JP2007180211A - Core substrate for manufacturing wiring board and manufacturing method of wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a core substrate for manufacturing wiring board with which high reliability can be given to the wiring board superior in outgassing property. <P>SOLUTION: The core substrate for manufacturing wiring board has an inner core 39, an outer core, and an inner core conductor layer 80. A product forming region 28, and a region 29 outside product which encloses the region, are established in the inner core 39. The outer core is formed on an inner core main face 41 of the inner core 39. The inner core conductor layer 80 is arranged in the product forming region 28 on the inner core main face 41. A plurality of dummy conductor layers 81 are formed in the region 29 outside product on the inner core main face 41. A plurality of communicating paths 82 which extend along the inner core main face 41 and communicate the product forming region 28, and an inner core outermost peripheral part 43, are formed among a plurality of the dummy conductor layers 81. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wiring board manufacturing core board having an inner core, an outer core, and an inner core conductor layer, and a manufacturing method of a wiring board using the same.

  As one of techniques for efficiently producing a wiring board, a technique of taking a large number of pieces is well known. Here, the multi-cavity is a technique for obtaining a plurality of products from a single large-sized wiring board. Usually, such a large-sized wiring board has a product formation region in which a plurality of parts to be products are arranged. And a non-product area surrounding the periphery of the product formation area. For example, the wiring substrate 211 shown in FIG. 11 is formed by laminating a buildup layer composed of a wiring layer and an interlayer insulating layer on a core substrate. A product formation region 212 in which a plurality of product portions are arranged is formed in the approximate center of the wiring substrate 211 in plan view, and an outside product region 213 is formed around the product formation region 212.

  Incidentally, no conductor layer has been conventionally formed on the surface of the non-product region 213 that does not become a product. However, as shown in FIG. 11, a dummy conductor layer 214 made of plating is provided, for example, in a mesh shape on the surface of the outside product region 213 for the purpose of reducing the level difference or the like.

However, if a process (cure, drying, etc.) involving heating is performed during the production of the wiring substrate 211, moisture and chemicals remaining on the surface of the dummy conductor layer 214 and the like are vaporized to become gas, and the dummy conductor layer 214 and the interlayer insulation are formed. Accumulate between layers. As a result, the adhesion strength of the portion where the gas has accumulated decreases, which causes blistering and peeling, leading to a decrease in reliability. Therefore, conventionally, a structure in which a plurality of island-shaped conductors are arranged in the out-of-product region 213 in the buildup layer has been proposed (see, for example, Patent Document 1). If it does in this way, the accumulated gas can be extracted outside through between island-like conductors.
JP 2001-267553 A (see FIG. 7)

  By the way, when manufacturing the wiring substrate 211 having the core substrate, the build-up layer is formed by alternately laminating the wiring layers and the interlayer insulating layers based on the normal core substrate. Therefore, in order to form the buildup layer with high accuracy, it is necessary to form a core substrate with high flatness. However, when the core substrate is composed of an inner core and an outer core, the outer core is formed, for example, by stacking prepregs, so that moisture and chemicals are easily confined between the inner core and the outer core at the time of stacking. Therefore, when the buildup layer is formed in this state, it is necessary to repeatedly heat and cool the wiring substrate 211 until the wiring substrate 211 is completed. There is a high possibility that the dimensional accuracy of the core substrate will decrease due to the occurrence of peeling.

  However, since the island-shaped conductor described in Patent Document 1 is formed not on the core substrate but on the buildup layer side, if it has this structure, it may be possible to vent the buildup layer side. Absent. However, even if it has this structure, the gas accumulated between the inner core and the outer core cannot be removed. As a result, the reliability of the core substrate is lowered, and as a result, the reliability of the wiring substrate 211 is lowered.

  The present invention has been made in view of the above problems, and a first object of the present invention is to provide a core substrate for manufacturing a wiring board capable of imparting high reliability to the wiring board because of its excellent gas escape properties. There is to do. A second object is to provide a method for manufacturing a wiring board using the above-described preferred core board for manufacturing a wiring board.

