Power conversion device

Abstract

To provide a power conversion device that reduces a size, ensures an insulation distance, reduces inductance, and improves the reliability of a solder bonded part.SOLUTION: A power conversion device includes: a semiconductor package which has semiconductor elements and constitutes upper and lower arm circuits; and a wiring board which has a wiring layer and electrically connects the wiring layer to one surface of the semiconductor package. The semiconductor package includes: a first conductor which is connected to a main electrode formed on one surface of the semiconductor element and to the high-potential side of the upper and lower arm circuits; and a second conductor which is connected to a main electrode formed on the other surface of the semiconductor element and to the low-potential side of the upper and lower arm circuits. The wiring board and the semiconductor package form a conductive path of an inverter main circuit including the upper and lower arm circuits through connection of the second conductor connected to the low-potential side to the wiring layer.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a power conversion device. [Background technology]

[0002] For example, when a structure in which terminals protruding from a semiconductor module are bent in the stacking direction is adopted for the inverter structure, there is an advantage in that the stress in the solder joints between the terminals and the wiring board can be alleviated, thereby ensuring the reliability of the solder joints. The following Patent Document 1 discloses a configuration in which, in an inverter having the above structure, multiple semiconductor packages are simultaneously mold-sealed, thereby improving reliability and yield. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5370308 Summary of the Invention [Problem to be solved by the invention]

[0004] The structure described in Patent Document 1 ensures the reliability of the solder joints, but it raises the issue of increasing the size of the semiconductor module, and at the same time, it is necessary to solve the issue of ensuring the insulation distance between the terminals. [Means for solving the problem]

[0005] The power conversion device comprises a semiconductor package having a semiconductor element and constituting upper and lower arm circuits, and a wiring board having a wiring layer and electrically connecting the wiring layer to one side of the semiconductor package, the semiconductor package having a main electrode formed on one side of the semiconductor element and a first conductor connected to the high potential side of the upper and lower arm circuits, and a main electrode formed on the other side of the semiconductor element and a second conductor connected to the low potential side of the upper and lower arm circuits, the wiring board and the semiconductor package form a conductive path of an inverter main circuit including the upper and lower arm circuits by connecting the second conductor connected to the low potential side to the wiring layer. Effect of the Invention

[0006] It is possible to provide a power conversion device that achieves reduced size, ensured insulation distance, reduced inductance, and improved reliability of solder joints. [Brief description of the drawings]

[0007] [Figure 1] 1 is a cross-sectional view showing a connection structure between a semiconductor package and a wiring board in a power conversion device according to an embodiment of the present invention, and a power circuit diagram showing upper and lower arm circuits. [Diagram 2] FIG. 1 is a plan view showing a configuration of a terminal provided on a first conductor side according to an embodiment of the present invention; [Diagram 3] FIG. 1 is a cross-sectional view showing a configuration in which a cooler is connected to a wiring board according to an embodiment of the present invention. [Figure 4] FIG. 1 is a cross-sectional view showing a double-sided cooling structure according to an embodiment of the present invention. [Diagram 5] First Modification [Figure 6] Second Variation [Figure 7] Third Modification DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The following description and drawings are examples for explaining the present invention, and appropriate omissions and simplifications have been made for clarity of explanation. The present invention can be implemented in various other forms. Unless otherwise specified, each component may be singular or plural.

[0009] In order to facilitate understanding of the invention, the position, size, shape, range, etc. of each component shown in the drawings may not represent the actual position, size, shape, range, etc. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings.

[0010] (One embodiment of the present invention and overall configuration) (Fig. 1, Fig. 2) FIG. 1(a) is a diagram showing a semiconductor package mounted on a wiring board, and FIG. 1(b) is a power circuit diagram of the upper and lower arm circuits of FIG. 1(a).

[0011] The wiring board 1 has a plurality of wiring layers 2. The wiring board 1 has an upper arm semiconductor package 11 and a lower arm semiconductor package 12 mounted thereon, and one surface of each package is electrically connected to the wiring layer 2 that is provided in the topmost layer of the plurality of wiring layers 2 on the front surface side of the board. This forms a conductive path of the main circuit of the power conversion device including the upper and lower arm circuits. The upper arm semiconductor package 11 and the lower arm semiconductor package 12 respectively constitute the upper and lower arm circuits in the semiconductor package, and have a first conductor 4, a second conductor 5, a semiconductor element 6, a high potential side terminal 9, and a signal terminal 13, and these components are molded and sealed with a resin sealing member 3.

