JP2017045846A - Circuit board and method of manufacturing circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circuit board capable of suppressing warpage of a core substrate including a glass cloth, and a method of manufacturing the same.SOLUTION: A circuit board 10 of the present invention includes: a core substrate 11 including a glass cloth 70; conductor heat transfer layers 13A and 13B formed on both front and rear sides of the core substrate 11 respectively; through hole heat transfer conductors 17 which are formed by filling heat-transferring through holes 16 penetrating the core substrate 11 with plating and connect the conductor heat transfer layers 13A and 13B to each other; build-up layers 20A and 20B laminated on the conductor heat transfer layers 13A and 13B; and an electronic component mounting part 80J which is provided at the outermost part of the build-up layer 20A on the front side and on which an electronic component 80 is mounted. The heat-transferring through holes 16 include outside heat-transferring through holes 16S which are arranged outside the electronic component mounting part 80J when viewed from the thickness direction of the circuit board 10 and extend in a direction intersecting warp 71A and weft 71B forming the glass cloth 70.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a circuit board having an insulating layer containing glass cloth and a method for manufacturing the circuit board.

  Conventionally, as this type of circuit board, one including a glass cloth formed by weaving warp yarns and weft yarns on an insulating base material of a core substrate is known (for example, see Patent Document 1).

JP2012-69926A (paragraph [0010])

  However, in the conventional circuit board described above, there is a problem that the core board tends to warp when the temperature of the core board rises and falls.

  This invention is made | formed in view of the said situation, and aims at provision of the circuit board which can suppress the curvature of the core board containing a glass cloth, and its manufacturing method.

  A circuit board according to the present invention comprises an insulating layer containing glass cloth, a conductor layer formed on both the front side and the back side of the insulating layer, and a through-hole penetrating the insulating layer filled with plating, A through-hole conductor that connects between the conductor layers on the front and back sides of the insulating layer, a buildup layer that is laminated on the conductor layer, and an electronic component mounted on the outermost part of the buildup layer on the front side A circuit board having an electronic component mounting portion, wherein the through hole includes a first through hole extending in a direction intersecting at least one of the warp and the weft forming the glass cloth. The first through hole includes a first outer through hole arranged outside the electronic component mounting portion when viewed from the thickness direction of the circuit board.

  The method for manufacturing a circuit board according to the present invention includes forming a plurality of through holes penetrating an insulating layer including a glass cloth, filling the through holes with plating to form a through hole conductor, and Forming a conductive layer conductively connected to each other by the through-hole conductor on the front side and the back side of the layer, laminating a buildup layer on the conductor layer, and on the outermost side of the buildup layer on the front side A method of manufacturing a circuit board for forming an electronic component mounting portion on which an electronic component is mounted, and intersecting at least one of warp and weft forming the glass cloth in forming the through hole Forming a first through hole extending in the direction of the first through hole, and in forming the first through hole, a first outer through hole disposed outside the electronic component mounting portion when viewed from the thickness direction of the circuit board. To form.

The top view of the circuit board concerning a 1st embodiment of the present invention. Plan view of product area on circuit board Sectional drawing of the circuit board in the AA cut surface of FIG. Enlarged view around the through-hole heat transfer conductor in Fig. 3 Plan sectional view of the end surface of the conductor heat transfer layer on the circuit board Sectional view showing the circuit board manufacturing process Sectional view showing the circuit board manufacturing process Sectional view showing the circuit board manufacturing process Sectional view showing the circuit board manufacturing process Cross section of PoP including circuit board Sectional drawing of the circuit board of 2nd Embodiment Sectional drawing of the circuit board of 3rd Embodiment Sectional view showing an example of circuit board use The top view of the circuit board of a 4th embodiment Sectional drawing of the circuit board in the BB cut surface of FIG. Plan sectional view of the end surface of the conductor heat transfer layer on the circuit board The top view of the circuit board of a 5th embodiment Sectional drawing of the circuit board in the CC cut surface of FIG. Sectional drawing of the circuit board which concerns on other embodiment Sectional drawing around the through-hole heat transfer conductor of the circuit board according to another embodiment

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. As shown in the plan view of FIG. 1, the circuit board 10 according to the present embodiment has, for example, a frame-shaped discarding region R1 along the outer edge, and the inside of the discarding region R1 is a plurality of squares. It is partitioned into product areas R2. 2 shows one product region R2 in an enlarged manner, and FIG. 3 shows an enlarged cross-sectional structure of the circuit board 10 obtained by cutting the product region R2 along the line AA.

  As shown in FIG. 3, the circuit board 10 has build-up layers 20 </ b> A and 20 </ b> B on both the front and back surfaces of the core board 11. The core substrate 11 has a structure having conductor circuit layers 12A and 12B on an F surface 11F which is a front surface and an S surface 11S which is a rear surface of an insulating base material 11K corresponding to the “insulating layer” of the present invention. It has become. As shown in FIG. 4, the insulating base material 11K is formed by impregnating and curing an insulating resin 75 in a glass cloth 70 as a reinforcing material. The glass cloth 70 is embedded in the insulating resin 75 in a direction substantially along the plane direction of the core substrate 11 due to its blending form, pressure received during manufacture, and the like. As shown in FIG. 5, the glass cloth 70 is formed by weaving warps 71A and wefts 71B made of glass fibers. Here, the planar shape of the core substrate 11 is a substantially square shape or a substantially rectangular shape (see FIG. 2), and the warp 71A is a first outer side H1 (see FIG. 5) which is one side of the outer shape line of the core substrate 11. ) And the weft thread 71B is arranged along the second outer side H2 (see FIG. 5) orthogonal to the first outer side H1. The thicknesses of the warp yarn 71A and the weft yarn 71B are both 100 to 400 μm, and the interval between the adjacent warp yarns 71A and 71A and the interval between the adjacent weft yarns 71B and 71B are both 200 to 600 μm. ing.

