JP2011023475A - Insulating substrate, insulating circuit board, semiconductor device, method of manufacturing the insulating substrate, and method of manufacturing the insulating circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insulating substrate excellent in heat dissipation characteristics and capable of preventing thermal stress from working to a semiconductor element while a temperature cycle is loaded, an insulating circuit board and a semiconductor device using the insulating substrate, as well as a method for manufacturing the insulating substrate and a method for manufacturing the insulating circuit board. <P>SOLUTION: The insulating substrate 10 includes a substrate body 11 made of a metallic base composite material and an insulative film 15 formed on one of surfaces of the substrate body 11. A thermal expansion coefficient of the substrate body 11 from a room temperature to 200°C is set to be 10×10<SP>-6</SP>/°C or lower, heat conductivity is set to be 190 W/(m×K) or higher, and transverse strength is set to be 30 MPa or higher. The insulative film 15 is formed by colliding powder of an insulative material against one of surfaces of the substrate body 11. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an insulating substrate on which a semiconductor element is mounted, an insulating circuit substrate having a circuit layer formed on the insulating substrate, a semiconductor device using the insulating substrate, a method of manufacturing the insulating substrate, and manufacturing of the insulating circuit substrate It is about the method.

As the above-mentioned insulating substrate, a ceramic base plate such as AlN, Al ₂ O ₃ , Si ₃ N _4, or a metal base substrate in which an insulating coating is formed on the surface of a metal plate or the like is used.

For example, Patent Document 1 discloses a power element (semiconductor element) on an insulating circuit substrate in which a circuit layer made of Al or Cu is provided on one surface of a ceramic plate such as AlN, Al ₂ O ₃ , or Si ₃ N _4. A power module (semiconductor device) mounted with is disclosed.
In Patent Document 2, a semiconductor element is mounted on an insulating substrate made of ceramics, a cooler is disposed on the lower surface side of the insulating circuit board, and an insulating substrate made of ceramics is also formed on the upper part of the semiconductor element. A semiconductor device having a double-sided cooling structure, in which a cooler is disposed via, has been proposed.

In Patent Document 3, an insulating substrate (metal base substrate) in which an insulating layer made of an epoxy resin, a polyimide resin or the like is formed on a metal plate made of Al, Fe, Cu or the like is used, and a copper foil is formed on the insulating layer. There is disclosed a semiconductor device in which a circuit is formed by disposing a semiconductor element on the circuit.
In Patent Document 4, an insulating substrate (metal base substrate) in which an insulating layer made of, for example, a glass epoxy sheet is formed on a metal plate made of Al, Cu or the like is used, and a wiring board (circuit) is formed on the insulating layer. An LED package (semiconductor device) in which an LED chip (semiconductor element) is mounted on the wiring board has been proposed.

Here, as disclosed in Patent Documents 1 and 2, in a semiconductor device using an insulating substrate made of ceramics, the thermal expansion coefficient of the insulating substrate approximates the thermal expansion coefficient of a semiconductor element made of Si or the like. Therefore, it is possible to suppress the thermal stress from acting on the semiconductor element itself at the time of the cooling / heating cycle load.
In addition, as disclosed in Patent Documents 3 and 4, in an insulating substrate in which an insulating layer such as a resin is formed on a metal plate, the heat conductivity of the metal plate is high, and thus the heat dissipation characteristics are excellent.

JP 2004-288828 A JP 2005-123233 A JP 2005-142356 A JP 2006-339224 A

Incidentally, the insulating substrates made of ceramics disclosed in Patent Documents 1 and 2 have a problem that heat conductivity is poor and heat generated from the semiconductor element cannot be efficiently dissipated. Further, since ceramics is a brittle material, there is a risk of cracking and breakage when bending stress is applied.
On the other hand, as disclosed in Patent Documents 3 and 4, in an insulating substrate in which an insulating layer such as a resin is formed on the surface of a metal plate, the thermal expansion coefficient is dominated by the metal plate. The thermal expansion coefficient is significantly different from that of the configured semiconductor element, and there is a possibility that the semiconductor element itself may be damaged due to a large thermal stress during a cooling cycle load.
That is, there is a problem with heat dissipation in an insulating substrate made of ceramics, and thermal stress is a problem with an insulating substrate in which an insulating layer is formed on a metal plate. For this reason, conventionally, depending on the application of the semiconductor device, the above-described insulating substrate has been selected and used at the expense of any of these heat radiation characteristics and thermal stress.

  The present invention has been made in view of the above-described circumstances, and is an insulating substrate that is excellent in heat dissipation characteristics and that can suppress thermal stress from acting on a semiconductor element during a cold cycle load. An object of the present invention is to provide an insulating circuit board and a semiconductor device using the substrate, a method for manufacturing the insulating substrate, and a method for manufacturing the insulating circuit board.

In order to solve such problems and achieve the above object, an insulating substrate of the present invention includes a substrate body made of a metal matrix composite material, and an insulating film formed on one surface of the substrate body. An insulating substrate provided with a thermal expansion coefficient of 10 × 10 ⁻⁶ / ° C. or less from room temperature to 200 ° C. of the substrate body and a thermal conductivity of 190 W / (m · K) or more (surface of the metal matrix composite material) When there is anisotropy in the thermal conductivity with respect to the direction parallel to or perpendicular to the direction, the higher thermal conductivity is set to 190 W / (m · K) or higher, and the bending strength is set to 30 MPa or higher. The insulating coating is formed by causing a powder made of an insulating material to collide with one surface of the substrate body.

