JP2022038019A - Semiconductor device, manufacturing method of semiconductor device, and power converter - Google Patents

Abstract

To provide a semiconductor device capable of improving reliability by reducing warp of a heat dissipation member.SOLUTION: A semiconductor device 100 includes: an Al heat dissipation member 1; a Cu copper foil 10 as a metal layer formed over a substrate part 1a of the heat dissipation member 1; a wiring board 2 joined with a Cu first conductor layer 2b via solder 11 on the Cu copper foil 10; and a semiconductor element 4 joined via solder 3 on a second conductor layer 2c of the wiring board 2. The thickness of the Cu copper foil 10 is equal to or less than 50% of the thickness of the substrate part 1a of the heat dissipation member 1.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to semiconductor devices, methods for manufacturing semiconductor devices, and power conversion devices.

In a conventional semiconductor device, a wiring board on which a semiconductor element is mounted and a heat-dissipating member joined to the wiring board are provided, and Al (aluminum) is widely used as a material for the heat-dissipating member. In order to solder the heat dissipation member made of Al and the conductor layer of the wiring board, surface treatment such as plating the Al surface with Cu (copper) that is soldered is required, but the Al surface is dense. An oxide film is easily formed and plating is difficult. Therefore, there is a technique of using a Cu—Al clad material in which an Al layer and a Cu layer are integrally bonded as a heat dissipation member (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 9-298259

However, in the semiconductor device described in Patent Document 1, since the heat radiating member is formed of bimetal in which Cu and Al having different coefficients of thermal expansion are bonded together, there is a problem that warpage occurs due to heating.

The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to obtain a semiconductor device in which the warp of a heat radiating member is reduced.

The semiconductor device according to the present disclosure includes a heat radiating member having a substrate portion made of Al or Al alloy, and a metal provided on the substrate portion of the heat radiating member and formed of Cu or Cu alloy or Ni or Ni alloy. A first conductor provided on a layer, a first bonding material provided on a metal layer, and a first conductor provided on the first bonding material and having at least a surface layer on the metal layer side formed of Cu or Cu alloy, or Ni or Ni alloy. A wiring board having a layer, an insulating layer provided on the first conductor layer, and a second conductor layer provided on the insulating layer is joined to the second conductor layer of the wiring board via a second bonding material. It is characterized in that the thickness of the metal layer is 50% or less of the thickness of the substrate portion of the heat radiating member.

The method for manufacturing a semiconductor device according to the present disclosure includes a substrate portion of a heat dissipation member having a substrate portion made of Al or an Al alloy, and a metal layer made of Cu or Cu alloy or Ni or Ni alloy. The first step of joining, the opposite side of the side joined to the substrate portion of the metal layer, and the surface layer provided on one surface of the insulating layer and the insulating layer and at least the opposite side of the insulating layer side are Cu or Cu alloy. Alternatively, a second step of joining the surface layer of the first conductor layer of the wiring substrate having the first conductor layer formed of Ni or Ni alloy and the second conductor layer provided on the other surface of the insulating layer. A third step of joining the second conductor layer of the wiring substrate and the semiconductor element is included, and the thickness of the metal layer is 50% or less of the thickness of the substrate portion of the heat dissipation member. And.

Since the thickness of the metal layer of the semiconductor device according to the present disclosure is 50% or less of the thickness of the substrate portion of the heat radiating member, it has an effect that the warp of the heat radiating member can be reduced and the reliability can be improved. ..

In the method for manufacturing a semiconductor device according to the present disclosure, since the thickness of the metal layer is 50% or less of the thickness of the substrate portion of the heat radiation member, the warp of the heat radiation member is reduced to obtain a semiconductor device with improved reliability. It has the effect of being able to.

It is sectional drawing which shows the semiconductor device of Embodiment 1. FIG. It is a perspective view which shows the structure of a part of the semiconductor device of Embodiment 1. FIG. It is sectional drawing for demonstrating the process of the first half of the manufacturing method of the semiconductor device of Embodiment 1. FIG. It is sectional drawing for demonstrating the latter half process of the manufacturing method of the semiconductor device of Embodiment 1. FIG. It is a perspective view which shows the structure of a part of the modification of the semiconductor device of Embodiment 1. FIG. It is sectional drawing for demonstrating the modification of the manufacturing method of the semiconductor device of Embodiment 1. FIG. It is sectional drawing which shows the semiconductor device of Embodiment 2. It is a perspective view which shows the structure of a part of the semiconductor device of Embodiment 2. It is sectional drawing for demonstrating the process of the first half of the manufacturing method of the semiconductor device of Embodiment 2. It is sectional drawing for demonstrating the latter half process of the manufacturing method of the semiconductor device of Embodiment 2. It is a perspective view which shows the structure of a part of the 1st modification of the semiconductor device of Embodiment 2. FIG. It is sectional drawing which shows the structure of a part of the 2nd modification of the semiconductor device of Embodiment 2. It is a perspective view which shows the structure of a part of the semiconductor device of Embodiment 3. It is sectional drawing for demonstrating the structure of the semiconductor device of Embodiment 3. It is sectional drawing which shows the semiconductor device of Embodiment 4. It is sectional drawing for demonstrating the process of the first half of the manufacturing method of the semiconductor device of Embodiment 4. It is sectional drawing for demonstrating the latter half process of the manufacturing method of the semiconductor device of Embodiment 4. It is sectional drawing which shows the semiconductor device of Embodiment 5. It is sectional drawing for demonstrating the process of the first half of the manufacturing method of the semiconductor device of Embodiment 5. It is sectional drawing for demonstrating the latter half process of the manufacturing method of the semiconductor device of Embodiment 5. It is a block diagram for demonstrating the power conversion apparatus of Embodiment 6.

Hereinafter, embodiments will be described with reference to the drawings. In the following drawings, the same or corresponding parts are designated by the same reference numerals, and the description thereof will not be repeated. Further, the numerical values such as dimensions, temperature, and time described below are examples, and may be other numerical values. Further, in the following description, terms that mean a specific direction of "up" or "down" may be used, but these terms are used for convenience and are used in practice. It has nothing to do with the direction.

Further, in the present disclosure, the term "upper" does not prevent the presence of inclusions between the components. For example, when the description "B provided on A" is described, it includes those in which another component C is provided or not provided between A and B.

Further, in the present disclosure, each member may be described as being made of Al (aluminum), Cu (copper) or Ni (nickel), but Al is an Al alloy containing Al or Al as a main component. What is formed is Cu, which is formed of Cu or a Cu alloy containing Cu as a main component, and Ni, which is formed of Ni or a Ni alloy containing Ni as a main component. It shall mean each.

Embodiment 1.
The semiconductor device of the first embodiment and the manufacturing method of the semiconductor device will be described with reference to FIGS. 1 to 4.

First, the semiconductor device of the first embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a cross-sectional view showing the semiconductor device 100 of the present embodiment, and FIG. 2 is a perspective view showing a partial configuration of the semiconductor device 100.

