JP2022034335A - Wiring board - Google Patents

Abstract

To provide a wiring board which allows efficient heat dissipation.SOLUTION: A wiring board 10 in an embodiment has: a first surface 10F having a component mounting region A on which an electronic component EC is mounted, and a second surface 10S which is on the opposite side to the first surface 10F; a plurality of insulation layers 11 and conductor layers 12 which are alternately laminated between the first surface 10F and the second surface 10S; and a Peltier element 100 which is disposed between the first surface 10F and the second surface 10S. The Peltier element 100 has: an endothermic surface 101 facing the first surface 10F side; and an exothermic surface 102 facing the second surface 10S side. A distance D2 between the exothermic surface 102 and the second surface 10S is shorter than a distance D1 between the endothermic surface 101 and the first surface 10F.SELECTED DRAWING: Figure 1

Description

The present invention relates to a wiring board.

Patent Document 1 discloses a heat dissipation substrate. A Pelche element module housed in a cavity penetrating the core substrate is arranged in the central portion in the thickness direction of the heat radiating substrate. An insulating layer and a conductor layer are laminated on both sides of the core substrate.

Japanese Unexamined Patent Publication No. 2019-201066

In the heat dissipation substrate of Patent Document 1, the Pelche element module is arranged at the center in the thickness direction of the substrate. It is considered that heat tends to stay on the heat generating surface side of the Pelche element module. It is considered that the retention of heat on the heat absorbing surface side causes a decrease in the endothermic amount on the endothermic surface side, and it is difficult to obtain the desired cooling effect on the endothermic surface side.

The wiring board of the present invention is alternately laminated between the first surface having a component mounting area on which electronic components are mounted and the second surface opposite to the first surface, and the first surface and the second surface. It has a plurality of insulating layers and conductor layers to be formed, and a Pelche element arranged between the first surface and the second surface. The Pelche element has an endothermic surface facing the first surface side and a heat generating surface facing the second surface side, and the distance between the heat generating surface and the second surface is the endothermic surface and the above. It is smaller than the distance to the first surface.

According to the embodiment of the present invention, it is possible to provide a wiring board capable of efficiently dissipating heat generated from an electronic component or the like mounted in a component mounting area to the outside.

The cross-sectional view which shows an example of the wiring board of one Embodiment of this invention. The cross-sectional view which shows the other example of the wiring board of one Embodiment of this invention. FIG. 6 is a cross-sectional view showing still another example of the wiring board according to the embodiment of the present invention. FIG. 6 is a cross-sectional view showing still another example of the wiring board according to the embodiment of the present invention. FIG. 6 is a cross-sectional view showing still another example of the wiring board according to the embodiment of the present invention. The cross-sectional view which shows the manufacturing method of the wiring board of one Embodiment of this invention. The cross-sectional view which shows the manufacturing method of the wiring board of one Embodiment of this invention. The cross-sectional view which shows the manufacturing method of the wiring board of one Embodiment of this invention. The cross-sectional view which shows the manufacturing method of the wiring board of one Embodiment of this invention. The cross-sectional view which shows the manufacturing method of the wiring board of one Embodiment of this invention. The cross-sectional view which shows the manufacturing method of the wiring board of one Embodiment of this invention. The cross-sectional view which shows the manufacturing method of the wiring board of one Embodiment of this invention. The cross-sectional view which shows the manufacturing method of the wiring board of one Embodiment of this invention. The cross-sectional view which shows the manufacturing method of the wiring board of one Embodiment of this invention. The cross-sectional view which shows the manufacturing method of the wiring board of one Embodiment of this invention. The cross-sectional view which shows the manufacturing method of the wiring board of one Embodiment of this invention. The cross-sectional view which shows the manufacturing method of the wiring board of one Embodiment of this invention. The cross-sectional view which shows the manufacturing method of the wiring board of one Embodiment of this invention.

Next, a wiring board according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a wiring board 10 which is an example of an embodiment. As shown in FIG. 1, the wiring board 10 of the present embodiment has a first surface 10F and a second surface 10S opposite to the first surface 10F. The wiring board 10 includes a plurality of alternately laminated insulating layers 11 and conductor layers 12. Of the plurality of insulating layers 11, the insulating layer 11p has a Pelche element 100 inside thereof. The insulating layer 11p containing the Pelche element 100 is also referred to as an element built-in layer 11p. The endothermic element 100 is arranged in a storage port 11pc provided in the element built-in layer 11p with its endothermic surface 101 facing the first surface 10F side and the heat generating surface 102 facing the second surface 10S side. The Pelche element 100 is arranged in the wiring board 10 at a position closer to the second surface 10S.