  As means for solving the above problems (means 1), an inner core having an inner core main surface and having a product forming region and a product outer region surrounding the product forming region, and the inner core main surface Support for a buildup layer having an outer core formed on the upper core and an inner core conductor layer disposed in the product formation region on the inner core main surface, and a laminate of a wiring layer and an interlayer insulating layer A core substrate used as a body, wherein a plurality of dummy conductor layers are formed in an area outside the product on the inner core main surface, and the product extends along the inner core main surface between the plurality of dummy conductor layers. There is a core substrate for manufacturing a wiring board, in which a plurality of communication paths are formed to communicate the formation region and the outermost peripheral portion of the inner core.

  Therefore, according to the core substrate of the means 1, the gas generated on the surface of the dummy conductor layer or the like does not collect between the inner core and the outer core but escapes to the outside of the core substrate through the communication path. As a result, the adhesion strength between the inner core and the outer core is maintained, so that it is possible to prevent a decrease in the yield of the core substrate due to swelling and peeling, and high reliability is provided to the wiring substrate manufactured using the core substrate. it can.

  Further, as another means (means 2) for solving the above problems, an inner core having an inner core main surface and having a product forming region and a product outer region surrounding the product forming region, and the inner core Build-up comprising an outer core formed on a core main surface and an inner core conductor layer disposed in the product formation region on the inner core main surface, and a wiring layer and an interlayer insulating layer laminated. A core for use in manufacturing a wiring board, comprising: a core substrate used as a support for a layer, wherein a plurality of dummy conductor layers are formed in a scattered manner in the region outside the product on the main surface of the inner core The gist is the substrate.

  Therefore, according to the core substrate of the means 2, the gas generated on the surface of the dummy conductor layer or the like does not collect between the inner core and the outer core but passes through the dummy conductor layer and escapes to the outside of the core substrate. As a result, the adhesion strength between the inner core and the outer core is maintained, so that it is possible to prevent a decrease in the yield of the core substrate due to swelling and peeling, and high reliability is provided to the wiring substrate manufactured using the core substrate. it can.

  Here, the product formation region refers to a region in which a plurality of portions to be products (wiring boards) are arranged vertically and horizontally along the plane direction. In general, the inner core, the product formation region, and the part to be the product are all formed in a substantially rectangular shape in plan view. Further, the area of the part to be the product is set to be considerably smaller than the area of the product formation region. Therefore, for example, several tens to several hundreds of parts to be products are arranged in the product formation region. On the other hand, the non-product area is not a product but is a part that is separated and removed from the product formation area during manufacture, and surrounds the product formation area.

  A plurality of dummy conductor layers are formed in the outside-product region. The shape of the dummy conductor layer is not particularly limited, and examples thereof include a circular shape, an elliptical shape, a triangular shape, and a quadrangular shape. A circular shape is particularly preferable. In this way, the flow of gas that escapes to the outside of the core substrate is not easily blocked by the dummy conductor layer. Moreover, since the burden of pattern design can be reduced if it is circular, it is easy to achieve high cost prevention. Further, the dummy conductor layers are preferably arranged regularly from the viewpoint of reducing the pattern design burden, but are particularly preferably arranged in a lattice pattern. In this way, since the communication path formed by the plurality of dummy conductor layers is linear, the gas passage resistance is reduced, and the gas is more easily removed from the outside of the core substrate. Moreover, since it is a lattice shape, the burden of pattern design can be reduced, so that it is easy to prevent cost increase.

  Further, the plurality of dummy conductor layers are preferably set to the same size. This also reduces the burden of pattern design, and makes it easy to prevent cost increases. The plurality of dummy conductor layers are preferably arranged at intervals of 1 mm or more and 10 mm or less. The thickness of the dummy conductor layer is preferably 10 μm or more and 80 μm or less, for example, 35 μm. If the thickness of the dummy conductor layer is less than 10 μm, the gap between the inner core and the outer core becomes too small, and the gas is difficult to escape to the outside of the core substrate. On the other hand, when the thickness of the dummy conductor layer exceeds 80 μm, the unevenness of the main surface of the inner core increases, and the adhesion with the outer core may be reduced.

