JP2014157949A - Wiring board and electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring board which is excellent in heat radiation performance.SOLUTION: A wiring board 1 includes: an insulation substrate 11 having a main surface including a mounting region 11a of an electronic component 2; and a heat transfer member 12 provided in the insulation substrate 11. The transfer member 12 includes: a first heat transfer part 12a which is provided at a position overlapping with the mounting region 11a in a plane view and has an upper surface and a lower surface having an area smaller than the upper surface; and a second heat transfer part 12b which is provided at an area ranging from the first heat transfer part 12a to a side surface of the insulation substrate 11 and is exposed from the side surface of the insulation substrate 11.

Description

  The present invention relates to a wiring board for mounting an electronic component such as a semiconductor element or a light emitting element, and an electronic device.

  2. Description of the Related Art Conventionally, a wiring board on which an electronic component is mounted and incorporated in an electronic device has an insulating base having a main surface including a mounting area for the electronic component, and heat transfer provided in the insulating base so as to overlap the mounting area in plan view. What has a member is known (for example, refer patent document 1).

  The heat transfer member has, for example, a columnar shape, and transfers heat generated in the electronic component mounted on the upper surface of the wiring board from the upper surface to the lower surface of the wiring board, thereby transferring the heat generated in the electronic component to the wiring board. It is used to escape from the underside of the outside. As a material for such a heat transfer member, a material having a higher thermal conductivity than that of the insulating base is used.

Japanese Unexamined Patent Publication No. 2006-66409

  However, in such a wiring board, there is a possibility that the insulating base is deformed or damaged by a thermal stress due to a thermal expansion difference between the insulating base and the heat transfer member. When such deformation or breakage occurs in the lower part of the insulating base, which is a mounting part on the external circuit board, there is a problem that the mounting reliability of the wiring board on the external circuit board may be lowered.

  A wiring board according to an aspect of the present invention includes an insulating base having a main surface including a mounting area for electronic components, and a heat transfer member provided in the insulating base. The heat transfer member is provided at a position overlapping the mounting region in plan view, and has a first heat transfer unit having an upper surface and a lower surface having a smaller area than the upper surface, and is provided from the first heat transfer unit to the side surface of the insulating base. And a second heat transfer portion exposed from the side surface of the insulating base.

  An electronic device according to another aspect of the present invention includes a wiring board and an electronic component mounted on the wiring board.

  According to the wiring board according to one aspect of the present invention, the heat transfer member is provided from the upper surface and the lower surface having a smaller area than the upper surface, and from the first heat transfer portion to the side surface of the insulating base. And a second heat transfer portion exposed from the side surface of the insulating base. Since it is such a structure, since the area of the lower surface of the first heat transfer section is smaller than the area of the upper surface, the thermal stress due to the thermal expansion difference between the insulating base and the heat transfer member is reduced below the insulating base. The deformation or breakage in the lower part of the insulating substrate can be reduced. Also, heat generated in the electronic component is transferred from the first heat transfer section to the second heat transfer section and dissipated from the exposed portion of the side of the insulating base of the second heat transfer section. It is possible to reduce the decrease in performance.

  According to another aspect of the present invention, since the electronic device includes the wiring board having the above-described configuration and an electronic component, the heat dissipation of the wiring board can be improved and the long-term reliability can be improved.

(A) is a top view which shows the electronic device in the 1st Embodiment of this invention, (b) is a bottom view of (a). It is an internal top view which shows the inside of the wiring board of the electronic device in the 1st Embodiment of this invention. It is a longitudinal cross-sectional view in the AA line of Fig.1 (a). (A) is a top view which shows the electronic device in the 2nd Embodiment of this invention, (b) is a bottom view of (a). It is an internal top view which shows the inside of the wiring board of the electronic device in the 2nd Embodiment of this invention. It is a longitudinal cross-sectional view in the AA line of FIG. (A) is a top view which shows the electronic device in the 3rd Embodiment of this invention, (b) is a bottom view of (a). It is an internal top view which shows the inside of the wiring board of the electronic device in the 3rd Embodiment of this invention. (A) is a longitudinal cross-sectional view in the AA line of Fig.7 (a), (b) is a longitudinal cross-sectional view in the BB line of Fig.7 (a). (A) is a top view which shows the electronic device in the 4th Embodiment of this invention, (b) is a bottom view of (a). It is an internal top view which shows the inside of the wiring board of the electronic device in the 4th Embodiment of this invention. It is a longitudinal cross-sectional view in the AA line of Fig.10 (a).