Each of the plurality of conductor layers 12 is appropriately patterned so as to have a desired conductor pattern. The insulating layer 11 in contact with the conductor layer 12 includes a connecting conductor for connecting the conductor layer 12 in contact with the insulating layer 11. Specifically, the element built-in layer 11p includes a through-hole conductor 14p that connects the conductor layers 12p that are in contact with each other on both sides thereof, and the other insulating layer 11 contains a via conductor 14v.

In the illustrated example, the element built-in layer 11p and the conductor layers 12p in contact with both sides of the element built-in layer 11p constitute the core substrate 3 of the wiring board 10. Build-up layers are formed on both sides of the core substrate 3. Specifically, the first build-up portion 1 having the first surface 10F is laminated on one surface (heat absorbing surface 101 of the Pelche element 100) of the core substrate 3, and the other surface (heat generation of the Pelche element 100) is generated. A second build-up portion 2 having a second surface 10S is laminated on the surface 102). The number of layers of the insulating layer 11 and the conductor layer 12 of the second build-up unit 2 is smaller than the number of layers of the insulating layer 11 and the conductor layer 12 of the first build-up unit 1.

In the description of the wiring board 10 of the present embodiment, in the thickness direction of the wiring board 10, the side closer to the first surface 10F or the second surface 10S is "upper" or "outer" with respect to the element built-in layer 11p. , Or simply "upper" or "outer", and the side closer to the element built-in layer 11p is also referred to as "lower side" or "inside", or simply "lower" or "inside".

In the illustrated example, the wiring board 10 includes a coating layer 13 on the conductor layer 12 and the insulating layer 11 of the outermost layers on the first surface 10F side and the second surface 10S side. The covering layer 13 is formed with an opening 13a that exposes the conductor pad 12c of the outermost conductor layer 12. The coating layer 13 can be a solder resist layer.

The first surface 10F of the wiring board 10 has a component mounting area A on which external electronic components and the like can be mounted, and can function as a component mounting surface. In the component mounting area A, for example, a semiconductor integrated circuit device such as a memory, a microcomputer, a CPU, or an electronic component EC which is an optical semiconductor device such as an LED or a PD (photodiode) may be mounted. In the illustrated example, the portion of the first surface 10F corresponding to the component mounting area A constitutes a recess 10FR recessed inside the wiring board 10. In the illustrated example, the bottom surface of the recess 10FR is composed of a component mounting pad 120 formed over the entire area of the component mounting region A as a conductor pattern of the conductor layer 12. The side wall (portion other than the bottom surface) of the recess 10FR is composed of an exposed surface of the insulating layer 11 and the covering layer 13. The portion of the first surface 10F other than the recess 10FR is composed of the coating layer 13 and the conductor layer 12 (conductor pad 12c) exposed from the opening 13a provided in the coating layer 13.

The second surface 10S of the wiring board 10, which is composed of the conductor layer 12 and the coating layer 13, functions as a heat dissipation surface for releasing the heat of the wiring board 10 to the outside. The heat generated from the electronic component EC that can be mounted in the component mounting area A on the first surface 10F is transferred to the second surface 10S via the Pelche element 100 and dissipated to the outside of the wiring board 10. In the illustrated example, the second surface 10S has a heat dissipation pattern 12ce formed as a part of the conductor pattern of the conductor layer 12. A heat sink (not shown) may be connected to the second surface 10S via, for example, an adhesive member having high thermal conductivity in order to efficiently release the heat inside the wiring board 10 to the outside.

The Pelche element 100 arranged on the wiring board 10 has a first surface 101 on one side and a second surface 102 on the opposite side to the first surface 101. In the present embodiment, the first surface 101 functions as a cooling surface (endothermic surface), and the second surface 102 functions as a heating surface (heating surface). The Pelche element 100 is arranged so that the first surface 101 faces the component mounting region A side of the first surface 10F and the second surface 102 faces the second surface 10S side. The Pelche element 100 functions as a heat pump that absorbs heat generated from the electronic component EC arranged in the component mounting region A from the first surface 101 and dissipates heat from the second surface 102.