According to the insulating substrate having this configuration, since the thermal expansion coefficient of the substrate body is set to 10 × 10 ⁻⁶ / ° C. or less, the thermal expansion coefficient approximates that of a semiconductor element, and the semiconductor is subjected to a thermal cycle load. It can suppress that a thermal stress acts on an element. Moreover, since the thermal conductivity of the substrate body is set to 190 W / (m · K) or more, the heat generated from the semiconductor element can be efficiently dissipated. Furthermore, since the bending strength of the substrate body is set to 30 MPa or more, the rigidity as the insulating substrate is ensured, and the semiconductor device can be configured.

  In addition, since the insulating film is formed by colliding powder made of an insulating material, the insulating film has a dense structure and a high withstand voltage can be obtained. The insulating coating can be formed by, for example, a plasma spraying method in which a powder made of an insulating material collides with a high temperature, or an aerosol deposition method in which a powder made of an insulating material is made to collide with a gas at room temperature. is there.

Here, the insulating coating is preferably formed by an aerosol deposition method.
In the aerosol deposition method, a fine powder of submicron order is collided at high speed to form an insulating film. In this aerosol deposition method, the impacted powder is crushed and stacked, and the powders are firmly bonded together by the active surface formed by crushing, so the insulating coating has a very dense structure and the insulating coating is thinly formed. Even if it does, a high withstand voltage can be obtained.

Moreover, it is preferable that a metal skin layer is formed on one surface of the substrate body made of the metal matrix composite material, and the insulating coating is formed on the metal skin layer.
In this case, since one surface of the substrate body becomes a uniform surface by the metal skin layer, it is possible to form the insulating coating satisfactorily. That is, in the substrate body made of a metal matrix composite material, since the metal and a material other than the metal are exposed on the surface, when the insulating film is formed by colliding powder under the same conditions, the metal portion and Since there is a possibility that the formation state of the insulating film may be different between parts other than the metal, it is possible to form a more uniform insulating film by forming a metal skin layer and causing the powder to collide with the metal skin layer. It becomes.

The insulating substrate may have a metal skin layer formed on the other surface of the substrate body made of the metal matrix composite material.
In this case, for example, when a cooler made of Al, Cu, or the like is disposed on the other surface side of the insulating substrate, the insulating substrate and the cooler can be easily and reliably joined.

The insulated circuit board of the present invention has the above-described insulated substrate, and a circuit layer made of a conductive material is formed on the insulating film of the insulated substrate.
In the insulated circuit board having this configuration, by mounting the semiconductor element on the circuit layer, the semiconductor element can be electrically connected, and a high-quality semiconductor device can be configured. Moreover, since the board | substrate body and circuit layer which consist of metal matrix composite materials are insulated by the insulating film, it can prevent that a board | substrate body side and a semiconductor element short-circuit.

Here, it is preferable that the circuit layer is formed by causing metal powder to collide with the insulating coating.
In this case, since the circuit layer is formed by causing metal powder to collide with the insulating film, a dense circuit layer is formed, and the circuit layer is favorably formed on the insulating film. Can do. In addition, as a method of forming a circuit layer by colliding metal powder on an insulating coating, for example, it is formed by a plasma spraying method in which metal powder collides at high temperature or an aerosol deposition method in which metal powder collides with gas at normal temperature. Is possible.

Any one of Al, Ni, Cu, and Ag can be used for the circuit layer.
Here, since Al, Cu, and Ag are excellent in electrical conductivity, and Cu, Ni, and Ag are excellent in bondability with a solder material, the semiconductor element is favorably bonded using the solder material. be able to. Thus, it is preferable to select a material constituting the circuit layer according to the use of the semiconductor device. Or it is good also as a laminated film which used Al as the foundation layer and Ag as the upper layer, or two or more laminated films which used at least one of Al or Ag as the foundation layer, and Cu or Ni as the upper layer.

Here, it is preferable that a cooler is disposed on the other surface side of the insulating substrate.
In this case, the insulated circuit board can be cooled by a cooler disposed on the other surface side of the insulated substrate. Therefore, it is possible to efficiently dissipate heat generated from the semiconductor element mounted on the insulating circuit board.

A semiconductor device of the present invention has the above-described insulating substrate, and a semiconductor element is mounted on the insulating substrate.
According to the semiconductor device having this configuration, since the heat dissipation characteristic is excellent and the insulating substrate whose thermal expansion coefficient approximates that of the semiconductor element is used, the heat generated from the semiconductor element can be efficiently dissipated and the semiconductor element Can be prevented from being damaged. That is, a high-quality semiconductor device is provided.

A method for manufacturing an insulating substrate according to the present invention is a method for manufacturing an insulating substrate comprising a substrate body made of a metal matrix composite material and an insulating film formed on one surface of the substrate body. One surface of the substrate body having a thermal expansion coefficient up to 10 ° C. of 10 × 10 ⁻⁶ / ° C. or less, a thermal conductivity of 190 W / (m · K) or more, and a bending strength of 30 MPa or more is insulated. It is characterized by having an insulating coating forming step of forming an insulating coating by colliding powder made of material.

