JP2017152528A - Wiring board and semiconductor module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To more accurately measure a current value of a power semiconductor element.SOLUTION: A wiring board includes: a plate-like ceramic substrate part having a front surface and a rear surface; a first wiring part arranged on the front surface; a second wiring part arranged on the rear surface; at least one first via conductor which is arranged in a first through-hole providing communication between the front surface and the rear surface and electrically connects the first wiring part and the second wiring part; and a Rogowski coil which is at least partially embedded in the ceramic substrate part and surrounds the first via conductor.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a wiring board and a semiconductor module using the wiring board.

  Conventionally, in a power semiconductor module including a power semiconductor element, a technique for measuring a current value of a current path with respect to the power semiconductor element has been proposed (see, for example, Patent Documents 1 and 2).

Japanese Patent No. 5172287 Japanese Patent No. 5709161

In recent years, the switching speed of power semiconductor elements has been increased. In a power semiconductor module having a conventional configuration, when a conventional current sensor is connected, the wiring connected to the power semiconductor element is extended, so that the inductance of the wiring increases. When the current sensor is connected by extending the wiring in this way, if the power semiconductor element is switched at high speed, the current value or voltage value during the switching transient causes ringing, and the current value can be measured accurately. It will disappear. Therefore, a technique for measuring the current value without increasing the inductance of the wiring is desired.
Moreover, in the conventional power semiconductor module, in order to measure the electric current which flows into a power semiconductor element, the current sensor was arrange | positioned separately from the wiring board which mounts a power semiconductor element.

  The present invention has been made to solve the above-described problems, and can be realized as the following forms.

(1) According to one aspect of the present invention, a wiring board is provided. The wiring board includes a plate-shaped ceramic substrate portion having a front surface and a back surface, a first wiring portion disposed on the front surface, a second wiring portion disposed on the back surface, and the front surface and the back surface. And at least one first via conductor that electrically connects the first wiring portion and the second wiring portion, and at least inside the ceramic substrate. A Rogowski coil partially embedded and surrounding the first via conductor.

  Here, surrounding is not limited to the case of enclosing the entire circumference of the target part, but is a concept including the case of enclosing a half or more of the target part. Preferably, the wiring board includes a first via conductor group including a plurality of first via conductors.

  According to the wiring board of this form, when the first via conductor is part of the main wiring connected to the main electrode of the power semiconductor element, the current value of the current flowing through the first via conductor is set in the same substrate portion. In addition, the current value can be measured without extending the main wiring length for current measurement because the measurement can be performed by the Rogowski coil embedded in the vicinity of the first via conductor.

(2) In the wiring board of the above aspect, the first wiring board is arranged in a second through hole that communicates the third wiring part arranged on the back surface of the ceramic substrate part and the front surface and the back surface, And at least one second via conductor that electrically connects the wiring portion and the third wiring portion. Preferably, the wiring board includes a second via conductor group including a plurality of second via conductors.

(3) In the wiring board of the above aspect, the first via conductor and the Rogowski coil may be formed of a metal including at least one of tungsten and molybdenum. Since tungsten and molybdenum are refractory metals, the first via conductor and the Rogowski coil can be formed by sintering simultaneously with the ceramic substrate portion, and the wiring board of the present invention can be easily manufactured. Can do.

(4) In the wiring board according to (2), the first via conductor, the second via conductor, and the Rogowski coil are formed of a metal including at least one of tungsten and molybdenum. Also good. The first via conductor, the second via conductor, and the Rogowski coil can be formed by sintering simultaneously with the ceramic substrate portion, and the wiring board can be easily manufactured.

(5) In the wiring board of the above aspect, the first wiring portion and the second wiring portion may cover the Rogowski coil when viewed from a direction perpendicular to the surface. If it does in this way, since the Rogowski coil is covered with a conductor from both surfaces, the signal which flows into Rogowski coil from external electromagnetic noise can be protected.

(6) According to the other form of this invention, a semiconductor module provided with the wiring board of the said form and a power semiconductor element is provided. According to this semiconductor module, it is not necessary to increase the number of wires or to extend the wires in order to measure the value of the current flowing through the power semiconductor element. Therefore, the current flowing through the power semiconductor element can be accurately measured without increasing the inductance component of the wiring. It can be measured.

  The present invention can be realized in various forms, for example, in the form of a current detection wiring board, a semiconductor module wiring board, and the like.