If the heat generated by the electronic component EC arranged in the component mounting area A of the wiring board 10 stays in the wiring board 10, it may cause a malfunction of the electronic component EC or the like. In addition, it may cause delamination due to thermal expansion of each component of the wiring board 10. Therefore, the heat generated by the electronic component EC needs to be dissipated to the outside of the wiring board 10. The Pelche element 100 is provided to efficiently dissipate the heat generated by the electronic component EC from the second surface 10S to the outside of the wiring board 10.

In the wiring board 10 of the present embodiment, the Pelche element 100 is arranged at a position closer to the second surface 10S in the thickness direction of the wiring board 10. Specifically, the Pelche element 100 is arranged at a position where the distance D2 between the heat generating surface 102 and the second surface 10S of the Pelche element 100 is smaller than the distance D1 between the endothermic surface 101 and the first surface 10F of the Pelche element 100. Will be done. With such a configuration, heat generated from a heat source such as an electronic component EC mounted on the first surface 10F can be efficiently dissipated from the second surface 10S.

As described above, in the configuration in which the Pelche element module is arranged in the central portion in the thickness direction of the substrate, the heat generated from the heat generation surface of the Pelche element tends to stay in the substrate, and effective cooling is performed on the endothermic surface side. It is considered difficult to realize. It is difficult to effectively dissipate heat generated from a heat source such as an electronic component to the outside of the substrate, and therefore, it is considered that there is a possibility of causing a malfunction due to overheating of the electronic component connected to the substrate. On the other hand, when the distance D2 from the heat generating surface 102 to the second surface 10S is smaller than the distance D1 from the endothermic surface 101 to the first surface 10F as in the present embodiment, the effect on the outside of the wiring board 10 is achieved. Heat dissipation can be realized. Effective cooling can be realized on the endothermic surface 101, and defects such as malfunction of electronic components mounted on the wiring board 10 can be suppressed. From the viewpoint of effectively dissipating the heat generated from the heat generating surface 102, the ratio of the distance D2 from the heat generating surface 102 to the second surface 10S to the distance D1 from the endothermic surface 101 to the first surface 10F is 0.5 or less. The distance D2 from the heat generating surface 102 to the second surface 10S is preferably 400 μm or less.

As shown in the figure, in order to efficiently transfer the heat generated by the electronic component EC, which is a heat source, to the endothermic surface 101 and dissipate heat from the second surface 10S via the Pelche element 100, the Pelche element 100 is the first. It is preferable that the component mounting area A on the surface 10F is arranged in an area vertically projected on the second surface 10S side. Further, it is preferable that the endothermic surface 101 of the Pelche element 100 is connected to the component mounting pad 120 via a conductor (via conductor 14v, conductor layer 12) constituting the wiring board 10. Then, the heat generating surface 102 of the Pelche element 100 is connected to the heat dissipation pattern 12ce formed as a part of the conductor pattern of the conductor layer 12 constituting the second surface 10S via the conductor constituting the wiring board 10. Is preferable. Heat conduction from the heat source to the endothermic surface 101 and heat conduction from the heat generating surface 102 to the heat radiating surface (second surface 10S) can be efficiently performed.

The conductor layers 12, 12p, via conductor 14v, and through-hole conductor 14p can be formed using any material having appropriate conductivity, such as copper or nickel. The conductor layers 12 and 12p, the via conductor 14v, and the through-hole conductor 14p are, for example, a metal foil (preferably copper foil), a metal film layer (preferably a non-electrolytic copper plating film layer), and an electrolytic plating film layer (preferably electrolytic copper). It is composed of a plating film layer) or a combination thereof. In the example shown in FIG. 1, the conductor layer 12p in contact with the insulating layer 11p containing the Pelche element 100 has a three-layer structure including a metal foil, a metal film layer, and an electrolytic plating film layer. The other conductor layer 12, the via conductor 14v, and the through-hole conductor 14p constituting the wiring board 10 have a two-layer structure including a metal film layer and an electrolytic plating film layer. However, the configuration of each conductor layer 12 constituting the wiring board 10 is not limited to the multilayer structure exemplified in FIG. 1. For example, the conductor layer 12 other than the conductor layer 12p may also be composed of a three-layer structure of a metal foil layer, a metal film layer, and an electrolytic plating film layer.

