JP2017098427A - Wiring board, electronic device, and electronic module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring board and the like which has a high electric insulation property to an external part of a wiring conductor.SOLUTION: A wiring board 10 comprises: an insulation substrate 1 which is formed by laminating a plurality of insulation layers 2, and includes a first main surface 1a including a concave part 3 to which an electric component 21 is housed, and a second main surface 1b on a side opposite to the first main surface 1a; an insulation auxiliary layer 4 that coats the second main surface 1b; and a wiring conductor 5 that is provided from the concave part 3 to the first main surface 1a. The wiring board includes a mounting part 4b to which an outer surface 4a of the insulation auxiliary layer 4 is arranged so as to face to a circuit conductor 31 of the outer part, and the wiring conductor 5 is not provided to the insulation auxiliary layer 4.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a wiring board having a wiring conductor to which an electronic component is electrically connected, an electronic device including the wiring board, and an electronic module.

  As a wiring board on which electronic components such as a semiconductor element, a sensor element or a capacitor element are mounted, an insulating substrate having a concave portion in which the electronic component is accommodated on the upper surface of the insulating substrate, and from the concave portion of the insulating substrate to the outer surface such as the lower surface What has the wiring conductor provided is used. An electronic device is manufactured by mounting electronic components on the bottom surface of the recess. In the manufactured electronic device, the electronic component and the external electric circuit are electrically connected to each other through the wiring conductor.

  In recent years, a substrate in which a wiring conductor is provided from the inside of the concave portion to the upper surface of an insulating substrate has been used. The electronic device in this case is mounted on the external electric circuit by being turned upside down so that the upper surface of the insulating substrate faces the external electric circuit.

JP 2013-12062 A JP 2008-166358 A Special Table 2004-534392

In the above conventional technique, a circuit conductor may be further arranged on the lower surface side of the insulating substrate. The circuit conductor is, for example, for electrically connecting an electronic device to another electronic component or electronic device, and is connected to an inverter including an IGBT (Insulated Gate Bipolar Transistor) or a power module such as an ECU (Engine Control Unit). Circuit conductors included. In such a case, there is a problem that the electrical insulation between the wiring conductor and the circuit conductor may become insufficient due to, for example, a gap generated in the insulating substrate.

  A wiring board according to one aspect of the present invention includes a first main surface including a plurality of insulating layers and a concave portion in which an electronic component is accommodated, and a second main surface opposite to the first main surface. And an insulating auxiliary layer covering the second main surface, and a wiring conductor provided from the inside of the recess to the first main surface, the outer surface of the auxiliary auxiliary layer being external A mounting portion disposed opposite to the circuit conductor is included, and the wiring conductor is not provided in the auxiliary insulation layer.

  An electronic device according to one aspect of the present invention includes the wiring board having the above-described configuration and an electronic component housed in the recess.

  An electronic module according to an aspect of the present invention includes the electronic device having the above-described configuration and a circuit conductor disposed to face the mounting portion of the electronic device.

According to the wiring substrate of one aspect of the present invention, since the auxiliary insulation layer is disposed on the second main surface of the insulating substrate, for example, when the first main surface is mounted facing the external wiring substrate. In addition, it is possible to provide a wiring board having high electrical insulation between the outer surface of the auxiliary insulation layer, which is the outer surface of the wiring board on the second main surface side, and the wiring conductor.

  According to the electronic device of one aspect of the present invention, since the electronic component is mounted on the wiring board having the above configuration, when the circuit conductor is arranged on the second main surface side, the circuit conductor and the wiring conductor are arranged. An electronic device with high electrical insulation between the two can be provided.

  According to the electronic module of one aspect of the present invention, since the circuit conductor is disposed opposite to the mounting portion of the electronic device having the above configuration, an electronic module having high electrical insulation between the wiring conductor and the circuit conductor is provided. Can be provided.

It is sectional drawing which shows the wiring board and electronic device of embodiment of this invention. It is sectional drawing which shows the electronic module of embodiment of this invention. It is a perspective view which decomposes | disassembles and shows the electronic module of embodiment of this invention. It is sectional drawing which shows the modification of the wiring board and electronic device which are shown in FIG. It is sectional drawing which shows the modification of the electronic module shown in FIG.