It is a top view which shows typically the structure of the semiconductor module as 1st Embodiment of this invention. FIG. 2 is an end view schematically showing a vertical cross-sectional structure along the line AA of the semiconductor module of FIG. 1. FIG. 2 is an exploded plan view showing the wiring board of FIG. 1 in an exploded manner. It is explanatory drawing which shows the flow of the electric current in the semiconductor module of 1st Embodiment. It is a top view which shows typically the structure of the semiconductor module of 2nd Embodiment of this invention. FIG. 6 is an end view schematically showing a vertical cross-sectional structure along the line AA of the semiconductor module of FIG. 5. It is an electric circuit diagram for 1 arm which comprises an inverter circuit. It is a schematic bird's-eye view which shows the module which embodied the circuit structure shown in FIG. It is an end elevation which shows typically the section composition of the semiconductor module of the modification of the semiconductor module of a 2nd embodiment. It is a top view which shows typically the structure of the semiconductor module of 3rd Embodiment of this invention. FIG. 11 is an end view schematically showing a vertical cross-sectional structure along the line AA of the semiconductor module of FIG. 10. It is a top view which shows typically the structure of the semiconductor module of 4th Embodiment. It is an end view which shows schematic structure of the semiconductor module of 5th Embodiment. It is a top view which shows typically the example applied in order to detect the electric current value which the wiring board of 6th Embodiment flows into a bus-bar. FIG. 15 is an end view schematically showing a vertical cross section along the line AA of the wiring board of FIG. 14. It is a top view which shows typically the other example applied in order to detect the electric current value which the wiring board of 7th Embodiment flows into a bus-bar. It is a top view which shows schematic structure of the semiconductor module of 8th Embodiment. It is a top view which shows typically the structure of the semiconductor module of 9th Embodiment. FIG. 19 is an end view schematically showing a vertical cross section along the line AA of the semiconductor module of FIG. 18. It is an end view which shows typically the structure of the semiconductor module of 10th Embodiment. It is sectional drawing which shows typically the structure of the semiconductor module of 11th Embodiment. It is a top view which shows typically the planar structure of the wiring board of 12th Embodiment. FIG. 23 is an end view schematically showing a vertical cross section along the line AA of a semiconductor module to which the wiring board of FIG. 22 is applied. It is a top view which shows typically the plane structure of the wiring board of 13th Embodiment. FIG. 25 is an end view schematically showing a vertical cross section along the line AA of the semiconductor module to which the wiring board of FIG. 24 is applied. It is sectional drawing which shows typically the cross-section of the semiconductor module of 14th Embodiment.

A. First embodiment:
FIG. 1 is a plan view schematically showing the structure of the semiconductor module 1000 as the first embodiment of the present invention, and FIG. 2 is a schematic vertical cross section taken along the line AA in FIG. FIG. The semiconductor module 1000 mainly includes a wiring board 100, a power semiconductor element 200, and a heat dissipation board 300 as an embodiment of the present invention. In this embodiment, the semiconductor module 1000 is a so-called power module, and is used for power control in an electric vehicle, a train, a machine tool, and the like.

As shown in FIGS. 1 and 2, the wiring board 100 includes a ceramic substrate part 10, a main current path forming part 20, and a Rogowski coil 70. The ceramic substrate portion 10 is formed in a plate shape having a front surface 11 and a back surface 19 and having a substantially rectangular shape in plan view (FIG. 1). The ceramic substrate portion 10 has a laminated structure composed of four thin plate-like substrate layers (FIG. 2). In the present embodiment, the ceramic substrate unit 10 is made of alumina (aluminum oxide: Al ₂ O ₃ ). The ceramic substrate unit 10 may be formed of aluminum nitride (AlN), silicon nitride (Si ₃ N ₄ ), LTCC (low temperature co-fired ceramic), or the like.

  The main current path forming unit 20 includes a first wiring unit 40, a plurality of first via conductors 31, a plurality of second via conductors 32, a second wiring unit 50, and a third wiring unit 60. And a main current path (wiring) for the power semiconductor element 200 is formed. Hereinafter, the plurality of first via conductors 31 are referred to as a first via conductor group 30F, and the plurality of second via conductors 32 are referred to as a second via conductor group 30S.

  The first wiring portion 40 is formed on the surface 11 of the ceramic substrate portion 10 in the form of a thick film having a substantially rectangular shape in plan view by electrolytic plating of copper (FIG. 1), and the first via conductor group 30F and the second via conductor group 30F. The via conductor group 30S is electrically connected. The first wiring portion 40 may be formed using any conductive material such as silver, nickel, or aluminum. Further, the first wiring part 40 may be formed by any other method such as electroless plating or printing.

  The first via conductor 31 is filled in the entire first through hole 21 that communicates the front surface 11 and the back surface 19 of the ceramic substrate unit 10. Similarly, the second via conductor 32 fills the entire second through hole 22 that communicates the front surface 11 and the back surface 19 of the ceramic substrate unit 10. In the present embodiment, the first via conductor 31 and the second via conductor 32 are formed of a material mainly composed of tungsten and molybdenum. In addition, when the ceramic substrate part 10 is formed by LTCC, the 1st via conductor 31 and the 2nd via conductor 32 may be formed with the material containing at least one among silver and copper. In addition, any one of the first via conductor 31 and the second via conductor 32 may be formed of a metal including at least one of tungsten and molybdenum.

  The second wiring part 50 is a pad connected to the output terminal, and is formed in a thick film shape on the back surface 19 of the ceramic substrate part 10 by electrolytic plating of copper. What is the first via conductor group 30F? Are electrically connected. In the present embodiment, the second wiring unit 50 is connected to the output terminal via a metal conduction block 306 and a conduction pad 304. The third wiring portion 60 is a pad for mounting the power semiconductor element 200 on the wiring substrate 100, and is formed in a thick film shape on the back surface 19 of the ceramic substrate portion 10 by electrolytic plating of copper. The second via conductor group 30S is electrically connected. In the present specification, “mounting” is a concept including a form mounted on the back surface of the wiring substrate 100 (the back surface 19 side of the ceramic substrate portion 10 in FIG. 2). The 2nd wiring part 50 and the 3rd wiring part 60 may be formed using arbitrary conductive materials, such as silver, nickel, and aluminum. Further, the second wiring part 50 and the third wiring part 60 may be formed by other arbitrary methods such as electroless plating and printing. The second wiring part 50 and the third wiring part 60 are formed in different regions on the back surface 19 of the ceramic substrate part 10.