  The area ratio of the dummy conductor layer should not be limited, but it is preferable to set the area ratio of the dummy conductor layer to 5% or more and 40% or less, for example. If the area ratio of the dummy conductor layer is less than 5%, there is a possibility that the level difference when forming the outer core cannot be sufficiently reduced. On the other hand, if the area ratio of the dummy conductor layer is larger than 40%, there is a possibility that the flow of gas that flows out of the core substrate is easily blocked by the dummy conductor layer. Here, the “area ratio” refers to the ratio of the dummy conductor layer occupying a predetermined area on the surface of the non-product area.

  Further, as another means (means 3) for solving the above-mentioned problem, there is provided a method of manufacturing a wiring board using the core substrate for manufacturing a wiring board according to the above means 1 or 2, wherein an interlayer is formed on the core substrate. The gist of the present invention is a method for manufacturing a wiring board, comprising: an insulating layer forming step for forming an insulating layer; and a wiring layer forming step for forming a wiring layer having a predetermined pattern on the interlayer insulating layer.

  Therefore, according to the manufacturing method of the means 3, the core substrate for manufacturing the wiring board of the means 1 or 2 is a core substrate that is easy to extract gas to the outside. Therefore, even if heated and cooled, the inner core and the outer core The adhesion strength of is reliably maintained. Therefore, high reliability can be imparted to the wiring board manufactured by forming the interlayer insulating layer and the wiring layer on the core substrate of means 1 or means 2.

  Hereinafter, the manufacturing method of the wiring board concerning the means 3 is demonstrated.

  First, a core substrate for manufacturing a wiring board is manufactured. The step for manufacturing the core substrate for manufacturing a wiring board includes, for example, a preparation step of preparing an inner core having an inner core main surface and having a product formation region and a product outer region surrounding the product formation region, An inner core conductor layer is formed in the product formation region on the inner core main surface, a plurality of dummy conductor layers are formed in the product outer region on the inner core main surface, and the inner core is interposed between the plurality of dummy conductor layers. A conductor layer and a communication path forming step for forming a plurality of communication paths extending along the main surface of the core and communicating the product forming region and the outermost peripheral portion of the inner core, and after the conductor layer and the communication path formation process, Including an outer core forming step of forming the outer core by laminating and crimping a prepreg on the inner core main surface of the core. That.

  In the preparation step, an inner core is prepared in which a product formation region in which a plurality of parts to be products are arranged and an outside product region surrounding the product formation region is set. Here, the material forming the base material of the inner core is not particularly limited, but a preferable inner core is formed mainly of a polymer material. Specific examples of the polymer material for forming the inner core include, for example, EP resin (epoxy resin), PI resin (polyimide resin), BT resin (bismaleimide / triazine resin), PPE resin (polyphenylene ether resin), etc. There is. In addition, composite materials of these resins and glass fibers (glass woven fabric or glass nonwoven fabric) or organic fibers such as polyamide fibers may be used. Note that the thickness of the inner core is preferably set to 400 μm or more and 1200 μm or less, for example. In one embodiment of the present invention, a 600 μm one is used.

  In the subsequent conductor layer and communication path forming step, an inner core conductor layer is formed in the product formation region on the inner core main surface, and a plurality of dummy conductor layers are formed in the region outside the product on the inner core main surface. A plurality of communication paths extending along the main surface of the inner core between the plurality of dummy conductor layers and connecting the product formation region and the outermost peripheral portion of the inner core are formed. In addition, although formation of a conductor layer and formation of a communicating path may be performed separately, it is preferable to perform simultaneously. In this way, the number of steps for manufacturing the core substrate for manufacturing a wiring board is reduced, and therefore the core substrate for manufacturing a wiring board, and thus the wiring board, can be manufactured at low cost. As a method of forming the inner core conductor layer and the dummy conductor layer, a copper-clad laminate having copper foil attached to both sides of a base material is prepared, and the copper foil on both sides of the copper-clad laminate is etched to form an inner core. For example, the conductor layer and the dummy conductor layer may be patterned by a subtractive method.