As shown in FIG. 1, the semiconductor device 100 has a heat radiating member 1 having a substrate portion 1a and pin fins 1b, a copper foil 10 as a metal layer provided on the substrate portion 1a of the heat radiating member 1, and a copper foil 10 on the copper foil 10. 1 A semiconductor element bonded via a solder 3 as a second bonding material on a wiring board 2 to which the first conductor layer 2b is bonded via a solder 11 as a bonding material and a second conductor layer 2c of the wiring board 2. 4. A case 6 bonded to the outer peripheral side surface of the wiring board 2 with an adhesive 5, a main terminal 7a and a signal terminal 7b attached to the case 6, and a wire 8a for electrically connecting the main terminal 7a and the semiconductor element 4. A wire 8b for electrically connecting the signal terminal 7b and the semiconductor element 4 and a sealing material 9 filled in a region surrounded by the heat radiating member 1 and the case 6 are provided.

Here, the copper foil 10 is made of Cu and is bonded to the upper surface of the substrate portion 1a of the heat dissipation member 1 made of Al by silver oxide (not shown in FIG. 1). Further, the first conductor layer 2b and the second conductor layer 2c of the wiring board 2 are made of Cu. Then, the copper foil 10 and the first conductor layer 2b made of Cu are joined by the solder 11 as the first joining material. In other words, the solder 11 is provided on the copper foil 10, and the first conductor layer 2b of the wiring board 2 is provided on the solder 11.

As shown in FIGS. 1 and 2, the heat radiating member 1 has a substrate portion 1a and a plurality of pin fins 1b. The substrate portion 1a has, for example, a flat plate having external dimensions of 85 mm × 70 mm × thickness of 4 mm, and 256 prismatic pin fins 1b (16) having a side surface of 2 mm in width and a height of 8 mm on the lower surface of the substrate portion 1a. × 16) Provided. Further, the heat radiating member 1 is made of Al, and the substrate portion 1a and the pin fin 1b are integrally formed by forging, for example. A copper foil 10 is bonded to the upper surface of the substrate portion 1a of the heat radiating member 1 by silver oxide.

The heat radiating member 1 is not particularly limited as long as it is formed of Al or an Al alloy containing Al as a main component, but if it is formed of an Al alloy such as JIS A6063 or JIS A6061, the thermal conductivity is almost impaired. It is desirable because it is possible to increase the strength without increasing the strength. Further, the heat radiating member may be a member having at least a flat plate-shaped substrate portion, and may be provided with fins other than pin fins, or a fin such as a heat radiating member composed of only a flat plate-shaped substrate portion. It may not be prepared. The thickness of the substrate portion 1a of the heat radiating member 1 is not particularly limited, but is formed to be, for example, 0.5 mm or more and 10 mm or less.

The copper foil 10 is a metal layer made of Cu, and has external dimensions of, for example, 61 mm × 61 mm × thickness 0.2 mm before solder joining. Here, it is conceivable that the copper foil 10 after the solder bonding is diffused and melted in the solder 11 melted during the solder bonding with the first conductor layer 2b of the wiring board 2 to become thinner. The rate of diffusion melting of Cu is about 0.02 μm / s, and the melting time of the solder 11 in the reflow furnace is estimated to be 600 s, and the melting thickness is 12 μm. Therefore, it can be said that the copper foil 10 has sufficient heat resistance to solder bonding by having a thickness of 0.2 mm before solder bonding.

The thickness of the copper foil 10 before soldering is not limited to 0.2 mm, and a copper foil having a desired thickness can be used as the metal layer material, but it can be produced as a single foil. The thickness is preferably 20 μm or more in order to prevent the solder from being diffused and dissolved in the solder and disappearing at the time of solder joining as described above. By doing so, it is possible to prevent the copper foil 10 from being diffused and melted in the solder at the time of solder joining, exposing the substrate portion 1a of the heat radiating member 1 made of Al, and preventing the solder from getting wet, resulting in poor joining. ..

Further, as described above, if the thickness of the copper foil 10 before soldering is 0.2 mm, the thickness of the copper foil 10 after soldering is 0.2 mm or less in consideration of diffusion and melting, so that the thickness is thick. It has a thickness of 5% or less of the 4 mm substrate portion 1a. Since the thickness of the substrate portion 1a of the heat radiating member 1 and the copper foil 10 as the metal layer are significantly different from each other, there is a large difference in the rigidity between the substrate portion 1a and the copper foil 10. Warpage can be suppressed.

In the present embodiment, the copper foil 10 as the metal layer after soldering has a thickness of 5% or less of the substrate portion 1a of the heat radiation member 1, but is not limited to this, and is not limited to this, and is not limited to this. When the thickness of the metal layer is 50% or less of the thickness of the substrate portion of the heat radiating member 1, it is effective in reducing the warp due to the difference in rigidity between the heat radiating member 1 made of Al and the copper foil 10 made of Cu. However, in order to further suppress the warp, the thickness of the metal layer is preferably 20% or less, and more preferably 10% or less of the thickness of the substrate portion of the heat radiation member.

The thickness suitable for the metal layer after solder bonding in consideration of the above is not limited to this, but is 0.1 mm or more and 3 mm or less. The copper foil 10 is not particularly limited as long as it is made of Cu or a Cu alloy, but it is desirable to use a copper foil 10 having a high thermal conductivity such as JIS C1020 or JIS C1100.

As shown in FIG. 1, the wiring substrate 2 is a Cu-made first conductor layer provided on the lower surface of one surface of an AlN (aluminum nitride) ceramic base material 2a as an insulating layer and a ceramic base material 2a. It has a second conductor layer 2c made of Cu provided on the upper surface of the 2b and the other surface of the ceramic base material 2a. That is, the ceramic base material 2a as an insulating layer is provided on the first conductor layer 2b, and the second conductor layer 2c is provided on the ceramic base material 2a. In the wiring board 2, the external dimensions of the ceramic base material 2a are, for example, 65 mm × 65 mm × thickness 0.64 mm, and the external dimensions of the first conductor layer 2b and the second conductor layer 2c are, for example, 61 mm × 61 mm × thickness 0. It is 4 mm. The first conductor layer 2b of the wiring board 2 is provided on the solder 11 and is joined to the copper foil 10 via the solder 11. Further, as shown in FIG. 2, the second conductor layer 2c is composed of a conductor pattern divided into six pieces.

The wiring substrate 2 of the present embodiment has a ceramic base material 2a made of AlN as an insulating layer, but the present invention is not limited to this, and a ceramic base material made of Si _{3N 4 (} silicon nitride) is used. Therefore, the bending strength can be increased to suppress cracking. Further, by using a ceramic base material made of Al ₂ O ₃ (alumina), the coefficient of thermal expansion can be increased, the thermal stress can be reduced, and the reliability can be improved.

As shown in FIGS. 1 and 2, a plurality of semiconductor elements 4 are joined and provided on the second conductor layer 2c of the wiring board 2 via a solder 3. The semiconductor element 4 provided on each divided conductor pattern of the second conductor layer 2c is, for example, a diode made of Si (silicon) having an external dimension of 15 mm × 12 mm × 0.2 mm, and for example, an external dimension of 15 mm × 12 mm. It is an IGBT (Insulated Gate Bipolar Transistor) made of Si of × 0.2 mm. That is, two semiconductor elements 4 are mounted on each of the six conductor patterns constituting the second conductor layer 2c, and twelve semiconductor elements 4 are provided in the entire semiconductor device 100.

In this embodiment, a case where a Si diode and an IGBT are provided as the semiconductor element 4 will be described, but the present invention is not limited to this, and is not limited to this, for example, an IC (Integrated Circuit) or a MOSFET (Metal-Oxide-Semiconductor Field). -A semiconductor element such as an Effect Transistor) may be provided. Further, the semiconductor element is not limited to Si, and may be made of, for example, SiC (silicon carbide) or GaN (gallium nitride).