  Several exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

(First embodiment)
The electronic device according to the first embodiment of the present invention includes a wiring board 1 and an electronic component 2 provided on the upper surface of the wiring board 1 as in the example shown in FIGS. The electronic device is mounted on a circuit board that constitutes an electronic component module, for example.

  As in the example shown in FIGS. 1 to 3, the wiring board 1 in the present embodiment includes an insulating base 11 having a main surface including the mounting region 11 a of the electronic component 2 and a transmission provided in the insulating base 11. It has a thermal member 12, a wiring conductor 13 provided on the surface and inside of the insulating base 11, and a metal layer 14 provided so as to overlap the mounting region 11a in plan view. The mounting area 11a is an area surrounded by a one-dot chain line. 1 to 3, the electronic device is provided in a virtual xyz space, and the “upward direction” means the positive direction of the virtual z-axis for convenience.

  The insulating base 11 has an upper surface including the mounting area 11a of the electronic component 2 and has a rectangular plate shape in plan view. The insulating substrate 11 functions as a support for supporting the electronic component 2, and the electronic component 2 is bonded and fixed to the mounting area 11 a at the center of the upper surface via a bonding agent such as a low melting point brazing material or a conductive resin. Is done.

  The material of the insulating base 11 is a ceramic such as an aluminum oxide sintered body (alumina ceramic), an aluminum nitride sintered body, a mullite sintered body, and the like.

If the insulating substrate 11 is an aluminum oxide sintered body, for example, a raw material powder such as aluminum oxide (Al ₂ O ₃ ), silicon oxide (SiO ₂ ), magnesium oxide (MgO), calcium oxide (CaO), etc. A suitable organic binder, a solvent, etc. are added and mixed to prepare a slurry. A ceramic green sheet is produced by forming this mud into a sheet using a conventionally known doctor blade method or calendar roll method. Next, the ceramic green sheet is appropriately punched, and a plurality of ceramic green sheets are laminated as necessary to form a generated shape, and the generated shape is fired at a high temperature (about 1300 ° C to 1400 ° C). Thus, the insulating base 11 is manufactured.

  The heat transfer member 12 is embedded in the insulating base 11, and is used to release heat generated by the electronic component 2 mounted on the wiring board 1 to the outside of the wiring board 1 to improve the heat dissipation of the wiring board 1. It is.

  The heat transfer member 12 includes a first heat transfer portion 12a and a second heat transfer portion 12b. The first heat transfer unit 12a is provided at a position overlapping the mounting region 11a in plan view, and has an upper surface and a lower surface having a smaller area than the upper surface. The area of the upper surface of the first heat transfer unit 12a is It is larger than the area of the mounting region 11a in plan view. The first heat transfer unit 12a has, for example, a rectangular or circular columnar shape with an arcuate corner in plan view. The second heat transfer section 12 b is provided from the first heat transfer section 12 a to the side surface of the insulating base 11 and is exposed from each side face of the insulating base 11. Here, the second heat transfer section 12b may be provided from the side surface of the first heat transfer section 12a to the side surface of the insulating base 11, and is disposed on the lower layer side with the first heat transfer section 12a disposed on the upper layer side. You may arrange | position so that it may be pinched | interposed between the made 1st heat-transfer parts 12a.

  If the insulating substrate 11 is made of an aluminum oxide sintered body, the material of the heat transfer member 12 includes, for example, CuW or CuMo as a main component, and has a higher thermal conductivity than the aluminum oxide sintered body. Metal materials can be used.

  If the heat transfer member 12 is a metal material mainly composed of CuW, for example, first, a metal sheet that becomes the first heat transfer member 12 in the through holes provided in the first and second ceramic green sheets or Fill with metal paste. Next, a metal pattern to be the second heat transfer member 12 is printed on the surface of the first or second ceramic green sheet so as to be positioned between the first and second ceramic green sheets. Thereafter, the first and second ceramic green sheets are laminated and pressed, and then fired to produce the heat transfer member 12.

  The first heat transfer section 12a is formed by forming holes in the ceramic green sheet for the insulating substrate 11 by punching or laser processing using a die or punching, and then forming a metal sheet for the first heat transfer section 12a in the provided holes. Or it is produced by arranging a metal paste.

