JP2010080572A - Electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately dissipate heat from a heating element without incorporating a thicker heat sink, compared with individual layers of a multilayer substrate in the multilayer substrate, in electronic equipment configured such that the heating element is provided on one surface of the multilayer substrate. <P>SOLUTION: Electronic equipment is equipped with: a multilayer substrate 10 made by stacking a plurality of layers 1 to 6; and a heating element 20 provided on one surface 11 of the multilayer substrate 10. A heat diffusion layer 15, which has a thermal conductivity and consists of a graphite sheet or the like thinner than the individual layers 1 to 6, is provided between adjacent layers 1 to 6 inside the multilayer substrate 10. Inside the multilayer substrate 10, heat dissipation vias 14 are extended in the stacking direction of the layers 1 to 6 to thermally connect the heating element 20 and the heat diffusion layers 15. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electronic device in which a heating element is provided on one surface of a multilayer substrate, and more particularly to improvement in heat dissipation of the heating element.

Conventionally, this type of electronic device includes a multilayer substrate in which a plurality of layers made of resin, ceramic, and the like are laminated, and a heating element provided on one surface of the multilayer substrate. Has been proposed in which a heat sink is provided inside and the heat sink and the heat generating element are thermally connected to each other by a heat radiating via to radiate heat from the heat generating element (see, for example, Patent Document 1).
JP 2002-270743 A

  However, in a multilayer board incorporating a conventional heat sink, the thickness of the heat sink is larger than the thickness of each layer of the multilayer board, and the space for arranging electrical wiring and vias inside the board Will be limited by. In addition, it is unavoidable that the thickness of the multilayer substrate is increased by the heat sink.

  The present invention has been made in view of the above problems, and in an electronic device in which a heating element is provided on one surface of a multilayer substrate, a thick heat sink is incorporated in the multilayer substrate as compared to individual layers constituting the multilayer substrate. It aims at performing the heat dissipation of a heat generating element appropriately.

  In order to achieve the above object, according to the first aspect of the present invention, in an electronic device in which a heating element (20) is provided on one surface (11) of a multilayer substrate (10), the interior of the multilayer substrate (10) is provided. Between adjacent layers (1-6), a thermal diffusion layer (15) having thermal conductivity and thinner than the individual layers (1-6) is provided, and the inside of the multilayer substrate (10) Is provided with a heat dissipation via (14) provided so as to extend in the stacking direction of the layers (1-6) and thermally connecting the heat generating element (20) and the heat diffusion layer (15). And

  According to this, in the multilayer substrate (10), a thermal diffusion layer (15) having thermal conductivity and thinner than the individual layers (1 to 6) is provided between adjacent layers, and this thermal diffusion is performed. Since the layer (15) and the heat generating element (20) are thermally connected by the heat dissipation via (14), the heat generating element (20) can be formed without incorporating a thick heat sink into the multilayer substrate (10) as in the prior art. Can be appropriately radiated.

  Here, as in the invention described in claim 2, the heat radiation via (14) is disposed on the other surface (12) opposite to the one surface (11) of the multilayer substrate (10) from the heat diffusion layer (15). If it is exposed to the outside, the heat from the heat diffusion layer (15) can be efficiently released to the outside through the heat dissipation via (14), so that heat dissipation is improved.

  Further, as in the invention described in claim 3, it is preferable that the thermal diffusion layer (15) has a higher thermal conductivity in the plane direction than that of the metal, and the heat of the heating element (20) is transferred to the multilayer substrate. It becomes possible to escape widely in the plane direction of (10).

  In this case, as in the invention described in claim 4, the thermal diffusion layer (15) can be made of a graphite sheet, carbon fiber, or carbon nanotube.

  In addition, the code | symbol in the bracket | parenthesis of each means described in the claim and this column is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other are given the same reference numerals in the drawings in order to simplify the description.

(First embodiment)
FIG. 1 is a diagram showing a schematic cross-sectional configuration of an electronic device 100 according to the first embodiment of the present invention. The semiconductor device 100 according to the present embodiment is roughly configured to include a multilayer substrate 10 and a heating element 20 provided on one surface 11 of the multilayer substrate 10.