  As shown in FIG. 3, a conductor layer 11 </ b> V is formed on an F surface 11 </ b> F that is a front side surface of the core substrate 11, and the conductor layers 11 </ b> V are arranged in the same plane and separated from each other. 12A and conductor heat transfer layer 13A. A conductor layer 11W is also formed on the S surface 11S which is the back surface of the core substrate 11, and the conductor layer 11W is also disposed in the same plane and separated from the conductor circuit layer 12B. Layer 13B. Further, the core substrate 11 is formed with a plurality of conductive through holes 14 and a plurality of heat transfer through holes 16 (three heat transfer through holes 16 are shown in FIG. 3).

  The conductive through-holes 14 have a circular shape when viewed from the thickness direction of the core substrate 11 and are respectively perforated from both the F surface 11F and the S surface 11S of the core substrate 11 and gradually reduced in diameter toward the back side. It has an intermediate constriction shape in which the small-diameter side ends of the tapered holes 14A and 14B communicate with each other. On the other hand, in the heat transfer through hole 16, a plurality of small through holes 90 having the same shape as the conductive through hole 14 are arranged side by side and adjacent small through holes 90, 90 are partially overlapped with each other. It has a structure that is communicated with. Specifically, a plurality of small through-holes 90 having an intermediate constriction shape are arranged side by side and the large-diameter portions at both ends in the axial direction of the adjacent small through-holes 90, 90 are communicated with each other, and the adjacent small through-holes 90, 90 Insulating members constituting the core substrate 11 are left between the small-diameter portions in the middle in the axial direction at 90.

  The heat transfer through hole 16 extends in a direction intersecting at least one of the warp yarn 71A and the weft yarn 71B of the glass cloth 70. Specifically, as shown in FIG. 5, the heat transfer through hole 16 intersects both the warp yarn 71 </ b> A and the weft yarn 71 </ b> B of the glass cloth 70 (that is, the first outer side H <b> 1 of the core substrate 11 and It extends in an oblique direction with respect to both of the second outer sides H2. Further, when viewed from the thickness direction of the core substrate 11, the length of the heat transfer through hole 16 in the longitudinal direction is 1600 to 2200 μm, and the length of the heat transfer through hole 16 in the short direction (width direction) is It is 60-100 micrometers. With the arrangement of the heat transfer through holes 16, the warp yarns 71 </ b> A and the weft yarns 71 </ b> B of the glass cloth 70 are efficiently divided by the heat transfer through holes 16. In the example shown in FIG. 5, the angle formed by the direction in which the heat transfer through hole 16 extends and the direction in which the warp yarn 71 </ b> A extends is about 45 degrees, but may be 30 to 60 degrees. Further, in the example of FIG. 5, the heat transfer through-hole 16 is inclined about 45 degrees clockwise with respect to the first outer side H1 of the core substrate 11, and counterclockwise with respect to the first outer side H1. Two types are shown, which are inclined at about 45 degrees, but only one of them may be provided. The heat transfer through hole 16 corresponds to the “first through hole” of the present invention, and the conductive through hole 14 described above corresponds to the “second through hole” of the present invention.

  As shown in FIG. 3, each conductive through hole 14 is filled with plating to form a plurality of through-hole conductive conductors 15. The through-hole conductive conductors 15 form conductor circuit layers 12A and S on the F surface 11F. The surface 11S is connected to the conductor circuit layer 12B. The through-holes 16 for heat transfer are also filled with plating to form through-hole heat transfer conductors 17, respectively. The through-hole heat transfer conductors 17 form the conductor heat transfer layer 13 </ b> A on the F surface 11 </ b> F and the S surface 11 </ b> S. The conductor heat transfer layer 13B is connected. The through-hole heat transfer conductor 17 corresponds to the “first through-hole conductor” of the present invention, and the through-hole conductive conductor 15 corresponds to the “second through-hole conductor” of the present invention. The conductor heat transfer layers 13A and 13B correspond to the “first conductor layer” of the present invention, and the conductor circuit layers 12A and 12B correspond to the “second conductor layer” of the present invention.

  The buildup layer 20A on the F surface 11F side of the core substrate 11 includes a buildup insulation layer 21A laminated on the conductor layer 11V and a buildup conductor layer 22A laminated on the buildup insulation layer 21A. A solder resist layer 23A is laminated on the buildup conductor layer 22A. The build-up layer 20A and the solder resist layer 23A constitute the “build-up layer” of the present invention.

  The buildup conductor layer 22A includes a buildup conductor circuit layer 22A1 and a buildup conductor heat transfer layer 22A2 that are arranged in the same plane and are separated from each other. In the build-up insulating layer 21A, a plurality of conductive via holes 24A and a plurality of heat transfer via holes 26A are formed. Each of the conductive via holes 24A and each of the heat transfer via holes 26A has a tapered shape with a diameter gradually reduced toward the core substrate 11 side.