  In the present embodiment, the first heat transfer member 12a forms a first through hole in the first ceramic green sheet, and forms a second through hole smaller than the first through hole in the second ceramic green sheet. Then, these through holes are produced by filling a metal sheet or metal paste to be the first heat transfer member 12a. In the case of using a metal sheet, if the metal sheet is embedded at the same time when a hole is formed in the ceramic green sheet by punching, a molded body can be produced efficiently. For example, when a metal sheet is arranged on the upper surface of the ceramic green sheet for the insulating base 11, and a punching die that forms a through hole in the ceramic green sheet is used, the metal sheet and the ceramic green sheet are punched from the metal sheet side. A metal sheet punched to the same size as the through hole can be fitted into the through hole of the ceramic green sheet.

  The second heat transfer member 12b is a metal that becomes the second heat transfer member 12b in a predetermined region on the surface of the first or second ceramic green sheet so as to be positioned between the first and second ceramic green sheets. It is produced by printing a paste.

In the method for producing the metal sheet for the first heat transfer section 12a, first, an organic binder and an organic solvent are added to the metal powder as needed, and a predetermined amount of a plasticizer and a dispersant are added to obtain a slurry. Next, the slurry is coated on a resin or paper support such as PET (polyethylene terephthalate) by a molding method such as a doctor blade method, a lip coater method, or a die coater method to form a sheet. Then, it produces by drying by drying methods, such as warm air drying, vacuum drying, or a far infrared ray drying.

  When CuW is included as the main component of the first heat transfer section 12a, the material of the first heat transfer section 12a is a metal powder of tungsten (W) and copper (Cu). The metal powder may be mixed or alloyed. For example, a metal sheet in which Cu powder and W powder are mixed can be used.

  The metal paste for the first heat transfer section 12a or the second heat transfer section 12b is a ball mill, three roll mill by adding an organic binder, an organic solvent, and, if necessary, a dispersing agent to the metal powder as the main component. Alternatively, it is produced by mixing and kneading by a kneading means such as a planetary mixer.

  The addition amount of the organic binder used in the metal paste for the first heat transfer section 12a or the second heat transfer section 12b may be an amount that can be easily decomposed and removed during firing and can disperse the metal powder. The amount is desirably about 5 to 20% by mass with respect to the metal powder. The solvent is added in an amount of 4 to 15% by mass with respect to the metal powder, and is adjusted to about 15000 to 40000 cps.

  In addition, in order to match the firing shrinkage behavior or shrinkage rate of the ceramic green sheet during firing in the metal paste, or to ensure the bonding strength of the first heat transfer portion 12a or the second heat transfer portion 12b after firing, Glass or ceramic powder may be added.

  Further, when a metal paste is used as the metal material for the first heat transfer section 12a, the metal paste may be adjusted to have a viscosity that can be held in the hole of the ceramic green sheet. It is preferable that the hole has a bottom.

  The wiring conductor 13 is provided on the upper surface, the lower surface, and the inside of the insulating base 11, and electrically connects the electronic component 2 mounted on the wiring board 1 and an external circuit board, or the wiring board 1 and the outside. It is for joining with a circuit board. The wiring conductor 13 includes a wiring layer provided on the surface of or inside the insulating base 11, and a through conductor that electrically connects the wiring layers that pass through the insulating base 11 and are positioned above and below.

  The metal layer 14 is provided on the upper surface of the insulating base 11, and is for mounting the electronic component 2 and joining the wiring board 1 and the electronic component 2. The wiring conductor 13 and the metal layer 14 may be electrically connected. The metal layer 14 may be provided on the lower surface of the insulating base 11 and used to join the wiring board 1 and an external circuit board.

  The material of the wiring conductor 13 and the metal layer 14 is, for example, metal powder metallization mainly composed of tungsten (W), molybdenum (Mo), manganese (Mn), silver (Ag), or copper (Cu). When a high melting point metal material such as W or Mo is used as the main component of the wiring conductor 13 and the metal layer 14, it is preferably mixed or alloyed with Cu.

For the wiring layer and the metal layer 14, for example, a metallized paste for the wiring conductor 13 is printed on a ceramic green sheet for the insulating substrate 11 by printing means such as a screen printing method, and fired together with the ceramic green sheet for the insulating substrate 11. Formed by. Further, the through conductor is formed, for example, in a ceramic green sheet for the insulating base 11 by a die or punching process by punching or laser processing or the like, and through metal for the through conductor is formed in the through hole. It is formed by filling the paste with the above printing means and firing it together with the ceramic green sheet for the insulating substrate 11.