  The multilayer substrate 10 is a wiring substrate in which a plurality of layers 1 to 6 made of resin such as polyimide or liquid crystal polymer, ceramic such as alumina, and the like are laminated. The multilayer substrate 10 is manufactured by hot pressing a laminate of layers 1 to 6 in the same manner as a general resin or ceramic multilayer wiring substrate. The thicknesses of the individual layers 1 to 6 are, for example, about several tens to several hundreds of μm, as in the general case.

  The heating element 20 is an electrical element that generates heat when activated, and is, for example, a chip such as an IC chip or a transistor element made of a silicon semiconductor made of a general semiconductor process.

  Here, an electrical wiring 13 for taking out a signal from the heating element 20 is formed in the multilayer substrate 10 as in the case of a general multilayer wiring substrate. The electrical wiring 13 is located between the layers 1 to 6 and is formed in a desired pattern, and the electrical wiring 13 is provided through the individual layers 1 to 6 to electrically connect the interlayer wirings. And vias to be connected.

  The interlayer wiring is made of a patterned metal foil such as Cu or a printed conductor paste, and the via is made of a metal paste or plating filled in a through hole penetrating the layers 1 to 6 and cured. .

  The electrical wiring 13 is routed around the one surface 11 of the multilayer substrate 10 and is electrically connected to the heating element 20 via the solder balls 30. The electrical wiring 13 is routed to the other surface 12 opposite to the one surface 11 of the multilayer substrate 10, and is electrically connected to an external member on the other surface 12.

  Next, a heat dissipation configuration in the electronic device 100 will be described. First, heat radiation vias 14 are provided in the multilayer substrate 10 so as to extend in the stacking direction of the layers 1 to 6. The heat radiation via 14 penetrates the layers 1 to 6 from the one surface 11 to the other surface 12 of the multilayer substrate 10 and, like a general one, a conductor paste filled in a hole penetrating the layers 1 to 6. And plating.

  On the one surface 11 of the multilayer substrate 10, the heat generating element 20 and the heat radiating via 14 are thermally connected via the solder balls 30. The heat radiation via 14 is exposed to the outside on the other surface 12 of the multilayer substrate 10 and is thermally connected to an external member. Thereby, the heat generated in the heating element 20 is released from the other surface 12 side of the multilayer substrate 10 to the outside through the heat dissipation via 14.

  Furthermore, as a heat dissipation configuration of this embodiment, a thermal diffusion layer 15 having thermal conductivity is provided inside the multilayer substrate 10. The thermal diffusion layer 15 is provided between the adjacent layers 1 to 6, that is, between the layers, and the thickness thereof is thinner than the individual layers 1 to 6. Specifically, the thermal diffusion layer 15 is formed by the same manufacturing method as the interlayer wiring as the electrical wiring 13, and the thickness thereof is the same as that of the interlayer wiring, for example, about several tens of μm.

  The thermal diffusion layer 15 is naturally superior in thermal conductivity to the layers 1 to 6, but is made of a metal having excellent thermal conductivity such as copper or aluminum or a material equivalent to or more than the metal. When the thermal diffusion layer 15 is made of the metal, it is formed by paste, foil, plating, or the like.

  In addition, the material equivalent to or more than the metal constituting the thermal diffusion layer 15 is specifically a graphite sheet, carbon fiber, carbon nanotube, or the like. In the case of these materials, these materials may be formed into a sheet shape, and the sheet may be laminated together with the layers 1 to 6 on which the electrical wiring 13 and the heat dissipation vias 14 are formed.

  And the heat | fever diffusion layer 15 which consists of these materials becomes a thing whose heat conductivity of the plane direction (namely, direction parallel to the layer surface of the heat | fever diffusion layer 15) is higher than a metal. For example, the thermal conductivity in the planar direction of the layer made of metal is at most 400 W / mK, whereas in the case of the thermal diffusion layer 15 made of graphite sheet, the thermal conductivity in the planar direction is 1000 W / mK. That's it.

  Here, the thermal diffusion layer 15 is provided between the layers in the middle of the stacking direction of the plurality of layers 1 to 6, and extends in the thickness direction of the multilayer substrate 10, that is, extends from one surface 11 to the other surface 12. The heat diffusion layer 15 is interposed in the middle of the heat dissipation via 14 and is thermally connected to the heat dissipation via 14.

