JP2006066458A - Multilayer printed wiring board and its manufacturing process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayer printed wiring board in which a via hole is not required to be filled, the via hole structure is simple, a via hole directly above can be formed easily, and to provide its manufacturing process. <P>SOLUTION: The multilayer printed wiring board comprises in stacking a first wiring substrate 1 having a first insulation layer 2 in which a first layer via hole 5 is formed and metallization layers 3f and 3s laid on the surface of the first insulation layer 2, and a second wiring substrate 31 having a second insulation layer 32 in which a second layer via hole 35 is formed and a metallization layer 33 laid on the surface of the second insulation layer 32. The first insulation layer 2 has a first surface opposing the second surface of the second insulation layer 32, and first layer via hole wiring 6v recessed from the second surface toward the first surface of the first insulation layer 2 and having a land on the first surface of the first insulation layer 2 is formed in the first layer via hole 5. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a multilayer printed wiring board, and more particularly to a multilayer printed wiring board including a buildup wiring layer formed by a buildup method and a via hole as interlayer connection means, and a method for manufacturing the multilayer printed wiring board.

  The multilayer printed wiring board includes a plurality of conductor layers in which circuit wiring (wiring pattern) is formed by etching, an insulating layer that electrically insulates each conductor layer, and vias for connecting the conductor layers to each other. It is comprised by the hall | hole (for example, refer patent document 1). As a conventional method for forming a plurality of conductor layers and connecting the layers, various methods are known. As a typical method, a method using a build-up method will be described below.

  An outline of a build-up method using a conventional multilayer printed wiring board is as follows. First, an insulating resin is formed by laminating, coating, or laminating on the surface of the core substrate on which the inner layer circuit is formed. Next, microholes (via holes) for interlayer connection are processed in the insulating resin by some method, and then copper plating is applied to the surface of the insulating resin to form the surface of the insulating resin and the inner walls of the microholes. A conductor layer is formed. Then, the conductor layer is patterned by etching to form an outer layer circuit, thereby forming a multilayer printed wiring board having a multilayer structure in which the inner layer circuit and the outer layer circuit are connected through the minute holes. In order to cope with the complexity and increase in the density of circuit wiring (increase in wiring density), such a multilayer printed wiring board is provided with not only one insulating resin layer but also two layers and three layers. Many connection points are provided to improve the design flexibility of circuit wiring.

  8 to 12 are schematic sectional views showing an example of a manufacturing process using a conventional multilayer printed wiring board. This conventional multilayer printed wiring board is formed by a build-up method, and the insulating layer has a two-layer structure in which an inner insulating layer and an outer insulating layer are stacked, and the wiring layer has a six-layer structure.

  FIG. 8A shows a cross section of the core substrate before the wiring pattern is formed before the build-up process. The core substrate shown in the figure has a copper foil 102 stretched on both surfaces of a base material 101, and then a through hole 103 for interlayer conduction is formed. Thereafter, the copper foil 102 is plated by using a known technique. The copper plating 104 is formed in the through hole 103, the copper plating 104h is formed, the resin 105 or the like is further filled in the through hole 103, and then the copper plating 106 is applied to the surface again.

  8B shows a wiring pattern 107a, 107b by applying a well-known etching technique to the conductor layers (copper foil 102, copper plating 104, copper plating 106) formed on the core substrate of FIG. The cross section of the state which formed 107c is shown. The wiring pattern 107 a is a wiring pattern for connecting the copper foils 102 on both surfaces of the base material 101 to each other, and the wiring patterns 107 b and 107 c are wiring patterns formed independently on one surface of the base material 101. . Hereinafter, only the region disposed on the upper side (upper portion in the drawing) of the base material 101 will be described, but the region disposed on the lower side (lower portion in the drawing) of the base material 101 is similarly processed. It goes without saying that it is done.

  FIGS. 9C, 10D, 10E, 10F, and 11 show the state in each step of forming a multilayer printed wiring board by multilayering the core substrate shown in FIG. 8 by a build-up method. A cross section is shown. Since the lower part of the drawing is the same (symmetrical arrangement) as the upper part, the reference numerals are omitted as appropriate.