  According to the method for manufacturing an insulating substrate having this configuration, it is possible to manufacture an insulating substrate that has good heat conduction and a low thermal expansion coefficient and that approximates Si constituting a semiconductor element. Furthermore, since the insulating film forming step is configured to collide with a powder made of an insulating material, it is possible to form a dense insulating film and obtain a high withstand voltage.

In the insulating coating forming step, the insulating coating is preferably formed by an aerosol deposition method.
In this case, the insulating film has a very dense structure, and a high withstand voltage can be obtained even if the insulating film is formed thin. Moreover, it becomes possible to form an insulating film under normal temperature conditions, and the manufacturing cost of this insulating substrate can be reduced.

It is preferable to provide a metal skin layer forming step of forming a metal skin layer by causing metal powder to collide with at least one of the one surface and the other surface of the substrate body.
In this case, a metal skin layer made of any metal can be formed on the surface of the substrate body made of the metal matrix composite material. That is, a metal skin layer made of a metal other than the metal contained in the metal matrix composite material can be formed.

  An insulating circuit board manufacturing method of the present invention includes a substrate body made of a metal matrix composite material, an insulating substrate having an insulating coating formed on one surface of the substrate body, and a circuit layer formed on the insulating substrate. A method for manufacturing an insulating circuit board comprising: a circuit layer forming step of forming a circuit layer made of a conductive material on the insulating film of the insulating substrate described above.

  According to the method for manufacturing an insulated circuit board having this configuration, since the circuit layer is formed on the insulating film, the substrate body and the circuit layer made of the metal matrix composite material are insulated by the insulating film, and the substrate body and the circuit layer are formed. Are prevented from being short-circuited. In addition, this circuit layer formation process can employ | adopt various means, such as brazing of a metal plate, plating, vacuum evaporation, application | coating of an electrically conductive paste, for example.

The circuit layer forming step is preferably formed by causing metal powder to collide with the insulating coating.
In this case, the metal powder is made to collide with the insulating coating, for example, a plasma spraying method in which the metal powder is collided at a high temperature, or an aerosol deposition method in which the metal powder is collided with a gas at room temperature. A layer can be reliably formed.

  According to the present invention, an insulating substrate having excellent heat dissipation characteristics and capable of suppressing thermal stress from acting on a semiconductor element during a thermal cycle load, an insulating circuit substrate and a semiconductor device using the insulating substrate, In addition, a method for manufacturing an insulating substrate and a method for manufacturing an insulating circuit substrate can be provided.

It is a schematic explanatory drawing of the power module (semiconductor device) using the insulating substrate which is the 1st Embodiment of this invention. It is explanatory drawing which shows the insulated substrate which is the 1st Embodiment of this invention. It is a flowchart of the manufacturing method of the power module (semiconductor device) shown in FIG. It is explanatory drawing of the manufacturing method of the board | substrate body of the insulated substrate shown in FIG. It is a schematic explanatory drawing of the semiconductor device using the insulating substrate which is the 2nd Embodiment of this invention. It is a flowchart of the manufacturing method of the power module (semiconductor device) shown in FIG. It is explanatory drawing of the manufacturing method of the board | substrate body of the insulated substrate shown in FIG. It is a schematic explanatory drawing of the semiconductor device using the insulating substrate which is other embodiment of this invention.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
First, a power module (semiconductor device) using an insulating substrate according to a first embodiment of the present invention will be described with reference to FIGS.
A power module 1 shown in FIG. 1 is joined to an insulating substrate 10, a circuit layer 21 formed on one surface side of the insulating substrate 10 (upper side in FIG. 1), and a surface of the circuit layer 21 via a solder layer 2. And the cooler 30 disposed on the other surface side (lower side in FIG. 1) of the insulating substrate 10.

As shown in FIG. 2, the insulating substrate 10 includes a substrate body 11 made of a metal matrix composite material, and an insulating film 15 formed on one surface side of the substrate body 11.
In the present embodiment, the substrate body 11 is composed of an aluminum-based composite material in which a carbonaceous member is filled with aluminum or an aluminum alloy. More specifically, the substrate body 11 is made of an aluminum-graphite composite material in which a carbonaceous member is filled with aluminum (pure aluminum) having a purity of 99.0% or more, and the substrate body 11 has pores of the carbonaceous member. 90% by volume or more is replaced with pure aluminum, and the content of this pure aluminum is 35% or less based on the total volume of the aluminum-graphite composite material.

The carbonaceous member is a crystalline graphite member and has the following characteristics.
(1) The spacing between the (002) planes of graphite is 0.336 mm or less
(2) Hexagonal mesh surface consistency is 2.9 or more (3) The purity (carbon content) of the carbonaceous part is 99.9% by mass or more and the Na content is 0.02% by mass or less (4 ) Thermal conductivity of 250W / (m · K) or more

Here, the hexagonal mesh surface consistency of (2) is obtained as follows.
The sum of the peak areas at the diffraction peaks in the (101) plane, (102) plane, (103) plane and (112) plane of the carbonaceous part determined by X-ray diffraction is S1, and the diffraction angle 2θ is 30 to 40 degrees. When the integrated intensity value of the background is S2, the hexagonal mesh surface consistency = S1 / S2. However, incident angle (theta) shall be the range of 20-100 degrees.