  A wiring board, an electronic device, and an electronic module according to embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing a wiring board and an electronic device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing the electronic module of the embodiment of the present invention. FIG. 3 is an exploded perspective view showing the electronic module according to the embodiment of the present invention.

  A plurality of insulating layers 2 are laminated to form an insulating substrate 1. The insulating substrate 1 has a first main surface 1a including a recess 3 in which an electronic component is accommodated, and a second main surface 1b opposite to the first main surface 1a. The second main surface 1 b of the insulating substrate 1 is covered with the auxiliary insulating layer 4. A wiring conductor 5 is provided from the inside of the recess 3 to the first main surface 1a. A wiring substrate 10 is basically constituted by the insulating substrate 1, the auxiliary insulation layer 4, and the wiring conductor 5. In the wiring substrate 10, the outer surface 4 a of the auxiliary insulation layer 4 includes a mounting portion 4 b that is disposed to face the external circuit conductor 31. Further, the insulation conductor layer 4 is not provided with the wiring conductor 5. In FIG. 1, the insulating substrate 1 and the auxiliary insulating layer 4 are shown separately, but actually, the insulating substrate 1 and the auxiliary insulating layer 4 are integrated with each other to form a laminated body 6. The outer surface including the mounting portion 4b of the insulating auxiliary layer 4 is, for example, a main surface opposite to the insulating substrate 1 among two main surfaces of the insulating auxiliary layer 4 facing each other.

  An electronic device 21 is basically configured by housing an electronic component 21 in the recess 3 of the wiring board 10. In addition, the electronic module 30 is basically configured by arranging the circuit conductor 31 so as to face the mounting portion 4 b of the electronic device 20. Since the electronic device 20 is mounted on an external wiring board in an upside down state after electronic components are accommodated in the wiring board 10, FIGS. 1 and 2 show the wiring board 10 upside down. .

  The insulating substrate 1 is a base portion for mounting and fixing the electronic component 21. The insulating substrate 1 has, for example, a rectangular plate shape (a rectangular parallelepiped shape) such as a rectangular shape, and a first main surface 1a (upper surface in FIG. 1) and a second main surface 1b opposite to the first main surface 1a (in FIG. 1). In the example, it has a lower surface). The first main surface of the insulating substrate 1 is provided with a recess 3 for accommodating the electronic component 21.

The first main surface 1a and the second main surface 1b of the insulating substrate 1 are, for example, a quadrangular shape such as a rectangular shape, but may be other polygonal shapes such as a hexagonal shape or an octagonal shape, a circular shape or an elliptical shape. Etc. In other words, the insulating substrate 1 may have a polygonal plate shape or a disk shape.

  The insulating substrate 1 is formed by laminating a plurality of insulating layers 2 in the thickness direction (up and down) as described above. The insulating layer 2 has a function of securing a space for providing a wiring conductor 5 to be described later. A wiring conductor 5 is provided on each of the plurality of insulating layers 2 and these insulating layers 2 are laminated to form an insulating substrate 1 in which a space for routing the wiring conductor 5 is secured sufficiently large in the inside and on the surface. Has been.

  The wiring conductor 5 is provided, for example, from the inside of the recess 3 to the outer surface such as the first main surface 1a of the insulating substrate 1. An electronic component 21 accommodated in the recess 3 is electrically connected to a portion of the wiring conductor 5 located in the recess 3 through a conductive connecting material such as a bonding wire 22. Further, a portion of the wiring conductor 5 provided on the first main surface 1a and the like of the insulating substrate 1 is composed of an external wiring substrate (not shown in FIG. 1) and a conductive connection material such as solder (not shown in FIG. 1). )). That is, the wiring conductor 5 has a function of forming a conductive path that electrically connects the electronic component 21 housed in the recess 3 and an external wiring board.

  The insulating substrate 1 is formed of a ceramic sintered body such as an aluminum oxide sintered body, a glass ceramic sintered body, an aluminum nitride sintered body, or a mullite sintered body. If the insulating substrate 1 is made of, for example, an aluminum oxide sintered body, it can be manufactured as follows. That is, first, raw material powders such as aluminum oxide and silicon oxide are formed into a sheet shape together with an appropriate organic binder and an organic solvent to produce a square sheet-like ceramic green sheet. Thereafter, a plurality of the ceramic green sheets cut and molded to an appropriate size are stacked, and the stacked substrates are fired at a temperature of 1300 to 1600 ° C., whereby the insulating substrate 1 can be manufactured. The plurality of fired ceramic green sheets become the insulating layers 2 of the insulating substrate 1 respectively.