Further, in the present embodiment, the semiconductor device 100 having a 6in1 module configuration in which 6 pairs of IGBTs and diodes are provided will be described, but the present invention is not limited to this, and discrete components and semiconductor devices in which one semiconductor element is provided are described. It may be a 1in1 module in which one pair is provided, a 2in1 module in which two pairs of semiconductor elements are provided, or the like.

The materials of the solder 11 as the first bonding material and the solder 3 as the second bonding material are, for example, a composition ratio of 96.5 wt% Sn-3.0 wt% Ag-0.5 wt% Cu and a melting point of 219 ° C. A solder manufactured by Senju Metal Co., Ltd. (model number: M705) can be used. The external dimensions of the solder 11 before joining are, for example, 19 mm × 14 mm × thickness 0.3 mm, and the external dimensions of the solder 3 before joining are, for example, 15 mm × 12 mm × thickness 0.1 mm.

The composition ratio of the solders 3 and 11 is not limited to 96.5 wt% Sn-3.0 wt% Ag-0.5 wt% Cu, for example, 98.5 wt% Sn-1 wt% Ag-0.5 wt% Cu, or , 96 wt% Sn-3 wt% Sb-1 wt% Ag or the like may be used as a solder material having a composition ratio. Further, as the first bonding material and the second bonding material, instead of soldering, a highly heat-resistant Cu-Sn paste obtained by dispersing copper powder and coagulating it at an isothermal temperature, or low-temperature firing of nano-silver particles is performed. A nano-silver paste or the like to be bonded may be used.

The case 6 is formed of PPS (Polyphenylene Sulfide) resin and has a frame-like shape having a plurality of surfaces surrounding the outer periphery of the wiring board 2. The heat radiation member 1, the wiring board 2, the copper foil 10, and the solder 11 are made of silicone. It is adhered by the adhesive 5 of. The external dimensions of the case 6 are, for example, 85 mm × 85 mm × height 15 mm.

The case 6 is not limited to the one made of PPS resin, and may be formed by using, for example, an LCP (Liquid Crystal Polymer / liquid crystal polymer) resin or the like. Further, the case 6 is adhered to at least one of the heat radiating member 1, the copper foil 10 as the metal layer, the solder 11 as the first bonding material, and the wiring board 2 by the adhesive 5, and is the material of the sealing material 9. Any structure may be used as long as it does not leak when the solder is injected.

Further, a main terminal 7a and a signal terminal 7b are attached to the case 6 as external terminals by insert molding. The main terminal 7a and the signal terminal 7b are made of Cu and Ni-plated, and their respective thicknesses are, for example, 1.0 mm.

The wires 8a and 8b are made of Al. Of these, the wire 8a that electrically connects the semiconductor element 4 and the main terminal 7a forms a main power circuit, and has a diameter of, for example, 0.4 mm. On the other hand, the wire 8b connecting the semiconductor element 4 and the signal terminal 7b forms a signal circuit, and has a diameter of, for example, 0.15 mm. The wires 8a and 8b are not limited to those made of Al. For example, a ribbon bond made of Al or a wire made of Cu may be used for the wire 8a joined to the main terminal 7a, or a wire connected to the signal terminal 7b. Ag (silver) wire or Au (gold) wire may be used for 8b.

Here, in FIG. 1, the electrical connection between each semiconductor element and the wire is schematically shown, and in FIG. 1, the wire actually existing on the back side of the paper surface is also shown in the figure. The same applies to the illustration of the wire in the other cross-sectional views described below.

The sealing material 9 is filled in a region surrounded by the heat radiating member 1 and the case 6, and insulates and seals the semiconductor element 4 and the wires 8a and 8b. The encapsulant 9 is formed of, for example, a thermosetting silicone gel. The material of the sealing material 9 is not limited to the silicone gel, and may be formed by using, for example, an epoxy resin containing a silica filler or the like.

Next, the method of manufacturing the semiconductor device according to the first embodiment will be described with reference to FIGS. 3 and 4. FIG. 3 is a cross-sectional view for explaining the first half process of the manufacturing method of the semiconductor device 100 of the present embodiment, and FIG. 4 is a cross-sectional view for explaining the second half step of the manufacturing method of the semiconductor device 100. ..

First, as shown in FIG. 3A, silver oxide paste 10a is printed and applied to the upper surface of the substrate portion 1a of the heat radiating member 1 in a range where the copper foil 10 is arranged with a thickness of 50 μm. The silver oxide paste is a paste obtained by diffusing silver oxide powder in a reducing solvent. Then, the copper foil 10 is placed on the printed silver oxide paste 10a and heated at 400 ° C. for 10 minutes while applying a pressure of 1 MPa in the atmosphere to form the substrate portion 1a of the heat radiation member 1 and the copper foil 10. To join.

In addition, in order to suppress the deformation of the pin fin 1b in the above-mentioned joining step, the pin fin may not be arranged in the central portion of the substrate portion, and the central portion may be sandwiched between jigs to apply pressure, or the substrate portion may be applied. A thick pin fin may be provided in the central portion of the above, and the thick pin fin may be sandwiched between jigs to apply pressure. Further, it is also possible to suppress the deformation of the pin fin by forming a recess corresponding to the pin fin in the jig for applying the pressure so that the pressure is not directly applied to the pin fin.

In this way, after the copper foil 10 is bonded to the substrate portion 1a of the heat radiating member 1 via silver oxide (not shown in FIGS. 3B and later), the plate-shaped solder 11 is placed on the copper foil 10. Is arranged, and the wiring board 2 is arranged on the solder 11 so that the first conductor layer 2b side faces each other. Further, 12 plate-shaped solders 3 are arranged on the second conductor layer 2c of the wiring board 2, and the semiconductor element 4 is arranged on each solder 3. Then, by heating using a reflow furnace to melt the solders 3 and 11, the copper foil 10 and the first conductor layer 2b of the wiring board 2 are joined via the solder 11 and the second wiring board 2 is joined. The conductor layer 2c and the semiconductor element 4 are joined via the solder 3. In this way, as shown in FIG. 3C, solder bonding between the copper foil 10 provided on the heat radiating member 1 and the wiring board 2 and solder bonding between the wiring board 2 and the semiconductor element 4 are performed at the same time.

Next, as shown in FIG. 4A, the case 6 in which the main terminal 7a and the signal terminal 7b are insert-molded is subjected to the heat dissipation member 1, the copper foil 10, the solder 11 and the case 6 using the silicone adhesive 5. Adhere to the wiring board 2. At this time, for example, it is heated at 140 ° C. for 10 minutes. Here, the silicone gel injected into the case 6 described later may be adhered so as not to leak out.

After that, as shown in FIG. 4B, the main terminal 7a and the semiconductor element 4 are wired by a wire 8a using a wire bonder to form a main power circuit. Further, the signal terminal 7b and the semiconductor element 4 are wired by a wire 8b using a wire bonder to form a signal circuit.

Finally, as shown in FIG. 4C, the silicone gel is injected into the inside of the case 6, heated at 100 ° C. for 1.5 hours, and further heated at 140 ° C. for 1.5 hours to cure the encapsulant. Insulation sealing is performed as No. 9, and the semiconductor device 100 is completed.

The effect of the semiconductor device 100 and the manufacturing method of the semiconductor device 100 configured as described above will be described.