In the present embodiment, the area of each diffraction peak was calculated by using an X-ray diffraction data processing software JADE6 manufactured by MDI, USA, and performing a peak search under the following conditions.
<Peak search conditions>
Filter type: Parabola Data point: 19
Peak position definition: Peak top Threshold value σ: 1.0
Peak intensity% cutoff: 0.3
BG determination range: 1.0
BG averaging points: 7
The background intensity integrated value S2 was obtained by summing up the intensities of all measurement points (500 points) in the range with 2θ between 30 and 40 degrees as the background.

  The (002) plane spacing was calculated using the above X-ray diffraction data processing software JADE6 after correcting the diffraction angle of diffraction data measured under the following measurement conditions using an NBS silicon standard material. The peak search conditions are as described above. The crystal system is hexagonal (P63 / mmc), the initial values of lattice constants are a = 2.4704, c = 6.7244, and (002), (100), (101), (102), (004), (004) 103), (110), (112), (006), and (201) 10 peaks were included in the calculation. √ (I%) was used for intensity weighting. Note that angle weighting was not used.

For X-ray diffraction measurement, a fully automatic X-ray diffractometer MXP18VAHF manufactured by Bruker AXS (formerly MacScience) was used. The measurement conditions are as follows.
X-ray used: CuKα ray Tube voltage, tube current: 40 kV, 350 mA
Optical system: Concentration method Scanning method: Step scan 2θ scanning range: 20 to 100 degrees 2θ step: 0.02 degrees Integration time of 1 step: 1 second Divergence slit: 0.5 degree Scattering slit: 0.5 degree Light receiving slit: 0.15mm
The counter graphite monochromator was used. The measurement sample was set so as to measure a crystal plane perpendicular to the extrusion direction of graphite.

Here, the thermal expansion coefficient of the substrate body 11 from room temperature to 200 ° C. is set to 10 × 10 ⁻⁶ / ° C. or lower, the thermal conductivity is set to 190 W / (m · K) or higher, and the bending strength is set to 30 MPa or higher. Yes.
Metal skin layers 12 and 13 made of aluminum are formed on one surface and the other surface of the substrate body 11, respectively. In the present embodiment, the metal skin layers 12 and 13 are made of the same material as pure aluminum filled in the carbonaceous member.
The thickness tb of the substrate body 11 is set within a range of 1 mm ≦ tb ≦ 6 mm, and in this embodiment, tb = 3 mm. Further, the thickness ts of the metal skin layers 12 and 13 is set within a range of 0.05 mm ≦ ts ≦ 0.5 mm. In the present embodiment, the metal skin layers 12 and 13 have the same thickness, ts = 0.25 mm.

The insulating coating 15 is formed by colliding a powder made of an insulating material on the metal skin layer 12 formed on one surface side of the substrate body 11. In this embodiment, alumina powder having a particle size of submicron order is mixed with a gas to form an aerosol, and this is collided at high speed through a nozzle, so that it is made from alumina (Al ₂ O ₃ ) by a so-called aerosol deposition method. An insulating film 15 is formed. Here, in the aerosol deposition method, the alumina powder which collided is laminated in a crushed state, and the alumina powder is firmly bonded by the active surface formed by the crushing, so that the insulating coating with a very dense structure 15 will be formed.
The thickness ti of the insulating coating 15 is set to 5 μm ≦ ti ≦ 50 μm, and in this embodiment, ti = 10 μm.

The circuit layer 21 is formed by laminating a conductive material on the surface of the insulating film 15 of the insulating substrate 10. In the present embodiment, the circuit layer 21 is formed by an aerosol deposition method in which an aluminum powder is collided at a temperature below its melting point. In addition, the thickness of the circuit layer 21 is set to 0.01 mm or more and 1.0 mm or less, and is set to 0.1 mm in this embodiment.
As described above, by forming the circuit layer 21 on the insulating substrate 10, the insulating circuit substrate 20 according to the present embodiment is configured.

  The cooler 30 is for cooling the insulating circuit board 20 described above, and has a multi-hole tube structure provided with a plurality of flow paths 31 for circulating a cooling medium (for example, cooling water). The cooler 30 is preferably made of a material having good thermal conductivity, and is made of A6063 (aluminum alloy) in the present embodiment.

  The semiconductor chip 3 is made of Si, and the semiconductor chip 3 is connected to the circuit layer 21 via a solder layer 2 made of, for example, a Sn—Ag, Sn—In, or Sn—Ag—Cu solder material. Joined on top. In the present embodiment, a Ni plating layer (not shown) is provided between the circuit layer 21 and the solder layer 2.