[0012] In each semiconductor package, the first conductor 4 is connected to the high potential side of the upper and lower arm circuits, which is the collector side in the case of an IGBT and the drain side in the case of a MOSFET. The second conductor 5 is connected to the low potential side of the upper and lower arm circuits, which is the emitter side in the case of an IGBT and the source side in the case of a MOSFET. In the explanation of the present invention, the semiconductor package will be described as having a MOSFET structure.

[0013] The first conductor 4 is connected to a main electrode formed on one surface of the semiconductor element 6 and a high potential side terminal 9. A part of the high potential side terminal 9 protrudes to the outside of the sealing member 3 from a surface of the sealing member 3 different from the surface on which the exposed surface of the second conductor 5 connected to the wiring layer 2 is provided. The high potential side terminal 9 has a bent portion 9a bent in the stacking direction, which can reduce the rigidity of the terminal portion and improve the solder reliability.

[0014] The high-potential side terminal 9 is electrically connected at the tip of the terminal protruding outward from the sealing member 3 to the wiring layer 2 of the wiring board 1 via a bonding member 8. The bonding member 8 is, for example, a thermally conductive and electrically conductive material such as solder or sintering.

[0015] The semiconductor element 6 is connected to a signal terminal 13 via a bonding wire. In the semiconductor package, the signal terminal 13 protruding from the surface opposite to the high-potential side terminal 9 to the outside of the sealing member 3 similarly has a bent portion 13a bent in the stacking direction, and the tip of the terminal is electrically connected to the wiring layer 2 of the wiring board 1 via a bonding member 8.

[0016] 2, for example, three high potential side terminals 9 and two signal terminals 13 are provided so as to protrude outward from opposing surfaces of the semiconductor package. The three high potential side terminals are adjacent to each other in the planar direction, which allows the load of stress acting on the terminals to be distributed.

[0017] The signal terminal 13 protrudes to the outside from the sealing member 3, and has a structure in which a bent portion is provided that is bent in the stacking direction, similar to the high potential side terminal 9. The signal terminal 13 is electrically connected to the wiring board 1 via a bonding member 8 at the tip of the terminal that protrudes to the outside from the sealing member 3.

[0018] The second conductor 5 is connected to the surface of the semiconductor element 6 opposite to the surface connected to the first conductor 4. The wiring board 1 has a first through hole 7a in the plate thickness direction at a portion connected to an exposed surface of the second conductor 5 provided on one surface of the semiconductor package. The first through hole 7a is provided so as to pass through the wiring board 1 in the plate thickness direction. The second conductor 5 is electrically and thermally connected to each wiring layer 2 of the wiring board 1 via the first through hole 7a.

[0019] In this way, by consolidating the drain side electrical connection with the first conductor 4 and the source side electrical connection with the second conductor 5, which are at the same potential and are arranged on different sides of the semiconductor package, not only can the insulation distance be secured in advance, but also noise can be reduced since the signal terminal 13 is far from the source side. In addition, the number of drain terminals increases the number of current paths, and the second conductor 5 connected to the low potential side of the semiconductor package is connected to the wiring board 1 to form the inverter main circuit, so that the positive and negative currents are opposed within the wiring board 1, which contributes to reducing inductance.

[0020] (Figure 3) The first wiring board 1 is thermally connected to the first cooler 20a via an insulating heat dissipation member 10 on the surface opposite to the surface where the upper arm semiconductor package 11 and the lower arm semiconductor package 12 are connected. The heat dissipation member 10 is an insulating member such as a heat dissipating resin or a ceramic plate. This ensures insulation between the upper arm semiconductor package 11, the lower arm semiconductor package 12, and the first cooler 20a, and dissipates heat generated by the semiconductor element 6 and the wiring board 1 in the semiconductor package to the first cooler 20a via the through holes 7, thereby reducing the temperature.

[0021] (Figure 4) Upper arm semiconductor package 11 and lower arm semiconductor package 12 are thermally connected to second cooler 20b via heat dissipation member 10 on the surface opposite to the surface connected to wiring board 1. In this manner, the power conversion device may have not only a single-sided cooling structure as shown in FIG. 3, but also a double-sided cooling structure.

