JP2011035308A - Radiator plate, semiconductor device, and method of manufacturing radiator plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiator plate excelling in a heat radiation characteristic and capable of preventing thermal stress from acting on a heating element such as a semiconductor element in a cold cycle load, a semiconductor device using the radiator plate, and a method of manufacturing the radiator plate. <P>SOLUTION: This radiator plate 30 for dissipating heat generated from a mounted heating element 3 includes: a plate body 31 formed of a metal matrix composite material with a metal material filled in a black carbonaceous member; and metal skin layers 32, 33 formed on at least one plate surface of the plate body 31; wherein the metal matrix composite material constituting the plate body is formed by impregnating a molten metal material into the carbonaceous member, and the metal skin layers 32, 33 are formed by making metal powder collide with the plate surface of the plate body 31. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a heat radiating plate on which a heat generating element such as a semiconductor element is mounted and which spreads and dissipates heat generated from the heat generating element, a semiconductor device provided with the heat radiating plate, and a method of manufacturing the heat radiating plate. .

In recent years, with the increase in functionality, capacity, and size of electronic devices, the amount of heat generated from the electronic devices tends to increase, and it is required to dissipate these heat efficiently.
For example, in a semiconductor device in which a semiconductor element is mounted as a heating element, a heat radiating plate with good thermal conductivity is used to spread and dissipate the heat generated from the semiconductor as disclosed in Patent Document 1. Has been.

  Moreover, in the heat sink used in the above-described semiconductor device, since the mounted semiconductor element is made of, for example, Si and has a relatively small thermal expansion coefficient, it is made of a metal plate or the like and has a relatively large thermal expansion coefficient. In the case of using a heat sink, thermal stress acts on the mounted semiconductor element during a cooling / heating cycle load, which may damage the semiconductor element itself. For this reason, the heat sink with a small thermal expansion coefficient is calculated | required.

Therefore, metal matrix composites composed of carbonaceous members and metals have been widely proposed as heat sinks having high thermal conductivity and a small thermal expansion coefficient. Specifically, Patent Document 2 proposes a heat dissipation plate made of a metal matrix composite material obtained by pressurizing and infiltrating copper into a carbon fiber felt made of carbon fiber. Patent Document 3 proposes a heat dissipation plate made of a metal matrix composite material in which a carbon molded body is press-impregnated with aluminum, copper, and silver by melt forging.
Since such a metal matrix composite material contains a metal having good thermal conductivity, high thermal conductivity can be ensured. Moreover, since the graphite member with a small coefficient of thermal expansion is contained, the coefficient of thermal expansion can be kept low.

In such a heat sink, a heating element such as a semiconductor element or a circuit board on which the semiconductor element is mounted is joined to the plate surface via a brazing material or a solder material. Here, in the heat sink made of the metal matrix composite material, since the carbon member and the metal are exposed on the plate surface, there is a possibility that the heating element cannot be firmly bonded using the solder material or the brazing material.
Therefore, it is conceivable to form a metal skin layer by eluting the metal impregnated in the carbonaceous member on the plate surface of the metal matrix composite material, or to form a metal skin layer by plating or vacuum deposition.

JP 2004-296493 A Japanese Patent Laid-Open No. 11-097593 JP 2001-058255 A

  By the way, as described above, when the metal skin layer is formed by eluting the metal impregnated in the carbonaceous member on the plate surface of the metal matrix composite material, it is difficult to form the metal skin layer uniformly. There is a possibility that a heating element such as a semiconductor element cannot be bonded satisfactorily. Further, since the metal skin layer is formed by the metal impregnated in the carbonaceous member, there is a problem that the material of the metal skin layer cannot be changed.