In semiconductor devices, Al, which has excellent heat dissipation and is lighter than Cu, is widely used as a material for heat dissipation members. Soldering is generally used as a method for joining the heat dissipation member and the wiring board, but since the Al surface does not get wet with solder, in order to solder join the wiring board and the Al heat dissipation member, the heat dissipation member Surface treatment such as plating the surface of the substrate portion with Cu or Ni that is soldered is required. However, there is a problem that plating on the Al surface is difficult because an oxide film on the surface is easily formed and is dense.

Therefore, it is conceivable to provide a solder-wet metal layer made of Cu or the like on the heat-dissipating member, but if the thickness of the substrate portion of the heat-dissipating member and the metal layer are about the same, the heat-dissipating member made of Al and Cu Since the coefficient of thermal expansion of Al is 21 ppm / K and the coefficient of thermal expansion of Cu is 17 ppm / K, the coefficient of thermal expansion is different from that of the metal layer made of copper. There was a concern that the wiring board would crack when the temperature returned to room temperature, and that reliability such as temperature cycle performance would be poor.

Therefore, in the semiconductor device 100 of the present embodiment, since the copper foil 10 is provided on the upper surface of the substrate portion 1a of the heat dissipation member 1, it is not necessary to perform surface treatment such as plating, and the semiconductor device 100 is solder-bonded to the wiring board 2. In addition, since the copper foil 10 made of Cu is sufficiently thin as 5% or less as compared with the substrate portion 1a of the heat radiation member 1 made of Al, warpage due to heating can be suppressed due to the difference in rigidity. , Has the effect of improving reliability. As described above in the description of the copper foil 10, if the metal layer made of Cu has a thickness of 50% or less of the thickness of the substrate portion of the heat dissipation member made of Al, it is effective in reducing the warp due to the difference in rigidity. Yes, a thickness of 20% or less is more preferable, and a thickness of 10% or less is further preferable.

Further, here, in order to plate the substrate portion of the heat dissipation member with Cu, Ni, etc., it is necessary to remove the oxide film on the Al surface as a pretreatment, but the oxide film formed on the Al surface is stable. Therefore, it is necessary to use a strong acid or a strong alkali, and its management and processing are complicated. On the other hand, when copper foil is joined to and attached to the substrate portion of the heat radiation member, brazing or the like is usually used, but in brazing, heating at 600 ° C. needs to be performed in a nitrogen atmosphere, and the conditions are limited. Therefore, in the method for manufacturing the semiconductor device 100 of the present embodiment, the substrate portion 1a of the heat dissipation member 1 and the copper foil 10 are joined to each other by using the silver oxide paste 10a to dissipate heat from Al having an oxide film on the surface. It has the effect that it can be directly bonded to the substrate portion 1a of the member 1 and can be bonded by heating at 400 ° C. in the atmosphere.

Further, since the silver oxide contained in the silver oxide paste 10a described in the present embodiment is a collection of powdered silver, it is easily deformed. Therefore, the strain is smaller than that of directly bonding materials having different coefficients of thermal expansion by solid phase diffusion bonding or the like, and it is possible to reduce the warp. Further, silver oxide has heat resistance against heating at the time of solder bonding between the wiring board 2 and the copper foil 10 as the metal layer, so that it has an effect of high bonding reliability.

In the present embodiment, the case where the copper foil 10 as the metal layer is made of Cu has been described, but the metal layer can be solder-bonded instead of the copper foil 10, and is more diffused into the solder than Cu. By using a nickel foil made of Ni (diffusion rate is about 0.005 μm / s) having a low melting rate, the heat resistance at the time of solder bonding becomes higher. Further, in the present embodiment, since the copper foil 10 as the metal layer is 0.2 mm or less, it is referred to as "copper foil", but it is not necessarily called "metal foil" like "copper foil" or "nickel foil". It does not have to be thin, and any one having a thickness of 50% or less as compared with the thickness of the substrate portion 1a of the heat radiating member 1 is effective.

Further, in the present embodiment, the case where silver oxide is used for joining the substrate portion 1a of the heat radiation member 1 and the copper foil 10 has been described, but the present invention is not limited to this, and the aluminum silicon-based brazing material (bonding temperature) is not limited to this. Can be joined using a brazing material of zinc aluminum (joining temperature is 400 ° C). Furthermore, by eutectic reaction between copper and aluminum (bonding temperature is 540 ° C or higher) or solid phase diffusion bonding (heating at 320 ° C for 30 minutes while pressurizing), bonding as a separate member to the interface It enables bonding with excellent heat conduction without leaving any material.

Further, in the wiring substrate 2 of the present embodiment, the first conductor layer 2b and the second conductor layer 2c are both made of Cu, that is, the first conductor layer 2b and the second conductor layer 2c are made of Cu or Cu alloy, respectively. The first conductor layer and the second conductor layer may be made of Cu or Ni as the surface layer joined by the solders 3 and 11. More specifically, the first conductor layer and the second conductor layer include an inner layer made of Al provided on the ceramic substrate side and a surface layer made of Cu or Ni laminated on the inner layer made of Al. It can be a layered structure including. Here, the surface layer of the first conductor layer is a layer on the opposite side of the ceramic base material 2a as the insulating layer and formed on the solder 11 side as the first bonding material. The surface layer of the second conductor layer is a layer formed on the side opposite to the ceramic base material 2a side and on the solder 3 side as the second bonding material for joining the semiconductor element 4. In other words, the surface layer of the first conductor layer and the second conductor layer of the wiring board may be at least made of Cu or Ni regardless of the layer structure.

As described above, it is desirable that the first conductor layer and the second conductor layer of the wiring board have a layer structure formed of the same material from the viewpoint of moldability. That is, if the first conductor layer 2b is made of Cu, it is desirable that the second conductor layer 2c is made of Cu. Further, if the first conductor layer has a layer structure including an inner layer made of Al and a surface layer made of Cu, it is desirable that the second conductor layer also has a layer structure including an inner layer made of Al and a surface layer made of Cu. If the first conductor layer has a layer structure including an inner layer made of Al and a surface layer made of Ni, it is desirable that the second conductor layer also has a layer structure including an inner layer made of Al and a surface layer made of Ni.

Needless to say, the above-mentioned modifications of the materials and the joining method can be applied to the modifications described below and other embodiments.

A modified example of the semiconductor device according to the first embodiment will be described with reference to FIG. FIG. 5 is a perspective view showing a partial configuration of a semiconductor device according to a modified example of the semiconductor device 100 of the present embodiment.

As shown in FIG. 5, the semiconductor device of the present embodiment is different from the semiconductor device 100 in that the copper foil 13 is a punching metal having a plurality of holes formed therein. Since other configurations of the semiconductor device according to the modified example are the same as those of the semiconductor device 100, the differences from the semiconductor device 100 will be mainly described below.

The copper foil 13 is a punching metal having a plurality of holes penetrating in the thickness direction. Such a copper foil 13 can be formed, for example, by press working. The copper foil 13 is joined onto the substrate portion 1a of the heat radiating member 1 by using a silver oxide paste, similarly to the semiconductor device 100 of the present embodiment. Then, the first conductor layer 2b of the wiring board 2 is bonded onto the copper foil 13 via the plate-shaped solder 11.

In the semiconductor device according to the modified example configured as described above, since air can escape from a plurality of holes, it is possible to suppress the formation of an unjoined portion due to the biting of air. ..