  As shown in FIG. 1, the Rogowski coil 70 is embedded in the ceramic substrate portion 10 and surrounds the first via conductor group 30 </ b> F, and has a substantially annular return line 78 and a spiral around the return line 78. The coil part 71 wound is provided. The coil unit 71 includes a plurality of first coil elements 72, a plurality of second coil elements 76, and a plurality of third via conductors 74 that connect the first coil elements 72 and the second coil elements 76, respectively. Are arranged in the order of the first coil element 72, the third via conductor 74, the second coil element 76, and the third via conductor 74. Furthermore, one end of the coil portion 71 is connected to the measurement terminal 82 on the surface 11 of the ceramic substrate portion via a via conductor constituting the terminal connection portion 86, and one end of the return line 78 is a via constituting the terminal connection portion 88. It is connected to a measurement terminal 84 on the surface 11 of the ceramic substrate portion through a conductor. The other end of the coil unit 71 and the other end of the return line 78 are connected via a via conductor. Here, “substantially annular” means an annular shape in which a part is cut out.

  In the present embodiment, the first via conductor group 30 </ b> F is disposed inside the ring formed by the coil portion 71 of the Rogowski coil 70. In other words, the coil portion 71 is disposed so as to surround the first via conductor group 30F in plan view.

  The power semiconductor element 200 is a semiconductor element intended for power conversion. In the present embodiment, the power semiconductor element 200 uses a diode made of SiC (Silicon carbide, silicon carbide). As a material of the power semiconductor element 200, Si (Silicon, silicon), GaN (Gallium Nitride, gallium nitride) or the like may be used. Further, as the power semiconductor element 200, a power MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), an IGBT (Insulated Gate Bipolar Transistor), a thyristor, or the like may be used. The power semiconductor element 200 has a cathode electrode 201 formed on the ceramic substrate portion 10 side, and is mounted on the third wiring portion 60 via a bonding material 210 (FIG. 2). Here, the bonding material 210 is, for example, a solder bump. Further, the heat generated in the power semiconductor element 200 is transmitted to the heat dissipation substrate 300 through the copper conductive pad 302.

  FIG. 3 is an exploded plan view showing the wiring substrate 100 in an exploded manner. 3A2, 3 </ b> B <b> 2, 3 </ b> C <b> 2, and 3 </ b> D <b> 2, only the pattern formed on the lower surface of the substrate layer is illustrated for clarity of illustration, and the via pattern is illustrated. Is omitted. 3 (A1) to (A3) are the first substrate layer 12, (B1), (B2) are the second substrate layer 14, (C1), (C2) are the third substrate layer 16, (D1), (D2 ) Shows the fourth substrate layer 18 in plan view together with the via pattern and the wiring pattern formed on the surface. Hereinafter, when the first to fourth substrate layers are not distinguished, they are also simply referred to as substrate layers. FIG. 3 shows a plan view of each substrate layer viewed from the upper side in FIG. Hereinafter, the surface on the surface 11 side of the ceramic substrate portion in FIG. 2 is referred to as an upper surface, and the surface on the back surface 19 side of the ceramic substrate portion in FIG. In FIG. 2, the first coil element 72, the second coil element 76, and the return line 78 are illustrated on the inner side (inside the layer) from the surface of each substrate layer for convenience of illustration. A thick film is formed on the surface.

  As shown in FIG. 3, each of the first substrate layer 12 to the fourth substrate layer 18 is provided with a plurality of through holes. Further, all the through holes are filled with via conductors. A conductor layer having a predetermined shape is formed on at least one of the upper surface and the lower surface. These via conductors and conductor layers are in a conductive state. Details will be described below. In the present embodiment, the wiring board 100 includes 42 first via conductors 31 and 40 second via conductors 32. In FIG. 3, the number is reduced for convenience of illustration. It is shown.

  As shown in FIG. 3A1, the first wiring portion 40 and the measurement terminals 82 and 84 are disposed on the upper surface 121 of the first substrate layer 12. The measurement terminals 82 and 84 are formed in a thick film by electrolytic plating of copper, like the first wiring part 40. As shown in FIG. 3 (A2), a plurality of first coil elements 72 constituting the coil portion 71 are disposed on the lower surface 122 of the first substrate layer 12, and have a substantially annular shape in plan view. In addition, since the 1st coil element 72 is formed in the lower surface 122 of the 1st board | substrate layer 12, it shows with a dotted line and attaches | subjects the code | symbol to one 1st coil element 72, and abbreviate | omits illustration of another code | symbol doing. Hereinafter, similarly, the pattern formed on the lower surface of the substrate layer is illustrated by a dotted line.

  FIG. 3A3 is a diagram showing only the via conductors arranged in the first substrate layer 12. As shown in FIG. 3 (A3), the first substrate layer 12 includes a via conductor 862 that constitutes the terminal connection portion 86 in FIG. 1, a via conductor 882 that constitutes the terminal connection portion 88, and a plurality of via conductors in FIG. A plurality of via conductors 312 constituting the first via conductor 31 and a plurality of via conductors 322 constituting the plurality of second via conductors 32 are formed. In FIG. 3A3, the plurality of via conductors 312 and the plurality of via conductors 322 are surrounded by broken lines and denoted by reference numerals. The plurality of via conductors 312 are connected to the first wiring part 40 on the upper surface 121 side of the first substrate layer 12, and are formed by the plurality of first coil elements 72 on the lower surface 122 side of the first substrate layer 12. It is arranged in the ring. The plurality of via conductors 322 are connected to the first wiring part 40 on the upper surface 121 side of the first substrate layer 12. The via conductor 862 and the via conductor 882 are connected to the measurement terminal 82 and the measurement terminal 84 on the upper surface 121 side of the first substrate layer 12, respectively. 3 (B1), (C1), and (D1) described below, as in FIG. 3 (A3), a plurality of via conductors are indicated by being surrounded by broken lines and denoted by reference numerals. .