[0022] (First Modification) (Figure 5) In the double-sided cooling structure shown in Fig. 4, for example, the second cooler 20b (Fig. 4) may have cooling fins 22, and the upper arm semiconductor package 11 and the lower arm semiconductor package 12 may be thermally connected to the cooling fins 22 via insulating heat dissipation members 10 on the surfaces opposite to the surfaces connected to the wiring board 1. The cooling fins 22 are provided separately corresponding to the upper arm semiconductor package 11 and the lower arm semiconductor package 12, and separate coolers 21 are provided between the cooling fins 22.

[0023] Split cooler 21 forms a flow path with cooler cover 23, and a refrigerant flows through the inside, thereby ensuring heat dissipation from the semiconductor package via cooling fins 22. Split cooler 21 also ensures airtightness of the water path by filling the connection between upper arm semiconductor package 11 and lower arm semiconductor package 12 with seal member 23a. This configuration not only ensures a heat dissipation configuration that matches the respective semiconductor packages, but also allows heat dissipation member 10 between the semiconductor packages and cooling fins 22 to be made as thin as possible, thereby reducing thermal resistance.

[0024] (Second Modification) (Figure 6) Fig. 6(a) is a cross-sectional view showing an example in which through holes of different sizes are provided in wiring board 1, and Fig. 6(b) is a plan view explaining the through holes of different sizes in Fig. 6(a). In addition to first through holes 7a (Fig. 1) connecting upper arm semiconductor package 11 and lower arm semiconductor package 12 to heat dissipation member 10 and first cooler 20a, wiring board 1 may have second through holes 7b provided in the same position in the stacking direction as semiconductor element 6 is provided, and inserted in the plate thickness direction.

[0025] The second through hole 7b has a larger diameter than the first through hole 7a and is connected to the second conductor 5. The second through hole 7b may be filled with a highly thermally conductive bonding material 8. In this manner, by separating the current path by the first through hole 7a and the heat path by the second through hole 7b and aligning the second through hole 7b with the stacking direction of the semiconductor element 6 in the semiconductor package, the heat dissipation of the semiconductor package can be improved.

[0026] (Third Modification) (Figure 7) 6, the wiring board 1 may be provided with a conductor member 24 having thermal conductivity, which is inserted in the thickness direction at the same position as the semiconductor element 6 in the stacking direction. The conductor member 24 is, for example, a copper inlay or a metal block. In this way, the current path by the first through hole 7a and the heat path by the conductor member 24 are separated, and electrical connection and heat dissipation are secured, thereby further improving heat dissipation.

[0027] According to the embodiment of the present invention described above, the following advantageous effects are achieved.

[0028] (1) The power conversion device includes semiconductor packages 11 and 12 having a semiconductor element 6 and constituting upper and lower arm circuits, and a wiring board 1 having a wiring layer 2 and electrically connecting the wiring layer 2 to one side of the semiconductor packages 11 and 12, the semiconductor packages 11 and 12 having a first conductor 4 connected to a main electrode formed on one side of the semiconductor element 6 and the high potential side of the upper and lower arm circuits, and a second conductor 5 connected to a main electrode formed on the other side of the semiconductor element 6 and the low potential side of the upper and lower arm circuits, and the wiring board 1 and the semiconductor packages 11 and 12 form a conductive path of an inverter main circuit including the upper and lower arm circuits by connecting the second conductor 5 connected to the low potential side to the wiring layer 2. In this way, a power conversion device can be provided that realizes size reduction, securing insulation distance, reducing inductance, and improving reliability of solder joints.

[0029] (2) The semiconductor packages 11 and 12 have a high-potential side terminal 9 electrically connected to the first conductor 4, and a sealing member that seals the first conductor 4, the second conductor 5, the semiconductor element 6, and the high-potential side terminal 9, and the high-potential side terminal 9 protrudes to the outside of the sealing member 3 from a surface of the sealing member 3 different from the surface on which the exposed surface of the second conductor 5 is provided. This contributes to ensuring the insulation distance.

[0030] (3) The high potential side terminal 9 includes a plurality of terminals adjacent to each other in the planar direction, which allows the load of the stress applied to the terminals to be distributed.

[0031] (4) The wiring board 1 has a first through hole 7a in the plate thickness direction at a portion connected to the second conductor 5, and the second conductor 5 is electrically and thermally connected to each wiring layer 2 of the wiring board 1 via the first through hole 7a. This contributes to improving heat dissipation.