Since the substrate portion 1a of the heat dissipation member 1 made of Al is exposed from the holes in the copper foil 13, the solder 11 for joining to the first conductor layer 2b of the wiring substrate 2 does not partially get wet. It is possible that it will be repelled, but even if voids are generated due to the solder not getting wet, if the voids are small, there will be no problem of poor bonding or thermal resistance.

A modified example of the method for manufacturing the semiconductor device according to the first embodiment will be described with reference to FIG. FIG. 6 is a cross-sectional view for explaining a modified example of the manufacturing method of the semiconductor device 100 of the present embodiment.

As shown in FIG. 6, the method for manufacturing a semiconductor device according to a modification is different from the method for manufacturing a semiconductor device 100 in that the jig 90 for pressurization has a protrusion 91. Since the other steps of the method for manufacturing the semiconductor device according to the modified example are the same as the method for manufacturing the semiconductor device 100, the differences from the method for manufacturing the semiconductor device 100 will be mainly described below.

In the method for manufacturing the semiconductor device 100, as described with reference to FIG. 3A, the copper foil 10 is placed on the printed silver oxide paste 10a and heated while being pressurized to form a substrate portion of the heat radiating member 1. The step of joining 1a and the copper foil 10 is included. In this modification, in this step, a jig 90 having a plurality of protrusions 91 formed at positions in contact with the copper foil 10 is used. The protrusions 91 have, for example, a height of 0.2 mm and are provided at a pitch of 15 mm. The copper foil 10 is pressed by the protrusion 91 of the jig 90 so as to be fitted into the substrate portion 1a of the heat radiation member 1. As shown in FIG. 6, the semiconductor device thus formed has protrusions periodically formed on the copper foil 10 as a metal layer and is embedded in the substrate portion 1a of the heat dissipation member 1. ..

As described above in the description of the first embodiment, the silver oxide paste 10a is used to join the copper foil 10 without removing the oxide film formed on the upper surface of the substrate portion 1a of the heat dissipation member 1 made of Al. However, it is conceivable that the new surface, which is a pure metal surface on which no oxide film or the like is formed, is exposed, so that the joint spreads from the exposed new surface and the joint is accelerated. Therefore, in the method of manufacturing a semiconductor device according to a modified example, the bonding strength can be increased by periodically forming large points of pressurization, which are the starting points of bonding, at equal intervals by the protrusions 91. Play.

Embodiment 2.
The semiconductor device of the second embodiment and the manufacturing method of the semiconductor device will be described with reference to FIGS. 7 to 10. FIG. 7 is a cross-sectional view showing the semiconductor device 200 of the present embodiment, and FIG. 8 is a perspective view showing a partial configuration of the semiconductor device 200. Further, FIG. 9 is a cross-sectional view for explaining the first half process of the manufacturing method of the semiconductor device 200 of the present embodiment, and FIG. 10 is a cross-sectional view for explaining the second half process of the manufacturing method of the semiconductor device 200. Is.

As shown in FIGS. 7 and 8, the semiconductor device 200 of the present embodiment has the semiconductor of the first embodiment in that the copper foil 20 as a metal layer has a slit 22 and is divided into a plurality of portions. Different from device 100. Since the other configurations of the semiconductor device 200 are the same as those of the semiconductor device 100 of the first embodiment, the differences from the semiconductor device 100 will be mainly described below.

As shown in FIG. 7, in the semiconductor device 200, similarly to the semiconductor device 100 of the first embodiment, a copper foil 20 as a metal layer is provided on the substrate portion 1a of the heat radiation member 1, and the copper foil 20 and the wiring board are provided. The first conductor layer 2b of 2 is joined via the solder 21. As shown in FIGS. 7 and 8, the copper foil 20 is divided into a plurality of pieces by the slits 22, and is provided corresponding to the arrangement of the semiconductor elements 4.

The external dimensions of the divided copper foil 20 before solder joining are, for example, 19 mm × 14 mm × thickness 0.2 mm, respectively, and the distance between adjacent copper foils 20, that is, the width of the slit 22 is the vertical direction shown in FIG. It is arranged so as to be 2 mm and 1.25 mm in the depth direction. As shown in FIG. 8, the divided structure of the copper foil 20 as the metal layer provided in the semiconductor device 200 of the present embodiment is a structure divided into 12 so as to have 4 columns × 3 rows in a plan view. .. Here, the second conductor layer 2c of the wiring board 2 has a conductor pattern divided into six, and two semiconductor elements 4 are mounted on each conductor pattern. That is, the copper foil 20 is divided and provided according to the arrangement of the semiconductor elements 4.

In this way, the copper foil 20 is formed so as to exist directly under the semiconductor element 4, and the slit 22 is located directly under the portion where the semiconductor element 4 does not exist, thereby suppressing the deterioration of heat dissipation. At the same time, it is possible to suppress the biting of voids. Therefore, it is desirable that the copper foil 20 is formed in a shape that is the same size as the semiconductor element 4 or larger than the semiconductor element 4 in a plan view and can cover the entire semiconductor element 4.

Next, the manufacturing method of the semiconductor device 200 will be described with reference to FIGS. 9 and 10, focusing on the differences from the semiconductor device 100 of the first embodiment.

First, as shown in FIG. 9A, printing is applied to the upper surface of the substrate portion 1a of the heat radiating member 1 in a range of 12 locations where the copper foil 20 obtained by dividing the silver oxide paste 20a is arranged, each having a thickness of 50 μm. do. Then, the copper foil 20 is placed on the printed silver oxide paste 20a and heated at 400 ° C. for 10 minutes while applying a pressure of 1 MPa in the atmosphere to form the substrate portion 1a of the heat radiation member 1 and the copper foil 20. To join.

After that, 12 plate-shaped solders 21 (external dimensions: 19 mm × 14 mm × thickness 0.3 mm) corresponding to the copper foil 20 are arranged on the copper foil 20, and the first conductor layer 2b faces the solder 21. The wiring board 2 is arranged in such a manner. Further, 12 plate-shaped solders 3 are arranged on the second conductor layer 2c of the wiring board 2, and the semiconductor element 4 is arranged on each solder 3. Then, by heating using a reflow furnace to melt the solders 3 and 11, the copper foil 10 and the first conductor layer 2b of the wiring board 2 are joined via the solder 11 and the second wiring board 2 is joined. The conductor layer 2c and the semiconductor element 4 are joined via the solder 3. In this way, as shown in FIG. 9C, solder bonding between the copper foil 20 provided on the heat radiating member 1 and the wiring board 2 and solder bonding between the wiring board 2 and the semiconductor element 4 are performed at the same time. Then, a slit 22 is formed between the divided adjacent copper foils 20 and between the solders 21. In the solder 21, adjacent plate-shaped solders may be connected to each other at the time of joining.

Next, as shown in FIG. 10 (A), the case 6 in which the main terminal 7a and the signal terminal 7b are insert-molded is subjected to the same as the semiconductor device 100 of the first embodiment by using the silicone adhesive 5. Glue.

After that, as shown in FIG. 10B, the main terminal 7a and the semiconductor element 4 are wired by a wire 8a using a wire bonder to form a main power circuit. Further, the signal terminal 7b and the semiconductor element 4 are wired by a wire 8b using a wire bonder to form a signal circuit.