  When the conductor layer and communication path forming step is completed, an inner core having an inner core main surface and having a product forming region and a product outer region surrounding the product forming region, and the inner core main surface An inner core conductor layer disposed in the product forming region, wherein a plurality of dummy conductor layers are formed in the region outside the product on the inner core main surface, and the inner core main layer is formed between the plurality of dummy conductor layers. An intermediate product of the core substrate for manufacturing a wiring board is completed, wherein a plurality of communication passages extending along the surface and communicating the product formation region and the outermost peripheral portion of the inner core are formed. Here, the intermediate product of the core substrate for manufacturing the wiring board is a concept for the finished product of the core substrate for manufacturing the wiring board, and specifically, the core for manufacturing the wiring substrate in a state where the formation of the outer core is not completed. Refers to the substrate.

  In the subsequent outer core formation step, the outer core is formed by laminating and pressing a prepreg on the inner core main surface of the inner core. At this point, the wiring board manufacturing core board is completed. In addition, as a temperature at the time of crimping | bonding a prepreg, it is preferable that it is 100 degreeC or more and 230 degrees C or less, and as a pressure at the time of crimping | bonding a prepreg, it is preferable that it is 0.5 MPa or more and 5 MPa or less. In one embodiment of the present invention, the prepreg is pressure-bonded (cured) at 195 ° C. and 2 MPa. Here, the “prepreg” refers to a semi-cured sheet obtained by impregnating a base material such as glass fiber (glass woven fabric or glass nonwoven fabric) or paper with a prepared resin varnish and drying. The thickness of the prepreg is set to, for example, 50 μm or more and 200 μm or less, and is thicker than the interlayer insulating layer.

  After completion of the core substrate for manufacturing the wiring substrate, an insulating layer forming step for forming an interlayer insulating layer and a wiring layer forming step for forming a wiring layer having a predetermined pattern are performed. Here, if the insulating layer forming step and the wiring layer forming step are alternately performed, a buildup layer formed by alternately stacking the wiring layers and the interlayer insulating layers can be formed on the core substrate. . In the interlayer insulating layer, a via hole (blind hole) may be formed in advance in order to form a via conductor for interlayer connection.

  Then, by removing the non-product region from the product formation region and cutting along the planned cutting line in the product formation region to divide the products, a multi-piece product (wiring board) is obtained.

  Hereinafter, an embodiment embodying the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic plan view showing an intermediate product 12 of a wiring board manufacturing core board 31 (hereinafter referred to as “core board 31”) in the present embodiment. FIG. 2 is a main part schematic plan view showing the intermediate product 12.

  As shown in FIGS. 1 and 2, the inner core 39 constituting the intermediate product 12 has a substantially rectangular shape in plan view, a product formation region 28 in which a plurality of portions 27 to be products are arranged, and the product formation thereof. A frame-shaped non-product area 29 surrounding the area 28 is set. The portions 27 to be products are all rectangular, and a plurality of portions 27 are arranged vertically and horizontally in the product formation region 28.

  Further, FIG. 3 shows the intermediate product 11 of the wiring board in a state where the manufacturing process is further advanced than the intermediate product 12 of the core board 31 for manufacturing the wiring board. The intermediate product 11 includes a core substrate 31 and build-up layers 51 formed on the upper surface 32 and the lower surface 33 of the core substrate 31, respectively. That is, the core substrate 31 is used as a support for the buildup layer 51. The core substrate 31 includes an inner core 39 and an outer core 40 formed on each of the inner core upper surface 41 (inner core main surface) and the inner core lower surface 42 (inner core main surface). In the present embodiment, the inner core 39 is a substantially rectangular substrate made of copper in a plan view, and the outer core 40 is a plan view made by impregnating an organic material such as an epoxy resin in an inorganic material such as a glass cloth. It is a rectangular substrate. In addition, an inner core conductor layer 80 is disposed in each of the product formation regions 28 on the inner core upper surface 41 and the inner core lower surface 42.

