JP2011249576A - Diamond-aluminum joined body and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a diamond-aluminum joined body which includes a diamond plate and a metal film composed of pure aluminum or aluminum alloy to mount exothermic materials such as a power semiconductor device and has high adhesion between the diamond plate and the metal film even on a large area with 2 square centimeters of the metal film with small warpage, and its manufacturing method.SOLUTION: The diamond-aluminum joined body has a vapor phase synthesized diamond plate 11 onto which an intermediate layer 31 composed of aluminum alloy including silicon and a metal film 21 composed of pure aluminum or aluminum alloy are formed in order from the vapor phase synthesized diamond plate 11.

Description

  The present invention relates to a diamond-aluminum bonded body that can be used as a heat sink for a power semiconductor element and a method for manufacturing the same.

The power semiconductor element is a semiconductor element used for power control or the like. A heat sink of a power semiconductor element such as an IGBT (Insulated Gate Bipolar Transistor) or a MOSFET (a kind of field effect transistor) includes a heat sink base having high thermal conductivity and insulating properties, and a metal film bonded to the surface of the heat sink base. I have. The heat sink base is made of ceramics such as AlN, Si ₃ N ₄ , Al ₂ O ₃ .

  The metal film to which the power semiconductor element is bonded needs to have a thickness corresponding to the amount of current flowing through the power semiconductor element, and has a thickness of 100 μm or more. This metal film also plays a role of thermal stress relaxation between the power semiconductor element and the heat sink base and a heat spreader. For metal films, Cu and Al are frequently used because they are required to have high conductivity and high thermal conductivity and to be practically inexpensive.

  By the way, instead of the heat sink substrate made of ceramics, a heat sink substrate made of diamond can be used to extend the life of the power semiconductor element, and the power semiconductor element can cope with higher output. It becomes possible. Diamond has a high thermal conductivity (maximum of all materials at room temperature), a low coefficient of thermal expansion and excellent electrical insulation.

  Japanese Patent Application Laid-Open No. 11-26887 discloses a semiconductor laser provided with a diamond heat sink. This semiconductor laser is shown in FIG. FIG. 3 is a diagram for explaining the prior art, and is a cross-sectional view showing the structure of a semiconductor laser provided with a diamond heat sink.

  As shown in FIG. 3, the semiconductor laser covers a plate-like substrate 55, a gas phase synthetic diamond layer 54 having a thickness of 3 μm to 9 μm formed on the surface of the substrate 55, and the surface of the gas phase synthetic diamond layer. And a semiconductor laser chip 51 bonded to the metallized layer 53 by a brazing material layer 52 having a thickness of 2 μm to 8 μm.

  The substrate 55 is made of Si. The metallized layer (metallized layer) 53 is necessary for brazing the semiconductor laser chip 51 to the vapor phase synthetic diamond layer 54 formed on the surface of the substrate 55. The metallized layer 53 is formed by laminating Ti, Pt, and Au in this order from the side in contact with the vapor phase synthetic diamond layer 54. The gas phase synthetic diamond layer 54 and the metallized layer 53 formed on the surface of the substrate 55 constitute a diamond heat sink. The diamond-coated substrate having a gas phase synthetic diamond layer 54 coated on its surface has a square shape of 0.75 mm × 0.75 mm, and as shown in FIG. , Side surfaces) are metallized with Ti, Pt, and Au. Then, a semiconductor laser chip 51 made of InGaAsP of 0.3 mm × 0.3 mm × 0.1 mm is brazed at a brazing temperature of 290 ° C. using an AuSn alloy brazing material on the metallized diamond coated plate. .

  The conventional diamond heat sink described above is for a small semiconductor laser chip having a size of about 0.3 mm × 0.3 mm. Therefore, the metallized layer may be a thin film having a thickness of several μm. Even if a noble metal such as Au or Pt, which is an ideal material for the metallized layer, is used, the cost does not increase so much.

  However, a diamond heat sink having a metallized layer made of a noble metal such as Au or Pt cannot be used for a power semiconductor element of 1 cm square class capable of flowing a large current because of a large cost increase.