Finally, as shown in FIG. 10C, the silicone gel is injected into the inside of the case 6 and heated to be cured to perform insulation sealing as the sealing material 9. At this time, by injecting the silicone gel while evacuating, filling can be performed without voids. In this way, the semiconductor device 200 is completed.

In the method of manufacturing the semiconductor device 200 and the semiconductor device 200 configured as described above, in addition to the same effects as the method of manufacturing the semiconductor device 100 and the semiconductor device 100 of the first embodiment, the copper foil as the metal layer Since the 20 is divided, air can escape from the slit 22, and the effect of suppressing the air from being trapped in the joint and existing as a void can be obtained.

A first modification of the semiconductor device of the second embodiment will be described with reference to FIG. FIG. 11 is a perspective view showing a partial configuration of the semiconductor device according to the first modification of the semiconductor device 200 of the present embodiment.

As shown in FIG. 11, the first modification of the semiconductor device of the present embodiment is a semiconductor device in that the copper foil 20 is divided according to the conductor pattern of the second conductor layer 2c of the wiring board 2. Different from 200. Since the other configurations of the semiconductor device according to the first modification are the same as those of the semiconductor device 200, the differences from the semiconductor device 200 will be mainly described below.

As shown in FIG. 11, the copper foil 20 of the semiconductor device according to the first modification is provided corresponding to the arrangement of the six-divided conductor pattern in the second conductor layer 2c of the wiring board 2. Even if it is formed in this way, it is desirable that the copper foil 20 is formed so as to exist directly under the semiconductor element 4, and the slit 22 is arranged directly under the portion where the semiconductor element 4 does not exist. By dividing the copper foil 20 into six parts, the number of parts is reduced as compared with the case of using the copper foil divided into twelve parts, so that the productivity can be improved, and the area occupied by the slit 22 becomes smaller, so that the thermal conductivity is improved. , The heat dissipation can be improved.

The divided structure of the copper foil 20 as the metal layer described above is characterized in that the semiconductor device 200 has a divided structure corresponding to the arrangement of the semiconductor elements 4, and in the first modification, the wiring substrate 2 is used. It is characterized by having a divided structure corresponding to the conductor pattern of the second conductor layer 2c. Therefore, when it is applied to a semiconductor device having a different module configuration, a divided structure corresponding to the arrangement of semiconductor elements or the conductor pattern arrangement of the second conductor layer of the wiring substrate may be used, and the above-mentioned 12-divided or 6-divided structure may be used. Not limited.

A second modification of the semiconductor device of the second embodiment will be described with reference to FIG. FIG. 12 is a cross-sectional view showing a partial configuration of the semiconductor device according to the second modification of the semiconductor device 200 of the present embodiment.

As shown in FIG. 12, a second modification of the semiconductor device of the present embodiment has a frame shape around the upper surface side of the substrate portion 1a of the heat radiation member 1, that is, the side where the copper foil 20 as a metal layer is provided. It differs from the semiconductor device 200 in that the convex portion 1c is provided. Since the other configurations of the semiconductor device according to the first modification are the same as those of the semiconductor device 200, the differences from the semiconductor device 200 will be mainly described below.

As shown in FIG. 12, the heat radiating member 1 has a substrate portion 1a, pin fins 1b provided on the lower surface of the substrate portion 1a, and a convex portion 1c provided in a frame shape on the upper surface of the substrate portion 1a. The convex portion 1c is formed to have a thickness of, for example, 4 mm, and the substrate portion 1a is formed to have a thickness of, for example, 2 mm. In other words, the convex portion 1c and the substrate portion 1a have a total thickness of 6 mm, and the central portion where the convex portion 1c is not provided is a concave portion having a depth of 4 mm. The concave portion has, for example, an external dimension of 66 mm × 66 mm. In this way, the convex portion 1c is provided so as to surround the copper foil 20 as the metal layer.

If the substrate portion 1a of the heat radiating member 1 is made thin, the heat radiating property is improved, but warpage occurs at the time of solder joining, the warp of the wiring board 2 also becomes large, and there is a concern that cracks may occur. Therefore, the rigidity is ensured by leaving a thick portion in the peripheral portion of the heat radiating member 1, and the difference in rigidity from the copper foil 20 has the effect of further suppressing the warp.

Embodiment 3.
The semiconductor device of the third embodiment will be described with reference to FIGS. 13 and 14. FIG. 13 is a perspective view showing a partial configuration of the semiconductor device of the present embodiment, and FIG. 14 is a cross-sectional view for explaining the configuration of the semiconductor device of the present embodiment.

As shown in FIG. 13, the semiconductor device of the present embodiment is different from the semiconductor device 100 of the first embodiment in that a mesh 30 in which a fine wire made of Cu is woven instead of the copper foil 10 is used as the metal layer. .. Since other configurations of the semiconductor device of the present embodiment are the same as those of the semiconductor device 100 of the first embodiment, the differences from the semiconductor device 100 will be mainly described below.

As shown in FIGS. 13 and 14, the mesh 30 as a metal layer is formed by weaving a thin wire made of Cu. As shown in FIG. 14 (A), the mesh 30 has a thickness H1 by knitting a thin wire made of Cu before joining, but is pressurized at the time of joining, so that it is shown in FIG. 14 (B). As such, after joining, it has a thickness H2 smaller than that of H1. Note that FIG. 14B shows a case where the Al substrate portion 1a and the Cu mesh 30 are directly bonded by, for example, solid phase diffusion bonding, and in this case, the mesh 30 is the substrate portion 1a. It is joined so that it digs into it.

Further, as shown in FIG. 14C, the mesh 30 can also be joined using the silver oxide paste 30a. At this time, the mesh 30 may be joined so as to be embedded in the silver oxide paste 30a and may be partially in contact with the substrate portion 1a of the heat radiating member 1. Even in this case, similarly to FIG. 14B, the mesh 30 after joining has a thickness H2 smaller than the thickness H1 before joining.

In the method of manufacturing the semiconductor device and the semiconductor device of the present embodiment configured as described above, in addition to the same effect as the method of manufacturing the semiconductor device 200 and the semiconductor device 200 of the second embodiment, the mesh 30 is used. When used, the contact area is smaller than that of a single foil, so that the surface pressure rises, the Al surface is deformed, the oxide film is broken, and the plastic deformation is easily performed, so that the bondability is improved.

Embodiment 4.
The semiconductor device of the fourth embodiment and the manufacturing method of the semiconductor device will be described with reference to FIGS. 15 to 17. FIG. 15 is a cross-sectional view showing the semiconductor device 400 of the present embodiment. Further, FIG. 16 is a cross-sectional view for explaining the first half process of the manufacturing method of the semiconductor device 400 of the present embodiment, and FIG. 17 is a cross-sectional view for explaining the second half process of the manufacturing method of the semiconductor device 400. Is.

In the semiconductor device 400 of the present embodiment, as shown in FIG. 15, the semiconductor element 4 is joined to the main terminals 41 and 42 via the solder 43 to form a main power circuit. It is different from the semiconductor device 200 of. Since the other configurations of the semiconductor device 400 are the same as those of the semiconductor device 200 of the second embodiment, the differences from the semiconductor device 200 will be mainly described below.