  As shown in FIGS. 2 and 3, a plurality of dummy conductor layers 81 are formed on the inner core upper surface 41 and the inner core lower surface 42 on the product outside region 29 in a scattered manner. More specifically, the dummy conductor layers 81 are arranged in a lattice pattern at intervals of about 3 mm. In the present embodiment, the dummy conductor layer 81 has a circular shape in plan view, and has a diameter of 150 μm and a thickness of 35 μm. Further, the area ratio of the dummy conductor layer 81 with respect to the outside product region 29 is set to about 20%. A plurality of communication paths 82 (see, for example, the arrows in FIG. 2) are formed between the dummy conductor layers 81. The communication path 82 extends along the inner core upper surface 41 (or the inner core lower surface 42), and communicates the product formation region 28 with the inner core outermost peripheral portion 43. Also, the upper surface of the outer core 40 formed on the inner core upper surface 41 (ie, the upper surface 32 of the core substrate 31) and the lower surface of the outer core 40 formed on the inner core lower surface 42 (ie, the lower surface 33 of the core substrate 31). ) Are each provided with a conductor pattern 35.

  As shown in FIG. 3, a through hole 38 is formed in the core substrate 31, and a through hole conductor 37 for electrically connecting the buildup layers 51 is formed on the inner peripheral surface of the through hole 38. Is formed. A hollow portion in the through-hole conductor 37 is filled with a filler 36. The build-up layer 51 is formed by alternately laminating wiring layers 62 and 72 having a thickness of 35 μm and interlayer insulating layers 61 and 71 having a thickness of 33 μm (provided that the portion without the wiring layers 62 and 72 is about 60 μm). Is made up of. A via conductor 63 for interlayer connection is formed inside the interlayer insulating layer 61 covering the conductor pattern 35, and a wiring layer 62 having a predetermined pattern is formed on the interlayer insulating layer 61. A via conductor 73 for interlayer connection is formed inside the interlayer insulating layer 71 covering the interlayer insulating layer 61, and a wiring layer 72 having a predetermined pattern is formed on the interlayer insulating layer 71.

  As shown in FIG. 2, the intermediate product 11 of this wiring board is cut along the outline of the portion 27 to be the product. Such a line along the outline is defined as a planned cutting line 121.

  Next, a method for manufacturing a wiring board will be described.

  Here, first, the core substrate 31 is manufactured. First, in the preparation step, a copper clad laminate (inner core 39) is prepared in which a copper foil 111 (see FIG. 4) having a thickness of 35 μm is attached to both surfaces of a base having a length of 500 mm × width of 500 mm × thickness of 0.8 mm. .

  In the subsequent conductor layer and communication path forming step, a photosensitive plating resist forming material is provided on the copper-clad laminate, and exposure is performed in a state where a photomask (not shown) is disposed, and development is performed. By this process, a plating resist 112 having an opening 113 at a predetermined position is formed (see FIG. 4). Next, etching is performed to partially dissolve and remove the copper foil 111, thereby forming the inner core conductor layer 80 in the portion 27 to be the product in the product formation region 28 and a plurality of dummy conductor layers in the region 29 outside the product. 81 is formed (see FIG. 5). Thereby, a plurality of communication paths 82 extending along the inner core upper surface 41 and the inner core lower surface 42 and communicating the product forming region 28 and the inner core outermost peripheral portion 43 are formed between the plurality of dummy conductor layers 81. At this point, the intermediate product 12 of the core substrate 31 is completed.

  In the subsequent outer core formation step, the prepreg 114 with the copper foil 115 attached on one side is disposed on the inner core upper surface 41 and the inner core lower surface 42 of the inner core 39 (see FIG. 6). In the present embodiment, the thickness of the prepreg 114 is 115 μm, and the thickness of the copper foil 115 is 35 μm. Then, a pressing force (2 MPa) is applied in the laminating direction (bonding direction) while heating to a temperature of 180 ° C. or higher (hot pressing). Along with this, the inner core 39, the prepreg 114, and the copper foil 115 are pressed along the stacking direction, and the viscosity of the organic material in the prepreg 114 is increased by heat. As a result, the prepreg 114 and the copper foil 115 are bonded (thermocompression bonding) on the inner core upper surface 41 and the inner core lower surface 42, respectively, and the prepreg 114 becomes the outer core 40 (see FIG. 7).