  As shown in FIG. 3 (B1), the second substrate layer 14 includes a via conductor 864 that forms the terminal connection portion 86, a via conductor 884 that forms the terminal connection portion 88, and a plurality of first via conductors 31. A plurality of via conductors 314, a plurality of via conductors 324 constituting a plurality of second via conductors 32, and a plurality of via conductors 744 constituting a plurality of third via conductors 74 are formed. Each via conductor 744 is arranged so as to form two rings having different sizes. Each via conductor 744 is connected to the corresponding first coil element 72 on the upper surface 141 side of the second substrate layer 14. As shown in FIG. 3 (B2), a conductor layer constituting the return line 78 is disposed on the lower surface 142 of the second substrate layer 14. The return line 78 is disposed between two rings formed by the plurality of via conductors 744. The return line 78 is connected to a via conductor 744 </ b> P located around the via conductor 884 among the plurality of via conductors 744. Thereby, the return line 78 and the coil part 71 are connected.

  As shown in FIG. 3C1, the third substrate layer 16 includes a via conductor 866 that forms the terminal connection portion 86, a plurality of via conductors 316 that form the plurality of first via conductors 31, and a plurality of second conductors. A plurality of via conductors 326 constituting the plurality of via conductors 32 and a plurality of via conductors 746 constituting the plurality of third via conductors 74 are formed. As shown in FIG. 3 (C2), a plurality of second coil elements 76 constituting the coil portion 71 are disposed on the lower surface 162 of the third substrate layer 16, and have a substantially annular shape in plan view. The plurality of second coil elements 76 are each formed in a thick film shape. The second coil element 76 is connected to the corresponding via conductor 746. One second coil element 76P of the plurality of second coil elements 76 is connected to the via conductor 866. As a result, the measurement terminal 82 is connected to the coil portion 71.

  As shown in FIG. 3 (D1), the fourth substrate layer 18 includes a plurality of via conductors 318 constituting a plurality of first via conductors 31 and a plurality of via conductors constituting a plurality of second via conductors 32. 328 is formed. As shown in FIG. 3 (D 2), the second wiring part 50 and the third wiring part 60 are arranged on the lower surface 182 of the fourth substrate layer 18. The second wiring unit 50 is connected to the plurality of via conductors 318, and the third wiring unit 60 is connected to the plurality of via conductors 328. Similar to the first wiring unit 40, the second wiring unit 50 and the third wiring unit 60 are formed into a thick film by electrolytic plating of copper.

  As described above, the wiring substrate 100 has a structure in which four substrate layers are stacked, and the via conductor 312 (FIG. 3 (A3)), the via conductor 314 (FIG. 3 (B1)), and the via conductor 316. (FIG. 3 (C1)) and the via conductor 318 (FIG. 3 (D1)) constitute a first via conductor 31, and a via conductor 322 (FIG. 3 (A3)) and a via conductor 324 (FIG. 3 (B1)). ), Via conductor 326 (FIG. 3C1), and via conductor 328 (FIG. 3D1) constitute a second via conductor 32. Further, the first coil element 72 (FIG. 3 (A2)), the via conductor 744 (FIG. 3 (B1)), the via conductor 746 (FIG. 3 (C1)), and the second coil element 76 (FIG. 3 (C2)). Thus, the coil portion 71 of the Rogowski coil 70 is configured.

  The measurement terminal 82 (FIG. 3 (A1)) is connected via the via conductor 862 (FIG. 3 (A3)), the via conductor 864 (FIG. 3 (B1)), and the via conductor 866 (FIG. 3 (C1)). , Connected to the second coil element 76 which is one end of the coil portion 71, the measurement terminal 84 (FIG. 3 (A1)), the via conductor 882 (FIG. 3 (A3)), the via conductor 884 (FIG. 3 (B1)). And is connected to one end of a return line 78. A signal processing circuit including an integrator (not shown) is connected to the measurement terminals 82 and 84, and the current value of the current flowing through the main current path forming unit 20 is calculated using the Rogowski coil 70 as will be described later. It can be measured.

  FIG. 4 is an explanatory diagram showing the flow of current in the semiconductor module 1000 of the present embodiment. In FIG. 4, hatching is omitted to clearly show the current flow. When the power semiconductor element 200 is in the ON state, the current supplied to the power semiconductor element 200 through the conduction pad 302 is the third wiring part 60, the plurality of second via conductors 32, the first wiring part 40, The plurality of first via conductors 31 and the second wiring unit 50 flow in the order of the main current path forming unit 20 and flow into the output terminal via the conduction block 306 and the conduction pad 304. When the power semiconductor element 200 is turned on / off, the current flowing through the first via conductor group 30F changes. In the present embodiment, since the Rogowski coil 70 surrounds the first via conductor group 30F in plan view, a voltage signal corresponding to the amount of change in the current flowing through the first via conductor group 30F is measured. 82 and 84. Therefore, by connecting a signal processing circuit including an integrator (not shown) to the measurement terminals 82 and 84, the current value of the current flowing through the main current path forming unit 20 with respect to the power semiconductor element 200 can be measured.