  Each conductive via hole 24A is filled with plating to form a plurality of via conductive conductors 25A, and the via conductive conductors 25A connect the build-up conductor circuit layer 22A1 and the conductor circuit layer 12A. Each of the heat transfer via holes 26A is filled with plating to form a plurality of via heat transfer conductors 27A, and the via heat transfer conductors 27A form the build-up conductor heat transfer layer 22A2 and the conductor heat transfer layer 13A. Are connected.

  A plurality of pad holes are formed in the solder resist layer 23A, and a part of the build-up conductor layer 22A is located in the pad hole to become a pad 31A. The buildup conductor circuit layer 22A1 located in the pad hole serves as the conductive pad 31A1, and the buildup conductor heat transfer layer 22A2 located in the pad hole serves as the heat transfer pad 31A2. The conductive pad 31A1 is connected to the conductor circuit layer 12A through the conductive via 25A. Further, the heat transfer pad 31A2 is connected to the conductor heat transfer layer 13A via the heat transfer via 27A.

  The build-up layer 20B on the S surface 11S side of the core substrate 11 has the same layer structure as the build-up layer 20A on the F surface 11F side described above. Similarly to the buildup layer 20A, a solder resist layer 23B is laminated on the buildup layer 20B. A plurality of pad holes are formed in the solder resist layer 23B, and a part of the build-up conductor layer 22B is located in the pad hole and becomes a pad 31B. 3 to 5, each part of the build-up layer 20B on the S surface 11S side has “A” in the reference numerals of the parts of the build-up layer 20A on the F surface 11F side corresponding to those parts. "Is changed to" B ".

  As shown in FIG. 2, the plurality of pads 31A on the F surface 10F (front side surface) of the circuit board 10 include a group of middle pads 31AM arranged in two rows along the outer edge portion of the product region R2, and the middle pads 31AM. A group of small pads 31AS arranged in a plurality of vertical and horizontal rows in an inner region surrounded by the group. As shown in FIG. 10, the small pad 31AS group constitutes an electronic component mounting portion 80J according to the present invention, and a CPU 80 as an electronic component is mounted on the small pad 31AS group. The CPU 80 and the circuit board 10 form a first package substrate 10P. Further, the middle pad 31AM group of the F surface 10F constitutes the upper circuit board mounting portion 82J according to the present invention, and is arranged on the middle pad 31AM group so as to have an outer shape larger than the CPU 80 and to cover the CPU 80. A second package substrate 82 as an upper circuit board is mounted.

  As shown in FIG. 3, the plurality of pads 31B on the S surface 10S (front side surface) of the circuit board 10 are large pads 31BL larger than the middle pad 31M, and the F surface of the circuit board 10 among the large pads 31BL. The large pad 31BL directly under or near the heat transfer pad 31A2 on the 10F side constitutes the heat transfer pad 31B2, and the other large pads 31BL are conductive pads 31B1. The conductive pad 31B2 is connected to the conductor circuit layer 12B through the via conductive conductor 25B. The heat transfer pad 31B2 is connected to the conductor heat transfer layer 13B via the via heat transfer conductor 27B.

  As shown in FIG. 3, the heat transfer through hole 16 described above includes an inner heat transfer through hole 16 </ b> U disposed inside the electronic component mounting portion 81 </ b> J and an outer surface disposed outside the electronic component mounting portion 81 </ b> J. Heat transfer through holes 16S are provided. The number of outer heat transfer through holes 16S is larger than the number of inner heat transfer through holes 16U. In the example of FIG. 2, nine outer heat transfer through holes 16 </ b> S are provided, and two inner heat transfer through holes 16 </ b> U are provided. The outer heat transfer through hole 16S corresponds to the “first outer through hole” of the present invention, and the inner heat transfer through hole 16U corresponds to the “first inner through hole” of the present invention.

  As shown in FIGS. 3 and 10, the outer through-hole heat transfer conductor 17S formed in the outer heat transfer through hole 16S among the through-hole heat transfer conductors 17 is a middle pad that constitutes the upper circuit board mounting portion 82J. It is connected to the second package substrate 82 via 31AM. In addition, the inner through-hole heat transfer conductor 17U formed in the inner heat transfer through hole 16U among the through-hole heat transfer conductors 17 is connected to the CPU 80 via the small pad 31AS constituting the electronic component mounting portion 80J. .

The circuit board 10 of this embodiment is manufactured as follows.
(1) As shown to FIG. 6 (A), the copper clad laminated board 11Z by which the copper foil 11C is laminated on the both surfaces of the front and back of the insulating base material 11K is prepared. The insulating substrate 11K is made of an epoxy resin or BT (bismaleimide triazine) resin as the insulating resin 75 and a glass cloth 70 (see FIG. 4).

  (2) As shown in FIG. 6B, for example, a CO2 laser is irradiated on the copper-clad laminate 11Z from the F surface 11F side of the insulating base material 11K to form a conductive through hole 14 (see FIG. 3). For the purpose of forming the heat transfer through hole 16 (see FIG. 3), a plurality of taper holes 90A having the same shape as the taper hole 14A are drilled side by side. At that time, the tapered hole 90A is arranged so that a part of the large diameter portions of the adjacent tapered holes 90A and 90A are overlapped and communicated with each other.