In recent years, for inverter circuits for high power, for example, a plate-shaped ceramic heat sink base made of AlN, Al ₂ O _{3 and the} like having a size of about 20 mm × 30 mm, and a metal made of Al or Cu with a thickness of several hundred μm A ceramic heat sink with a brazed film is incorporated. A power semiconductor element such as a large 1 cm square IGBT or FWD (regenerative operation diode) is joined to the metal film. Solder bonding is often used for bonding power semiconductor elements. The metal film serves as a heat spreader as well as a current path.

  When a diamond heat sink substrate is used as an alternative to such a relatively large area ceramic heat sink substrate, expensive metal such as Au cannot be used for the metal film, and it is reasonable to use inexpensive Al or Cu. It is. Al and Cu have advantages and disadvantages, respectively, and are considered to be properly used depending on the application. For example, when lightening the heat sink itself, Al is advantageous.

JP 11-26887 A

  Accordingly, an object of the present invention is to provide a diamond plate and a metal film made of pure aluminum or an aluminum alloy for mounting a heat generating product such as a power semiconductor element, and a diamond plate and the metal even in a 2 cm square class large area metal film. An object of the present invention is to provide a diamond / aluminum bonded body having high adhesion to a film and low warpage, and a method for producing the same.

  In order to solve the above problems, the present invention takes the following technical means.

  The invention of claim 1 is characterized in that a diamond plate comprising an intermediate layer made of a silicon-containing aluminum alloy and a metal film made of pure aluminum or an aluminum alloy on the diamond plate in this order from the diamond plate side. It is an aluminum joined body.

  According to a second aspect of the present invention, in the diamond-aluminum bonded body according to the first aspect, the intermediate layer has a tilted structure, and a thickness of a portion having an average Si content of 5% by mass or more is 5 μm to 100 μm. It is characterized by.

  According to a third aspect of the present invention, in the diamond-aluminum bonded body according to the first or second aspect, the total thickness of the metal film and the intermediate layer is 20 μm to 1 mm.

  According to a fourth aspect of the present invention, in the diamond-aluminum bonded body according to any one of the first to third aspects, the surface roughness Ra of the surface on the intermediate layer side of the diamond plate is in the range of 1 to 10 μm. It is characterized by this.

  The invention of claim 5 is a method for producing a diamond-aluminum joined body having an intermediate layer made of a silicon-containing aluminum alloy and a metal film made of pure aluminum or an aluminum alloy on the diamond plate in this order from the diamond plate side. A first member in which a metal layer made of pure aluminum or a silicon-containing aluminum alloy is formed on a diamond plate, and a second member in which a metal film made of pure aluminum or an aluminum alloy is clad with a silicon-containing aluminum alloy brazing material The brazing flux is applied to the surface of the metal layer of the first member and / or the surface of the silicon-containing aluminum alloy brazing material of the second member, and the brazing flux is applied. In addition, the first member and the second member are arranged so that the surface becomes an overlapping surface. The first member and the second member are heated in an inert gas atmosphere or a vacuum atmosphere, and the silicon-containing aluminum alloy brazing material is melted by heating to overlap the first member and the second member. It is a method for producing a diamond / aluminum bonded body, wherein the metal film is brazed to one member.

  According to a sixth aspect of the present invention, in the method for producing a diamond-aluminum bonded body according to the fifth aspect, the brazing is performed at a brazing temperature of 590 to 605 ° C. and a brazing time of 5 to 10 minutes. It is what.

  The diamond / aluminum bonded body according to the present invention has a structure in which a metal film made of pure aluminum or an aluminum alloy is bonded to the surface of a diamond plate with an intermediate layer made of a silicon-containing aluminum alloy interposed therebetween. Even a large-area metal film has high adhesion between the diamond plate and the metal film and a small warp, and can be suitably used as a heat sink for a power semiconductor element of 1 cm square class, for example.

  According to the method for producing a diamond-aluminum bonded body according to the present invention, a diamond-aluminum bonded body having a high adhesion between a diamond plate and the metal film and a small warpage can be obtained even with a metal film having a large area of 2 cm square. it can.

It is sectional drawing for demonstrating the manufacturing process of the diamond aluminum joined body by one Example of this invention. It is sectional drawing for demonstrating the manufacturing process following the manufacturing process shown in FIG. It is a figure for demonstrating a prior art, Comprising: It is sectional drawing which shows the structure of the semiconductor laser provided with the heat sink made from a diamond.