  The thermal connection between the heat dissipation via 14 and the thermal diffusion layer 15 is easily realized by thermocompression bonding or the like. Thereby, in this embodiment, the heat generated in the heating element 20 located on the one surface 11 of the multilayer substrate 10 is transferred to the other surface 12 side of the multilayer substrate 10 through the heat dissipation via 14 → the heat diffusion layer 15 → the heat dissipation via 14. A heat dissipation path is configured to escape from the outside to the outside.

  Further, in FIG. 1, the heat of the heat generating element 20 is transmitted directly below the heat generating element 20 through the heat radiating vias 14 near the one surface 11 of the multilayer substrate 10, and in the substrate plane direction in the heat diffusion layer 15. Further, the heat spreads from the heat radiation via 14 near the other surface 12 of the multilayer substrate 10 to the outside.

  In the example shown in FIG. 1, one thermal diffusion layer 15 is provided between the third layer 3 and the fourth layer 4 from the one surface 11 side in the six layers 1 to 6. However, the thermal diffusion layer 15 may be provided between other layers. Even in that case, it is the same that a heat dissipation path is configured for each thermal diffusion layer 15 via the heat dissipation via 14.

  In the present embodiment, the thermal diffusion layer 15 is provided in the multilayer substrate 10 immediately below the heating element 20, that is, in a region where the heating element 20 is projected onto the multilayer substrate 10. The planar size of the thermal diffusion layer 15 is larger than the planar size of the heat generating element 20. For example, when the heating element 20 is a rectangular plate-like chip, the heat diffusion layer 15 is a rectangular layer that is slightly larger than that.

  Therefore, in the present embodiment, as shown in FIG. 1, the multilayer structure is larger than the thermal diffusion layer 15 as compared with the thermal radiation via 14 located on the heating element 20 side, that is, the one surface 11 side of the multilayer substrate 10, relative to the thermal diffusion layer 15. The number of the heat radiation vias 14 located on the other surface 12 side of the substrate 10 is larger and the arrangement area is wider. Therefore, it is possible to efficiently dissipate heat by utilizing the characteristic of the thermal diffusion layer 15 that has a high thermal conductivity in the plane direction.

  Next, a method for manufacturing the electronic device 100 will be described. First, the electrical wiring 13 and the heat radiation via 14 are formed in each layer 1-6. In the case where the heat diffusion layer 15 is made of paste, the heat diffusion layer 15 is preliminarily disposed on the layer where the heat diffusion layer 15 is located by printing or the like, and the heat diffusion layer 15 is made of a sheet or foil. Is previously attached to the layer where the thermal diffusion layer 15 is located.

  And these layers 1-6 are aligned and laminated | stacked, and this is pressed collectively with a predetermined | prescribed heat and pressure. Thereby, each layer 1-6 is joined by thermocompression bonding etc., and the multilayer substrate 10 is completed.

  Thereafter, the heating element 20 is connected to the one surface 11 of the multilayer substrate 10 via the solder balls 30 by a general method. Thus, the electronic device 100 of this embodiment is completed. The electronic device 100 is used by being connected to an external member (not shown) via, for example, solder.

  By the way, according to the present embodiment, the thermal diffusion layer 15 having thermal conductivity and thinner than the individual layers 1 to 6 is provided between the adjacent layers 3 and 4 in the multilayer substrate 10. Since the heat diffusion layer 15 and the heat generating element 20 are thermally connected by the heat dissipation via 14, the heat generating element 20 can be appropriately radiated without incorporating a thick heat sink in the multilayer substrate 10 as in the prior art. Can do. As a result, restrictions on the installation space for the electrical wiring 13 in the multilayer substrate 10 are reduced.

  Further, although the heat dissipation via 14 may not be exposed on the other surface 12 of the multilayer substrate 10, in this embodiment, the heat dissipation via 14 is exposed to the outside from the heat diffusion layer 15 on the other surface 12 of the multilayer substrate 10. Therefore, the heat transmitted from the heating element 10 to the thermal diffusion layer 15 can be efficiently released to the outside through the heat dissipation via 14.