On the other hand, when a metal skin layer is formed on the plate surface of the metal matrix composite material by plating or vacuum deposition, the material of the metal skin layer can be different from the metal impregnated in the carbonaceous member. Further, there is a possibility that the bonding property between the metal skin layer and the plate surface of the metal matrix composite material may be deteriorated, and there is a possibility that a heating element such as a semiconductor element cannot be bonded well.
In addition, when a metal skin layer is formed by plating, tensile stress remains in the metal skin layer, and when the metal skin layer is deteriorated, cracks are likely to occur, so that it can be bonded to a heating element such as a semiconductor element. There was a risk of malfunction.
Furthermore, when vacuum deposition is used, a great amount of labor is required to form the metal skin layer, and there is a problem that the manufacturing cost of the heat sink increases significantly.

  The present invention has been made in view of the above-described circumstances, has excellent heat dissipation characteristics, and can dissipate thermal stress from acting on a heating element such as a semiconductor element under a heat cycle load. It aims at providing the board, the semiconductor device using this heat sink, and the manufacturing method of this heat sink.

  In order to solve the above problems and achieve the above-mentioned object, the radiator plate of the present invention is a radiator plate that dissipates heat generated from the mounted heating element, and includes a metal material in the carbonaceous member. And a metal skin layer formed on at least one plate surface of the plate body. The metal matrix composite material constituting the plate body is a carbonaceous member. The metal skin layer is formed by impregnating a molten metal material therein, and the metal skin layer is formed by colliding metal powder against the plate surface of the plate body.

  According to the heat radiating plate of this configuration, the plate body made of a metal matrix composite material in which a carbonaceous member is filled with a metal material, and a metal skin layer formed on at least one plate surface of the plate body. And the metal skin layer is formed by colliding the metal powder against the plate surface of the plate body, so that the metal powder is laminated even on the plate surface where the carbonaceous member and the metal are exposed. Thus, a metal skin layer can be formed, and a metal skin layer firmly bonded to the plate body can be formed.

In addition, the metal skin layer can be composed of a metal material different from the metal material filled in the metal matrix composite material, and the material of the metal skin layer can be selected according to the joining method of the heating elements to be mounted. Can do.
Furthermore, since the metal powder is collided to form the metal skin layer, a compressive stress acts on the plate surface of the plate body and the inside of the metal skin layer due to the peening effect. Therefore, even when the metal skin layer is deteriorated, cracks or the like are hardly generated in the metal skin layer, and the joining reliability with the heating element can be greatly improved.

Here, the metal skin layer is preferably formed by an aerosol deposition method.
In the aerosol deposition method, a metal skin layer is formed by colliding fine powder of submicron order at high speed. In this aerosol deposition method, the collided powder is plastically deformed and laminated, and the powder is firmly bonded by the active surface formed by plastic deformation, so that the metal skin layer can have a very dense structure. it can. Moreover, it becomes possible to form a metal skin layer under conditions of normal temperature and low pressure, and the manufacturing cost of this heat sink can be reduced.

The plate body made of the metal matrix composite material 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. It is preferable that it is set to.
In this case, since the coefficient of thermal expansion from room temperature to 200 ° C. is 10 × 10 ⁻⁶ / ° C. or less, the coefficient of thermal expansion approximates that of a semiconductor element or the like. It can suppress that a thermal stress acts. Further, since the thermal conductivity is set to 190 W / (m · K) or more, the heat conduction is good and the heat generated from the heating element can be efficiently dissipated. Furthermore, since the bending strength is 30 MPa or more, rigidity as a heat sink is ensured, and a semiconductor device or the like can be configured.

Further, the metal material filled in the metal matrix composite material constituting the plate body and the metal material constituting the metal skin layer may be different from each other.
In this case, for example, the metal material filled in the metal matrix composite material can be made to have excellent fluidity of the molten metal, and the metal material constituting the metal skin layer can employ a metal having a high bondability with the solder or brazing material. It becomes.