  The wiring conductor 5 is made of, for example, a metal material such as tungsten, molybdenum, manganese, copper, silver, palladium, gold, platinum, nickel, or cobalt, or an alloy material containing these metal materials. Such a metal material or the like is provided on the surface of the insulating layer 2 as a metal layer such as a metallized layer or a plating layer.

  Further, the wiring conductor 5 includes a through conductor (no sign as a through conductor) that penetrates the insulating layer 2 in the thickness direction. The through conductor portion is also made of the same material as described above, and is formed by the same method.

  When the wiring conductor 5 is, for example, a tungsten metallized layer, the surface of the ceramic green sheet that becomes the insulating layer 2 of the insulating substrate 1 or a metal paste prepared by mixing tungsten powder with an organic solvent and an organic binder or In the through-hole previously provided, it can form by the method of printing and baking by methods, such as a screen printing method. This metallized layer was further coated with a plating layer such as nickel and gold by a plating method such as an electrolytic plating method or an electroless plating method at a portion exposed to the outer surface such as the first main surface 1a of the insulating substrate 1. It may be a thing.

  The auxiliary insulation layer 4 covering the second main surface 1b of the insulating substrate 1 is for enhancing the electrical insulation with respect to the outside of the insulating substrate 1 on the second main surface 1b side. By covering the second main surface 1b of the insulating substrate 1 with the auxiliary insulation layer 4, the auxiliary insulation layer 4 is further interposed between the portion of the wiring conductor 5 close to the second main surface 1b and the outside. Therefore, the electrical insulation with respect to the outside of the wiring conductor 5 is improved according to the thickness and material of the auxiliary insulation layer 4.

The outer surface of the auxiliary insulation layer 4 (the surface not in contact with the second main surface of the insulating substrate 1) includes a mounting portion 4b on which the circuit conductor 31 is disposed so as to face. In the example shown in FIG. 1, the lower surface and side surfaces of the auxiliary insulating layer 4 are the outer surface 4a, and the entire lower surface is the mounting portion 4b. When the external circuit conductor is arranged facing the mounting portion 4b, for example, the electrical or magnetic state of the circuit conductor 31 is detected by the electronic component 21 or the like housed in the multilayer body 6 (wiring board 10). Or can be measured. Details of the circuit conductor 31 will be described later.

  The insulating auxiliary layer 4 can be formed by using the same material as that of the insulating substrate 1 and using the same method. That is, the ceramic green sheet for the auxiliary insulation layer 4 manufactured by the same method using the same material as the ceramic green sheet used as the insulating layer 2 is placed under the plurality of ceramic green sheets used as the insulating layer 2 (second A green sheet laminate is produced by laminating on the main surface 1b side). A metal paste for the wiring conductor 5 or the like is not printed on the ceramic green sheet for the auxiliary insulation layer 4. Then, the auxiliary insulation layer 4 which coat | covers the 2nd main surface 1b of the insulated substrate 1 can be formed by baking this green sheet laminated body integrally. That is, it is possible to manufacture the insulating substrate 1 in which the second main surface 1b is covered with the insulating auxiliary layer 4.

  As described above, the insulating substrate 1 and the auxiliary insulating layer 4 are laminated together to form the laminated body 6. The laminated body 6 can also be regarded as a base on which the electronic component 21 is mounted. That is, the wiring conductor 5 provided on the uppermost surface of the multilayer body 6 as a base is electrically connected to an external wiring board, and the circuit conductor 31 faces the surface of the multilayer body 6 on the second main surface 1b side. Arranged. The electrical or magnetic state of the external circuit conductor can be detected or measured by the electronic component 21, and the result can be transmitted as an electrical signal from the wiring conductor 5 to the external wiring board.

  Examples of the electronic component 21 include a semiconductor integrated circuit element such as an IC or LSI, an optical semiconductor element such as an LED (light emitting diode), PD (photodiode), or CCD (charge coupled device), a current sensor element, or a magnetic sensor element. And various electronic elements such as a micromachine (so-called MEMS element) in which a minute electromechanical mechanism is formed on the surface of a semiconductor substrate. Further, the electronic component 21 may be a piezoelectric element, a capacitive element, a resistor, or the like, and may include a plurality of types.