A surface of the wiring conductor 13 and the metal layer 14 exposed from the insulating base 11 is coated with a metal plating layer having excellent corrosion resistance such as nickel or gold. Corrosion of the wiring conductor 13 and the metal layer 14 can be reduced, and the electronic component 2, the bonding wire or the external circuit board, and the wiring conductor 13 and the metal layer 14 can be firmly bonded. For example, a nickel plating layer having a thickness of about 1 to 10 μm and a gold plating layer having a thickness of about 0.1 to 3 μm are sequentially deposited on the surfaces of the wiring conductor 13 and the metal layer 14 exposed from the insulating base 11.

  When a light emitting element is used as the electronic component 2, a silver plating layer of about 1 to 10 μm may be applied to the surface exposed from the insulating base 11 of the wiring conductor 13 and the metal layer 14. When the surfaces of the wiring conductor 13 and the metal layer 14 are made of a silver plating layer, a light emitting device that can favorably reflect light emitted from the light emitting element toward the wiring conductor 13 or the metal layer 14 can be obtained.

  Further, a Cu plating layer may be deposited on the surface of the metal layer 14 on which the electronic component 2 is mounted exposed from the insulating base 11. For example, when a Cu plating layer of about 10 to 80 μm is deposited between the nickel plating layer and the gold plating layer or the underlying layer of the nickel plating layer and the gold plating layer, the heat generated in the electronic component 2 is generated by the metal layer. Therefore, it is possible to make an electronic device with higher heat dissipation.

  An electronic component 2 is bonded and mounted on the upper surface of the wiring board 1 so as to overlap the first heat transfer section 12a in plan view. The electronic component 2 is, for example, a semiconductor element or a light emitting element. Further, a small electronic component 2 such as a capacitor or a diode may be mounted together with a semiconductor element or a light emitting element. For example, when the electronic component 2 mounted on the upper surface of the wiring board is a light emitting element, the wiring board 1 may be further mounted with an electronic component 2 such as a Zener diode. The electronic component 2 is bonded to the upper surface of the wiring substrate 1 by a conductive bonding material such as a brazing material mainly composed of a gold (Au) -silicon (Si) alloy or an epoxy resin containing silver (Ag). Further, the electrode of the electronic component 2 and the wiring conductor 13 are electrically connected via a connecting member 3 such as a bonding wire mainly composed of Au. The electronic component 2 is sealed with a sealing material 4 such as a resin material as necessary. Further, the electrodes of the electronic component 2 and the wiring conductor 13 or the metal layer 14 may be electrically connected by solder bumps or gold bumps. Moreover, you may seal with the cover body etc.

  The wiring board 1 of the present embodiment includes an insulating base 11 having a main surface including the mounting area 11a of the electronic component 2 and a heat transfer member 12 provided in the insulating base 11. Is provided at a position overlapping the mounting region 11a in plan view, and has a first heat transfer portion 12a having an upper surface and a lower surface having a smaller area than the upper surface, and is provided from the first heat transfer portion 12a to the side surface of the insulating base 11. And a second heat transfer portion 12b exposed from the side surface of the insulating base. Since it is such a configuration, the area of the lower surface of the first heat transfer section 12a is smaller than the area of the upper surface, reducing the thermal stress due to the difference in thermal expansion between the lower portion of the insulating base 11 and the heat transfer member 12, It is possible to reduce deformation or breakage in the lower part of the insulating substrate 11. Further, the heat generated in the electronic component 2 is transferred from the first heat transfer section 12a to the second heat transfer section 12b and is dissipated from the portion exposed from the side surface of the insulating base 11 of the second heat transfer section 12b. The heat dissipation of the wiring board 1 can be improved.

  Further, since the area of the first heat transfer section 12a on the lower surface side is smaller than the area of the first heat transfer section 12a on the upper surface side, a region for arranging the wiring conductor 13 on the lower surface side of the insulating base 11 It is effective to secure

  Since the electronic device of the present embodiment includes the wiring board 1 and the electronic component 2 mounted on the wiring board 1, the heat dissipation of the wiring board 1 is improved and the long-term reliability is excellent. I can do it.

(Second Embodiment)
Next, an electronic device according to a second embodiment of the present invention will be described with reference to FIGS.