Here, the metal material filled in the metal matrix composite material constituting the plate body is preferably an Al-Si alloy, and the metal material constituting the metal skin layer is preferably pure aluminum having a purity of 99.0% or more. .
In this case, since the metal material filled in the metal matrix composite material is an Al—Si alloy, the molten metal has good flowability, and the carbonaceous member is reliably impregnated with the Al—Si alloy. Is possible. Further, since the metal material constituting the metal skin layer is pure aluminum having a purity of 99.99% or more, the deformation resistance of the metal skin layer is lowered, and the thermal stress acting during the cooling cycle is reduced by this metal skin layer. Relaxation absorption is possible. Further, a heating element such as a semiconductor element can be satisfactorily bonded to the metal skin layer via a brazing material. Alternatively, by forming Ni plating on the metal skin layer, a heating element such as a semiconductor element can be satisfactorily bonded via the solder material.

The metal material filled in the metal matrix composite material constituting the plate body is preferably aluminum or an aluminum alloy, and the metal material constituting the metal skin layer is preferably nickel.
In this case, since the metal material filled in the metal matrix composite material is aluminum or an aluminum alloy, the melting point has a low melting point, and a plate body made of the metal matrix composite material can be configured by processing at a relatively low temperature. It becomes possible. Moreover, since the metal material which comprises a metal skin layer is nickel, heat generating bodies, such as a semiconductor element, can be favorably joined via a solder material, without forming Ni plating in a metal skin layer.

A semiconductor device according to the present invention includes the above-described heat sink and a semiconductor element mounted on the heat sink.
According to the semiconductor device having this configuration, the heat generated from the semiconductor element that is a heating element can be efficiently dissipated, and the thermal stress is suppressed from acting on the semiconductor element when a cooling cycle is applied. The damage of the semiconductor element can be prevented. Therefore, a highly reliable semiconductor device can be provided.

  Further, the method for manufacturing a heat sink of the present invention has a plate body made of a metal matrix composite material in which a carbonaceous member is filled with a metal material, and a metal skin layer is formed on at least one plate surface of the plate body. A manufacturing method of a formed heat sink, a plate body forming step of forming a plate body made of a metal matrix composite material by impregnating a molten metal material in a carbonaceous member, and a plate surface of the plate body, And a metal skin layer forming step of forming a metal skin layer by colliding with metal powder.

  According to the manufacturing method of the heat sink having this configuration, a heat sink having good heat conduction and a low thermal expansion coefficient and approximating Si constituting the semiconductor element can be manufactured. Furthermore, since the metal skin layer forming step is configured to form a film by colliding metal powder, the metal skin layer can be reliably formed on the plate surface of the plate body made of the metal matrix composite material. .

Here, the metal skin layer forming step may be configured to form the metal skin layer by an aerosol deposition method.
In this case, a metal skin layer having a very dense structure can be formed on the plate surface of the plate body made of the metal matrix composite material. Moreover, it becomes possible to form a metal skin layer under conditions of normal temperature and low pressure, and the manufacturing cost of this heat sink can be reduced.

  ADVANTAGE OF THE INVENTION According to this invention, it is excellent in a heat dissipation characteristic, and the heat sink which can suppress that a thermal stress acts on heat generating bodies, such as a semiconductor element, at the time of a thermal cycle load, a semiconductor device using this heat sink, and The manufacturing method of this heat sink can be provided.

It is a schematic explanatory drawing of the power module (semiconductor device) using the heat sink which is the 1st Embodiment of this invention. It is explanatory drawing which shows the heat sink 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 plate main body of the heat sink shown in FIG. It is a schematic explanatory drawing of the semiconductor device using the heat sink 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.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
First, a power module (semiconductor device) using a heat sink according to a first embodiment of the present invention will be described with reference to FIGS.
A power module 1 shown in FIG. 1 includes a power module substrate 10, a semiconductor chip 3 bonded to one surface side (upper side in FIG. 1) of the power module substrate 10 via a solder layer 2, and a power module. 1 is provided with a heat radiating plate 30 disposed on the other surface side (lower side in FIG. 1) of the substrate 10 and a cooler 40 disposed on the other surface side of the heat radiating plate.