  For example, if the electronic component 21 is a current sensor element, the magnitude of the current flowing through the circuit conductor 31 can be detected. In this case, it is possible to detect (so-called monitoring or the like) the electrical state of another electronic component or electronic device (for example, a battery, a generator, a motor, or an inverter) electrically connected to the circuit conductor 31. . In addition, if the electronic component 21 is a magnetic sensor element, it is possible to detect fluctuations in the current flowing through the circuit conductor 31 (electromagnetic numerical fluctuations accompanying fluctuations). In this case, the electromagnetic state of other components (such as a transmitter or an antenna) electrically connected to the circuit conductor 31 can be detected.

  The electronic component 21 is accommodated in the wiring board 10 and the electronic device 20 is manufactured, for example, as follows. That is, first, as shown by an arrow (A) in FIG. 3, the electronic component 21 is bonded to the bottom surface of the recess 3 with a bonding material such as an adhesive or a low melting point brazing material. Next, the electronic component 21 and the wiring conductor 5 are electrically connected by a conductive connecting material such as a bonding wire 22. Thereafter, as shown by an arrow (B) in FIG. 3, the lid 23 is joined to the first main surface 1 a of the insulating substrate 1 so as to close the recess 3 and the electronic component 21 is placed in the recess 3 as necessary. Seal hermetically. Thus, the electronic device 20 can be manufactured. The electronic component 21 may be sealed by means other than the lid 23 depending on the type, and may not be sealed.

The electronic module 30 including the electronic device 20 is manufactured by disposing a circuit conductor 31 so as to face the mounting portion 4b as shown by an arrow (C) in FIG. The circuit conductor 31 includes, for example, a bus bar, and is used to electrically connect the electronic device 20 to other electronic components or electronic devices as described above. The electronic module 30 shown in FIG. 2 constitutes a part of a power module such as an inverter including an IGBT (Insulated Gate Bipolar Transistor) or an ECU (Engine Control Unit). The power module is configured by electrically connecting other electronic devices or electronic circuits (not shown) to the circuit conductor 31.

  The circuit conductor 31 does not need to be directly electrically connected to the electronic device 20. For example, the circuit conductor 31 may be disposed at a position where the circuit conductor 31 and the wiring conductor 5 can be electromagnetically coupled. This electromagnetic coupling enables, for example, monitoring of the circuit conductor 31 and other electronic components electrically connected thereto.

  In the electronic device 20 and the electronic module 30 described above, the wiring conductor 5 arranged on the first main surface side may be electrically connected to the external wiring board 41 as described above. In the example shown in FIG. 2, the external wiring conductor 42 and the wiring conductor 5 included in the external wiring board 41 face each other and are electrically connected to each other through the solder bumps 43. The electronic device 20 and the electronic module 30 are turned upside down and mounted on the external wiring board 41, for example, as shown by an arrow (C ') in FIG. Note that the circuit conductor 31 may be disposed on the mounting portion 4b after the electronic device 20 is first mounted on the external wiring board 41. The external wiring board 41 has functions such as analysis of signals transmitted from the electronic module 30, for example.

  In the wiring substrate 10 of the embodiment, since the auxiliary insulation layer 4 is disposed on the second main surface 1b of the insulating substrate 1, for example, when the first main surface 1a is mounted facing the external wiring substrate 41, for example. The wiring board 10 having high electrical insulation between the outer surface of the auxiliary insulation layer 4 that is the outer surface of the wiring board 10 on the second main surface 1b side and the wiring conductor 5 can be provided. That is, in the wiring board 10, the electrical insulation with respect to the outside of the wiring conductor 5 can be improved. In this case, the electrical insulation of the wiring conductor 5 with respect to the outside is the electrical insulation between the circuit conductor 31 and the wiring conductor 5 disposed between the layers of the insulating layer 2 closest to the mounting portion 4 b of the wiring board 10. Equivalent to.