  Hereinafter, the present invention will be described in more detail.

  (1) The diamond / aluminum bonded body of the present invention comprises an intermediate layer (hereinafter referred to as “Al-Si intermediate layer”) made of a silicon-containing aluminum alloy on a vapor phase synthetic diamond plate in this order from the vapor phase synthetic diamond plate side. And a metal film made of pure aluminum or an aluminum alloy (hereinafter also simply referred to as “Al metal film”), which is referred to as a vapor-phase synthetic diamond plate / Al—Si intermediate layer / Al metal film. It has a laminated structure. A high temperature is required for direct chemical bonding between Al and diamond C (carbon), and a strong bond cannot be formed at 600 ° C. or lower. In the diamond / aluminum bonded body of the present invention, by interposing an Al-Si intermediate layer between the vapor-phase synthetic diamond plate and the Al metal film, a part of Si in the Al-Si intermediate layer is vapor-phase synthetic diamond. It can be chemically bonded to C of the plate to form a strong bonding interface.

  In the diamond / aluminum bonded body according to the present invention, an Al-Si intermediate layer is interposed between the vapor-phase synthetic diamond plate and the Al metal film, so that the Al metal film is brazed to the vapor-phase synthetic diamond plate. When joining by brazing, brazing temperature can be 590 to 600 ° C., and brazing can be performed at a relatively low temperature compared to the case where the metal film is Cu. Due to the low brazing temperature, the diamond-aluminum bonded body of the present invention reduces the stress generated in the bonded body when it is returned to room temperature after brazing, and the warpage of the bonded body and the peeling off of the Al metal film occur. It becomes difficult to occur.

  It should be noted that a layered structure of vapor phase synthetic diamond plate / Si single layer / Al—Si layer / Al metal film, or a layer of vapor phase synthetic diamond plate / Si single layer / Al layer / Al—Si layer / Al metal film. With the structure, the effect of firmly bonding the Al metal film to the vapor-phase synthetic diamond plate cannot be obtained.

  This is because in the layered structure having the Si simple layer, the layer in contact with the vapor-phase synthesized diamond plate is brittle and the bonding strength with the Al metal film is low. In addition, when the Al metal film is joined to the vapor phase synthetic diamond plate by brazing, Si atoms of the Si single layer diffuse to the Al-Si layer side during the brazing process at a brazing temperature of about 600 ° C. However, heat treatment (brazing) must be continued for a long time until the diffusion reaches a state close to equilibrium. If the brazing time is insufficient, a mixed layer of high-concentration Si and Al remains at the interface with the vapor-phase synthetic diamond plate, and this mixed layer is brittle microcrystals, which reduces the bonding strength of the bonded body. .

  In the case of a laminated structure having a single Si layer, when an Al metal film is joined to a vapor phase synthetic diamond plate by brazing, the formation of an Si single layer on the vapor phase synthetic diamond plate and an aluminum layer Alternatively, it is necessary to perform a two-stage film formation process of forming a silicon-containing aluminum alloy layer. For this reason, there is a disadvantage that productivity per unit time is inferior (throughput is low). On the other hand, the diamond / aluminum bonded body of the present invention does not require the formation of a single Si layer and has excellent productivity per unit time (high throughput).

  (2) Next, the vapor phase synthetic diamond plate will be described. According to a vapor phase synthesis method such as a microwave plasma chemical vapor deposition (CVD) method, a large area polycrystalline diamond of, for example, 2 cm square can be easily formed. In general, polycrystalline diamond has higher mechanical strength than single-crystal diamond. The gas phase synthetic diamond plate in the diamond / aluminum bonded body of the present invention preferably has a surface roughness Ra (arithmetic average roughness Ra defined in JIS B0601) of 1 to 10 μm. If surface roughness Ra is the said range, joining strength with the layer formed in the surface by an anchor effect will become high. When the surface roughness Ra is smaller than the above range, the bonding strength with the layer formed on the surface becomes weak. On the other hand, when the surface roughness Ra is larger than the above range, voids are likely to occur at the bonding interface with the layer formed on the surface, which is not preferable.