Next, the manufacturing method of the power module which is this embodiment is demonstrated with reference to FIG.3 and FIG.4.
First, a substrate body 11 made of an aluminum-graphite composite material is formed (substrate body formation step S1). In this substrate body forming step, as shown in FIG. 4, a graphite plate 41 made of a crystalline graphite member having a porosity of 10 to 30% by volume is prepared, and a porosity of 5 volumes is provided on both surfaces of the graphite plate 41, respectively. % Sandwiching plates 42, 42 made of graphite or less, and the sandwiching plates 42, 42 and the graphite plate 41 are sandwiched between stainless steel pressing plates 43, 43. This is heated to 750 to 850 ° C. under a pressure of, for example, 100 to 200 MPa, impregnated with molten aluminum having a purity of 99.0% or more into the graphite plate 41, cooled and solidified, and an aluminum-graphite composite material is obtained. obtain. At this time, a part of the molten aluminum oozes out on the surface of the graphite plate 41 to form the aluminum layer 44. The substrate body 11 is manufactured by cutting the aluminum layer 44 to adjust the thickness to form the metal skin layers 12 and 13.

Next, an insulating film 15 is formed on one surface side of the substrate body 11 (insulating film forming step S2). In this embodiment, since the metal skin layer 12 is formed on one surface side of the substrate body 11, the insulating coating 15 is formed on the metal skin layer 12.
In this insulating film forming step S2, an alumina deposition (aluminum (Al ₂ O ₃ ) powder) having a particle size of 0.1 μm or more and 1 μm or less is mixed with gas to form an aerosol, which is collided at high speed through a nozzle. The insulating coating 15 made of alumina (Al ₂ O ₃ ) is formed by the method. The film formation conditions of the aerosol deposition method in this insulating film forming step S2 were that oxygen gas having an atmospheric temperature: room temperature and a flow rate: 1-20 l / min was used as a carrier gas in an atmospheric pressure atmosphere.
In this way, by forming the insulating coating 15 on one surface side of the substrate body 11, the insulating substrate 10 according to the present embodiment is manufactured.

Next, the circuit layer 21 is formed on one surface of the insulating substrate 10 (circuit layer forming step S3).
In this circuit layer forming step S3, the aluminum powder having a particle size of 1 μm or more and 10 μm or less is formed by an aerosol deposition method in which the powder collides at a temperature below its melting point. The film formation conditions of the aerosol deposition method in this circuit layer forming step S3 are that an atmospheric pressure atmosphere, an oxygen temperature of room temperature, a flow rate of 1 to 20 l / min is used as a carrier gas.

Next, the cooler 30 is joined to the other surface side of the insulating substrate 10 (cooler joining step S4). In this embodiment, since the metal skin layer 13 is formed on the other surface side of the insulating substrate 10, the metal skin layer 13 and the cooler 30 are bonded. The cooler 30 is joined via a brazing material, and the brazing temperature is set to 550 to 610 ° C.
Thus, the insulated circuit board 20 which is this embodiment is formed.

And while forming Ni plating on the surface of the circuit layer 21, the semiconductor chip 3 is mounted via a solder material, and it solder-joins in a reduction furnace (semiconductor element joining process S5).
Thereby, the semiconductor chip 3 is joined on the circuit layer 21 via the solder layer 2, and the power module 1 which is this embodiment is produced.

According to the insulating substrate 10, the insulating circuit substrate 20, and the power module 1 according to the present embodiment configured as described above, the insulating substrate 10 includes the substrate body 11 made of an aluminum-graphite composite material. The thermal expansion coefficient from room temperature to 20 ° C. is set to 10 × 10 ⁻⁶ / ° C. or less, and approximates the thermal expansion coefficient of the semiconductor chip 3. In addition, it is possible to suppress the thermal stress from acting on the semiconductor chip 3 and prevent the semiconductor chip 3 from being damaged.
Further, since the thermal conductivity of the substrate body 11 is set to 190 W / (m · K) or more, the heat generated from the semiconductor chip 3 mounted on one surface side of the insulating substrate 10 is transferred to the insulating substrate 10. It becomes possible to dissipate efficiently to the cooler 30 arranged on the other surface side.
Furthermore, since the bending strength of the substrate body 11 is set to 30 MPa or more, the rigidity as the insulating substrate 10 is ensured and the power module 1 can be configured.

  Further, the insulating coating 15 is formed by a so-called aerosol deposition method in which an alumina powder having a particle size of submicron order is mixed with a gas to be collided at high speed through a nozzle as an aerosol, and has a very dense structure. Therefore, even if the thickness ti of the insulating coating 15 is set to 5 μm ≦ ti ≦ 50 μm, more specifically, ti = 10 μm, a high withstand voltage can be obtained. Therefore, by using this insulating substrate 10, the highly reliable power module 1 can be provided.

Further, a metal skin layer 12 made of aluminum is formed on one surface side of the substrate body 11, and an insulating film 15 is formed on the metal skin layer 12, so that the aluminum is relatively exposed. The alumina powder is collided and laminated on the uniform surface, and the uniform insulating coating 15 can be formed.
Furthermore, since the insulating film 15 is formed by the aerosol deposition method as described above, the insulating film 15 can be formed under normal temperature conditions, and the manufacturing cost of the insulating substrate 10 can be reduced. .

Furthermore, the insulating circuit substrate 20 is configured by forming a circuit layer 21 made of aluminum as a conductive material on one surface side of the insulating substrate 10, that is, on the surface of the insulating coating 15. In this insulated circuit board 20, insulation between the substrate body 11 made of an aluminum-graphite composite material and the circuit layer 21 is achieved by the insulating coating 15, and the power module 1 with high reliability can be configured.
Further, since the circuit layer 21 is formed by the aerosol deposition method in which the aluminum powder is collided at a temperature equal to or lower than its melting point, the circuit layer 21 made of aluminum can be satisfactorily formed on the insulating coating 15. Moreover, since the aerosol deposition method can be performed at a temperature equal to or lower than the melting point of the powder and under atmospheric pressure, the manufacturing cost of the insulating circuit board 20 can be reduced.