Similar to the semiconductor device 200 of the second embodiment, the semiconductor device 400 has a copper foil 20 as a plurality of divided metal layers, and the copper foil 20 and the first conductor layer 2b of the wiring board 2 are soldered to each other. It is joined via 21. The semiconductor device 400 does not use wires to form the circuit of the main power circuit, and the main power circuit is formed by soldering the main terminals 41 and 42 attached to the case 6 by insert molding onto the semiconductor element 4. Has been done. Further, the semiconductor element 4 is not only electrically bonded to the main terminals 41 and 42, but also wire-bonded to a signal terminal (not shown) insert-molded in the case 6.

Next, the manufacturing method of the semiconductor device 400 will be described with reference to FIGS. 16 and 17, focusing on the differences from the semiconductor device 200 of the second embodiment.

First, as shown in FIG. 16A, similarly to the semiconductor device 200 of the second embodiment, the copper foil 20 obtained by dividing the silver oxide paste 20a is arranged on the upper surface of the substrate portion 1a of the heat radiating member 1. Print and apply to 12 areas. Then, the copper foil 20 is placed on the printed silver oxide paste 20a and heated while being pressurized in the atmosphere to join the substrate portion 1a of the heat radiating member 1 and the copper foil 20.

After that, as shown in FIG. 16B, the copper foil 10 and the first conductor layer 2b of the wiring board 2 are joined via the solder 21, and the second conductor layer 2c of the wiring board 2 and the semiconductor element 4 are joined. Is joined via the solder 3. In this way, as shown in FIG. 16C, solder bonding between the copper foil 20 provided on the heat radiating member 1 and the wiring board 2 and solder bonding between the wiring board 2 and the semiconductor element 4 are performed at the same time. Then, a slit 22 is formed between the divided adjacent copper foils 20 and between the solders 21.

Next, as shown in FIG. 17A, the case 6 in which the main terminals 41 and 42 and the signal terminal (not shown) are insert-molded is bonded to each other using a silicone adhesive 5. At this time, the case 6 is adhered, and the plate-shaped solder 43 is sandwiched between the upper surface of the semiconductor element 4 and the main terminals 41 and 42. Then, the main terminals 41 and 42 and the semiconductor element 4 are joined by melting the solder 43 to form a main power circuit. Further, the signal terminal (not shown) and the semiconductor element 4 are wired with a wire made of Al (not shown) using a wire bonder to form a signal circuit. In this way, the case 6 is joined and the circuit is formed as shown in FIG. 17 (B).

Finally, as shown in FIG. 17C, the silicone gel is injected into the inside of the case 6 and heated to be cured to perform insulation sealing as the sealing material 9. In this way, the semiconductor device 400 is completed.

Even in the method of manufacturing the semiconductor device 400 and the semiconductor device 400 configured in this way, the same effect as the manufacturing method of the semiconductor device 200 and the semiconductor device 200 of the second embodiment can be obtained.

Embodiment 5.
The semiconductor device of the fifth embodiment and the manufacturing method of the semiconductor device will be described with reference to FIGS. 18 to 20. FIG. 18 is a cross-sectional view showing the semiconductor device 500 of the present embodiment. Further, FIG. 19 is a cross-sectional view for explaining the first half process of the manufacturing method of the semiconductor device 500 of the present embodiment, and FIG. 20 is a cross-sectional view for explaining the second half process of the manufacturing method of the semiconductor device 500. Is.

As shown in FIG. 18, the semiconductor device 500 of the present embodiment is different from the semiconductor device 200 of the second embodiment in that it does not have a case and has a transfer-molded structure. Since the other configurations of the semiconductor device 500 are the same as those of the semiconductor device 200 of the second embodiment, the differences from the semiconductor device 200 will be mainly described below.

Similar to the semiconductor device 200 of the second embodiment, the semiconductor device 500 has a copper foil 20 as a plurality of divided metal layers, and the copper foil 20 and the first conductor layer 2b of the wiring board 2 are soldered to each other. It is joined via 21. The semiconductor device 500 does not have a case, and has a structure in which the sealing material 51 is molded by a transfer mold and insulated and sealed.

Further, since the semiconductor device 500 does not have a case, the main terminal 7a and the signal terminal 7b are fixed to the heat dissipation member 1, the wiring board 2, the copper foil 20 and the solder 21 by the silicone adhesive 5. It has a structure. Further, the main terminal 7a and the signal terminal 7b are a part of the lead frame.

Next, the manufacturing method of the semiconductor device 500 will be described with reference to FIGS. 19 and 20, focusing on the differences from the semiconductor device 200 of the second embodiment.

First, as shown in FIG. 19A, similarly to the semiconductor device 200 of the second embodiment, the copper foil 20 obtained by dividing the silver oxide paste 20a is arranged on the upper surface of the substrate portion 1a of the heat radiating member 1. Print and apply to 12 areas. Then, the copper foil 20 is placed on the printed silver oxide paste 20a and heated while being pressurized in the atmosphere to join the substrate portion 1a of the heat radiating member 1 and the copper foil 20.

After that, as shown in FIG. 19B, the copper foil 10 and the first conductor layer 2b of the wiring board 2 are joined via the solder 21, and the second conductor layer 2c of the wiring board 2 and the semiconductor element 4 are joined. Is joined via the solder 3. In this way, as shown in FIG. 19C, solder bonding between the copper foil 20 provided on the heat radiating member 1 and the wiring board 2 and solder bonding between the wiring board 2 and the semiconductor element 4 are performed at the same time. Then, a slit 22 is formed between the divided adjacent copper foils 20 and between the solders 21.

Next, as shown in FIG. 20 (A), a Cu lead frame having a thickness of, for example, 0.6 mm including a main terminal 7a and a signal terminal 7b is attached to a heat dissipation member 1 using a silicone adhesive 5. Adhere to the wiring board 2, the copper foil 20, and the solder 21. At this time, for example, it is heated at 140 ° C. for 10 minutes.

After that, as shown in FIG. 20A, the main terminal 7a and the semiconductor element 4 are wired by a wire 8a using a wire bonder to form a main power circuit. Further, the signal terminal 7b and the semiconductor element 4 are wired by a wire 8b using a wire bonder to form a signal circuit.

Finally, as shown in FIG. 20 (B), the entire mold is sandwiched between the upper mold 93 and the lower mold 94, and the transfer mold resin is injected and cured to perform insulation sealing, and FIG. 20 (C). ), The semiconductor device 500 insulated and sealed by the sealing material 51 is completed.

Even in the method of manufacturing the semiconductor device 500 and the semiconductor device 500 configured in this way, the same effect as the manufacturing method of the semiconductor device 200 and the semiconductor device 200 of the second embodiment can be obtained.

Embodiment 6.
The power conversion device of the sixth embodiment, which is equipped with the semiconductor device according to any one of the above-described embodiments 1 to 5, will be described with reference to FIG. FIG. 21 is a block diagram for explaining the power conversion device of the present embodiment, and FIG. 21 as a whole shows a power conversion system to which the power conversion device of the present embodiment is applied. Hereinafter, the case where the sixth embodiment is a three-phase inverter will be specifically described.

The power conversion system shown in FIG. 21 includes the power conversion device 600, the power supply 610, and the load 620 of the present embodiment. The power supply 610 is a DC power supply and supplies DC power to the power conversion device 600. The power supply 610 can be configured with various things, for example, it can be configured with a DC system, a solar cell, a storage battery, or it can be configured with a rectifier circuit or an AC / DC converter connected to an AC system. May be good. Further, the power supply 610 may be configured by a DC / DC converter that converts the DC power output from the DC system into a predetermined power.