  In the electronic device according to the present embodiment, the difference from the electronic device according to the first embodiment described above is that the side surface of the first heat transfer section 12a is inclined in a cross-sectional view as in the examples illustrated in FIGS. The second heat transfer section 12b has a shape extending radially toward the side surface of the insulating base 11 around the first heat transfer section 12a in plan view. In such a case, since the portion where the second heat transfer portion 12b is exposed from the side surface of the insulating base 11 is provided so as to extend over the entire circumference of the side surface of the insulating base 11, the amount of heat dissipation is improved. The heat dissipation of the wiring board 1 can be improved.

  In the present embodiment, either the side surface on the upper surface side of the first heat transfer unit 12a or the side surface on the lower surface side of the first heat transfer unit 12a is perpendicular to the upper surface and the lower surface of the insulating base 11 in a cross-sectional view. It may be a shape.

  Further, in a cross-sectional view, the side surface of the first heat transfer unit 12a on the upper surface side may be inclined so as to become wider from the upper surface side toward the center side, and the side surface of the first heat transfer unit 12a on the lower surface side. May be made narrower from the center side toward the lower surface side.

(Third embodiment)
Next, an electronic device according to a third embodiment of the present invention will be described with reference to FIGS.

  The electronic device according to the present embodiment differs from the electronic device according to the first embodiment described above in that the second heat transfer portion 12b is substantially the entire surface of the insulating substrate 11 in plan view, as in the example shown in FIG. 7 to 9, and has a side heat transfer layer 12 c that is provided on the side surface of the insulating base 11 and is in contact with the second heat transfer portion 12 b, as shown in FIGS. 7 to 9. The lower surface heat transfer layer 12d is provided on the lower surface of the base 11. In such a case, the heat transferred to the second heat transfer section 12b is further transferred to the side heat transfer layer 12c and spreads and dissipated in the surface direction of the side surface of the insulating base 11, so that heat dissipation is improved. It can be further improved.

  In the present embodiment, the second heat transfer portion 12b is electrically connected to the wiring conductor 13 provided on the upper surface of the insulating base 11, and the side heat transfer layer 12c is provided on the lower surface of the insulating base 11. The second heat transfer portion 12b and the side heat transfer layer 12c can be used as a part of the current path since the wiring conductor 13 is joined.

  Further, when the wiring conductor 13, the side heat transfer layer 12c and the lower heat transfer layer 12d provided on the lower surface or the side surface of the insulating base 11 are used as external terminals, the heat generated in the electronic component 2 is good for the external circuit board. Heat can be transferred to.

  The side heat transfer layer 12c and the bottom heat transfer layer 12d can be manufactured by the same method using the same material as that of the second heat transfer portion 12b. In this embodiment, the side heat transfer layer 12c is provided so as to extend in the thickness direction of the insulating base 11 along the inner peripheral surface of the notch 15 provided on the side of the insulating base 11. Similar to the wiring conductor 13 and the metal layer 14, the metal plating layer is deposited on the exposed surfaces of the side heat transfer layer 12c and the bottom heat transfer layer 12d.

  When the material of the side heat transfer layer 12c and the lower surface heat transfer layer 12d has a higher thermal conductivity than the second heat transfer portion 12b, the side heat transfer layer 12c and the lower surface heat transfer layer from the second heat transfer portion 12b Heat transfer to the layer 12d can be increased.

  The insulating base 11 has a lower surface side first heat transfer portion 12a smaller than the upper surface side first heat transfer portion 12a, so that a region for the notch 15 is secured on the lower surface side of the insulating base 11. In addition to improving the heat dissipation of the wiring board 1, it is possible to improve the bonding with an external circuit board.

  The lower heat transfer layer 12d is larger than the lower surface of the first heat transfer unit 12a in plan view and overlaps the entire lower surface of the first heat transfer unit 12a as in the example shown in FIG. 7B. . For this reason, the heat generated in the electronic component 2 is efficiently transferred from the first heat transfer section 12a to the lower heat transfer layer 12d, and is efficiently dissipated from the lower heat transfer layer 12d. Note that it is effective to improve heat dissipation if the lower heat transfer layer 12d is made thicker than the wiring conductor 13 provided on the outer peripheral portion of the insulating base 11. Further, the metal plating layer on the surface of the lower heat transfer layer 12d has a structure in which a Cu plating layer of about 10 to 80 μm is applied to the underlayer of the nickel plating layer and the gold plating layer, thereby improving the heat dissipation. It is effective for.