  Further, the surface of the vapor phase synthetic diamond plate may be composed of typical low-order crystal planes such as {100}, {111}, {311}, {110}, more preferably, It is preferable that the surface is rough enough that a low-order crystal plane cannot be clearly distinguished by surface observation with a scanning electron microscope at a magnification of about 5000 times.

  Such a rough surface state can be realized by etching in an oxygen-containing atmosphere. Specific methods include oxygen plasma treatment, heat treatment in oxygen, and gas phase synthetic diamond plate surface in the air with a flame of a gas burner. As a result, when the Al-Si intermediate layer is present on the surface of the gas phase synthetic diamond plate, not only the anchor effect due to the surface roughness of the gas phase synthetic diamond plate but also the surface area of the gas phase synthetic diamond plate increases. The bond strength with the Al—Si intermediate layer increases due to an increase in chemical bonding sites with the Si atoms in the Al—Si intermediate layer.

  Further, as a secondary matter, the surface of the gas phase synthetic diamond plate is oxygen-terminated, and a bond between C of the gas phase synthetic diamond plate and Si atoms in the Al—Si intermediate layer can also exist in the form of C—O—Si. As described above, when the surface of the gas phase synthetic diamond plate is oxygen-terminated, even when the surface area is the same, the number of chemical bonding sites is increased and the bonding strength is increased as compared with those having many hydrogen terminations.

  (3) Next, the Al—Si intermediate layer will be described. In the diamond-aluminum bonded body of the present invention, the interface between the Al—Si intermediate layer and the Al metal film may not be clear, and the Al—Si intermediate layer may have a gradient composition. In addition, the Al—Si intermediate layer may not have a uniform structure and may have a dispersed structure. The Al—Si intermediate layer usually has a gradient composition because Si is diffused by brazing (heat treatment). Also, it tends to be a distributed structure. On the other hand, the fact that the Al—Si intermediate layer has a graded structure or a dispersed structure is also evidence that brazing (heat treatment) is appropriately performed. The Si content in the Al—Si intermediate layer is preferably in the range of 5 to 30% by mass.

  In the Al—Si intermediate layer, the thickness of the portion having an average Si content of 5% by mass or more is preferably 5 to 100 μm, and more preferably 10 to 50 μm. The thin Al—Si intermediate layer means that when the Al—Si intermediate layer is formed by brazing, a thin silicon-containing aluminum alloy brazing material is naturally used.

  For this reason, when the Al—Si intermediate layer having a thickness of less than 5 μm is formed between the gas phase synthetic diamond plate and the Al metal film by brazing, the uneven surface on the gas phase synthetic diamond plate side and the Al metal are formed. The thin silicon-containing aluminum alloy brazing material does not spread over the uneven surface on the film side. For this reason, a space | gap arises in a junction part or a pinhole arises in the formed Al-Si intermediate | middle layer, and the joining strength of a junction structure falls. The voids not only reduce the bonding strength, but also cause a decrease in thermal resistance. On the other hand, since the Al-Si intermediate layer has a higher resistivity and lower thermal conductivity than pure aluminum, when the thickness of the Al-Si intermediate layer exceeds 100 μm, the Al-Si intermediate layer becomes thinner than pure aluminum. This is not preferable because of its high resistivity and low thermal conductivity.

  (4) Next, the Al metal film will be described. The Al metal film is most preferably made of pure aluminum from the viewpoint of low resistance and high thermal conductivity, but is not limited thereto and may contain some impurities, or may be made of an aluminum alloy. Although it does not specifically limit as an additive element (alloy element) of an aluminum alloy, For example, Mg, Ti, Si, Zn etc. are mentioned, You may contain about 10 mass% in total.

  It is appropriate that the thickness of the Al metal film is determined not by the Al metal film alone but by the thickness including the Al-Si intermediate layer. That is, the total thickness of the Al metal film and the Al—Si intermediate layer is preferably 20 μm to 1 mm, and more preferably 100 to 200 μm.