  That is, even if a gap due to a gap between ceramic materials exists in a part of the insulating layer 2 on the lowermost layer side including the second main surface 1b of the insulating substrate 1, it is positioned below the gap. By the insulating auxiliary layer 4 to be reduced, a decrease in electrical insulation between the wiring conductor 5 and the outside via the gap is effectively suppressed. In addition, the space | gap of the insulating layer 2 arises between the particle | grains of the ceramic material which forms the ceramic sintered compact which is a polycrystal, for example. In the air gap (that is, air or the like), the dielectric breakdown voltage is smaller than that of the insulating layer 2. In addition, moisture in the outside air may enter. For this reason, the above-described deterioration in electrical insulation is likely to occur.

  In the wiring board 10 and the electronic device 20 in which the electronic component 21 is accommodated in the wiring board 10, the circuit conductor 31 faces the mounting portion 4 b of the auxiliary insulation layer 4 that is the outer surface on the second main surface 1 b side. Therefore, the electrical insulation between the wiring conductor 5 and the circuit conductor 31 can be increased. That is, the electronic module 30 having high electrical insulation between the wiring conductor 5 and the circuit conductor 31 can be manufactured. This can be regarded as an effect of improving electrical insulation between conductors of the electronic module 30 itself.

Since the auxiliary insulating layer 4 itself is formed of the same material as that of the insulating layer 2 as described above, there may be a void similar to that of the insulating layer 2. No wiring conductor (not shown) is formed. For this reason, there is no reduction in electrical insulation with respect to the outside as the wiring board 10 due to the presence of the wiring conductor. Insulating layer 2 including second main surface 1b
The possibility that the respective positions of the gap and the gap of the auxiliary insulation layer 4 are the same in a plan view is very small. Therefore, there is very little possibility that the electrical insulation between the wiring conductor 5 and the outside is lowered due to these gaps being connected vertically.

The insulation auxiliary layer 4 is thicker than the insulation layer 2 included in the insulation substrate 1 in order to enhance the electrical insulation between the wiring conductor 5 on the second main surface 1b side and the circuit conductor 31. Is good. Specifically, when the insulating layer 2 has a thickness of about 50 to 400 μm, the insulating auxiliary layer 4 has a thickness of about 100 to 500.
It may be set to μm.

When the thicknesses of the insulating layer 2 and the auxiliary insulation layer 4 are set as described above, the wiring conductor 5 disposed between the layers of the insulating layer 2 closest to the mounting portion 4b and the circuit conductor 31 The electrical insulation between them is 0.5 mm thick and the dielectric breakdown voltage is about 25 kV · DC. Also, if it is assumed that the other conditions are the same and the insulation auxiliary layer 4 does not exist (assumed wiring board and the like are not shown), the insulating layer closest to the mounting portion of the wiring conductors The electrical insulation between the circuit conductor and the one disposed between the layers is 0.1 mm thick and the dielectric breakdown voltage is about 10 kV.
Therefore, in this example, the electrical insulation of about 15 kV can be improved for the wiring board 10 of the embodiment and the electronic device 20 and the electronic module 30 including the wiring board 10.

  FIG. 4 is a cross-sectional view showing a modification of the wiring board 10 and the electronic device 20 shown in FIG. 4, parts similar to those in FIG. 1 are denoted by the same reference numerals. In the example shown in FIG. 4, the wiring conductor 5 is also arranged between the recess 3 and the second main surface 1 b (mounting portion 4 b) in the insulating substrate 1 (below the recess 3 in FIG. 4). . The wiring conductor 5 disposed below the recess 3 The wiring conductor 5 is disposed vertically with the insulating layer 2 interposed therebetween. These wiring conductors 5 are located immediately below the electronic component 21 in the electronic device 20 shown in FIG.

  The wiring conductor 5 positioned immediately below the electronic component 21 is not limited to one that forms a conductive path that electrically connects the electronic component 21 in the recess 3 and the external wiring board 41 as described above, for example, but is electromagnetic. It may be for noise reduction. A part of the wiring conductor 5 is located immediately above the electronic component 21 when the electronic device 20 is turned over as in the example shown in FIG. 3, and the wiring conductor 5 is interposed between the electronic component 21 and the external wiring board 41. A part will be located. The wiring conductor 5 positioned between the electronic component 21 and the external wiring board 41 is set to, for example, a ground potential, and the electronic component 21 and the external wiring board 41 are effectively electromagnetically shielded from each other. A part of the wiring conductor 5 having an electromagnetic shielding function may have a size (area) equal to or larger than that of the concave portion 3 in a plan view.