The insulating layers 11 and 11p can be formed by using an insulating resin such as an epoxy resin, a bismaleimide triazine resin (BT resin) or a phenol resin. Each insulating layer 11, 11p may contain a reinforcing material such as glass fiber and / or an inorganic filler such as silica. In the example shown in FIG. 1, the insulating layer 11p contains a reinforcing material containing glass fiber. On the other hand, the insulating layer 11 other than the insulating layer 11p does not contain a reinforcing material. The coating layer 13 is formed by using, for example, a photosensitive epoxy resin or a polyimide resin.

The recess 10FR formed on the first surface 10F side of the wiring board 10 exposes the component mounting pad 120 on which the electronic component EC should be mounted over the entire bottom surface thereof. In this component mounting pad 120, a part of one of the conductor layers 12 constituting the wiring board 10 is exposed on the bottom surface of the recess 10FR. The electronic component EC may be mounted on the component mounting pad 120 via a mounting member such as an insulating adhesive formed of an epoxy resin or a conductive adhesive containing conductive particles. An electronic component (not shown) such as a controller for controlling the electronic component EC may be connected to the upper side of the electronic component EC.

The insulating layer 11p has a through hole (accommodation port) 11pc for accommodating the Pelche element 100 inside. The accommodation port 11pc is formed to be slightly larger than the size of the Pelche element 100. The gap between the inner surface of the accommodating port 11pc and the Pelche element 100 is filled with the resin constituting the insulating layer 11 closest to the insulating layer 11p among the insulating layers 11 constituting the wiring board 10.

The Pelche element 100 has a plurality of rectangular parallelepiped P-type thermoelectric semiconductor elements 100p and N-type thermoelectric semiconductor elements 100n which are alternately arranged at regular intervals. In the Pelche element 100, among the plurality of alternately arranged P-type and N-type thermoelectric semiconductor elements 100p and 100n, the end portions of the adjacent P-type and N-type thermoelectric semiconductor elements 100p and 100n are attached to the electrode plate 100e. It consists of connecting in a staggered manner. Of the plurality of alternately arranged P-type and N-type thermoelectric semiconductor elements 100p and 100n, the terminal P-type or N-type thermoelectric semiconductor element 100p and 100n have electrodes 100A at the end opposite to the electrode plate 100e. 100B is provided. The electrode plate 100e and the electrodes 100A and 100B are made of a metal having appropriate conductivity such as Cu. In the Pelche element 100, a plurality of P-type and N-type thermoelectric semiconductor elements 100p and 100n provided with the electrode plate 100e and the electrodes 100A and 100B are provided with two insulating plates (first insulating plate 100c and second insulating plate 100h). ) Is sandwiched between them.

The P-type thermoelectric semiconductor element 100p and the N-type thermoelectric semiconductor element 100n have substantially the same shape and are formed to have the same size. As the P-type thermoelectric semiconductor device 100p, for example, a bismuth-tellu compound to which antimony is added can be used, and as the N-type thermoelectric semiconductor element 100n, a bismuth-tellu compound to which selenium is added can be used. The space between the thermoelectric semiconductor elements 100p and 100n of the Pelche element 100 is filled with a sealing agent such as an insulating resin. As the sealing agent, for example, an insulating resin such as an epoxy resin can be used.

The first and second insulating plates 100c and 100h constituting both sides of the Pelche element 100 are configured by using a material having high thermal conductivity and electrical insulation such as a ceramic plate. For the first and second insulating plates 100c and 100h, for example, alumina (Al ₂ O ₃ ), aluminum nitride (AlN) and the like can be used. The surface of the first insulating plate 100c opposite to the P-type and N-type thermoelectric semiconductor elements 100p and 100n constitutes the first surface (endothermic surface) 101. The surface of the second insulating plate 100h opposite to the P-type and N-type thermoelectric semiconductor elements 100p and 100n constitutes the second surface (heating surface) 102.

In the Pelche element 100 of the illustrated example, the electrodes 100A and 100B are provided on the first surface 101 side, and the portion of the first insulating plate 100c that overlaps with the electrodes 100A and 100B is a part of the electrodes 100A and 100B. An opening is formed to expose. However, the positions of the electrodes 100A and 100B in the Pelche element 100 are not limited to this. Both the electrodes 100A and 100B may be provided on the second surface 102 side, and one of the electrodes 100A and 100B is provided on the first surface 101 side and the other is provided on the second surface 102 side. May be. The electrodes 100A and 100B of the Pelche element 100 are electrically connected to the conductor pad 12c formed on the surface of the wiring board 10 via the via conductor 14v and the conductor layer 12 in order to receive power supply from the outside. ..