The power module substrate 10 has a ceramic substrate 11, a circuit layer 12 disposed on one surface (the upper surface in FIG. 1) of the ceramic substrate 11, and the other surface (lower surface in FIG. 1) of the ceramic substrate 11. And a disposed metal layer 13.
The ceramic substrate 11 prevents electrical connection between the circuit layer 12 and the metal layer 13, and is made of highly insulating AlN (aluminum nitride). In addition, the thickness of the ceramic substrate 11 is set within a range of 0.2 to 1.5 mm, and in this embodiment is set to 0.635 mm.

  The circuit layer 12 is formed by brazing a metal plate having conductivity to one surface of the ceramic substrate 11. In the present embodiment, the circuit layer 12 is formed by brazing a metal plate made of an aluminum (so-called 4N aluminum) rolled plate having a purity of 99.99% or more to the ceramic substrate 11. In this embodiment, the metal plates are joined using an Al—Si brazing material.

  The metal layer 13 is formed by brazing a metal plate to the other surface of the ceramic substrate 11. In the present embodiment, the metal layer 13 is brazed to the ceramic substrate 11 with a metal plate made of a rolled plate of aluminum (so-called 4N aluminum) having a purity of 99.99% or more, like the circuit layer 12. Is formed. In this embodiment, the metal plates are joined using an Al—Si brazing material.

  The cooler 40 is for cooling the power module substrate 10 described above, and has a multi-hole tube structure provided with a plurality of flow paths 41 for circulating a cooling medium (for example, cooling water). The cooler 40 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 12 via a solder layer 2 made of, for example, a Sn—Ag, Sn—In, or Sn—Ag—Cu solder material. Mounted on top. In the present embodiment, a Ni plating layer (not shown) is provided between the circuit layer 12 and the solder layer 2.

And the heat sink 30 is equipped with the plate main body 31 comprised with the metal matrix composite material, and the metal skin layers 32 and 33 formed in the one surface side and the other surface side of this plate main body 31, respectively. Yes.
Here, the thermal expansion coefficient of the heat sink 30 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. .

  The plate body 31 is made of an aluminum-based composite material in which a carbonaceous member is filled with aluminum or an aluminum alloy. More specifically, the plate body 31 is impregnated with an aluminum alloy (in this embodiment, an Al—Si alloy) having a melting point higher than the brazing temperature described later and not higher than 630 ° C. in the carbonaceous member. 90% by volume or more of the pores of the carbonaceous member is replaced with an Al—Si alloy, and the content of this Al—Si alloy is 35% on the basis of the total volume of the aluminum graphite composite material. It is as follows.

The metal skin layers 32 and 33 formed on one surface and the other surface of the plate body 31 are made of aluminum having a purity of 99.0% or more (so-called pure aluminum).
In the present embodiment, the metal skin layer is formed by a so-called aerosol deposition method in which Al powder having a particle size of submicron order is mixed with a gas to be collided at high speed through a nozzle. Here, in the aerosol deposition method, the collided Al powder is laminated in a plastically deformed state, and the Al powder is firmly bonded by the active surface formed by the plastic deformation, so that a very dense structure is formed. Metal skin layers 32 and 33 are formed.
Note that the thickness ts of the metal skin layers 32 and 33 is set to 0.05 mm ≦ ts ≦ 0.5 mm. In the present embodiment, the thicknesses of the metal skin layers 32 and 33 are the same, and ts = It is set to 0.25 mm.

Next, the manufacturing method of the power module which is this embodiment is demonstrated with reference to FIG.3 and FIG.4.
First, a plate body 31 made of an aluminum graphite composite material is formed (plate body forming step S1). In this substrate body forming step, as shown in FIG. 4, a graphite plate 36 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 36, respectively. % Sandwiching plates 37 and 37 made of graphite or less, and the sandwiching plates 37 and 37 and the graphite plate 36 are sandwiched by stainless pressing plates 38 and 38. This is heated to, for example, 750 to 850 ° C. under a pressure of 100 to 200 MPa, and the graphite plate 36 is impregnated with molten aluminum made of an Al—Si alloy, and this is cooled and solidified to obtain an aluminum graphite composite material. become.

