１０００以下の範囲内にあって、
    　前記絶縁層を構成する各層の１００℃における弾性率ＥＲ（単位：ＧＰａ）に対する膜厚ＴＲ（単位：μｍ）の比ＴＲ／ＥＲの合計が３０以上１０００以下の範囲内にあり、
    　前記絶縁層を構成する各層の熱伝導度ＣＲ（単位：Ｗ/ｍＫ）に対する膜厚ＴＲ（単位：μｍ）の比ＴＲ／ＣＲの合計が２以上４０以下の範囲内にあることを特徴とする金属ベース基板。     A metal base substrate in which a metal substrate, at least one insulating layer, and a circuit layer are laminated in this order,
    The plate thickness TM of the metal substrate is in the range of 0.5 mm or more and 1.1 mm or less,
    The product TM 3 × EM of the cube value of the plate thickness TM (unit: mm) of the metal substrate and the elastic modulus EM (unit: GPa) at 25° C of the metal substrate is 10 or more and 1000 or less. within the range of
    The sum of the ratios T R /E R of the film thickness T R (unit: μm) to the elastic modulus E R (unit: GPa) at 100° C. of each layer constituting the insulating layer is in the range of 30 or more and 1000 or less,
    The sum of the ratios T R /C R of the film thickness T R (unit: μm) to the thermal conductivity C R (unit: W/mK) of each layer constituting the insulating layer is in the range of 2 or more and 40 or less. A metal base substrate characterized by:
  2. 　前記金属基板が、アルミニウム、銅、鉄からなる群より選ばれる少なくとも１種の金属を含む請求項１に記載の金属ベース基板。 The metal base substrate according to claim 1, wherein the metal substrate contains at least one metal selected from the group consisting of aluminum, copper and iron.
  3. 　前記絶縁層が単層体または積層体である請求項１または２に記載の金属ベース基板。 The metal base substrate according to claim 1 or 2, wherein the insulating layer is a single layer or laminate.
  4. 　前記絶縁層が前記単層体であって、前記単層体は、フィラーの含有率が３０体積％以上８５体積％以下の範囲内にある樹脂組成物である請求項３に記載の金属ベース基板。 4. The metal base substrate according to claim 3, wherein the insulating layer is the single layer body, and the single layer body is a resin composition having a filler content of 30% by volume or more and 85% by volume or less. .
  5. 　前記絶縁層が金属層の上に形成された第１絶縁層と前記第１絶縁層の上に積層された第２絶縁層とを有する前記積層体であって、前記第１絶縁層および前記第２絶縁層の一方の層は、フィラーの含有率が５０体積％以上８５体積％以下の範囲内にある樹脂組成物の層であって、他方の層は、樹脂もしくはフィラーの含有率が１体積％以下の樹脂組成物の層である請求項３に記載の金属ベース基板。 The laminated body, wherein the insulating layer has a first insulating layer formed on a metal layer and a second insulating layer laminated on the first insulating layer, wherein the first insulating layer and the second insulating layer One of the two insulating layers is a layer of a resin composition having a filler content in the range of 50% by volume or more and 85% by volume or less, and the other layer has a resin or filler content of 1 volume. % or less of the resin composition.
  6. 　前記絶縁層の膜厚が１００μｍ以下である請求項１～５のいずれか１項に記載の金属ベース基板。 The metal base substrate according to any one of claims 1 to 5, wherein the insulating layer has a thickness of 100 µm or less.
  7. 　前記回路層の膜厚が８０μｍ以下である請求項１～６のいずれか１項に記載の金属ベース基板。 The metal base substrate according to any one of claims 1 to 6, wherein the film thickness of the circuit layer is 80 µm or less.
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01238930A (en) * 1988-03-22 1989-09-25 Hitachi Chem Co Ltd Metal plate base copper-laminated plate
WO2019151122A1 (en) * 2018-01-30 2019-08-08 三菱マテリアル株式会社 Metal base substrate
JP2019169619A (en) * 2018-03-23 2019-10-03 三菱マテリアル株式会社 Metal base substrate and module
JP2020013874A (en) * 2018-07-18 2020-01-23 三菱マテリアル株式会社 Metal base substrate
WO2020137339A1 (en) * 2018-12-26 2020-07-02 住友ベークライト株式会社 Resin composition and metal base copper-clad laminate

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01238930A (en) * 1988-03-22 1989-09-25 Hitachi Chem Co Ltd Metal plate base copper-laminated plate
WO2019151122A1 (en) * 2018-01-30 2019-08-08 三菱マテリアル株式会社 Metal base substrate
JP2019169619A (en) * 2018-03-23 2019-10-03 三菱マテリアル株式会社 Metal base substrate and module
JP2020013874A (en) * 2018-07-18 2020-01-23 三菱マテリアル株式会社 Metal base substrate
WO2020137339A1 (en) * 2018-12-26 2020-07-02 住友ベークライト株式会社 Resin composition and metal base copper-clad laminate

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