  In the present embodiment, the wiring board 100 is manufactured as follows. The first substrate layer 12 in a state where the first wiring portion 40 and the measurement terminals 82 and 84 shown in FIG. 3A1 are not formed (hereinafter, the first substrate layer 12 in this state is referred to as the first substrate layer 12A). 2), the second substrate layer 14 (FIG. 3 (B1), (B2)), the third substrate layer 16 (FIG. 3 (C1), (C2)), and the second substrate shown in FIG. 3 (D2). The fourth substrate layer 18 in a state where the wiring portion 50 and the third wiring portion 60 are not formed (hereinafter, the fourth substrate layer 18 in this state is referred to as a fourth substrate layer 18A) is laminated and pressure-bonded. To do. The pressure-bonded laminate is fired at the firing temperature (about 1400 to 1600 ° C.) of the first to fourth substrate layers. That is, the ceramic substrate layer and the via conductor group are simultaneously sintered. After that, the first wiring portion 40 and the measurement terminals 82 and 84 shown in FIG. 3A1 are formed on the upper surface 121 of the first substrate layer 12A by electrolytic plating, and the lower surface 182 of the fourth substrate layer 18A is formed with FIG. The second wiring part 50 and the third wiring part 60 shown in D2) are formed by electrolytic plating. Thereby, the wiring board 100 is completed. As a method for manufacturing the wiring board 100 of the present embodiment, a method may be adopted in which a multi-piece substrate in which a plurality of wiring boards 100 are connected is produced and finally divided into each wiring board 100. In the present embodiment, since the wiring board 100 is configured by laminating four board layers, a wiring board integrally including the main current path forming unit 20 for the power semiconductor element 200 and the Rogowski coil 70 is provided. It can be manufactured easily.

  In the present embodiment, the wiring board 100 includes the main current path forming unit 20 for the power semiconductor element 200 and the Rogowski coil 70. Therefore, in order to measure the current value of the current flowing through the main current path forming unit 20 with respect to the power semiconductor element 200, a wiring for measuring the current value is newly provided compared to the case where an ammeter is provided outside the semiconductor module 1000. It is not necessary to provide or extend the cable, and an increase in inductance of the main current path can be suppressed.

  Further, according to the wiring board 100 of the present embodiment, the Rogowski coil 70 is disposed so as to surround the first via conductor group 30F, and the positional relationship between the main current path forming unit 20 and the Rogowski coil 70 is related. Since it is fixed, a stable detection value can be obtained in the detection using the Rogowski coil 70 of the current flowing through the main current path forming unit 20.

  Further, since the first via conductor 31, the second via conductor 32, and the Rogowski coil 70 are all formed of a refractory metal including at least one of tungsten and molybdenum, the ceramic substrate portion 10 and At the same time, it can be formed by sintering, and can be manufactured easily and at low cost.

B. Second embodiment:
FIG. 5 is a plan view schematically showing the structure of a semiconductor module 1000A according to the second embodiment of the present invention, and FIG. 6 is a schematic vertical cross section taken along the line AA in FIG. 5 of the semiconductor module 1000A. FIG. The semiconductor module 1000A of the second embodiment includes terminals 3 and 4 instead of the second via conductor group 30S in the semiconductor module 1000 of the first embodiment. Further, the ceramic substrate 400 may be replaced with the heat dissipation substrate 300 in the semiconductor module 1000 of the first embodiment. In the semiconductor module 1000A of the present embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. In FIG. 5, the display of the power semiconductor element 200 is omitted.

  The terminals 3 and 4 are terminals for exchanging electricity with the outside of the module. The terminal 3 is electrically connected and fixed to the conductor 302 and the terminal 4 is electrically connected to the first wiring portion 40 with solder or the like. The power semiconductor element 200 is connected to the second wiring unit 50. In the present embodiment, a diode chip is used as the power semiconductor element 200. The power semiconductor element 200 has a cathode electrode 201 formed on one surface and is electrically connected to the second wiring part 50 by a bonding material 210. Here, the bonding material 210 is, for example, a solder bump. In FIG. 5, the display of the second wiring unit 50 is omitted for the sake of clarity, but the planar shape of the second wiring unit 50 is a rectangle corresponding to the electrode shape of the power semiconductor element 200. An anode electrode (not shown) is formed on the other surface of the power semiconductor element 200 and is electrically connected to the conductor 302 formed on the ceramic substrate 400 by solder or the like. Therefore, the main current path of the semiconductor module 1000A in the present embodiment is as follows: terminal 3-conductor 302-power semiconductor element 200-second wiring portion 50-first via conductor 31-first wiring portion 40-terminal 4. Become.

As a comparative example, another method for measuring a current value flowing in a conventional semiconductor chip will be described with reference to FIGS.
FIG. 7 is an electric circuit diagram for one arm constituting the inverter circuit, and FIG. 8 is a schematic bird's-eye view schematically showing a module that embodies the circuit structure shown in FIG. In the comparative example, two transistors Q1 and Q2 and diodes D1 and D2 are connected as shown in FIG. P and N are terminals to be connected to the anode and cathode of the DC power source, U is an output terminal to the load, G1, S1, G2, and S2 are control signal terminals and signal feedback terminals of the transistors Q1 and Q2, respectively. is there. The thick line in FIG. 8 is an aluminum wire, and an ultrasonic wave is applied to the surface of the aluminum electrode on the surface of the semiconductor chip (diodes D1, D2 and transistors Q1, Q2) and the nickel-plated copper foil on the ceramic substrate. It is joined. The sizes of the transistors Q1 and Q2 and the diodes D1 and D2 are 5 mm to 1 cm on a side.