Here, the graphite plate 36 made of a crystalline graphite member has the following characteristics.
(1) Interplanar spacing of (002) plane of graphite is 0.336 mm or less (2) Hexagonal network surface consistency is 2.9 or more (3) Purity (carbon content) of carbonaceous part is 99.9% by mass or more In addition, the Na content is 0.02% by mass or less. (4) Thermal conductivity is 250 W / (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.

Metal skin layers 32 and 33 made of pure aluminum having a purity of 99.0% or more are formed on one surface and the other surface of the plate body 31 made of the aluminum graphite composite material thus obtained (metal skin layer). Forming step S2).
In the metal skin layer forming step S2, the metal skin layer 32 is formed by an aerosol deposition method in which an Al powder having a particle size of 1 μm or more and 10 μm or less is mixed with a gas to form an aerosol and collides at high speed through a nozzle 39. , 33 are formed. In addition, the conditions of the aerosol deposition method in this metal skin layer formation process S2 used the oxygen gas of atmosphere temperature: room temperature and flow rate: 1-20 l / min as carrier gas in air | atmosphere atmosphere.
Thus, the heat sink 30 which is this embodiment is manufactured by forming the metal skin layers 32 and 33 on the one surface and the other surface of the plate body 31.

  Next, the power module substrate 10 is bonded to one surface side of the heat radiating plate 30 (power module substrate bonding step S3). The power module substrate 10 is placed on the metal skin layer 32 of the heat radiating plate 30 via a brazing material, and brazing is performed in a heating furnace. As a result, the metal layer 13 of the power module substrate 10 and the metal skin layer 32 of the heat sink 30 are joined. Here, the brazing temperature is set to 550 to 610 ° C.

  Next, the cooler 40 is joined to the other surface side of the heat radiating plate 30 (cooler joining step S4). A brazing material is interposed between the metal skin layer 33 of the heat radiating plate 30 and the cooler 40, and the brazing process is performed by inserting the brazing material into a heating furnace. Thereby, the cooler 40 and the heat sink 30 are joined. Here, the brazing temperature is set to 550 to 610 ° C. The power module substrate bonding step S3 and the cooler bonding step S4 may be performed simultaneously in the same heating furnace.

And while forming Ni plating on the surface of the circuit layer 12 of the board | substrate 10 for power modules, the semiconductor chip 3 is mounted via a solder material, and it solder-joins within a reduction furnace (semiconductor element joining process S5).
Thereby, the semiconductor chip 3 is joined on the circuit layer 12 via the solder layer 2, and the power module 1 which is this embodiment is manufactured.

  According to the heat sink 30 and the power module 1 of the present embodiment configured as described above, the heat sink 30 is a plate body 31 made of an aluminum graphite composite material in which a carbonaceous member is filled with an aluminum alloy. And metal skin layers 32 and 33 respectively formed on one surface and the other surface of the plate body 31, and the metal skin layers 32 and 33 are made of Al powder having a particle size of submicron order. Is formed by the so-called aerosol deposition method in which gas is mixed with gas and collided at high speed through a nozzle, so that one surface and the other surface of the plate body 31 on which the carbonaceous member and aluminum are exposed In addition, it is possible to laminate aluminum powder and form metal skin layers 32 and 33 firmly bonded to the plate body 31. Can.

  Further, in the above-described aerosol deposition method, the colliding aluminum powder is plastically deformed and laminated, and the aluminum powder is firmly bonded by the active surface formed by the plastic deformation. Therefore, the metal skin layers 32 and 33 are formed. A very dense structure can be obtained. In addition, the metal skin layers 32 and 33 can be formed under normal temperature and low pressure conditions, and the manufacturing cost of the heat sink 30 can be reduced.