(Second Embodiment)
FIG. 2 is a diagram showing a schematic cross-sectional configuration of an electronic device according to the second embodiment of the present invention. The present embodiment is different from the first embodiment in the thermal connection configuration of the heating element 20 and the thermal diffusion layer 15 on the one surface 11 side of the multilayer substrate 10. Here, the difference is as follows. It will be described in the center. In FIG. 2, the electrical wiring 13 is omitted, but the electrical wiring 13 similar to that in the first embodiment is also provided in the present embodiment.

  In the first embodiment, the heating element 20 and the thermal diffusion layer 15 are thermally connected via the plurality of solder balls 30 and the plurality of heat dissipation vias 14, but as shown in FIG. In this embodiment, the heating element 20 and the thermal diffusion layer 15 are thermally connected via one large metal member 40 instead of the solder ball 30 and the heat dissipation via 14.

  In this case, an opening that reaches the thermal diffusion layer 15 from the one surface 11 of the multilayer substrate 10 is formed by punching such as pressing, cutting, or etching, and a metal paste such as solder, copper, aluminum, or the like is formed in the opening. What is necessary is just to comprise the said filling material as the metal member 40 by filling a block.

  According to this embodiment, the heat generated in the heating element 20 is released from the other surface 12 side of the multilayer substrate 10 to the outside through the metal member 40 → the heat diffusion layer 15 → the heat dissipation via 14. A route is constructed. Thereby, also in this embodiment, the heat dissipation of the heating element 20 can be appropriately performed without incorporating a thick heat sink in the multilayer substrate 10 as in the prior art.

(Third embodiment)
FIG. 3 is a diagram showing a schematic cross-sectional configuration of an electronic device according to the third embodiment of the present invention. The present embodiment is different from the first embodiment in that the multilayer substrate 10 is an interposer. In FIG. 3, the electrical wiring 13 is omitted, but the electrical wiring 13 similar to that in the first embodiment is also provided in this embodiment.

  As shown in FIG. 3, the electronic device of the present embodiment has a configuration in which the heating element 20 is mounted on a circuit board 50 via a multilayer substrate 10 as an interposer. This interposer is a member that is rewired to match the land pitch of both members when, for example, the land pitch of the heating elements 20 and the land pitch of the circuit board 50 do not correspond, and is configured as a multilayer substrate.

  In the present embodiment, the multilayer substrate 10 as an interposer has the same configuration as the multilayer substrate of the first embodiment, and the electrical wiring 13 and the heat dissipation via 14 exposed on the other surface 12 of the multilayer substrate 10 are respectively soldered. The ball 30 is electrically and thermally connected to the circuit board 50.

  Accordingly, in the present embodiment, heat generated in the heat generating element 20 is released from the other surface 12 side of the multilayer substrate 10 to the outside air and the circuit board 50 through the heat dissipation via 14 → the heat diffusion layer 15 → the heat dissipation via 14. The heat dissipation path is configured.

  Also in the present embodiment, it is possible to appropriately dissipate heat from the heating element 20 without incorporating a thick heat sink in the multilayer substrate 10 as in the prior art. The multilayer substrate 10 of the present embodiment may adopt the same configuration as that of the second embodiment.

(Fourth embodiment)
4A, 4B, and 4C are schematic cross-sectional views illustrating a first example, a second example, and a third example of an electronic device according to a fourth embodiment of the present invention. 4A to 4C, the electrical wiring 13 is omitted, but in the present embodiment, the electrical wiring 13 similar to the above is provided.

  In the present embodiment, a part of the multilayer substrate 10 is modified as compared to the first embodiment, and the multilayer substrate 10 including the metal layer 7 is obtained. Specifically, the configuration of the portion from the one surface 11 side on which the heating element 20 is mounted in the multilayer substrate 10 to the thermal diffusion layer 15 is the same as in the first embodiment, but the thermal diffusion layer in the multilayer substrate 10 is the same. The portion from 15 to the other surface 12 is replaced with the metal layer 7.