  In such a structure, when a conventional current sensor is inserted and the current flowing through the diode is measured, for example, a configuration in which the current sensor is inserted between the diode D1 and the terminal P can be considered. However, in order to insert a current sensor between the diode D1 and the terminal P, the wiring must be greatly extended even if a small current sensor is used, and the inductance of the main current path is greatly increased. As a result, ringing may occur and an accurate current value may not be measured.

  In contrast to the comparative example, according to the semiconductor module 1000A of the second embodiment, an induced electromotive force is generated at both ends of the Rogowski coil 70 according to the amount of change in the current value flowing through the power semiconductor 200 and the first via conductor 31. By applying this to an integrator, the current value of the current flowing through the main current path can be measured. Therefore, the current value can be measured with a compact mounting form without increasing the wiring length necessary for measuring the current value of the power semiconductor element 200.

Modification Example of Second Embodiment FIG. 9 is an end view schematically showing a cross-sectional configuration of a semiconductor module 1000B that is a modification example of the semiconductor module 1000A of the second embodiment. In this example, the second coil element 76 constituting the Rogowski coil 70 is formed on the back surface 19 of the ceramic substrate unit 10. That is, in this example, a part of the Rogowski coil 70 is embedded in the ceramic substrate unit 10. Even in this case, the current value can be measured in a compact mounting form without changing the wiring length necessary for mounting the power semiconductor element 200.

C. Third embodiment:
FIG. 10 is a plan view schematically showing the structure of a semiconductor module 1000C according to the third embodiment of the present invention. FIG. 11 is a schematic vertical cross section taken along the line AA in FIG. 10 of the semiconductor module 1000C. FIG. Similar to the semiconductor module 1000 of the first embodiment, the semiconductor module 1000C of the third embodiment includes a first via conductor group 30FC and a second via conductor group 30SC. However, the number of first via conductors 31 constituting the first via conductor group 30FC and the number of second via conductors 32 constituting the second via conductor group 30SC are different from those of the first embodiment. Further, in the semiconductor module 1000C of the third embodiment, the power semiconductor element 200 is disposed on the first via conductor group 30FC side. The power semiconductor element 200 uses a diode chip as in the second embodiment. Note that the semiconductor module 1000C includes the heat dissipation substrate 300 as in the second embodiment. Even in this case, the current value of the current flowing through the first via conductor group 30FC can be directly measured, and the same effect as in the first embodiment can be obtained. However, when the power semiconductor element 200 is arranged on the second via conductor group 30SC side where the Rogowski coil 70 is not provided as in the first embodiment, the Rogowski coil 70 is connected to the power semiconductor element 200. This is preferable because the influence on the control can be suppressed.

D. Fourth embodiment:
FIG. 12 is a plan view schematically showing the structure of the semiconductor module 1000D of the fourth embodiment. The semiconductor module 1000D uses, as the power semiconductor element 200, a power MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) made of SiC (Silicon carbide). The semiconductor module 1000D further includes a gate unit in addition to the configuration of the wiring board 100 of the first embodiment. The same components as those of the wiring board 100 are denoted by the same reference numerals, and the description thereof is omitted. The gate portion includes a first gate terminal portion G1 formed on the front surface 11 of the ceramic substrate portion 10, a second gate terminal portion (not shown) formed on the back surface 19 of the ceramic substrate portion 10, and a first gate. The first gate via conductor 92, the second gate via conductor 94, the first gate via conductor 92, and the second gate that electrically connect the terminal portion G1 and the second gate terminal portion. And a connection portion 96 for electrically connecting the via conductor 94 for use. Note that the semiconductor module 1000D of the fourth embodiment may include the heat dissipation substrate 300.

E. Fifth embodiment:
FIG. 13 is an end view showing a schematic structure of a semiconductor module 1000E of the fifth embodiment. The semiconductor module 1000E includes a wiring board 100E having the same configuration as that of the wiring board 100A of the second embodiment (same as the wiring board 100A except that the number of first via conductors 31 is different), and a power semiconductor element 200 (second semiconductor module 1000E). The same diode chip as in the embodiment) and a ceramic substrate 400 are provided. In this embodiment, the power semiconductor element 200 is joined to the first wiring portion 40 of the wiring substrate 100E mounted on the conductor 402 of the ceramic substrate 400 by soldering. The cathode electrode 201 is electrically connected to the wiring 404 on the ceramic substrate 400 by the wire W.

F. Sixth embodiment:
FIG. 14 is an explanatory diagram (plan view) for explaining an example in which the wiring board 100G of the sixth embodiment is applied to a bus bar, and FIG. 15 schematically shows a vertical section along the line AA in FIG. FIG. The wiring board 100G includes a first via conductor group 30FG and a second via conductor group 30SG as in the wiring board 100 of the first embodiment. However, the number and arrangement of the first via conductors 31 and the second via conductors 32 are different from those of the wiring substrate 100 of the first embodiment. In the sixth embodiment, the wiring board 100G is attached to the bus bar 502 and the bus bar 504. Here, as shown in FIG. 15, among the pair of bus bars through which the counter current flows, the upper bus bar 502 and the bus bar 504 are divided and electrically connected by the wiring board 100 </ b> G. Moreover, the width | variety of the bus-bar 502 and the bus-bar 504 is about 2-3 cm. For example, when the current flows in the order of bus bar 502-third wiring portion 60-second via conductor group 30SG-first wiring portion 40-first via conductor group 30FG-second wiring portion 50-bus bar 504. If a signal processing circuit including an integrator (not shown) is connected to the measurement terminals 82 and 84, the current value of the path can be measured. That is, a current sensor can be configured using the wiring board 100G. If it does in this way, a current sensor can be reduced in size.