  (3) As shown in FIG. 6C, the taper hole 14B is perforated by irradiating the CO2 laser to the position directly behind the taper hole 14A on the F surface 11F side in the copper clad laminate 11Z. A conductive through hole 14 is formed from the holes 14A and 14B. Further, a CO2 laser is irradiated to a position directly behind the above-described tapered surface 90A on the F surface 11F side of the S surface 11S in the core substrate 11 to form a tapered hole 90B having the same shape as the tapered hole 14B, and the tapered hole 90A. 90B, a plurality of small through holes 90 are formed, and the plurality of small through holes 90 form the heat transfer through hole 16.

(4) An electroless plating process is performed, and an electroless plating film (not shown) is formed on the copper foil 11C and the inner surfaces of the conductive through holes 14 and the heat transfer through holes 16.
(5) As shown in FIG. 6D, a predetermined pattern of plating resist 33 is formed on the electroless plating film on the copper foil 11C.

  (6) As shown in FIG. 7 (A), electrolytic plating is performed, and electrolytic plating is filled in the conductive through holes 14 to form the through-hole conductive conductors 15, and the electrolytic plating is used for heat transfer. A through-hole heat transfer conductor 17 is formed by filling the through-hole 16, and is further exposed from the plating resist 33 among the electroless plating films (not shown) on the F surface 11 F and the S surface 11 S of the core substrate 11. Electrolytic plating films 34, 34 are formed on the portions that are present.

  (7) The plating resist 33 is peeled off, and the electroless plating film (not shown) and the copper foil 11C below the plating resist 33 are removed. As shown in FIG. The conductor circuit layer 12A and the conductor heat transfer layer 13A are formed on the F surface 11F of the insulating base material 11K by the film 34, the electroless plating film, and the copper foil 11C, and the S surface 11S of the insulating base material 11K. Conductive circuit layer 12B and conductive heat transfer layer 13B are formed on top. The conductor circuit layer 12A on the F surface 11F of the core substrate 11 and the conductor circuit layer 12B on the S surface 11S are connected by the through-hole conductive conductor 15, and the conductor heat transfer layer 13A on the F surface 11F of the core substrate 11 is connected. And the conductor heat transfer layer 13B on the S surface 11S are connected by the through-hole heat transfer conductor 17. Thereby, the core substrate 11 is obtained.

  (8) As shown in FIG. 7C, an inorganic filler is contained as a build-up insulating layer 21A on the conductor layer 11V including the conductor circuit layer 12A and the conductor heat transfer layer 13A on the F surface 11F of the core substrate 11. A prepreg (a B-stage resin sheet in which a core material is impregnated with a resin containing an inorganic filler) and a copper foil 37 are laminated, and the conductor circuit layer 12B and the conductor heat transfer on the S surface 11S of the core substrate 11 are laminated. A prepreg containing an inorganic filler is laminated as a build-up insulating layer 21B on the conductor layer 11W made of the layer 13B, and a copper foil 37 is laminated and heated and pressed. At that time, the conductor circuit layers 12A, 12A on the F surface 11F side of the core substrate 11 and between the conductor circuit layers 12A and the conductor heat transfer layer 13A are filled with the prepreg, and the S surface 11S side of the core substrate 11 is the same. The conductor circuit layers 12B and 12B and the space between the conductor circuit layer 12B and the conductor heat transfer layer 13B are filled with a prepreg. As the build-up insulating layers 21A and 21B, a resin film that does not include a core material and contains an inorganic filler may be used instead of the prepreg. In that case, a conductor circuit layer can be directly formed on the surface of the resin film by a semi-additive method without laminating a copper foil.

  (9) As shown in FIG. 8A, the copper foil 37 on the F surface 11F side of the core substrate 11 is irradiated with a CO2 laser, and the taper-shaped conductive material that penetrates the copper foil 37 and the build-up insulating layer 21A The via hole 24A and the heat transfer via hole 26A are formed, and the copper foil 37 on the S surface 11S side of the core substrate 11 is irradiated with a CO2 laser, so that the taper-like conductivity penetrating the copper foil 37 and the build-up insulating layer 21B. A via hole 24B and a heat transfer via hole 26B are formed. Then, the conductive via holes 24A and 24B and the heat transfer via holes 26A and 26B are cleaned (desmear treatment) with an oxidizing agent such as permanganate.

  (10) An electroless plating process is performed, and an electroless plating film (not shown) is formed on the copper foils 37, 37 on the front and back surfaces of the core substrate 11 and the inner surfaces of the conductive via holes 24A, 24B and the heat transfer via holes 26A, 26B. ) Is formed.

  (11) As shown in FIG. 8B, a predetermined pattern of plating resist 40 is formed on the electroless plating film on the copper foil 37.

  (12) The electrolytic plating process is performed, and as shown in FIG. 8C, the electrolytic plating is filled in the conductive via holes 24A and 24B to form the via conductive conductors 25A and 25B, and the electrolytic plating is transmitted. Via heat transfer conductors 27A and 27B are formed by filling the thermal via holes 26A and 26B, and further, a plating resist among electroless plating films (not shown) on the F surface 11F and the S surface 11S of the core substrate 11 Electroplated films 39 and 39 are formed on the portions exposed from 40.