Further, since the thermal expansion coefficient from room temperature to 200 ° C. of the plate body 31 is set to 10 × 10 ⁻⁶ / ° C. or less, the thermal expansion coefficient of the radiator plate 30 approximates that of the semiconductor chip 3 or the power module substrate 10. In other words, it is possible to suppress thermal stress from acting on the semiconductor chip 3 and the power module substrate 10 during a cooling cycle load. Further, since the thermal conductivity of the plate body 31 is 190 W / (m · K) or more, heat conduction is good, and heat generated from the semiconductor chip 3 and the power module substrate 10 can be efficiently dissipated. Is possible. Furthermore, since the bending strength of the plate body 31 is 30 MPa or more, the rigidity as the heat radiating plate 30 is ensured, and the power module 1 can be configured.

Further, since the metal material impregnated in the aluminum graphite composite material constituting the plate body 31 is an Al—Si alloy having a relatively low melting point and excellent fluidity of the molten metal, Al— The Si alloy can be reliably impregnated.
On the other hand, since the metal skin layers 32 and 33 are made of pure aluminum having a purity of 99.0% or more, the deformation resistance of the metal skin layers 32 and 33 is reduced, and the thermal stress acting during the cooling and heating cycle is reduced. The skin layers 32 and 33 can relax and absorb.

Next, the heat sink which is the 2nd Embodiment of this invention and the semiconductor device using this heat sink are demonstrated.
As shown in FIG. 5, the semiconductor device 101 includes a heat sink 130, a semiconductor chip 103 mounted on one surface side of the heat sink 130 (upper side in FIG. 5), and the other surface side of the heat sink 130. And a cooler 140 (on the lower side in FIG. 5).

  The cooler 140 is for cooling the semiconductor chip 103 and has a multi-hole tube structure in which a plurality of flow paths 141 for circulating a cooling medium (for example, cooling water) are provided. The cooler 140 is preferably made of a material having good thermal conductivity. In the present embodiment, the cooler 140 is made of A6063 (aluminum alloy).

  The semiconductor chip 103 is made of Si. The semiconductor chip 103 is, for example, a heat dissipation plate 130 via a solder layer 102 made of a Sn-Ag, Sn-In, or Sn-Ag-Cu solder material. Mounted on top.

The heat radiating plate 130 includes a plate body 131 made of a metal matrix composite material, and metal skin layers 132 and 133 respectively formed on one surface side and the other surface side of the plate body 131.
Here, the thermal expansion coefficient of the heat sink 130 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. .

The plate body 131 is made of an AlSiC composite material in which a base material made of SiC is filled with aluminum or an aluminum alloy.
The metal skin layer 132 formed on one surface of the plate body 131 is made of Ni, and the metal skin layer 133 formed on the other surface is made of aluminum having a purity of 99.0% or more (so-called Pure aluminum).

In the present embodiment, the metal skin layer 132 formed on one surface is formed by an aerosol deposition method in which Ni powder is collided at a temperature lower than its melting point.
Further, the metal skin layer 133 formed on the other surface is formed by a cold spray method in which an Al powder is collided at a temperature lower than its melting point.
Note that the thickness ts of the metal skin layers 132 and 133 is set to 0.05 mm ≦ ts ≦ 0.5 mm, and in the present embodiment, ts = 0.25 mm.

Next, a method for manufacturing the semiconductor device according to the present embodiment will be described with reference to FIG.
First, the plate body 31 made of a metal matrix composite material is formed. (Plate main body formation process S11). In this embodiment, an AlSiC composite material is formed by filling a base material made of SiC with aluminum or an aluminum alloy.