  That is, the wiring conductor 5 disposed below the recess 3 is not limited to a linear pattern, but may be a so-called solid pattern such as a ground conductor or a power supply conductor. Further, a part of the wiring conductor 5 disposed on the lower side of the recess 3 may function as a pair of capacitive electrodes facing each other. This capacitive electrode (a part of the wiring conductor 5) may be for decoupling, for example.

  Even in the case where more wiring conductors 5 are provided at positions relatively close to the mounting portion 4b as in this example, the wiring board 10 is effective for improving the electrical insulation of the wiring conductor 5 to the outside. Can be provided. In addition, it is possible to provide an electronic device 20 including such a wiring board 10 and capable of easily manufacturing an electronic module 30 having excellent electrical insulation between more wiring conductors 5 and circuit conductors 31.

  Note that, as in the example illustrated in FIG. 4, when more wiring conductors 5 are disposed at positions relatively close to the mounting portion 4 b, a plurality of insulating auxiliary layers 4 may be provided. That is, when such a wiring conductor 5 is arranged, the distance between the wiring conductor 5 and the mounting portion 4b of the multilayer body 6 tends to be short. On the other hand, by disposing a plurality of auxiliary insulation layers 4 as will be described later, high electrical insulation between the wiring conductor 5 and the mounting portion 4b, that is, electrical insulation with respect to the outside of the wiring conductor 5 is ensured. be able to.

  FIG. 5 is a cross-sectional view showing a modification of the electronic module shown in FIG. In FIG. 5, the same parts as those in FIG. 2 are denoted by the same reference numerals. The electronic module 30 of the modification includes a modification of the wiring board 10 shown in FIG. 1 and a modification of the electronic device 20 shown in FIG.

  Also in the example shown in FIG. 5, a plurality of layers of wiring conductors 5 are arranged between the recess 3 and the mounting portion 4 b in the insulating substrate 1 (on the upper side of the recess 3 in FIG. 5). In the example shown in FIG. 5, the auxiliary insulation layer 4 is formed of a plurality of sub-insulating layers 7 stacked on each other. The insulating auxiliary layer 4 may include a plurality of sub-insulating layers 7 as described above. Each of the sub-insulating layers 7 can be formed by the same method using the same material as the auxiliary insulating layer 4 (single layer) in the wiring substrate 10 of the above embodiment. In this case, a plurality of ceramic green sheets for auxiliary insulation layers may be laminated together with a plurality of ceramic green sheets to be the insulating substrate 1 and fired simultaneously.

  In the example shown in FIG. 5 as well, as in the example shown in FIG. 4, the above-described effect can be obtained by arranging a plurality of layers of wiring conductors 5 between the recess 3 and the second main surface 1 b. . In addition, the electrical insulation between the wiring conductor 5 and the circuit conductor 31 can be effectively improved.

  Further, when the auxiliary insulation layer 4 is composed of a plurality of layers (sub-insulating layer 7) as in the example shown in FIG. 5, it is effective for further improving the electrical insulation between the wiring conductor 5 and the circuit conductor 31. is there. That is, even if one layer of the plurality of sub-insulating layers 7 has voids, the voids in the one layer can be effectively blocked by the other sub-insulating layers 7. Further, even if the plurality of sub-insulating layers 7 have gaps in each, the possibility that these gaps are connected to each other vertically is small.

  That is, a void included in one sub-insulating layer 7 is blocked by a portion of the other one sub-insulating layer 7 in contact with the sub-insulating layer 7 where no void exists. In other words, the plurality of sub-insulating layers 7 can close the gaps. Further, the possibility that the gaps of the plurality of sub-insulating layers 7 are connected to the gaps of the insulating layer 2 on the second main surface 1b side is even smaller. Therefore, the electrical insulation between the wiring conductor 5 and the circuit conductor 31 is effectively improved.

  Further, if the thickness of the auxiliary insulation layer 4 is constant, the case where the auxiliary insulation layer 4 is composed of a plurality of sub-insulation layers 7 as compared with the case where the auxiliary insulation layer 4 is a single layer as described above. Since it is easy to close the gap between the plurality of sub-insulating layers 7, there is a high possibility that the electrical insulation between the wiring conductor 5 and the outside is improved.