  When the total thickness is less than 20 μm, since the stress at the bonding interface is small, the possibility that the bonded structure is warped or the Al metal film is peeled off becomes low. On the other hand, when the total thickness exceeds 1 mm, the stress at the bonding interface becomes too large, and the effect of eliminating the warpage of the bonded structure and the peeling of the Al metal film cannot be obtained. In addition, in order to be able to cancel out the warpage as well as the front side surface of the vapor phase synthetic diamond plate, an Al-Si intermediate layer having the same area and thickness as the front side surface is also provided on the back surface of the vapor phase synthetic diamond plate. And a structure including an Al metal film.

  (5) Next, a method for producing a diamond / aluminum bonded body according to the present invention will be described. In this manufacturing method, first, a first member in which a metal layer made of pure aluminum or a silicon-containing aluminum alloy is formed on the surface of a gas phase synthetic diamond plate, and a metal film made of pure aluminum or an aluminum alloy (hereinafter referred to as “Al metal film”). And a second member clad with a silicon-containing aluminum alloy brazing material.

  The gas phase synthetic diamond plate is produced by, for example, a microwave plasma CVD method. Further, the formation of the metal layer on the surface of the vapor-phase synthetic diamond plate is performed by vapor deposition or sputtering.

  As described above, by previously forming the metal layer on the vapor-phase synthetic diamond plate, the metal layer can be brought into close contact with the uneven surface of the vapor-phase synthetic diamond plate prior to brazing. it can. When a silicon-containing aluminum alloy layer is formed as the metal layer, the silicon-containing aluminum alloy layer has a Si content lower than that of the silicon-containing aluminum alloy brazing material. This can prevent the silicon-containing aluminum alloy layer from being softened and peeled off before the silicon-containing aluminum alloy brazing material in brazing.

  Next, a brazing flux is applied to the surface of the metal layer of the first member and / or the surface of the silicon-containing aluminum alloy brazing material of the second member, and the brazing flux is applied. The first member and the second member are overlapped so that the surface becomes an overlapping surface.

The brazing flux is preferably a K-Al-F flux whose flux component is fluoride. The K-AlF Flux, for _{example, KAlF 4 · K 2 AlF 5 ·} H 2 O.

  Next, in the inert gas atmosphere (in a nitrogen gas or argon gas atmosphere) or in a vacuum atmosphere while applying pressure and pressure so that the two members are in close contact with each other, The silicon-containing aluminum alloy brazing material is melted by heating, and the Al metal film is brazed to the first member.

  The brazing may be performed under the conditions of brazing temperature: 590 to 605 ° C. and brazing time: 5 to 10 minutes.

  In this way, on the vapor-phase synthetic diamond plate, in order from the vapor-phase synthetic diamond plate side, an intermediate layer made of a silicon-containing aluminum alloy and a metal film made of pure aluminum or an aluminum alloy have a 1 cm square class. A diamond-aluminum bonded body suitable as a heat sink for power semiconductor elements can be obtained.

  The metal layer formed on the vapor phase synthetic diamond plate may be made of pure aluminum not containing Si. This is because Si contained in the silicon-containing aluminum alloy brazing material diffuses into the metal layer in a relatively short time by brazing. As a result, the obtained diamond / aluminum bonded structure has a structure in which the layer in contact with the vapor phase synthetic diamond plate contains Si, and an Al-Si intermediate layer is interposed between the vapor phase synthetic diamond plate and the Al metal film. Become.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a cross-sectional view for explaining a manufacturing process of a diamond / aluminum bonded body according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view for explaining a manufacturing process subsequent to the manufacturing process shown in FIG.

  (A) As shown in FIG. 1A, a vapor-phase synthetic diamond film 2 was formed on a Si substrate 1 having a 20 mm square and a 1 mm thickness by a microwave plasma CVD method. A mixed gas of hydrogen at a flow rate of 1980 sccm and a flow rate of 20 sccm is flowed into the chamber of the microwave CVD apparatus, and the gas pressure in the chamber is set to 16 kPa. A microwave having a microwave power of 60 kW and a frequency of 915 MHz is introduced into the chamber. Thereby, the mixed gas is turned into plasma, and a vapor-phase synthetic diamond film 2 is formed on the upper surface of the Si substrate 1. The Si substrate 1 is placed on a substrate holder so as to be in contact with plasma. The metal substrate holder was water-cooled from the back side of the holder, so that the surface temperature of the Si substrate 1 was adjusted to 950 ° C. The surface temperature of the Si substrate 1 was measured with an infrared radiation thermometer. The film formation speed under these film formation conditions was measured in advance to form a gas phase synthetic diamond film 11 ′ having a thickness of 200 μm.