G. Seventh embodiment:
FIG. 16 is a plan view showing an example in which the wiring board 100H of the seventh embodiment is applied to detect the value of the current flowing through the bus bar. In the seventh embodiment, the width of the bus bar 502A and the bus bar 504A is about 1 to 2 cm, and the width is narrower than the bus bar 502 and the bus bar 504 shown in FIG. In the wiring board 100H, the Rogowski coil 70H is formed in an annular shape with a part cut away, and the Rogowski coil 70H is formed so as to surround the first via conductor group 30FH. In this way, even when the width of the bus bar is thin (for example, 1 to 2 cm), the current value of the current flowing between the bus bars can be measured.

H. Eighth embodiment:
FIG. 17 is a plan view showing a schematic structure of a semiconductor module 1000I according to the eighth embodiment. The semiconductor module 1000I includes a wiring board 100I obtained by adding a fourth via conductor group 30I to the wiring board 100C of the third embodiment. The semiconductor module 1000I includes two power semiconductor elements 200A and 200B. The power semiconductor element 200A is a transistor, and the power semiconductor element 200B is a diode. Here, for example, when the semiconductor module 1000I is used as a part of the switching device in the electric circuit shown in FIG. 7, the current flowing in the forward direction in the transistor chip Q1 or Q2 can be measured using the Rogowski coil 70. On the other hand, depending on the type of transistor (for example, an IGBT element), in principle, the diode is designed to pass a current in the opposite direction (reverse direction) to the aforementioned forward direction. Therefore, in this case, if the 1000I of the present embodiment is adopted, the current flowing only in the transistor or only in the diode can be easily measured without causing linking.

I. Ninth embodiment:
18 is a plan view schematically showing the structure of the semiconductor module 1000J of the ninth embodiment, and FIG. 19 is an end face schematically showing a vertical cross section taken along the line AA in FIG. 18 of the semiconductor module 1000J. FIG. The semiconductor module 1000J uses a wiring board 100J instead of the wiring board 100 of the first embodiment. In the wiring board 100J, the first wiring part 40J and the third wiring part 60J are formed larger than the first wiring part 40 and the third wiring part 60 of the wiring board 100 of the first embodiment. The coil 70 is covered. That is, the first wiring part 40J is arranged so as to cover the entire surface corresponding to the area where the Rogowski coil 70 is provided on the surface 11 of the ceramic substrate part 10. The third wiring portion 60J is arranged so as to cover the entire rear surface 19 of the ceramic substrate portion 10 and corresponding to the region where the Rogowski coil 70 is provided. In this way, since the Rogowski coil 70 is covered with the conductor from both sides, the signal flowing through the Rogowski coil can be protected from external electromagnetic noise. In this embodiment, the heat dissipation substrate 300 may be provided.

J. et al. Tenth embodiment:
FIG. 20 is an end view schematically showing the structure of the semiconductor module 1000K of the tenth embodiment. In the semiconductor module 1000K, the power semiconductor element 200 is made of GaN (Gallium Nitride, gallium nitride) and uses a so-called “lateral” diode. The wiring board 100K includes a fourth via conductor group 30K, a fourth wiring part 40K, and a fifth wiring part 50K in addition to the configuration of the wiring board 100 of the first embodiment. The fourth wiring part 40 </ b> K is provided on the front surface 11 of the ceramic substrate part 10, and the fifth wiring part 50 </ b> K is provided on the back surface 19 of the ceramic substrate part 10. The second wiring part 50 is electrically connected to the cathode electrode 201 of the power semiconductor element 200, and the fifth wiring part 50 K is electrically connected to the anode electrode 202 of the power semiconductor element 200. Even in this case, the current value of the current flowing through the power semiconductor element 200 can be accurately measured.

K. Eleventh embodiment:
FIG. 21 is a cross-sectional view schematically showing the structure of the semiconductor module 1000L of the eleventh embodiment. In the wiring substrate 100L, the second coil element 76 is formed on the back surface of the ceramic substrate portion 10L, thereby realizing the wiring substrate 100L having a three-layer structure. In the wiring substrate 100L, a part of the Rogowski coil 70 is embedded in the ceramic substrate portion 10L.

L. Twelfth embodiment:
FIG. 22 is a plan view schematically showing a planar structure of the wiring board 100M of the twelfth embodiment. FIG. 23 is an end view schematically showing a vertical cross section along the line AA in FIG. 22 of the semiconductor module 1000M to which the wiring board 100M is applied. In FIG. 23, the cut surface corresponding to the AA cut surface in FIG. 22 is shown. The Rogowski coil 70M of the wiring board 100M is not provided in a region corresponding to the first wiring part 40. That is, the Rogowski coil 70 is not provided between the first via conductor group 30F and the second via conductor group 30S. The Rogowski coil 70M is formed in an annular shape with a part cut away in a plan view from a direction perpendicular to the surface 11 of the ceramic substrate portion 10M. The notch is formed between the first via conductor group 30F and the first via conductor. It is located in a region corresponding to the two via conductor groups 30S. Since the Rogowski coil 70 is not provided between the first via conductor group 30F and the second via conductor group 30S, the first coil element 72 can be disposed on the surface 11 of the ceramic substrate portion 10M. . Therefore, in the wiring substrate 100M, the first coil element 72 is disposed on the front surface 11 of the ceramic substrate portion 10M, and the second coil element 76 is disposed on the back surface 19 of the ceramic substrate portion 10L, whereby the wiring substrate 100M having a two-layer structure. Is realized. In the wiring substrate 100M, a part of the Rogowski coil 70M is embedded in the ceramic substrate portion 10M.