The power conversion device 600 is a three-phase inverter connected between the power supply 610 and the load 620, converts the DC power supplied from the power supply 610 into AC power, and supplies AC power to the load 620. As shown in FIG. 21, the power conversion device 600 converts the input DC power into AC power and outputs the main conversion circuit 601 and outputs the control signal for controlling the main conversion circuit 601 to the main conversion circuit 601. It is provided with a control circuit 603.

The load 620 is a three-phase electric motor driven by AC power supplied from the power converter 600. The load 620 is not limited to a specific application, and is an electric motor mounted on various electric devices, and is used as an electric motor for, for example, a hybrid vehicle, an electric vehicle, a railroad vehicle, an elevator, or an air conditioner.

Hereinafter, the details of the power conversion device 600 of the present embodiment will be described. The main conversion circuit 601 includes a switching element and a freewheeling diode (not shown), and by switching the switching element, the DC power supplied from the power supply 610 is converted into AC power and supplied to the load 620. .. There are various specific circuit configurations of the main conversion circuit 601. The main conversion circuit 601 according to the present embodiment is a two-level three-phase full bridge circuit, and has six switching elements and each switching element. It can consist of six anti-parallel freewheeling diodes. The semiconductor device according to any one of the above-described embodiments 1 to 5 is applied to at least one of each switching element and each freewheeling diode of the main conversion circuit 601. The six switching elements are connected in series for each of the two switching elements to form an upper and lower arm, and each upper and lower arm constitutes each phase (U phase, V phase, W phase) of the full bridge circuit. Then, the output terminals of each upper and lower arm, that is, the three output terminals of the main conversion circuit 601 are connected to the load 620.

Further, although the main conversion circuit 601 includes a drive circuit (not shown) for driving each switching element, the drive circuit may be built in the semiconductor device 602, or a drive circuit may be provided separately from the semiconductor device 602. It may be provided. The drive circuit generates a drive signal for driving the switching element of the main conversion circuit 601 and supplies the drive signal to the control electrode of the switching element of the main conversion circuit 601. Specifically, according to the control signal from the control circuit 603 described later, a drive signal for turning on the switching element and a drive signal for turning off the switching element are output to the control electrode of each switching element. When the switching element is kept on, the drive signal is a voltage signal (on signal) equal to or higher than the threshold voltage of the switching element, and when the switching element is kept off, the drive signal is a voltage equal to or lower than the threshold voltage of the switching element. It becomes a signal (off signal).

The control circuit 603 controls the switching element of the main conversion circuit 601 so that the desired power is supplied to the load 620. Specifically, the time (on time) in which each switching element of the main conversion circuit 601 should be in the on state is calculated based on the electric power to be supplied to the load 620. For example, the main conversion circuit 601 can be controlled by PWM control that modulates the on-time of the switching element according to the voltage to be output. Then, a control command (control signal) is output to the drive circuit provided in the main conversion circuit 601 so that an on signal is output to the switching element that should be turned on at each time point and an off signal is output to the switching element that should be turned off. Is output. The drive circuit outputs an on signal or an off signal as a drive signal to the control electrode of each switching element according to this control signal.

In the power conversion device of the present embodiment, the semiconductor device according to any one of the first to fifth embodiments is applied to at least one of the switching element and the freewheeling diode of the main conversion circuit 601, so that the reliability can be improved. It has the effect of being able to do it.

In this embodiment, an example of application to a two-level three-phase inverter has been described, but the present invention is not limited to this, and can be applied to various power conversion devices. In the present embodiment, a two-level power conversion device is used, but a three-level or multi-level power conversion device may be used, and when supplying power to a single-phase load, it is applied to a single-phase inverter. It doesn't matter. Further, when supplying electric power to a DC load or the like, it is also possible to apply this embodiment to a DC / DC converter or an AC / DC converter.

Further, the power conversion device of the present embodiment is not limited to the case where the load described above is an electric motor, and is, for example, a power supply device of an electric discharge machine, a laser machine, an induction heating cooker, or a non-contact power supply system. It can also be used as a power conditioner for a photovoltaic power generation system, a power storage system, or the like.

It should be noted that it is also included in the scope of the present disclosure that each embodiment is appropriately combined, modified or omitted.

1 Heat dissipation member, 2 Wiring board, 2a Ceramic base material (insulating layer), 2b 1st conductor layer, 2c 2nd conductor layer, 3 Solder (2nd bonding material), 4 Semiconductor element,
10, 13, 20 Copper foil (metal layer), 11, 21 solder (first bonding material), 22 slits, 30 mesh (metal layer),
100, 200, 400, 500, 602 semiconductor devices,
600 power converter, 601 main converter circuit, 603 control circuit

Claims (11)

A heat-dissipating member having a substrate portion made of Al or an Al alloy, and
A metal layer provided on the substrate portion of the heat radiating member and formed of Cu or Cu alloy, or Ni or Ni alloy.
The first bonding material provided on the metal layer and
A first conductor layer provided on the first bonding material, at least the surface layer on the metal layer side is made of Cu or Cu alloy, or Ni or Ni alloy, and an insulating layer provided on the first conductor layer. And a wiring board having a second conductor layer provided on the insulating layer, and
A semiconductor element bonded to the second conductor layer of the wiring board via a second bonding material is provided.
A semiconductor device characterized in that the thickness of the metal layer is 50% or less of the thickness of the substrate portion of the heat radiation member. The semiconductor device according to claim 1, wherein the substrate portion of the heat radiating member and the metal layer are joined by silver oxide. The semiconductor device according to claim 1 or 2, wherein the metal layer has a plurality of holes formed therein. The semiconductor device according to claim 1 or 2, wherein the metal layer has a mesh structure formed by weaving fine wires. The semiconductor device according to any one of claims 1 to 3, wherein the metal layer is divided into a plurality of parts. The semiconductor device according to claim 5, wherein the divided metal layer is provided directly below the semiconductor element. The one according to any one of claims 1 to 6, wherein the heat radiating member has a frame-shaped convex portion provided around the metal layer on the side of the substrate portion where the metal layer is provided. The semiconductor device described. The first step of joining the substrate portion of the heat dissipation member having the substrate portion formed of Al or an Al alloy and the metal layer formed of Cu or Cu alloy or Ni or Ni alloy.
The surface layer on the opposite side of the metal layer to the substrate portion, the insulating layer, and at least the opposite side of the insulating layer side is Cu or Cu alloy, or Ni or Ni. A second step of joining a first conductor layer formed of a Ni alloy and the surface layer of the first conductor layer of a wiring board having a second conductor layer provided on the other surface of the insulating layer.
A third step of joining the second conductor layer of the wiring board and the semiconductor element is included.
A method for manufacturing a semiconductor device, wherein the thickness of the metal layer is 50% or less of the thickness of the substrate portion of the heat radiation member. The method for manufacturing a semiconductor device according to claim 8, wherein in the first step, the substrate portion of the heat radiating member and the metal layer are joined to each other by using a silver oxide paste. The manufacture of the semiconductor device according to claim 8 or 9, wherein in the first step, a jig provided with a protrusion is used to pressurize the metal layer so as to be fitted into the substrate portion. Method. A main conversion circuit having the semiconductor device according to any one of claims 1 to 7 and converting and outputting input power.
A control circuit that outputs a control signal that controls the main conversion circuit to the main conversion circuit, and a control circuit that outputs the control signal to the main conversion circuit.
Power conversion device equipped with.

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