When electric power is supplied to the Pelche element 100, a temperature gradient is formed in which the temperature is low on the first insulating plate 100c side of the Pelche element 100 and the temperature is high on the second insulating plate 100h side on the opposite side. That is, an endothermic phenomenon occurs on the first insulating plate 100c side, and a heat generation phenomenon occurs on the second insulating plate 100h side. As a result, the heat on the first surface 101 side of the Pelche element 100 in the wiring board 10 is transferred to the second surface 102 side via the Pelche element 100.

The wiring board 10 of FIG. 1 is shown as an example in which the component mounting pad 120 and the electronic component EC are electrically insulated from each other. The electric power to the electronic component EC may be supplied from another electronic component or the like that can be connected on the electronic component EC via, for example, a connection pad provided on the upper portion of the electronic component EC. However, the power supply to the electronic component EC may be performed via the component mounting pad 120 provided in the component mounting area A. In the wiring board 10a shown in FIG. 2, an example is shown in which the electronic component EC is electrically connected to the component mounting pad 120 by flip-chip mounting.

In the wiring board 10a, the electronic component EC may be connected to, for example, a component mounting pad 120 exposed from an opening of a coating layer (solder resist layer) 13r provided immediately below the electronic component EC via a bump such as solder. In the illustrated example, the conductive path for supplying power to the Pelche element 100, which is connected to the electrodes 100A and 100B of the Pelche element 100, partially overlaps with the conductive path to the electronic component EC. Also in the wiring board 10a in this embodiment, the component mounting pad 120 and the Pelche element 100 are connected to each other via a conductor, similarly to the wiring board 10. As a result, the heat generated by the electronic component EC can be efficiently transferred to the Pelche element 100 while the electric power is supplied by the conductive path common to the electronic component EC and the Pelche element 100.

The wiring board of the present embodiment may have a configuration in which the heat generating surface 102 of the Pelche element 100 is exposed on the second surface 10S, as in the wiring board 10b shown in FIG. By exposing the heat generating surface 102 of the Pelche element 100, the heat generated from the heat generating surface 102 is directly discharged to the outside of the wiring board 10b, and the heat dissipation efficiency can be improved. The exposed heat generating surface 102 can be coupled to an external heat sink (not shown) via an adhesive having high thermal conductivity or the like.

Further, the wiring board of the present embodiment does not have to have a recess in which the first surface 10F is recessed in the component mounting area A, as in the wiring board 10c shown in FIG. In the illustrated example, the component mounting pad 120 is formed on the same surface as the conductor pad 12c exposed on the first surface 10F, and the electronic component EC is mounted on the first surface 10F via the component mounting pad 120. Also in the wiring board 10c, the distance D2 from the heat generating surface 102 of the Pelche element 100 to the surface of the wiring board is smaller than the distance D1 from the heat absorbing surface 101 to the first surface 10F, and the distance D2 to the outside of the wiring board 10c. Effective heat dissipation can be achieved.

In the wiring boards 10, 10a, 10b, and 10c shown in FIGS. 1 to 4, the Pelche element 100 is arranged in the core substrate 3, and the number of layers of the insulating layer 11 and the conductor layer 12 included in the second build-up portion 2 However, an example is shown in which the number of layers of the insulating layer 11 and the conductor layer 12 of the first build-up unit 1 is smaller than the number of layers. However, the wiring board of the present embodiment is not limited to the configuration in which the Pelche element 100 is arranged in the core board 3. It may also have a configuration in which the Pelche element 100 is arranged in the build-up layer laminated on the surface of the core substrate 3. FIG. 5 shows an example in which the Pelche element 100 is arranged in the second build-up unit 2 as the wiring board 10d.

In the wiring board 10d shown in FIG. 5, the first build-up portion 1 and the second build-up portion 2 laminated on both side surfaces of the core substrate 3 have a symmetrical layer structure. That is, the first build-up unit 1 and the second build-up unit 2 have an insulating layer 11 and a conductor layer 12 having the same number of layers. The Pelche element 100 is housed in the opening of the insulating layer 11 constituting the second build-up portion 2. Also in the wiring board 10d, a configuration is realized in which the distance D2 between the heat generating surface 102 of the Pelche element 100 and the second surface 10S is smaller than the distance D1 between the endothermic surface 101 of the Pelche element 100 and the first surface 10F. Efficient heat dissipation from the wiring board 10d to the second surface 10S side can be realized.