  Furthermore, in this embodiment, since the metal skin layer 13 made of aluminum is also formed on the other surface side of the substrate body 11, the cooler 30 can be satisfactorily bonded via the metal skin layer 13. It becomes. That is, since the metal skin layer 13 is made of aluminum and the cooler 30 is made of an aluminum alloy, the insulating substrate 10 and the cooler 30 can be easily used by using a general brazing material such as an Al—Si system. Can be joined together.

  In the present embodiment, when forming the substrate body 11 made of an aluminum-graphite composite material, the graphite plate 41 is impregnated with aluminum to be cooled and solidified, and a part of the molten aluminum is formed on the surface of the graphite plate 41. Since the metal skin layers 12 and 13 are formed by cutting the aluminum layer 44 formed by oozing, the substrate body 11 having the metal skin layers 12 and 13 can be relatively easily manufactured. .

Next, an insulating substrate and a semiconductor device using the insulating substrate according to the second embodiment of the present invention will be described.
As shown in FIG. 5, the semiconductor device 101 includes a semiconductor chip 103, an insulating circuit board 120 including a first insulating board 110 </ b> A disposed on the lower surface side of the semiconductor chip 103, and the insulating circuit board 120. A first cooler 130A disposed on the lower side, a second insulating substrate 110B disposed on the upper surface side of the semiconductor chip 103, and a second cooler disposed on the upper side of the second insulating substrate 110B. 130B, and a double-sided cooling type semiconductor device 101.

The first insulating substrate 110A and the second insulating substrate 110B include substrate bodies 111A and 111B made of a metal matrix composite material, and one surface side of the substrate bodies 111A and 111B (in FIG. 5, about the first insulating substrate 110A). Are provided with insulating coatings 115A and 115B formed on the upper surface side and on the lower surface side of the second insulating substrate 110B.
In the present embodiment, the substrate bodies 111A and 111B are made of an AlSiC composite material in which a base material made of SiC is filled with aluminum or an aluminum alloy.

Here, the thermal expansion coefficient of the substrate bodies 111A and 111B from room temperature to 20 ° C. is set to 10 × 10 ⁻⁶ / ° C. or lower, the thermal conductivity is set to 190 W / (m · K) or higher, and the bending strength is set to 30 MPa or higher. ing.
Further, metal skin layers 112A, 112B, 113A, and 113B made of copper are formed on one surface side and the other surface side of the substrate bodies 111A and 111B, respectively. That is, in this embodiment, the metal (aluminum) impregnated in the metal matrix composite material (AlSiC composite material) constituting the substrate bodies 111A and 111B and the metal (copper) constituting the metal skin layers 112A, 112B, 113A, and 113B. ) Is different.

The insulating coatings 115A and 115B are formed by causing a powder made of an insulating material to collide with the metal skin layers 112A and 112B formed on one surface side of the substrate bodies 111A and 111B. In the present embodiment, an insulating coating made of alumina (Al ₂ O ₃ ) is formed by a so-called aerosol deposition method in which alumina powder having a particle size of submicron order is mixed with a gas and collided at high speed through a nozzle as an aerosol. Is forming.

In addition, the circuit layer 121 is formed by laminating a conductive material on the surface of the insulating coating 115A of the first insulating substrate 110A, and the insulating circuit substrate 120 is configured.
In the present embodiment, the circuit layer 121 is formed by applying and sintering Ag paste.

  The first cooler 130A and the second cooler 130B are for cooling the semiconductor chip 103, and are bonded to the metal skin layers 113A and 113B formed on the other surface side of the substrate bodies 111A and 111B. Plate portions 132A and 132B, radiation fins 133A and 133B suspended from the top plate portions 132A and 132B, and flow paths 131A and 131B for circulating a cooling medium (for example, cooling water) are provided. The first cooler 130A and the second cooler 130B are preferably made of a material having good thermal conductivity, and in this embodiment, are made of a Cu alloy.

  The semiconductor chip 103 is made of Si, and the semiconductor chip 103 is connected to an insulating circuit via a solder layer 102A made of, for example, a Sn—Ag, Sn—In, or Sn—Ag—Cu solder material. It is mounted on the circuit layer 121 of the substrate 120. Furthermore, the second insulating substrate 110B is bonded to the upper surface side of the semiconductor chip 103 via the solder layer 102B.

Next, a method for manufacturing the semiconductor device according to the present embodiment will be described with reference to FIGS.
First, a metal matrix composite material is formed (metal matrix composite material formation step S10). In this embodiment, an AlSiC composite material is formed by filling a base material made of SiC with aluminum or an aluminum alloy.