[0032] (5) The wiring board 1 is thermally connected to the first cooler 20a via the insulating heat dissipation member 10. This can contribute to improving heat dissipation.

[0033] (6) The semiconductor package is thermally connected to the second cooler 20b via the insulating heat dissipation member 10. This can contribute to improving heat dissipation.

[0034] (7) The second cooler 20b has cooling fins 22 provided corresponding to the upper and lower arm semiconductor packages 11, 12. This can reduce thermal resistance.

[0035] (8) In the portion connected to the second conductor 5, the wiring board 1 has a second through hole 7b having a larger diameter than the first through hole 7a at the same position in the stacking direction as the semiconductor element 6, and the second through hole 7b is filled with a thermally conductive bonding member 8. This can improve heat dissipation.

[0036] (9) The wiring board 1 has a thermally conductive conductor member 24 that is inserted in the plate thickness direction at the same position in the stacking direction as the semiconductor element 6 is provided at the portion connected to the second conductor 5. This can improve heat dissipation.

[0037] The present invention is not limited to the above-mentioned embodiment, and various modifications and other configurations can be combined without departing from the spirit of the present invention. Furthermore, the present invention is not limited to those having all of the configurations described in the above-mentioned embodiment, and includes those in which some of the configurations are omitted. [Explanation of symbols]

[0038] 1. Wiring board 2 wiring layers 3 Sealing member 4 First Conductor 5 Second Conductor 6. Semiconductor elements 7 Through Hole 7a 1st through hole 7b 2nd through hole 8 Joining materials 9 High potential terminal 9a Bend part 10 Heat dissipation material 11 Upper arm semiconductor package 12 Lower arm semiconductor package 13 Signal terminal 13a Bend part 20 Cooler 20a 1st cooler 20b 2nd cooler 21 Split cooler 22 Cooling fins 23 Cooler cover 23a Sealing material 24 Conductive material

Claims

1. a semiconductor package having a semiconductor element and constituting upper and lower arm circuits, a wiring board having a wiring layer and electrically connecting the wiring layer to one surface of the semiconductor package; the semiconductor package includes a first conductor connected to a main electrode formed on one surface of the semiconductor element and to a high potential side of the upper and lower arm circuits, and a second conductor connected to a main electrode formed on the other surface of the semiconductor element and to a low potential side of the upper and lower arm circuits, The wiring board and the semiconductor package form a conductive path of an inverter main circuit including the upper and lower arm circuits by connecting the second conductor connected to the low potential side to the wiring layer. Power conversion equipment.

2. The power conversion device according to claim 1, the semiconductor package includes a high-potential side terminal electrically connected to the first conductor, and a sealing member that seals the first conductor, the second conductor, the semiconductor element, and the high-potential side terminal; The high potential side terminal protrudes to the outside of the sealing member from a surface of the sealing member different from a surface on which the exposed surface of the second conductor is provided. Power conversion equipment.

3. The power conversion device according to claim 2, The high potential side terminal includes a plurality of terminals adjacent to each other in a planar direction. Power conversion equipment.

4. The power conversion device according to claim 1, the wiring board has a first through hole in a thickness direction at a portion connected to the second conductor; The second conductor is electrically and thermally connected to each wiring layer of the wiring board via the first through hole. Power conversion equipment.

5. The power conversion device according to claim 1, The wiring board is thermally connected to the first cooler via an insulating heat dissipation member. Power conversion equipment.

6. The power conversion device according to claim 5, The semiconductor package is thermally connected to the second cooler via the insulating heat dissipation member. Power conversion equipment.

7. 7. The power conversion device according to claim 6, The second cooler has cooling fins provided corresponding to the upper and lower arm circuits of the semiconductor package. Power conversion equipment.

8. The power conversion device according to claim 4, the wiring board has a second through hole having a larger diameter than the first through hole at a position where the semiconductor element is provided in a stacking direction in a portion connected to the second conductor, The second through hole is filled with a thermally conductive material. Power conversion equipment.

9. The power conversion device according to claim 1, The wiring board has a thermally conductive conductor member that is inserted in a plate thickness direction at a portion connected to the second conductor and at the same position as the semiconductor element in the stacking direction. Power conversion equipment.

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