  (B) Since a diamond film is also formed on the side surface of the Si substrate 1 (see FIG. 1A), the diamond film on this side surface was removed by skiff polishing (see FIG. 1B). .

  (C) Next, the Si substrate 1 was polished and removed to obtain a vapor-phase synthetic diamond plate 11 that can be handled without the Si substrate 1. The gas phase synthetic diamond plate 11 from which the Si substrate 1 has been removed is slightly warped (see FIG. 1C).

  (D) The surface of the gas phase synthetic diamond plate 11 in which warpage has occurred is skiff-polished to obtain a gas phase synthetic diamond plate 11 without warping (see FIG. 1 (d)).

  (E) Next, the front and back surfaces of the vapor-phase synthetic diamond plate 11 are blown evenly for a short time (10 to 20 seconds) with a flame of a butane gas burner in the atmosphere, so that the surface of the vapor-phase synthetic diamond plate 11 is predetermined. The surface of the gas phase synthetic diamond plate 11 was oxygen-terminated (see (e) of FIG. 1). The surface roughness Ra of the vapor-phase synthetic diamond plate 11 was in the range of 1 to 10 μm. An Al—Si metal layer 12 made of a silicon-containing aluminum alloy, which will be described later, is formed on the surface of the gas phase synthetic diamond plate 11 whose surface roughness is adjusted (roughened) and oxygen-terminated.

  The fact that the surface of the gas phase synthetic diamond plate 11 is oxygen-terminated can also be confirmed by a physical measurement method such as XPS (photoelectron spectroscopy), but the contact angle cannot be measured when a water drop is dropped on the surface. It can be confirmed by being hydrophilic. If the target surface is hydrogen-terminated, it becomes hydrophobic, so that when the water droplet is dropped on the surface, the contact angle of the water droplet becomes 90 ° or more. This is well known.

(F) Next, the surface roughness adjustment (roughening) and the oxygen-terminated gas phase synthetic diamond plate 11 surface (in this embodiment, one side of the gas phase synthetic diamond plate 11) are made of silicon-containing aluminum alloy. An Al—Si metal layer 12 is formed. That is, the gas phase synthetic diamond plate 11 is arranged in the sputtering chamber of the magnetron sputtering apparatus in a state where the edge portion is covered with the adhesive tape so that the film is not formed on the edge portion within 0.5 mm from the edge of the four sides. The Then, an Al—Si metal layer (Si content: 7 mass%) 12 having a thickness of 0.2 is formed on the vapor-phase synthetic diamond plate 11 using a silicon-containing aluminum alloy target (Si content: 7 mass%). did. The sputtering conditions were atmospheric gas: argon gas, gas pressure: 0.3 Pa, DC current: 3 mA / cm ² . After forming the Al-Si metal layer 12, the adhesive tape was removed. Thus, the 1st member 10 by which the Al-Si metal layer 12 was formed in the gaseous-phase synthetic | combination diamond plate 11 surface was obtained (refer (f) of FIG. 2).

  (G) A second member 20 was prepared in which a 50 μm thick silicon-containing aluminum alloy brazing material 22 was clad on one surface of a 350 μm thick Al metal film 21 made of pure aluminum. As the silicon-containing aluminum alloy brazing material 22, a brazing material of JIS A4045 alloy (Al-10 mass% Si alloy) was used. The vertical and horizontal dimensions of the second member 20 are 19 mm square (19 mm × 19 mm).

Then, as shown in FIG. 2G, K-Al-F is formed on the surface of the Al-Si metal layer 12 of the first member 10 and the surface of the silicon-containing aluminum alloy brazing material 22 of the second member 20. A system flux 41 was applied (application amount: 5 g / m ² ).

(H) Next, as shown in (h) of FIG. 2, the first member 10 and the second member 20 are arranged so that the surface coated with the K—Al—F flux 41 becomes an overlapping surface. Are superimposed. The brazing is performed using a heat treatment furnace while applying a pressure load (about 10 g / cm ² ) to the first member 10 and the second member 20 which are the brazing objects. It was.