  Next, as shown in FIG. 7, copper powder having a particle size of 1 μm or more and 10 μm or less is caused to collide with both surfaces of the AlSiC composite material through a nozzle 146 at a temperature equal to or lower than its melting point, and the so-called aerosol deposition method is used. The metal skin layers 112A, 112B, 113A, 113B are formed (metal skin layer forming step S11). The film formation conditions of the aerosol deposition method in this metal skin layer forming step S11 are that an atmospheric pressure atmosphere, an oxygen temperature of room temperature and a flow rate of 1 to 20 l / min is used as a carrier gas. Thus, the substrate bodies 111A and 111B are formed.

Next, insulating coatings 115A and 115B are formed on one surface side of the substrate bodies 111A and 111B (insulating coating forming step S12). In this embodiment, since the metal skin layers 112A and 112B are formed on one surface side of the substrate bodies 111A and 111B, the insulating coatings 115A and 115B are formed on the metal skin layers 112A and 112B. It will be.
In this insulating coating forming step S12, alumina (Al ₂ O ₃ ) powder having a particle size of submicron order is mixed with gas to form an aerosol, and the alumina ( An insulating film made of Al ₂ O ₃ is formed. The film formation conditions of the aerosol deposition method in this insulating film forming step S12 were that oxygen gas having an atmosphere temperature: room temperature and a flow rate: 1 to 20 l / min was used as a carrier gas in an atmospheric pressure atmosphere. In this way, the first insulating substrate 110A and the second insulating substrate 110B are manufactured by forming the insulating coatings 115A and 115B on one surface of the substrate bodies 111A and 111B.

Next, the circuit layer 121 is formed on the surface of the insulating coating 115A of the first insulating substrate 110A (circuit layer forming step S13). In the circuit layer forming step S13, the circuit layer 121 made of Ag is formed by applying and baking Ag paste.
Further, the first cooler 130A is joined to the other surface side of the first insulating substrate 110A (first cooler joining step S14A). In the present embodiment, since the metal skin layer 113A is formed on the other surface side of the first insulating substrate 110A, the metal skin layer 113A and the first cooler 130A are joined. The first cooler 130A is joined via a brazing material, and the brazing temperature is set to 550 to 610 ° C.
Thus, the insulated circuit board 120 which is this embodiment is formed.

  Further, the second cooler 130B is joined to the other surface side of the second insulating substrate 110B (second cooler joining step S14B). In the present embodiment, since the metal skin layer 113B is formed on the other surface side of the second insulating substrate 110B, the metal skin layer 113B and the second cooler 130B are joined. In addition, the 2nd cooler 130B is joined via the brazing | wax material, and the temperature of brazing is set to 550-610 degreeC.

Then, the semiconductor chip 103 is placed on the insulating circuit substrate 120 using the first insulating substrate 110A via the solder material, and the second insulating substrate 110B is disposed on the upper surface side of the semiconductor chip 103 via the solder material. Then, solder bonding is performed in the reduction furnace (semiconductor element bonding step S15).
Thereby, the double-sided cooling type semiconductor device in which the first cooler 130A and the second cooler 130B are disposed on the upper surface side and the lower surface side of the semiconductor chip 103 via the first insulating substrate 110A and the second insulating substrate 110B. 101 is manufactured.

According to the insulating substrates 110A and 110B, the insulating circuit substrate 120, and the semiconductor device 101 according to the present embodiment configured as described above, as in the first embodiment, thermal stress is applied to the semiconductor chip 103 during a thermal cycle load. It can be prevented from acting, and heat generated from the semiconductor chip 103 can be efficiently dissipated toward the first cooler 130A and the second cooler 130B.
Further, since the insulating coatings 115A and 115B are formed by the aerosol deposition method and the insulating coatings 115A and 115B have a very dense structure, a high withstand voltage can be obtained, and the semiconductor chip 103 and the first A short circuit between the cooler 130A and the second cooler 130B can be reliably prevented.

In this embodiment, the metal skin layers 112A, 112B, 113A, and 113B are formed on one surface and the other surface of the substrate bodies 111A and 111B by the aerosol deposition method, and the metal matrix composite material (AlSiC) It is possible to produce substrate bodies 111A and 111B in which the metal impregnated therein (aluminum) and the metal skin layers 112A, 112B, 113A and 113B are different in structure (copper).
In the present embodiment, the metal skin layers 113A and 113B on the other surface side of the substrate bodies 111A and 111B are made of copper, and the first cooler 130A and the second cooler 130B are made of a copper alloy. The first insulating substrate 110A and the first cooler 130A, and the second insulating substrate 110B and the second cooler 130B can be bonded satisfactorily.

As mentioned above, although embodiment of this invention was described, this invention is not limited to this, It can change suitably in the range which does not deviate from the technical idea of the invention.
For example, the substrate main body has been described as having a metal skin layer, but the present invention is not limited to this, and the metal skin layer may not be formed as shown in FIG. Moreover, the metal skin layer may be formed only on one surface or the other surface. Furthermore, the thickness of the metal skin layer may be different on one side and the other side.
Moreover, although demonstrated as an insulated circuit board and a semiconductor device provided with the cooler, as shown in FIG. 8, it is not necessary to provide the cooler.

  Furthermore, although the aluminum-graphite composite material and the AlSiC composite material have been described as examples of the metal matrix composite material constituting the substrate body, the present invention is not limited to this, for example, Cu-graphite composite material, etc. The metal matrix composite material may be used.