  (13) The plating resist 40 is removed with 5% NaOH, and the electroless plating film (not shown) and the copper foil 37 below the plating resist 40 are removed. As shown in FIG. By the electroplated film 39, the electroless plated film and the copper foil 37, the buildup conductor layer 22A composed of the buildup conductor circuit layer 22A1 and the buildup conductor heat transfer layer 22A2 is formed on the F surface 11F side of the core substrate 11. At the same time, the buildup conductive layer 22B composed of the buildup conductor circuit layer 22B1 and the buildup conductor heat transfer layer 22B2 is formed on the S surface 11S side of the core substrate 11. The buildup conductor circuit layers 22A1, 22B1 and the conductor circuit layers 12A, 12B are connected by via conductive conductors 25A, 25B, and the buildup conductor heat transfer layers 22A2, 22B2 and the conductor heat transfer layers 13A, 13B are The via heat transfer conductors 27A and 27B are connected.

  (14) As shown in FIG. 9B, solder resist layers 23A and 23B are laminated on the build-up conductor layers 22A and 22B.

  (15) As shown in FIG. 9C, tapered pad holes are formed at predetermined locations of the solder resist layers 23A and 23B, and parts of the build-up conductor layers 22A and 22B become pads 31A and 31B. . At this time, part of the buildup conductor circuit layers 22A1 and 22B1 is exposed from the solder resist layers 23A and 23B to become the above-described conductive pads 31A1 and 31B1, and the buildup conductor heat transfer in the buildup conductor layers 22A and 22B. Part of the layers 22A2 and 22B2 are exposed from the solder resist layers 23A and 23B to become the heat transfer pads 31A2 and 31B2.

  (15) As shown in FIG. 3, a nickel layer and a gold layer are sequentially laminated on the pads 31A and 31B (the conductive pads 31A1 and 31B1 and the heat transfer pads 31A2 and 31B2) to form the metal film 41. . Thus, the circuit board 10 is completed. Instead of forming the metal film 41, surface treatment by OSP (preflux) may be performed.

  This completes the description of the structure and manufacturing method of the circuit board 10 of the present embodiment. Next, the effect of the circuit board 10 will be described together with an example of use of the circuit board 10. The circuit board 10 of this embodiment is used as follows, for example. That is, as shown in FIG. 10, on the large pad 31BL, the middle pad 31AM, and the small pad 31AS of the circuit board 10, large, medium, and small solder bumps that match the sizes of the pads 31BL, 31AM, and 31AS are provided. 79A, 79B, 79C are formed. Then, for example, a CPU 80 having a pad group arranged on the lower surface in the same manner as the small pad 31AS group on the F surface 10F of the circuit board 10 is mounted on the small solder bump 79C group in each product region R2 and soldered. First package substrate 10P is formed. At this time, for example, a ground pad included in the CPU 80 is soldered to the heat transfer pad 31A2 in the circuit board 10.

  Next, a second package substrate 82P formed by mounting the memory 81 on the F surface 82F of the circuit board 82 is disposed on the first package substrate 10P from above the CPU 80, and the circuit board 82 in the second package substrate 82P is disposed. PoP 83 (Package on Package 83) is formed by soldering the middle solder bumps 79B of the circuit board 10 of the first package substrate 10P to pads (not shown) provided on the S surface 82S. Note that a resin (not shown) is filled between the circuit boards 10 and 82 in the PoP 83.

  Next, the PoP 83 is disposed on the mother board 84, and the large solder bumps 79A of the circuit board 10 in the PoP 83 are soldered to the pad group of the mother board 84. At this time, for example, a ground pad included in the motherboard 84 is soldered to the heat transfer pad 31B2 in the circuit board 10. When the CPU 80 and the mother board 84 have pads dedicated for heat dissipation, the pads dedicated for heat dissipation and the heat transfer pads 31A2 and 31B2 of the circuit board 10 may be soldered.

  When the CPU 80 is operated and generates heat, the heat is transferred to the buildup conductor heat transfer layers 22A2 and 22B2 of the circuit board 10 on which the CPU 80 is mounted, the via heat transfer conductors 27A and 27B, and the conductor heat transfer on the core board 11. Heat is radiated to the mother board 84 on the opposite side of the circuit board 10 through the layers 13A and 13B and the through-hole heat transfer conductor 17.

  Here, since the core substrate 11 of the circuit board 10 includes the glass cloth 70 (see FIGS. 4 and 5), when the temperature of the core substrate 11 rises and falls, the glass cloth 70 and the insulating resin 75 are used. The warpage of the core substrate 11 due to the difference in the thermal expansion coefficient with respect to can be a problem. In particular, since the influence of the warp of the core substrate 11 is increased near the outer edge of the circuit board 10, a connection failure between the CPU 80 and the circuit board 10 and a connection failure between the second package substrate 82P and the circuit board 10 can be a problem. . However, in the circuit board 10 of the present embodiment, the heat transfer through hole 16 for forming the through-hole heat transfer conductor 17 uses the warp yarn 71A and the weft yarn 71N of the glass cloth 70 included in the core substrate 11 for heat transfer. It becomes possible to divide by the through-hole 16, and the warpage of the core substrate 11 can be suppressed. Moreover, the number of outer heat transfer through holes 16S arranged outside the electronic component mounting portion 80J in the heat transfer through holes 16 is equal to the number of inner heat transfer through holes 16U arranged inside the electronic component mounting portion 80J. Therefore, the warpage of the core substrate 11 near the outer edge of the circuit board 10 can be reduced, the connection failure between the CPU 80 and the circuit board 10, and the second package board 82P and the circuit board. 10 can be improved.