  The atmosphere in the heat treatment furnace is a nitrogen gas atmosphere having an oxygen concentration of 10 ppm or less. And after raising the said brazing object to 590 degreeC in time 30 minutes, it brazed on the conditions of temperature 590-600 degreeC x time 10 minutes. Next, after the temperature of the brazed object to be brazed was lowered to 200 ° C. in 30 minutes, it was taken out of the heat treatment furnace and allowed to cool naturally to room temperature.

  (I) In this way, on the vapor-phase synthetic diamond plate 11, the Al—Si intermediate layer 31 made of a silicon-containing aluminum alloy and the Al metal film 21 are sequentially formed from the vapor-phase synthetic diamond plate 11 side. A diamond-aluminum bonded body suitable as a heat sink for a 1 cm square class power semiconductor element was produced (see (i) of FIG. 2).

  The warpage of the produced diamond / aluminum bonded body was evaluated by the difference in height between the center point of the Al metal film 21 surface and the edge of the Al metal film 21 surface. Results were obtained. Further, when the cross section of the produced diamond / aluminum bonded body was observed, it was found that the Al metal film 21 was not peeled off from the vapor phase synthetic diamond plate 11 and a desired bonded structure was obtained.

  Further, a diamond / aluminum bonded body was manufactured by using, as a first member, a metal layer made of pure aluminum containing no Si instead of the Al—Si metal layer 12 on the vapor phase synthetic diamond plate 11. The diamond / aluminum bonded body was analyzed by an EDX method (energy dispersive X-ray spectroscopy) at the interface between the vapor-phase synthesized diamond plate and the intermediate layer. As a result, the presence of Si at the interface was detected. From this, Si contained in the silicon-containing aluminum alloy brazing material 22 is diffused into the metal layer made of pure aluminum by brazing, so that an Al—Si intermediate layer is formed as a layer in contact with the vapor-phase synthetic diamond plate 11. It was confirmed that

DESCRIPTION OF SYMBOLS 1 ... Si substrate 2 ... Gas phase synthetic diamond film 10 ... 1st member 11 ... Gas phase synthetic diamond plate 12 ... Al-Si metal layer 20 ... 2nd member 21 ... Al metal film 22 ... Silicon-containing aluminum alloy brazing material 31 ... Al-Si intermediate layer 41 ... K-Al-F flux

Claims (6)

  A diamond-aluminum joined body comprising an intermediate layer made of a silicon-containing aluminum alloy and a metal film made of pure aluminum or an aluminum alloy on a diamond plate in this order from the diamond plate side.   The diamond-aluminum bonded body according to claim 1, wherein the intermediate layer has a gradient structure, and a thickness of a portion having an average Si content of 5 mass% or more is 5 µm to 100 µm.   3. The diamond / aluminum bonded body according to claim 1, wherein a total thickness of the metal film and the intermediate layer is 20 μm to 1 mm.   The diamond-aluminum bonded body according to any one of claims 1 to 3, wherein a surface roughness Ra of the surface on the intermediate layer side of the diamond plate is in a range of 1 to 10 µm. A method for producing a diamond-aluminum joined body having an intermediate layer made of a silicon-containing aluminum alloy and a metal film made of pure aluminum or an aluminum alloy on the diamond plate in this order from the diamond plate side,
A first member in which a metal layer made of pure aluminum or a silicon-containing aluminum alloy is formed on a diamond plate, and a second member in which a metal film made of pure aluminum or an aluminum alloy is clad with a silicon-containing aluminum alloy brazing material are prepared. The brazing flux is applied to the surface of the metal layer of the first member and / or the surface of the silicon-containing aluminum alloy brazing material of the second member, and the surface is coated with the brazing flux. The first member and the second member are superposed so that becomes an overlapping surface, and the superposed first member and second member are heated in an inert gas atmosphere or a vacuum atmosphere. And melting the silicon-containing aluminum alloy brazing material by heating to braze the metal film to the first member, Producing a diamond-aluminum assemblies that.   The method for producing a diamond / aluminum bonded body according to claim 5, wherein the brazing is performed at a brazing temperature of 590 to 605 ° C and a brazing time in a range of 5 to 10 minutes.

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