  In the example shown in FIG. 5, the thickness of each of the plurality of sub-insulating layers 7 is larger than the thickness of the insulating layer 2. In this case, the relatively thick sub-insulating layer 7 can effectively improve the electrical insulation with respect to the outside of the wiring conductor 5.

  Note that the plurality of sub-insulating layers 7 may not all be thicker than the insulating layer 2. Also in this case, by including the relatively thick sub-insulating layer 7, the electrical insulation with respect to the outside of the wiring conductor 5 can be enhanced.

  In the example shown in FIG. 5, the circuit conductor 31 may be a bus bar, and the electronic component 21 may be a sensor element such as a current sensor element. That is, in the electronic module 30, the circuit conductor 31 may include a bus bar and the electronic component 21 may be a sensor element.

The bus bar as the circuit conductor 31 may be directly bonded to the mounting portion 4b by, for example, a bonding material or the like (not shown), or may be disposed so as to be simply in contact with the mounting portion 4b. When the circuit conductor 31 is not directly joined to the mounting portion 4b, both are fixed to another member (not shown) such as a casing and arranged in a predetermined positional relationship with each other.

  In each of the above examples, as in the example shown in FIG. 3, for example, the circuit conductor 31 has a width greater than the width of the insulating substrate 1 (the dimension in the short side direction of the rectangular plate-shaped insulating substrate 1) (bus bar Etc.). Thereby, for example, a large current can be transmitted and received between other electronic components including a generator or a large capacity battery.

  The electronic component 21 can be electromagnetically coupled to the circuit conductor 31 and is arranged so as to be able to measure the magnitude of the current flowing through the circuit conductor 31 and to detect fluctuations in the electromagnetic state. For example, if the electronic component 21 is a current sensor element as described above, the magnitude of the current flowing through the circuit conductor 31 can be measured. Thereby, for example, information such as the capacity of the battery electrically connected to the circuit conductor 31, the amount of power generation, or the magnitude of the radiated electromagnetic wave can be detected (monitored).

  The wiring board, electronic device, and electronic module of the present invention are not limited to the above embodiments, and various modifications can be made within the scope of the present invention. For example, a mark (not shown) for alignment with the circuit conductor 31 may be provided on at least one outer surface of the insulating substrate 1 and the auxiliary insulating layer 4 (that is, the outer surface of the multilayer body 6). Examples of the alignment mark include a pattern made of the same metal material as that of the wiring conductor 5 and a concave or convex portion that can be fitted to the convex or concave portion (not shown) of the circuit conductor. Etc. Such alignment marks may be provided on the circuit conductor 31, or may be provided on both the wiring board 1 (laminated body 6) and the circuit conductor 31.

DESCRIPTION OF SYMBOLS 1 ... Insulating substrate 1a ... 1st main surface 1b ... 2nd main surface 2 ... Insulating layer 3 ... Recessed part 4 ... Insulating auxiliary layer 4a ... (outside of insulating auxiliary layer) Surface 4b ... Mounting part 5 ... Wiring conductor 6 ... Laminated body 7 ... Sub-insulating layer
10 ... wiring board
20 ... Electronic device
21 ... Electronic components
22: Bonding wire
23 ... Lid
30 ・ ・ ・ Electronic module
31 ... Circuit conductor
41 ... External wiring board
42 ... External wiring conductor
43 ... Metal bump

Claims (6)

An insulating substrate having a first main surface including a recessed portion in which a plurality of insulating layers are stacked and an electronic component is accommodated, and a second main surface opposite to the first main surface;
An auxiliary insulation layer covering the second main surface;
A wiring conductor provided from the inside of the recess to the first main surface,
A wiring board characterized in that an outer surface of the auxiliary insulation layer includes a mounting portion arranged to face an external circuit conductor, and the auxiliary wiring layer is not provided with the wiring conductor. The wiring board according to claim 1, wherein the auxiliary insulation layer is formed of a plurality of sub-insulating layers stacked on each other. The wiring board according to claim 2, wherein a thickness of the sub-insulating layer is larger than a thickness of the insulating layer. The wiring board according to claim 1;
An electronic device comprising: an electronic component housed in the recess. An electronic device according to claim 4,
An electronic module comprising: a circuit conductor disposed to face the mounting portion of the electronic device. The electronic module according to claim 5, wherein the circuit conductor includes a bus bar, and the electronic component is a sensor element.