  Next, the laminated body composed of the inner core 39, the outer core 40 and the copper foil 115 is drilled using a drilling machine, and a through hole 38 for forming the through hole conductor 37 is formed in advance at a predetermined position. Keep it. Then, electroless copper plating is applied to the entire surface of the laminate, and a through-hole conductor 37 is formed on the inner peripheral surface of each through hole 38. Next, a resin paste is printed and filled into the through-hole conductor 37, and is heated and cured to form the filler 36. Further, each copper foil 115 is etched to pattern the conductor pattern 35 by, for example, a subtractive method. Specifically, after the electroless copper plating, electrolytic copper plating is performed using the electroless copper plating layer as a common electrode. Further, the dry film is laminated, and the dry film is exposed and developed to form a dry film in a predetermined pattern. In this state, unnecessary copper foil 115 is removed by etching. Thereafter, the core film 31 is obtained by peeling the dry film (see FIG. 8).

  After the core substrate 31 is completed, an insulating layer forming step for forming the interlayer insulating layers 61 and 71 and a wiring layer forming step for forming the wiring layers 62 and 72 having a predetermined pattern are alternately performed, and the upper surface 32 of the core substrate 31 is formed. A buildup layer 51 is formed on the upper and lower surfaces 33. More specifically, first, a sheet-like thermosetting epoxy resin is laminated on the upper surface 32 and the lower surface 33 of the core substrate 31 to form an uncured first interlayer insulating layer 61. Note that the interlayer insulating layer 61 may be formed by applying a liquid thermosetting epoxy resin instead of laminating a sheet-like thermosetting epoxy resin. Next, the interlayer insulating layer 61 is semi-cured by heating to 170 ° C. Further, a blind hole is formed at a position where the via conductor 73 is to be formed by a laser processing machine. Then, the interlayer insulating layer 61 is cured by heating to 180 ° C. Next, electrolytic copper plating is performed according to a conventionally known method (for example, a semi-additive method) to form a via conductor 63 in the blind hole and to form a wiring layer 62 on the interlayer insulating layer 61.

  Then, a sheet-like thermosetting epoxy resin is laminated on the first interlayer insulating layer 61 to form a second interlayer insulating layer 71 in an uncured state. The interlayer insulating layer 71 in an uncured state may be formed by applying a liquid thermosetting epoxy resin instead of laminating the sheet-like thermosetting epoxy resin. Next, the interlayer insulating layer 71 is semi-cured by heating to 170 ° C. Further, a blind hole is formed at a position where the via conductor 73 is to be formed by a laser processing machine. Then, the interlayer insulating layer 71 is cured by heating to 180 ° C. Further, electrolytic copper plating is performed according to a conventionally known method to form a via conductor 73 in the blind hole and to form a wiring layer 72 on the interlayer insulating layer 71. The buildup layer 51 is completed at this stage, and the intermediate product 11 of the wiring board shown in FIG. 3 is obtained.

  Thereafter, the outside product region 29 is cut and removed from the product formation region 28 using a conventionally known cutting device or the like, and cut along the planned cutting line 121 in the product formation region 28. Thereby, products are divided and a multi-piece product (wiring board) is obtained.

  Therefore, according to the present embodiment, the following effects can be obtained.

  (1) According to the core substrate 31 for manufacturing a wiring board of the present embodiment, the gas generated on the surface of the dummy conductor layer 81 and the like does not collect between the inner core 39 and the outer core 40, and the product formation region 28. To the outside of the core substrate 31 through a communication passage 82 that allows the inner core outermost peripheral portion 43 to communicate with each other. Thereby, since the adhesion strength between the inner core 39 and the outer core 40 is maintained, it is possible to prevent a decrease in the yield of the core substrate 31 due to swelling and peeling, and the wiring substrate manufactured using the core substrate 31 is high. Reliability can be imparted.