  Further, since the through-hole heat transfer conductor 17 is formed by filling the heat transfer through hole 16 penetrating the core substrate 11 with plating, the through-hole connecting the conductor circuit layers 12A and 12B on the front and back of the core substrate 11 is connected. It can be formed by the same plating process as the hole conductive conductor 15. Further, the heat transfer through hole 16 in which the through-hole heat transfer conductor 17 is accommodated has a plurality of small through holes 90 having the same shape as the conductive through hole 14 in which the through-hole conductive conductor 15 is accommodated side by side, and Since the adjacent small through holes 90 are partially overlapped to communicate with each other, the conductive through hole 14 and the heat transfer through hole 16 can be formed in the same process. The heat transfer through-hole 16 has a plurality of intermediate constricted small through-holes 90 arranged side by side and the large-diameter portions of the adjacent small through-holes 90 communicate with each other so that the core substrate is between the small-diameter portions. 11 remains, the contact area between the through-hole heat transfer conductor 17 formed by plating in the heat transfer through hole 16 and the core substrate 11 is widened, and the heat of the core substrate 11 is transferred to the through-hole heat transfer conductor. The heat can be efficiently exhausted to 17, and the warpage of the core substrate 11 can be suppressed.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described with reference to FIG. As shown in FIG. 11, in the circuit board 10V of the present embodiment, the buildup layers 20A and 20B are composed of a plurality of buildup insulating layers 21A and 21B and a plurality of buildup conductor layers 22A and 22B. . The buildup conductor circuit layers 22A1 and 22A1 adjacent to the thickness direction of the core substrate 11 are connected to each other by via conductive conductors 25A penetrating the buildup insulating layer 21A disposed between the buildup conductor circuit layers 22A1 and 22A1. ing. Also, the build-up conductor heat transfer layers 22A2 and 22A2 adjacent in the thickness direction of the core substrate 11 communicate with each other via heat transfer through the build-up insulating layer 21A disposed between the build-up conductor heat transfer layers 22A2 and 22A2. It is connected by a conductor 27A. The plurality of via heat transfer conductors 27 </ b> A formed in the plurality of buildup insulating layers 21 </ b> A are arranged linearly in the thickness direction of the core substrate 11 to constitute a heat transfer stack via 27 </ b> SA.

  The build-up layer 20B on the S surface 11S side of the core substrate 11 has the same layer structure as the build-up layer 20A on the F surface 11F side described above. In addition, in each part of the build-up layer 20B on the S surface 11S side in FIG. 11, “A” in the reference numerals of the parts of the build-up layer 20A on the F surface 11F side corresponding to these parts is changed to “B”. The changed code is attached.

  Since other configurations of the circuit board 10V are the same as those of the circuit board 10 of the first embodiment, the description thereof is omitted. The circuit board 10V is manufactured by repeating the steps of forming the build-up layers 20A and 20B (steps shown in FIGS. 7C to 9A) in the method for manufacturing the circuit board 10 of the first embodiment. Is done. According to the circuit board 10V of the present embodiment, it is possible to achieve the same effects as those of the first embodiment. In the circuit board 10V, the plurality of via heat transfer conductors 27A and 27B connected to the through-hole heat transfer conductor 17 form the heat transfer stack vias 27SA and 27SB. Heat transfer can be performed efficiently.

[Third Embodiment]
Hereinafter, a third embodiment of the present invention will be described with reference to FIGS. The circuit board 10W according to the present embodiment is a modification of the circuit board 10 according to the first embodiment. The F surface 10F includes only the small pads 31AS group, and the middle pad 31AM group (the diagram of the first embodiment described above). 2 and FIG. 3). The small pad 31AS group is disposed at the center of the F surface 10F of the circuit board 10. The S surface 10S of the circuit board 10W is provided with a group of large pads 31BL similar to those in the first embodiment.

  The through-hole heat transfer conductor 17 is disposed not only at a position directly below the small pad 31AS group but also at a position directly below the outer portion of the small pad 31AS group. That is, the through-hole heat transfer conductor 17 is also disposed outside the electronic component mounting portion 80J when viewed from the thickness direction of the circuit board 10W. The inner through-hole heat transfer conductor 17U disposed inside the electronic component mounting portion 80J is connected to the small pad 31AS on the F surface 10F and the large pad 31BL on the S surface 10S. In addition, the outer through-hole heat transfer conductor 17S arranged outside the electronic component mounting portion 80J is connected to the large pad 31BL on the S surface 10S.

  Since the other configuration of the circuit board 10W is the same as that of the circuit board 10 of the first embodiment, description thereof is omitted by attaching the same reference numerals. According to the circuit board 10W of the present embodiment, the same effects as those of the circuit board 10 of the first embodiment can be obtained.

  FIG. 13 shows a usage example of the circuit board 10W of the present embodiment. As shown in the figure, large and small solder bumps 79A and 79C corresponding to the sizes of the pads 31BL and 31AS are formed on the large pad 31BL and the small pad 31AS of the circuit board 10W. Then, for example, a mounting component 80W having a pad group arranged on the lower surface in the same manner as the small pad 31AS group on the F surface 10F of the circuit board 10W is mounted on the small solder bump 79C group in each product region R2 and soldered. Is done. At this time, for example, a ground pad included in the mounting component 80W is soldered to the heat transfer pad 31A on the circuit board 10W.