In addition, although the insulating coating is described as being made of alumina, the invention is not limited to this, and the insulating coating may be made of other insulating materials such as Si ₃ N ₄ , AlN, mullite, and SiO ₂ .
Furthermore, although the insulating coating has been described as being formed by the aerosol deposition method, the present invention is not limited to this, and the insulating coating may be formed by a plasma spraying method in which a powder made of an insulating material is collided at a high temperature. Good.

Moreover, although the circuit layer was demonstrated as what consists of aluminum or Ag, it is not limited to this, You may be comprised with other electroconductive materials, such as Cu and Ni.
Furthermore, although it has been described that the circuit layer is formed by an aerosol deposition method or Ag paste application / firing, there is no limitation on the method of forming the circuit layer, and it may be formed by a plasma spraying method or a metal plate may be joined. May be. Alternatively, it may be formed by plating.

Although the cooler has been described as being joined by brazing, the invention is not limited thereto, and the cooler may be joined using an adhesive or a solder material.
In addition, the material and structure of the cooler are not limited to the embodiment, and may be appropriately changed in design.

Moreover, although the power module and the double-sided cooling type semiconductor device have been described as examples, the present invention is not limited to this, and an LED semiconductor device in which LED elements are arranged as semiconductor elements may be used.
Furthermore, the thickness of the substrate body, the metal skin layer, the circuit layer, and the like are not limited to the present embodiment, and may be appropriately changed in design.

1 Power module (semiconductor device)
2 Solder layer 3 Semiconductor chip (semiconductor element)
DESCRIPTION OF SYMBOLS 10 Insulating board | substrate 11 Board | substrate body 12, 13 Metal skin layer 15 Insulating film 20 Insulating circuit board 21 Circuit layer 30 Cooler 101 Semiconductor device 102 Solder layer 103 Semiconductor chip (semiconductor element)
110A First insulating substrate (insulating substrate)
110B Second insulating substrate (insulating substrate)
111A, 111B Substrate body 112A, 112B, 113A, 113B Metal skin layer 120 Insulated circuit board 121 Circuit layer 130A First cooler (cooler)
130B second cooler (cooler)

Claims (15)

An insulating substrate comprising a substrate body made of a metal matrix composite material, and an insulating film formed on one surface of the substrate body,
The substrate body has a coefficient of thermal expansion from room temperature to 200 ° C. of 10 × 10 ⁻⁶ / ° C. or less, a thermal conductivity of 190 W / (m · K) or more, and a bending strength of 30 MPa or more.
The insulating substrate is characterized in that the insulating coating is formed by causing a powder made of an insulating material to collide with one surface of the substrate body.   The insulating substrate according to claim 1, wherein the insulating coating is formed by an aerosol deposition method.   The metal skin layer is formed on one surface of the substrate body made of the metal matrix composite material, and the insulating coating is formed on the metal skin layer. Item 3. The insulating substrate according to Item 2.   The insulating substrate according to any one of claims 1 to 3, wherein a metal skin layer is formed on the other surface of the substrate body made of the metal matrix composite material. It has an insulating substrate according to any one of claims 1 to 4,
A circuit layer made of a conductive material is formed on an insulating film of the insulating substrate.   6. The insulated circuit board according to claim 5, wherein the circuit layer is formed by causing metal powder to collide with the insulating coating.   The insulated circuit board according to claim 5 or 6, wherein the circuit layer is made of any one of Al, Ni, Cu, and Ag.   The circuit layer is composed of a laminated film in which Al is an underlayer and Ag is an upper layer, or a laminated film of two or more layers in which at least one of Al or Ag is an underlayer and at least one of Cu or Ni is an upper layer. The insulated circuit board according to claim 5, wherein the insulated circuit board is provided.   The insulated circuit board according to any one of claims 5 to 8, wherein a cooler is disposed on the other surface side of the insulated board. It has an insulating substrate according to any one of claims 1 to 4,
A semiconductor device in which a semiconductor element is mounted on the insulating substrate. A substrate main body made of a metal matrix composite material, and an insulating film formed on one surface of the substrate main body, comprising:
On one surface of the substrate body, the coefficient of thermal expansion from room temperature to 200 ° C. is set to 10 × 10 ⁻⁶ / ° C. or lower, the thermal conductivity is set to 190 W / (m · K) or higher, and the bending strength is set to 30 MPa or higher. A method of manufacturing an insulating substrate, comprising: an insulating coating forming step of forming an insulating coating by colliding powder made of an insulating material.   The method for manufacturing an insulating substrate according to claim 11, wherein the insulating coating is formed by an aerosol deposition method.   13. A metal skin layer forming step of forming a metal skin layer by causing a metal powder to collide with at least one of the one surface and the other surface of the substrate body. The manufacturing method of the insulated substrate as described in 2. A method of manufacturing an insulating circuit board comprising: a substrate body made of a metal matrix composite material; an insulating substrate having an insulating coating formed on one surface of the substrate body; and a circuit layer formed on the insulating substrate. There,
An insulating circuit board comprising a circuit layer forming step of forming a circuit layer made of a conductive material on the insulating film of the insulating substrate according to any one of claims 1 to 4. Manufacturing method.   The method for manufacturing an insulated circuit board according to claim 14, wherein the circuit layer forming step is performed by causing metal powder to collide with the insulating coating.

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