Hereinafter, a method for manufacturing the wiring board 10 shown in FIG. 1 will be described. First, as shown in FIG. 6A, a double-sided copper-clad laminate in which a copper foil 12f is laminated on both sides of an insulating layer 11p made of, for example, an epoxy resin or BT (bismaleimide triazine) resin and a reinforcing material such as glass cloth. A board is prepared. Next, as shown in FIG. 6B, carbon dioxide laser light is irradiated from both sides of the double-sided copper-clad laminate to taper from both sides toward the center in the thickness direction of the insulating layer 11p. A through hole 14ph with a reduced diameter is formed.

Next, as shown in FIG. 6C, a through-hole conductor 14p and a conductor layer 12p are formed. The electroless plating treatment is performed in the through hole 14ph and on the copper foil 12f, and an electroless plating film 12n is formed on the copper foil 12f and on the inner surface of the through hole 14ph. Then, after the plating resist of a predetermined pattern is formed on the electrolytic plating film 12n on the copper foil 12f, the electrolytic plating treatment is performed, the electrolytic plating film 12e is filled in the through hole 14ph, and the through hole conductor 14p is formed. It is formed. At the same time, the electrolytic plating film 12e is formed on the portion of the copper foil 12f exposed from the plating resist of the electroless plating film 12n. Subsequently, the plating resist is peeled off, and the electroless plating film 12n and the copper foil 12f below the plating resist are removed by etching. The remaining electrolytic plating film 12e, electroless plating film 12n, and copper foil 12f form conductor layers 12p on both sides of the insulating layer 11p, and the conductor layer 12p is connected by the through-hole conductor 14p.

Next, as shown in FIG. 6D, the accommodation port 11pc is formed in the insulating layer 11p by router processing or laser light irradiation.

Then, as shown in FIG. 6E, a tape TP made of, for example, a PET film is attached onto the conductor layer 12p so as to close one of the openings of the accommodation port 11pc. Then, the Pelche element 100 is housed inside the accommodating port 11pc by a mounter (not shown), and the second insulating plate 100h of the Pelche element 100 is fixed to the tape TP.

Subsequently, as shown in FIG. 6F, the resin film 11f is laminated on the conductor layer 12p opposite to the conductor layer 12p to which the tape TP is attached. When the resin film 11f is pressed, it enters between the conductor patterns of the conductor layer 12p and the gap between the Pelche element 100 and the inner wall of the accommodating port 11pc. The resin film 11f is, for example, a resin film containing an inorganic filler without containing a core material.

Next, as shown in FIG. 6G, the tape TP is removed from the conductor layer 12p and the Pelche element 100.

Next, as shown in FIG. 6H, the resin film 11f is laminated and pressed on the conductor layer 12p and the second surface 102 of the Pelche element 100. At that time, the resin film 11f is filled between the conductor patterns of the conductor layer 12p and the gap between the inner surface of the accommodating port 11pc and the Pelche element 100, and the gap is completely filled with the resin. As described above, the Pelche element 100 is arranged in the insulating layer (element built-in layer) 11p having the conductor layer 12p on both sides, and the formation of the core substrate 3 is completed. At the same time, the formation of the insulating layer 11 in contact with both sides of the core substrate 3 is completed.

Subsequently, as shown in FIG. 6I, the via conductor 14v is formed on the insulating layer 11 in contact with the first surface 101 of the Pelche element 100, and the conductor layer 12 in contact with the insulating layer 11 is formed. At the same time, the via conductor 14v is also formed on the insulating layer 11 in contact with the second surface 102 of the Pelche element 100, and the conductor layer 12 is also formed. A through hole for the via conductor 14v is formed in the insulating layer 11 by laser processing, and the conductor layer 12 having a desired conductor pattern composed of two layers, an electrolytic plating film and an electrolytic plating film, using a semi-additive method and The via conductor 14v is formed. The conductor layer 12 formed on the second surface 102 side of the Pelche element 100 is formed so as to have a conductor pattern including a heat dissipation pattern 12ce. At this time, on the first surface 101 side of the Pelche element 100, a via conductor 14v is formed on the electrodes 100A and 100B exposed from the opening of the first insulating plate 100c of the Pelche element 100, and the conductor layer 12 and the electrodes 100A and 100B are formed. And are connected.