  Next, the circuit board 10W is disposed on the mother board 84, and the large solder bumps 79A of the circuit board 10W are soldered to the pad group included in the mother board 84. At this time, for example, a ground pad included in the mother board 84 is soldered to the heat transfer pad 31 </ b> B in the circuit board 10. When the mounting component 80W and the motherboard 84 have pads dedicated for heat dissipation, the pads dedicated for heat dissipation and the heat transfer pads 31AS and 31BL of the circuit board 10 may be soldered.

[Fourth Embodiment]
Hereinafter, a fourth embodiment of the present invention will be described with reference to FIGS. The circuit board 10X of the present embodiment is a modification of the circuit board 10 of the first embodiment, and the arrangement of the heat transfer through holes 16 and the through-hole heat transfer conductors 17 is different from the circuit board 10. . Specifically, as illustrated in FIGS. 16A and 16B, the circuit board 10 </ b> X includes a first through-hole heat transfer conductor 171 and a second through-hole that are orthogonal to each other as the through-hole heat transfer conductor 17. A heat transfer conductor 172 is provided. In addition, the circuit board 10 </ b> X includes a first heat transfer through hole 161 and a second heat transfer through hole 162 that are orthogonal to each other as the heat transfer through hole 16. The first heat transfer through-hole 161 and the second heat transfer through-hole 162 are respectively disposed on the outer side of the electronic component mounting portion 80J as viewed from the thickness direction of the circuit board 10. The through hole 161S and the second heat transfer through hole 162S are included (see FIG. 15).

  The first through-hole heat transfer conductor 171 is formed by filling the first heat transfer through-hole 161 with plating, and the second through-hole heat transfer conductor 172 is filled with the second heat transfer through-hole 162 with plating. Is formed. Accordingly, the outer through-hole heat transfer conductor 17S disposed outside the electronic component mounting portion 80J includes a first outer through-hole heat transfer conductor 171S formed in the first outer heat transfer through-hole 161S, and a second A second outer through-hole heat transfer conductor 172S formed in the outer heat transfer through hole 162S is included (see FIG. 15). The first heat transfer through hole 161 has a shape extending in parallel with the first outer side H1 of the core substrate 11, and the second heat transfer through hole 162 has the second outer side H2 of the core substrate 11. (See FIG. 16).

  Since other configurations of the circuit board 10X are the same as those of the circuit board 10 of the first embodiment, description thereof is omitted by attaching the same reference numerals. Also with the circuit board 10X of the present embodiment, the same effects as those of the circuit board 10 of the first embodiment can be obtained.

[Fifth Embodiment]
Hereinafter, a fifth embodiment of the present invention will be described with reference to FIGS. The circuit board 10Y of the present embodiment is a modification of the circuit board 10 of the first embodiment, and is different from the circuit board 10 in the arrangement of the heat transfer through holes 16 and the through-hole heat transfer conductors 17. . Specifically, as shown in FIG. 17, the outer through-hole heat transfer conductor 17 </ b> S arranged outside the electronic component mounting portion 80 </ b> J among the through-hole heat transfer conductors 17 is viewed from the thickness direction of the circuit board 10 </ b> Y. The pad 31A is disposed at a position avoiding the pad 31A. As shown in FIG. 18, the conductor heat transfer layers 13A and 13B connected to each other by the outer through-hole heat transfer conductor 17S are not connected to the build-up conductor heat transfer layers 22A2 and 22B2. The outer through-hole heat transfer conductor 17S is inclined with respect to both the first outer side H1 and the second outer side H2 of the core substrate 11 as in the first embodiment, and is a warp of glass cloth. It extends in a direction crossing 71A and weft yarn 71B, and both warp yarn 71A and weft yarn 71B are divided (see FIG. 5 of the first embodiment).

  Since the other configuration of the circuit board 10Y is the same as that of the circuit board 10 of the first embodiment, description thereof is omitted by attaching the same reference numerals. The circuit board 10Y according to the present embodiment can achieve the same effects as those of the circuit board 10 according to the first embodiment. Further, in the circuit board 10Y, the outer through-hole heat transfer conductor 17S is formed in the space between the plurality of through-hole conductive conductors 15 connecting the conductor circuit layers 12A and 12B, so that the space in the circuit board 10Y is effectively used. It is possible to divide the warp yarn 71 and the weft yarn 71B of the glass cloth 70 by utilizing them.

[Other Embodiments]
The present invention is not limited to the above-described embodiment. For example, the embodiments described below are also included in the technical scope of the present invention, and various modifications are possible within the scope of the invention other than the following. It can be changed and implemented.

  (1) The circuit boards 10 and 10Y of the first and fifth embodiments may include the heat transfer through hole 16 extending in parallel with the first outer side H1 or the second outer side H2.

  (2) The circuit board 10X of the fourth embodiment may include the heat transfer through hole 16 extending obliquely with respect to both the first outer side H1 and the second outer side H2.

  (3) The circuit board 10Y of the fifth embodiment may include an outer through-hole heat transfer conductor 17S (outer heat transfer through-hole 16S) disposed immediately below the pad 31A.

  (4) In the circuit board 10V of the second embodiment, as shown in FIG. 19, the heat transfer through hole 16 may penetrate the core substrate 11 and the build-up insulating layers 21A and 21B.

  (5) As shown in FIG. 20, a plurality of glass cloths 70 thinner than the glass cloth 70 shown in FIG. 4 may be used for the core substrate 11.