  The wiring board 1 has the recessed part 11b in which the electronic component 2 is accommodated like the example shown by FIGS. When the electronic component 2 is made of a light emitting element, a reflection layer for reflecting light emitted from the light emitting element may be provided on the inner wall surface of the recess 11b. The reflective layer is formed by, for example, depositing a metallized layer and a plating layer on the insulating substrate 11 in order, or depositing a resin film or a metal film. The exposed surface of the reflective layer is coated with a metal such as nickel, gold or silver.

(Fourth embodiment)
Next, an electronic device according to a fourth embodiment of the present invention will be described with reference to FIGS.

  The electronic device according to this embodiment differs from the electronic device according to the first embodiment described above in that the second heat transfer portion 12b is substantially the entire surface of the insulating substrate 11 in a plan view as in the example shown in FIG. 10 to 12, the side heat transfer layer 12 c provided on the side surface of the insulating base 11 and in contact with the second heat transfer portion 12 b, and the bottom surface of the insulating base 11 are provided. The lower surface heat transfer layer 12d is in contact with the side heat transfer layer 12c, and the wiring conductor 13 is provided on the upper surface of the insulating base 11. In such a case, the heat transferred to the second heat transfer section 12b is further transferred to the side heat transfer layer 12c and the lower heat transfer layer 12d and spreads in the surface direction of the side surface and the lower surface of the insulating base 11. Since it is dissipated, the heat dissipation can be further improved.

  The side heat transfer layer 12c and the bottom heat transfer layer 12d can be manufactured by the same method using the same material as that of the second heat transfer portion 12b. In the present embodiment, a metal material such as aluminum (Al) or a ceramic material of an aluminum nitride sintered body may be used as the material for the side heat transfer layer 12c and the bottom heat transfer layer 12d.

  In the present embodiment, the wiring conductor 13 provided on the upper surface of the insulating base 11 is used as an external terminal to be joined to an external circuit board.

  In addition, this invention is not limited to the example of said embodiment, A various change is possible. For example, the conductor layer 13 may be exposed on the side surface of the insulating base 11. The conductor layer 13 can be used as a joint with a metal member such as a lid or an external terminal or an external circuit board.

Further, a groove may be provided on the side surface of the insulating base 11, and a so-called castellation conductor having a conductor attached to the inner surface of the groove may be provided.

  When the electronic component 2 is a light emitting element, a reflective layer for reflecting light emitted from the light emitting element may be provided on the insulating base 11 around the light emitting element. The reflective layer is formed by, for example, depositing a metallized layer and a plating layer on the insulating substrate 11 in order, or depositing a resin film or a metal film. A metal such as nickel, gold or silver is deposited on the exposed surface of the reflective layer.

  A plurality of electronic components 2 may be mounted on one metal layer 14.

  Further, the first heat transfer section 12a may be exposed from the upper surface or the lower surface of the insulating base 11.

  Further, the second heat transfer section 12b may be provided from the upper surface or the lower surface of the first heat transfer section 12a to the side surface of the insulating base 11 in addition to the central portion in the thickness direction of the first heat transfer section 12a. The amount of heat transfer from the first heat transfer section 12a to the second heat transfer section 12b can be improved.

1 ... Wiring board
11 ... Insulating substrate
11a ・ ・ Mounting area
11b ・ ・ Recess
12 ... Heat transfer member
12a ・ ・ 1st heat transfer section
12b .. Second heat transfer section
12c ・ ・ Side heat transfer layer
12d ・ ・ Lower heat transfer layer
13 ... Wiring conductor
14 ... Metal layer
15 ... Notch 2 ... Electronic component 3 ... Connection member 4 ... Sealing material

Claims (4)

An insulating substrate having a main surface including an electronic component mounting area;
A heat transfer member provided in the insulating base,
The heat transfer member is provided at a position overlapping the mounting region in plan view, and includes a first heat transfer portion having an upper surface and a lower surface having a smaller area than the upper surface, and the first heat transfer portion to the insulating base. And a second heat transfer portion that is exposed from the side surface of the insulating base.   The wiring board according to claim 1, further comprising a side heat transfer layer provided on the side surface of the insulating base and in contact with the second heat transfer unit.   The wiring board according to claim 2, further comprising a lower surface heat transfer layer provided on a lower surface of the insulating base and in contact with the side surface heat transfer layer. The wiring board according to claim 1;
An electronic device comprising: an electronic component mounted on the wiring board.