A metal skin layer is formed on one surface and the other surface of the plate body 131 made of the AlSiC composite material thus obtained. (Metal skin layer formation process S12).
Ni powder having a particle size of 0.1 μm or more and 10 μm or less is caused to collide with one surface of the plate body 131 through a nozzle at a temperature equal to or lower than the melting point thereof to form a metal skin layer 132 by a so-called aerosol deposition method. The conditions for forming the metal skin layer 132 were an air atmosphere, and an oxygen gas having an atmosphere temperature: room temperature and a flow rate: 1 to 20 l / min was used as a carrier gas.
Further, an Al powder having a particle size of 0.1 μm or more and 10 μm or less is caused to collide with the other surface of the plate body 131 through a nozzle at a temperature equal to or lower than the melting point thereof, thereby forming a metal skin layer 133 by a so-called aerosol deposition method. . The conditions for forming the metal skin layer 133 were as follows. In the air atmosphere, an oxygen gas having an atmosphere temperature: room temperature and a flow rate: 1 to 20 l / min was used as the carrier gas.
Thus, the heat sink 130 which is this embodiment is produced.

  Next, the cooler 140 is joined to the other surface side of the heat radiating plate 130 (cooler joining step S14). A brazing material is interposed between the metal skin layer 133 formed on the other surface of the heat sink 130 and the cooler 140, and the brazing process is performed by charging the brazing material. Thereby, the cooler 140 and the heat sink 130 are joined. Here, the brazing temperature is set to 550 to 610 ° C.

Then, the semiconductor chip 103 is placed on the surface of the metal skin layer 132 formed on one surface side of the heat sink 130 via a solder material, and soldered in a reduction furnace (semiconductor element bonding step S15).
Thereby, the semiconductor chip 103 is joined on the heat sink 130 via the solder layer 102, and the semiconductor device 101 which is this embodiment is manufactured.

  According to the heat sink 130 and the semiconductor device 101 according to the present embodiment configured as described above, the heat sink 130 is made of an AlSiC composite material in which aluminum or an aluminum alloy is filled in a base material made of SiC. A plate body 131 and metal skin layers 132 and 133 formed on one surface and the other surface of the plate body 131, respectively. These metal skin layers 132 and 133 are made of a metal powder and its melting point. Since it is formed by the aerosol deposition method in which collision is performed at the following temperature, it becomes possible to stack metal powder on one surface and the other surface of the plate body 131 where SiC and aluminum are exposed. The metal skin layers 132 and 133 that are firmly bonded to each other can be formed.

Further, in the above-described aerosol deposition method, a film is formed by jetting metal powder from a nozzle to collide using oxygen gas as a carrier gas at room temperature, and laminating the metal powder while plastically deforming. Therefore, the metal skin layers 132 and 133 having a very dense structure can be formed.
Therefore, the manufacturing cost of the heat sink 130 can be reduced.

  Further, since the metal skin layers 132 and 133 are formed by colliding with the metal powder, compressive stress is generated on one surface and the other surface of the plate body 131 and inside the metal skin layers 132 and 133 due to the peening effect. Will work. Therefore, even when the metal skin layers 132 and 133 are deteriorated, the metal skin layers 132 and 133 are hardly cracked, and the bonding reliability with the semiconductor chip 103 can be greatly improved.

In the present embodiment, since the metal skin layer 133 formed on the other surface side of the plate body 131 is made of pure aluminum having a purity of 99.0% or more, an aluminum alloy is formed on the other surface side of the heat sink 130. The cooler 140 can be satisfactorily bonded via the brazing material, the deformation resistance of the metal skin layer 133 is reduced, and the thermal stress acting during the cooling cycle is relaxed and absorbed by the metal skin layer 133. It becomes possible.
Further, since the metal skin layer 132 formed on one surface side of the plate body 131 is made of nickel, the solder layer 102 is formed on one surface side of the heat dissipation plate 130 without forming a Ni plating film. The semiconductor chip 103 can be bonded via the via.