A prepreg having a core material may be used for the insulating layer 11 in contact with the Pelche element 100 instead of the resin film having no core material, and a metal foil may be laminated on the prepreg. In this case, in the formation of the via conductor 14v formed on the insulating layer 11 closest to the Pelche element 100 and the formation of the conductor layer 12 formed in contact with the insulating layer 11, a subtractive method or a metal foil is used. The semi-additive method used can be used.

Subsequently, the insulating layer 11 and the conductor layer 12 are repeatedly laminated on the upper side of the first surface 101 of the Pelche element 100 by the build-up method. After the formation of the state shown in FIG. 6I is completed, when the insulating layer 11 and the conductor layer 12 are further laminated on the upper side of the first surface 101 of the Pelche element 100, the conductor on the second surface 102 side. The surface of the layer 12 is appropriately protected by using, for example, a PET film as a base film. As shown in FIG. 6J, up to the conductor layer 12 including the component mounting pad 120 is formed on the first surface 101 side. Next, a release layer 15 is formed on the component mounting pad 120, and a resin film having an opening based on the planar shape of the release layer 15 is laminated on the conductor layer 12 having the component mounting pad 120, and the release layer 15 is formed. The insulating layer 11 to be accommodated in the opening is formed. In the example shown in FIG. 6J, the release layer 15 has an adhesive layer 15a and a bonding layer 15b laminated on the adhesive layer 15a. The adhesive layer 15a is formed by using a material that does not firmly adhere to the conductor layer 12 (component mounting pad 120) but can adhere to the conductor layer 12. The adhesive layer 15a and the conductor layer 12 can be easily separated with a relatively weak force. For the adhesive layer 15a, for example, an acrylic resin is used. On the other hand, the bonding layer 15b is formed of a material capable of exhibiting sufficient adhesiveness to metals such as copper and epoxy resins. As the material of the bonding layer 15b, a polyimide resin is exemplified.

Next, as shown in FIG. 6K, the insulating layer 11 and the conductor layer 12 are further formed on the upper side of the layer provided with the release layer 15. As shown, a dummy pattern 12d may be provided on each conductor layer 12 formed above the release layer 15 in the region where the recess 10FR is formed. By providing the dummy pattern 12d, the partial removal of the insulating layer 11 and the conductor layer 12 in the step of forming the recess 10FR described later can be stably performed.

A coating layer 13 is formed on the outermost insulating layer 11 and the conductor layer 12. The coating layer 13 is formed by using, for example, a photosensitive epoxy resin or a polyimide resin, and an opening 13a is formed in the coating layer 13 by exposure and development. The conductor pad 12c included in the outermost conductor layer 12 is exposed from the opening 13a.

Subsequently, as shown in FIG. 6L, a groove G that reaches the component mounting pad 120 is formed along the edge of the release layer 15. The groove G is formed by irradiating a laser beam (not shown) such as a carbon dioxide laser or a YAG laser along a path along the edge of the release layer 15. The component mounting pad 120 included in the conductor layer 12 is formed so as to include the entire region which is the bottom surface of the recess 10FR in a plan view. Therefore, the component mounting pad 120 can function as a stopper for the laser beam when the groove G is formed.

After that, the removed portion R, which is a portion surrounded by the groove G, is removed together with the release layer 15. As a result, the recess 10FR is formed as shown in FIG. 6M. As described above, the adhesive layer 15a of the release layer 15 is not firmly adhered to the component mounting pad 120, but is merely adhered due to its adhesiveness. Therefore, the removed portion R can be easily removed by any method such as being adsorbed by a jig or the like and pulled up. With the formation of the recess 10FR, the component mounting pad 120 is exposed on the bottom surface of the recess 10FR.

The recess 10FR may be formed, for example, by irradiating the recess 10FR from the first surface 10F side over the entire forming region of the recess 10FR while feeding a laser beam at a pitch. The method of forming the concave portion 10FR is not limited to the method of utilizing the irradiation of laser light, and for example, the concave portion 10FR may be formed by drilling. After the formation of the recess 10FR, the resin residue (smear) remaining in the recess 10FR can be removed (desmear treatment) by treatment with a chemical solution containing, for example, permanganate.