  That is, as the multilayer substrate 10, a metal other than resin or ceramic may be used as a layer constituting the multilayer substrate 10 as long as electrical independence of each wiring portion is ensured as the wiring substrate.

  In this embodiment, the other surface 12 of the multilayer substrate 10 is constituted by a metal layer 7 made of a metal such as copper or aluminum, and the thermal diffusion layer 15 is thermally connected to the metal layer 7. . Here, the thermal connection between the metal layer 7 and the thermal diffusion layer 15 is performed through the heat dissipation via 14 in FIG. 4A, but as shown in FIGS. 4B and 4C, You may carry out by direct contact, such as providing a protrusion in the metal layer 7.

  The metal layer 7 is integrated with other layers by hot pressing in a lump. According to the present embodiment, heat can be radiated from the thermal diffusion layer 15 to the outside through the metal layer 7, and an improvement in heat dissipation is expected. In addition, this embodiment can be applied to the multilayer substrate 10 in each of the above-described embodiments.

(Fifth embodiment)
FIG. 5 is a diagram showing a schematic cross-sectional configuration of an electronic device according to the fifth embodiment of the present invention. Although the present embodiment is a reference example, a heat dissipation path that combines the heat diffusion layer 15 and the conventional heat sink 60 described in the above embodiments is configured.

  As shown in FIG. 5, in the present embodiment, a heat sink 60 made of copper, aluminum, or the like is provided inside the multilayer substrate 10, and the heat diffusion layer 15 is provided on the surface of the heat sink 60 on the side of the heat generating element 20. The configuration is pasted.

  In this case, the heat transmitted to the heat diffusion layer 15 is dissipated to the heat sink 60, and further, a heat radiation via 14 is provided between the heat sink 60 and the other surface 12 of the multilayer substrate inside the multilayer substrate 10, May be allowed to escape to the outside.

(Other embodiments)
Note that the electrical and thermal connection between the heating element 20 mounted on the one surface 11 of the multilayer substrate 10 and the electrical wiring 12 and the heat dissipation via 14 is not limited to the solder ball 30; Instead of the solder balls 30, bumps or bonding wires made of gold or copper may be used.

  In addition, the heat dissipation path for releasing heat from the heat generating element 20 to the outside through the heat diffusion layer 15 in each of the above embodiments includes the thick heat dissipation via 14 and the heat diffusion layer 15 having a large area. It may also be used as a wiring for electrically connecting the heat generating element 20 and the outside, such as a large current wiring.

1 is a schematic cross-sectional view of an electronic device according to a first embodiment of the present invention. It is a schematic sectional drawing of the electronic device which concerns on 2nd Embodiment of this invention. It is a schematic sectional drawing of the electronic device which concerns on 3rd Embodiment of this invention. (A), (b), (c) is a schematic sectional drawing which shows the 1st example of the electronic device which concerns on 4th Embodiment of this invention, a 2nd example, and a 3rd example. It is a schematic sectional drawing of the electronic device which concerns on 5th Embodiment of this invention.

Explanation of symbols

1 to 6 layers 10 multilayer substrate 11 one surface of multilayer substrate 12 other surface of multilayer substrate 14 heat dissipation via 15 heat diffusion layer 20 heating element

Claims (4)

A multilayer substrate (10) in which a plurality of layers (1-6) are laminated;
A heating element (20) provided on one surface (11) of the multilayer substrate (10),
Between the adjacent layers (1-6) inside the multilayer substrate (10), there is a thermal diffusion layer (15) having thermal conductivity and thinner than the individual layers (1-6). Provided,
A heat radiating via provided in the multilayer substrate (10) so as to extend in the stacking direction of the layers (1-6) and thermally connecting the heat generating element (20) and the heat diffusion layer (15). An electronic device comprising (14).   The heat radiation via (14) is exposed to the outside from the thermal diffusion layer (15) on the other surface (12) opposite to the one surface (11) of the multilayer substrate (10). The electronic device according to claim 1.   The electronic device according to claim 1 or 2, wherein the thermal diffusion layer (15) has a higher thermal conductivity in the plane direction than that of a metal.   The electronic device according to claim 3, wherein the thermal diffusion layer (15) is composed of a graphite sheet, carbon fiber, or carbon nanotube.

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