  In this embodiment, since the metal skin layer 132 formed on one surface side of the plate body 131 is formed by the aerosol deposition method using Ni powder, the Ni powder itself does not melt and the plate body It will be laminated | stacked on one side of 131, and the fine unevenness | corrugation resulting from Ni powder will arise in the surface of the metal skin layer 132. As a result, the surface area of the metal skin layer 132 is increased, the wettability of the solder material is improved, and the semiconductor chip 103 can be reliably bonded via the solder layer 102.

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 plate body of the heat radiating plate is described as being composed of an aluminum graphite composite material in which a carbonaceous member is impregnated with an Al-Si alloy or an AlSiC composite material in which a SiC base material is impregnated with aluminum or an aluminum alloy. However, the present invention is not limited to this, and other metal matrix composite materials such as a Cu-graphite composite material in which a carbonaceous member is impregnated with Cu may be used.

Moreover, although the metal skin layer was demonstrated as what was comprised with aluminum or nickel, it is not limited to this, You may be comprised with the other metal. It is preferable to change the design of the material constituting the metal skin layer as appropriate in consideration of a member to be bonded onto the metal skin layer, a bonding method, and the like.
Furthermore, the thicknesses of the plate body and the metal skin layer are not limited to the present embodiment, and may be appropriately changed in design.

Further, although the semiconductor chip has been described as an example of the heat generating element, the heat generating element is not limited thereto, and may be a heat radiating plate on which another heat generating element such as an electronic component is mounted.
Furthermore, although the semiconductor device provided with the cooler has been described as an example, the present invention is not limited to this and may be provided with no cooler. Moreover, although demonstrated as what joins a cooler by brazing, you may join using an adhesive agent and a solder material, without being limited to this. In addition, the material and structure of the cooler are not limited to the embodiment, and may be appropriately changed in design.

1 Power module (semiconductor device)
3 Semiconductor chip (heating element)
DESCRIPTION OF SYMBOLS 10 Power module substrate 30 Heat sink 31 Plate body 32, 33 Metal skin layer 101 Semiconductor device 102 Solder layer 103 Semiconductor chip (heating element)
130 heat sink 131 plate body 132, 133 metal skin layer

Claims (9)

A heat radiating plate that dissipates heat generated from the mounted heating element,
A plate body made of a metal matrix composite material in which a carbonaceous member is filled with a metal material, and a metal skin layer formed on at least one plate surface of the plate body,
The metal matrix composite material constituting the plate body is formed by impregnating a molten metal material in a carbonaceous member,
The metal skin layer is formed by causing metal powder to collide with the plate surface of the plate main body.   The heat sink according to claim 1, wherein the metal skin layer is formed by an aerosol deposition method. The plate body made of the metal matrix composite material 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 heat radiating plate according to claim 1, wherein the heat radiating plate is provided.   4. The metal material filled in the metal matrix composite material constituting the plate main body and the metal material constituting the metal skin layer are different from each other. 5. The heat sink described.   The metal material filled in the metal matrix composite material constituting the plate body is an Al-Si alloy, and the metal material constituting the metal skin layer is pure aluminum having a purity of 99.99% or more. Item 5. The heat sink according to Item 4.   5. The heat dissipation plate according to claim 4, wherein the metal material filled in the metal matrix composite material constituting the plate body is aluminum or an aluminum alloy, and the metal material constituting the metal skin layer is nickel.   A semiconductor device comprising: the heat sink according to any one of claims 1 to 6; and a semiconductor element mounted on the heat sink. It has a plate body made of a metal matrix composite material filled with a metal material in a carbonaceous member, and is a method of manufacturing a heat radiating plate in which a metal skin layer is formed on at least one plate surface of the plate body,
A plate body forming step of forming a plate body made of a metal matrix composite material by impregnating a molten metal material in a carbonaceous member;
A metal skin layer forming step of forming a metal skin layer by colliding metal powder with the plate surface of the plate body;
The manufacturing method of the heat sink characterized by comprising.   The method for manufacturing a heat sink according to claim 8, wherein the metal skin layer forming step forms the metal skin layer by an aerosol deposition method.

Images