M.M. Thirteenth embodiment:
FIG. 24 is a plan view schematically showing a planar structure of the wiring board 100P of the thirteenth embodiment. FIG. 25 is an end view schematically showing a cross section taken along line AA in FIG. 24 of the semiconductor module 1000P to which the wiring substrate 100P is applied. In FIG. 25, the cut surface corresponding to the AA cut surface in FIG. 24 is shown. In the wiring board 100P, the return line 78P of the Rogowski coil 70P is disposed outside the coil portion 71P. In this way, since the return line 78P can be disposed on the surface 11 of the ceramic substrate portion 10P, the wiring substrate 100P having a single layer structure can be realized. In the wiring substrate 100P, a part of the Rogowski coil 70P is embedded in the ceramic substrate portion 10P.

N. Fourteenth embodiment:
FIG. 26 is a cross-sectional view schematically showing a cross-sectional structure of a semiconductor module 1000Q of the fourteenth embodiment. The semiconductor module 1000Q is made of the GaN described in the eighth embodiment as the power semiconductor element 200, and uses a so-called “lateral” diode. The wiring substrate 100Q is obtained by forming the second coil element 76 on the back surface 19 of the ceramic substrate portion 10 and arranging the soft magnetic material 79 on the third substrate layer 16 in the wiring substrate 100K of the eighth embodiment. The soft magnetic body 79 may not have the same shape as the return line 78 as long as it exists inside the Rogowski coil along the return line 78 in a plan view from a direction perpendicular to the surface 11. Further, it may be formed in another adjacent layer as shown in FIG. 26 described later, or may be present intermittently. The current value detection sensitivity is increased by the soft magnetic material.

O. Variations:
For example, the present invention can be modified as follows.

(1) In the embodiment described above, the wiring substrate 100 including the power semiconductor element 200 and the main current path forming unit 20 disposed between the output terminals is illustrated. However, the main current path forming unit 20 is connected to the power semiconductor element 200. A main current path may be formed. For example, you may comprise as a wiring board provided with the main current path formation part which forms the main current path between two power semiconductor elements.

(2) In the above-described embodiment and modification, the first via conductor 31 and the second via conductor 32 are formed so as to fill the entire first through hole 21 and the second through hole 22, respectively. However, the entire through hole may not be filled with the via conductor. For example, it may be formed only on the wall surface of the through hole, or it may be filled in a part of the through hole and partly formed only on the wall surface.

(3) In the above-described embodiment and modification, when used in an environment where the use temperature of the wiring board 100 is low, for example, 150 ° C. or less, it is formed of a resin such as glass epoxy instead of the ceramic substrate 10. A resin substrate portion to be used may be used.

(4) In the embodiment and the modification, the wiring board 100 may be a laminated board having five or more layers.

  (5) In each of the above-described embodiments and modifications, a magnetic body may be disposed inside the coil portion 71 that forms the Rogowski coil 70. The magnetic material may be superimposed on the return line 78 or may be formed in a layer different from the layer where the return line 78 is formed. When a magnetic body is arranged inside the coil section 71, most of the magnetic field generated by the current to be measured is collected in the magnetic body, and thus the measurement sensitivity is increased.

DESCRIPTION OF SYMBOLS 10 ... Ceramic substrate part 11 ... Surface 12 ... 1st board | substrate layer 14 ... 2nd board | substrate layer 16 ... 3rd board | substrate layer 18 ... 4th board | substrate layer 19 ... Back surface 20 ... Main current path formation part 21 ... 1st through-hole 22 ... second through hole 30F ... first via conductor group 30S ... second via conductor group 31 ... first via conductor 32 ... second via conductor 40 ... wiring part 50 ... second wiring part 60 ... first 3 wiring part 70 ... Rogowski coil 71 ... coil part 72 ... first coil element 76 ... second coil element 78 ... return line 82, 84 ... measurement terminal 100 ... wiring board 200 ... power semiconductor element 300 ... heat dissipation board 302, 304 ... conductive pad 306 ... conductive block 1000 ... semiconductor module

Claims (6)

A plate-like ceramic substrate portion having a front surface and a back surface;
A first wiring portion disposed on the surface;
A second wiring portion disposed on the back surface;
At least one first via conductor disposed in a first through hole communicating the front surface and the back surface, and electrically connecting the first wiring portion and the second wiring portion;
A Rogowski coil that is at least partially embedded in the ceramic substrate portion and surrounds the first via conductor;
A wiring board comprising: The wiring board according to claim 1,
A third wiring portion disposed on the back surface of the ceramic substrate portion;
At least one second via conductor disposed in a second through-hole communicating the front surface and the back surface, and electrically connecting the first wiring portion and the third wiring portion;
A wiring board comprising: In the wiring board according to claim 1 or 2,
The wiring board, wherein the first via conductor and the Rogowski coil are formed of a metal including at least one of tungsten and molybdenum. The wiring board according to claim 2,
The wiring board, wherein the first via conductor, the second via conductor, and the Rogowski coil are formed of a metal including at least one of tungsten and molybdenum. In the wiring board according to any one of claims 1 to 4,
A wiring board in which the first wiring portion and the second wiring portion cover the Rogowski coil as viewed from a direction perpendicular to the surface.   A semiconductor module provided with the wiring board as described in any one of Claims 1-5, and a power semiconductor element.

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