10, 10V, 10W, 10X, 10Y Circuit board 11 Core board 12A, 12B Conductor circuit layer (second conductor layer)
13A, 13B Conductor heat transfer layer (first conductor layer)
14 Conductive through hole (second through hole)
15 Through-hole conductive conductor (second through-hole conductor)
16 Through hole for heat transfer (first through hole)
16S outer heat transfer through hole (first outer through hole)
16U inner heat transfer through hole (first inner through hole)
17 Through-hole heat transfer conductor (first through-hole conductor)
17S Outer through-hole heat transfer conductor 17U Inner through-hole heat transfer conductor 20A, 20B Build-up layer 80J Electronic component mounting part

Claims (13)

An insulating layer including glass cloth;
A conductor layer formed on both the front side and the back side of the insulating layer;
A through-hole conductor formed by filling a through hole penetrating the insulating layer, and connecting between the conductor layers on the front and back of the insulating layer;
A buildup layer laminated on the conductor layer;
An electronic component mounting portion provided on the outermost side of the build-up layer on the front side, on which an electronic component is mounted,
The through-hole includes a first through-hole extending in a direction intersecting at least one of the warp and weft forming the glass cloth,
The first through hole includes a first outer through hole disposed outside the electronic component mounting portion when viewed from the thickness direction of the circuit board. The circuit board according to claim 1,
In addition to the outer through hole, the first through hole includes a first inner through hole arranged inside the electronic component mounting portion when viewed from the thickness direction of the circuit board.
The number of the first outer through holes is larger than the number of the first inner through holes. The circuit board according to claim 2,
An upper circuit on which an upper circuit board is mounted on the outermost part of the build-up layer on the front side, outside the electronic component mounting portion, and having an outer shape larger than the electronic component and arranged to cover the electronic component Board component mounting part is provided,
The through-hole conductor formed in the first inner through hole is connected to the electronic component mounting portion, and the through-hole conductor formed in the first outer through hole is connected to the upper circuit board mounting portion. ing. The circuit board according to claim 2 or 3,
A pad provided on the electronic component mounting portion and disposed on the conductor layer;
And a stack via that penetrates the build-up layer on the front side and connects the pad and the conductor layer. A circuit board according to any one of claims 1 to 4,
The first outer through hole has a shape extending in a direction intersecting with both the warp and the weft. The circuit board according to claim 5,
The insulating layer is formed in a rectangular shape in plan view or a square shape in plan view,
The warp yarn or the weft yarn extends along a first outer edge that is one side of the outer shape of the insulating layer when viewed from the thickness direction of the insulating layer,
The first outer through hole extends obliquely with respect to the first outer side. A circuit board according to any one of claims 1 to 4,
The first outer through-hole includes the first outer through-hole extending along the first direction when viewed from the thickness direction of the insulating layer, and the first extending along a direction orthogonal to the first direction. At least two types of outer through holes are provided. A circuit board according to any one of claims 1 to 7,
In addition to the first through hole, the through hole includes a circular second through hole,
The conductor layer has a first conductor layer connected by a first through-hole conductor formed by filling the first through hole with plating, and is disposed in the same plane as the first conductor layer and the second through-hole. And a second conductor layer connected by a second through-hole conductor formed by filling a hole with plating,
The first through-hole has a structure in which a plurality of small through-holes having the same shape as the second through-hole are arranged side by side and adjacent small through-holes partially overlap each other. The circuit board according to claim 8,
The second through hole has a connecting portion formed by overlapping tapered holes drilled from the front side and the back side of the insulating layer, and the diameter of the hole is minimized at the connecting portion. The circuit board according to claim 9,
In the outer through hole, a plurality of small through holes having the same shape as the conductive through hole are arranged side by side, and a part of the large diameter portions at both ends in the axial direction in the adjacent small through holes are overlapped, The insulating layer is left between the connecting portions of the adjacent small through holes. Forming a plurality of through holes penetrating an insulating layer including a glass cloth;
Filling the through hole with plating to form a through hole conductor;
Forming a conductive layer electrically connected to each other by the through-hole conductor on the front side and the back side of the insulating layer;
Laminating a build-up layer on the conductor layer;
Forming an electronic component mounting part on which an electronic component is mounted on the outermost part of the build-up layer on the front side, and a method of manufacturing a circuit board,
In forming the through hole, a first through hole extending in a direction intersecting at least one of the warp and the weft forming the glass cloth is formed,
In forming the first through hole, a first outer through hole is formed which is disposed outside the electronic component mounting portion when viewed from the thickness direction of the circuit board. It is a manufacturing method of the circuit board according to claim 11,
In forming the first through hole, the first inner through hole is formed inside the electronic component mounting portion when viewed from the thickness direction of the circuit board,
The number of the first outer through holes is made larger than the number of the first inner through holes. A method of manufacturing a circuit board according to claim 11 or 12,
In forming the through hole, a circular second through hole is formed separately from the first through hole,
In forming the through hole conductor, the first through hole is filled with plating to form a first through hole conductor, and the second through hole is filled with plating to form a second through hole conductor,
In forming the conductor layer, a first conductor layer connected by the first through-hole conductor and a second conductor disposed in the same plane as the first conductor layer and connected by the second through-hole conductor Forming a layer, and
The formation of the first through-hole conductor and the formation of the second through-hole conductor are performed in the same plating process.

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