  (2) By the way, when the intermediate product 11 of the wiring board is manufactured, the build-up layer 51 is formed by alternately stacking the wiring layers 62 and 72 and the interlayer insulating layers 61 and 71 based on the core substrate 31. Therefore, in order to form the buildup layer 51 with high accuracy, it is necessary to form the core substrate 31 with high flatness. However, when the prepreg 114 is bonded to the inner core 39 to form the outer core 40, the prepreg 114 is bonded to the inner core 39 by increasing the viscosity of the organic material in the prepreg 114. The (glass fiber) itself is not bonded to the inner core 39. Therefore, since the base material of the prepreg 114 does not follow the inner core upper surface 41 of the inner core 39, moisture and chemicals are easily confined between the inner core 39 and the outer core 40. Therefore, when the buildup layer 51 is formed in this state, it is necessary to repeatedly heat and cool the intermediate product 11 until the intermediate product 11 is completed, so that the trapped moisture and chemicals are vaporized to become gas. Probability is high. Further, when the build-up layer 51 is formed, if it is heated to a temperature higher than the temperature at which the core substrate 31 is formed, there is a higher possibility that the remaining moisture or chemical solution becomes a gas. As a result, swelling and peeling occur and the dimensional accuracy of the core substrate 31 decreases, so that the dimensional accuracy of the build-up layer 51 also decreases and the reliability of the wiring substrate decreases.

  Therefore, in the present embodiment, a dummy conductor layer 81 is formed between the inner core 39 and the outer core 40 that are the places where gas is most likely to accumulate, and the gas is extracted outside the core substrate 31. Thereby, since the fall of the yield of the core board | substrate 31 by a swelling and peeling can be prevented more effectively, high reliability can be provided to a wiring board.

  (3) In the present embodiment, the plurality of dummy conductor layers 81 are formed in a scattered manner in the outside product area 29 by etching. For this reason, when the conductor layer and communication path forming step is carried out, the plating resist 112 remaining in the outside product area 29 also becomes scattered (see FIG. 4). Therefore, the etching solution used for dissolving and removing the copper foil 111 can be discharged to the outside of the inner core 39 through a location that later becomes the communication path 82 (location between the dummy conductor layers 81). That is, since the etching solution can easily flow, the dummy conductor layer 81 can be reliably formed.

  In addition, you may change embodiment of this invention as follows.

  The dummy conductor layer 81 in the above embodiment has a circular shape in plan view. However, the dummy conductor layer 81 may have other shapes such as a triangular shape in plan view (see FIG. 9) and a rectangular shape in plan view (see FIG. 10). Even in this case, the gas generated on the surface of the dummy conductor layer 81 and the like can be extracted outside the core substrate 31 as in the above embodiment. However, in order to reduce the resistance of the gas passing through the communication path 82, the dummy conductor layer 81 preferably has a circular shape in plan view.

  Next, the technical ideas grasped by the embodiment described above are listed below.

  (1) A preparation step of preparing an inner core having an inner core main surface and having a product formation region and a product outer region surrounding the product formation region; and an inner portion of the product formation region on the inner core main surface Forming a core conductor layer, forming a plurality of dummy conductor layers in the outer region on the inner core main surface, and extending along the inner core main surface between the plurality of dummy conductor layers; After a conductor layer and a communication path forming step for forming a plurality of communication paths that communicate with the outermost periphery of the core, and after the conductor layer and the communication path formation step, a prepreg is laminated on the inner core main surface of the inner core. A method of manufacturing a core substrate for manufacturing a wiring board, comprising: an outer core forming step of forming the outer core by pressure bonding.

  (2) A preparation step of preparing an inner core having an inner core main surface and a product forming region and a product outer region surrounding the product forming region and having a metal layer formed on the inner core main surface; By etching the metal layer, an inner core conductor layer is formed in the product forming region on the inner core main surface, and a plurality of dummy conductor layers are formed in the outer region on the inner core main surface. Forming a plurality of communication paths that extend along the inner core main surface between the plurality of dummy conductor layers and connect the product formation region and the innermost outermost peripheral portion; and a communication path formation step; After the conductor layer and communication path forming step, the prepreg is laminated and pressure-bonded on the inner core main surface of the inner core. A method for manufacturing a wiring board for producing a core substrate which comprises an outer core forming step of forming a Takoa.