By going through the above steps, the wiring board 10 is completed. After forming the recess 10FR, a protective film (not shown) may be formed on the surface of the component mounting pad 120 exposed on the bottom surface of the recess 10FR and the conductor pad 12c exposed in the opening 13a of the coating layer 13. For example, a protective film made of Ni / Au, Ni / Pd / Au, Sn, or the like can be formed by a plating method.

The wiring board of the embodiment is not limited to the structure exemplified in each drawing and the one provided with the structure and materials exemplified in the present specification. For example, the wiring board 10 may have any number of conductor layers 12 and insulating layers 11. The through-hole conductor 14p and each via conductor 14v do not necessarily have to have a tapered shape. The recess 10FR is formed so that the conductor layer 12 and the insulating layer 11 having an arbitrary pattern form the bottom surface, depending on, for example, the thickness of the electronic component EC and the configuration of the electric circuit in the wiring board 10. obtain. A plurality of component mounting areas may be provided on the bottom surface of the recess 10FR.

Further, the conditions and order described with respect to the method for manufacturing the wiring board of the embodiment may be appropriately changed, and some steps may be omitted depending on the structure of the wiring board actually manufactured. Steps may be added. The build-up method may not necessarily be used in laminating the insulating layer 11 and the conductor layer 12 on both sides of the element built-in layer 11p. For example, a batch laminating method in which a plurality of wiring boards formed by preliminarily laminating the insulating layer 11 and the conductor layer 12 are laminated via a prepreg can also be used. Further, in forming the conductor pattern of each conductor layer, a semi-additive method, a subtractive method, a full additive method, or the like can be appropriately used.

10 Wiring board 1 1st build-up part 2 2nd build-up part 3 Core board 10FR Recess 11 Insulation layer 11p Insulation layer (layer with built-in element)
12, 12p Conductor layer 12c Conductor pad 13 Coating layer 13a Opening 14v Via conductor 14p Through-hole conductor 100 Pelche element 101 First surface 102 First surface 102 Second surface 100A, 100B Electrode 100c First insulation plate 100h Second insulation plate 100n N type Thermoelectric semiconductor element 100p P-type thermoelectric semiconductor element 120 Component mounting pad D1, D2 Distance

Claims (11)

A plurality of insulating layers alternately laminated between a first surface having a component mounting area on which electronic components are mounted, a second surface opposite to the first surface, and the first surface and the second surface. A wiring board having a conductor layer and a Pelche element arranged between the first surface and the second surface.
The Pelche element has an endothermic surface facing the first surface side and a heat generating surface facing the second surface side.
The distance between the heat generating surface and the second surface is smaller than the distance between the endothermic surface and the first surface. The wiring board according to claim 1, further comprising a core board containing the Pelche element.
On the endothermic surface side of the Pelche element of the core substrate, a first build-up portion is formed by alternately laminated insulating layers and conductor layers.
A second build-up portion is formed on the heat generating surface side of the Pelche element of the core substrate by alternately laminated insulating layers and conductor layers.
The number of conductor layers possessed by the second build-up portion is smaller than the number of conductor layers possessed by the first build-up portion. The wiring board according to claim 1, further comprising a core board.
On one surface of the core substrate, a first build-up portion having the first surface is formed by alternately laminated insulating layers and conductor layers.
A second build-up portion having the second surface is formed on the other surface of the core substrate opposite to the one surface by the insulating layer and the conductor layer alternately laminated.
The Pelche element is built in the second build-up unit. In the wiring board according to claim 3, the number of conductor layers possessed by the first build-up portion is equal to the number of conductor layers possessed by the second build-up portion. The wiring board according to claim 1, wherein the Pelche element is arranged in a region in which the component mounting region is vertically projected onto the second surface side. The wiring board according to claim 1, wherein the first surface includes a component mounting pad in the component mounting region, and the component mounting pad is connected to the endothermic surface of the Pelche element via a conductor. The wiring board according to claim 1, wherein the wiring board has a recess in which the first surface is partially recessed, and the bottom surface of the recess has the component mounting area. The wiring board according to claim 1, wherein the conductor layer constituting the second surface has a heat dissipation pattern connected to the heat generating surface of the Pelche element via a conductor. The wiring board according to claim 1, wherein the heat generating surface of the Pelche element constitutes a part of the second surface. In the wiring board according to claim 1, the ratio of the distance from the heat generating surface to the second surface to the distance from the endothermic surface to the first surface is 0.5 or less. The wiring board according to claim 1, wherein the distance between the heat generating surface and the second surface is 400 μm or less.

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