  (3) A preparation step of preparing an inner core having an inner core main surface and a product forming region and a product outer region surrounding the product forming region, and having a metal layer formed on the inner core main surface; By etching the metal layer, an inner core conductor layer is formed in the product forming region on the inner core main surface, and a plurality of dummy conductor layers are formed in the outer region on the inner core main surface. Forming a plurality of communication paths that extend along the inner core main surface between the plurality of dummy conductor layers and connect the product formation region and the innermost outermost peripheral portion; and a communication path formation step; After the conductor layer and communication path forming step, a prepreg is laminated on the inner core main surface of the inner core, and the temperature is 100 ° C. or higher and 230 ° C. or lower. I, by crimping under conditions to be 0.5MPa or more 5MPa or less, the manufacturing method of the wiring board for producing a core substrate which comprises an outer core forming step of forming the outer core.

  (4) An inner core having an inner core main surface and having a product formation region and a product outer region surrounding the product formation region, and an inner core conductor disposed in the product formation region on the inner core main surface A plurality of dummy conductor layers are formed in the outer region on the main surface of the inner core, and extend along the main surface of the inner core between the plurality of dummy conductor layers. An intermediate product of a core substrate for manufacturing a wiring board, wherein a plurality of communication passages communicating with the outermost peripheral portion are formed.

The schematic plan view which shows the intermediate product of the core board for wiring board manufacture in this embodiment. The principal part schematic plan view which shows the intermediate product of the core board for wiring board manufacture. The schematic sectional drawing which shows the intermediate product of a wiring board. The principal part schematic sectional drawing which shows the manufacturing method of a wiring board (core board | substrate for wiring board manufacture). The principal part schematic sectional drawing which shows the manufacturing method of a wiring board (core board | substrate for wiring board manufacture). The principal part schematic sectional drawing which shows the manufacturing method of a wiring board (core board | substrate for wiring board manufacture). The principal part schematic sectional drawing which shows the manufacturing method of a wiring board (core board | substrate for wiring board manufacture). The principal part schematic sectional drawing which shows the manufacturing method of a wiring board (core board | substrate for wiring board manufacture). The principal part schematic plan view which shows the intermediate product of the core board for wiring board manufacture in other embodiment. The principal part schematic plan view which shows the intermediate product of the core board for wiring board manufacture in other embodiment. The principal part schematic plan view which shows the intermediate product of the wiring board in a prior art.

Explanation of symbols

28 ... Product formation region 29 ... Outside product region 31 ... Core substrate for manufacturing a wiring substrate (core substrate)
DESCRIPTION OF SYMBOLS 39 ... Inner core 40 ... Outer core 41 ... Inner core upper surface 42 as inner core main surface ... Inner core lower surface 43 as inner core main surface ... Inner core outermost peripheral part 51 ... Build-up layers 61, 71 ... Interlayer insulating layer 62 72 ... Wiring layer 80 ... Inner core conductor layer 81 ... Dummy conductor layer 82 ... Communication path

Claims (4)

An inner core having an inner core main surface and having a product formation region and a product outer region surrounding the product formation region, an outer core formed on the inner core main surface, and the inner core main surface An inner core conductor layer disposed in the product formation region, a core substrate used as a support for a buildup layer formed by laminating a wiring layer and an interlayer insulating layer,
A plurality of dummy conductor layers are formed in the region outside the product on the inner core main surface, and extend along the main surface of the inner core between the plurality of dummy conductor layers to communicate the product forming region with the innermost outermost peripheral portion. A core substrate for manufacturing a wiring board, wherein a plurality of communication paths are formed. An inner core having an inner core main surface and having a product formation region and a product outer region surrounding the product formation region, an outer core formed on the inner core main surface, and the inner core main surface An inner core conductor layer disposed in the product formation region, a core substrate used as a support for a buildup layer formed by laminating a wiring layer and an interlayer insulating layer,
A core substrate for manufacturing a wiring board, wherein a plurality of dummy conductor layers are formed in a scattered manner in the area outside the product on the inner core main surface.   The core substrate for manufacturing a wiring board according to claim 1, wherein the dummy conductor layer has a circular shape and is arranged in a lattice shape. A method for manufacturing a wiring board using the core substrate for manufacturing a wiring board according to any one of claims 1 to 3,
A method of manufacturing a wiring board, comprising: an insulating layer forming step of forming an interlayer insulating layer on the core substrate; and a wiring layer forming step of forming a wiring layer having a predetermined pattern on the interlayer insulating layer.

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