  FIG. 9C shows a cross section in a state where an insulating resin 109 serving as an inner insulating layer is laminated together with the conductor layer 110 on the surface of the core substrate on which the wiring patterns 107a, 107b, and 107c are formed in FIG. 8B. . The insulating resin 109 and the conductor layer 110 are made of, for example, a resin-coated copper foil (RCC: Resin Coated Copper), which is a well-known technique.

  FIG. 9D shows a cross section in a state where a non-penetrating via hole 111 is formed in the insulating resin 109 by a well-known technique. As a method for forming the via hole 111, a portion of the conductor layer 110 corresponding to the via hole diameter is removed by a known technique such as etching at a position where the via hole 111 is provided, and then the remaining conductor layer 110 is used as an etching mask. There is a method of removing the insulating resin 109 at the position of the via hole 111 with a carbon dioxide laser or the like.

  FIG. 10E shows a cross section in a state where after the via hole 111 is formed, the entire surface of the conductor layer 110 is plated to form the copper plating 112.

  FIG. 10F shows a cross section in a state in which the wiring patterns 113a, 113b, and 113c are formed by leaving only the portions necessary for the copper plating 112 formed in FIG. The wiring pattern 113a is connected to the wiring pattern 107a, and the wiring pattern 113b is connected to the wiring pattern 107b, respectively, to form necessary circuit wiring. The wiring pattern 107c is a single-layer wiring pattern, and the wiring pattern 113c is connected to a wiring pattern 118b (see FIG. 11) formed on the surface of the insulating resin 114 (see FIG. 11).

  FIG. 11 shows a cross section in a state in which after forming the wiring patterns 113a, 113b, and 113c shown in FIG. 10D, the insulating resin 114 and the wiring patterns 118b and 118c to be the outer insulating layer are formed. The insulating resin 114 and the wiring patterns 118b and 118c are formed through the same steps as those shown in FIGS. 9C, 9D, 10E, and 10F.

  That is, the insulating resin 114 and the conductor layer 115 are stacked, and the via hole 116 is formed as in FIG. The insulating resin 114 and the conductor layer 115 are made of, for example, a resin-coated copper foil. Thereafter, copper plating 117 is formed in the same manner as in FIG. 10E, and wiring patterns 118b and 118c are formed in the same manner as in FIG. The wiring pattern 118b is connected to the wiring pattern 113c through the via hole 116.

  The wiring patterns 107a and 107b formed on the surface of the substrate 101 and the wiring patterns 113a and 113b formed on the surface of the insulating resin 109 are connected to each other via the via holes 111, and the surface of the insulating resin 109 is also connected. The wiring pattern 113c formed on the surface of the insulating resin 114 and the wiring pattern 118b formed on the surface of the insulating resin 114 are connected to each other through a via hole 116, thereby forming a multilayer printed wiring board having a multilayer laminated structure. The wiring pattern 118c is a single layer wiring pattern.

  In the multilayer printed wiring board as shown in FIG. 9 to FIG. 11, an outer insulating layer (insulating) is formed immediately above the via hole 111 of the inner insulating layer (insulating resin 109) in order to cope with the complexity of wiring and the increase in wiring density. In some cases, the via hole 116 of the conductive resin 114) is desired to be overlapped. This structure is referred to as a via hole or stack via hole.

  When the via hole is provided directly above, the via hole in the inner insulating layer has a concave outer surface, so that the via hole cannot be formed directly on the via hole as it is. Therefore, the via hole recess in the inner insulating layer must be filled in some way. As a method, a conductive resin is buried in the via hole after forming the conductive plating layer (hole filling method), an insulating resin is buried in the via hole after the conductive plating layer is formed, and the surface is further filled with the insulating resin. Well-known techniques include a method of conducting conductive plating (hole filling method), a method of copper plating having a property of filling and depositing via holes (filled plating method), and the like. By these treatments, the outer surface of the via hole of the inner insulating layer becomes a flat surface, and the via hole of the outer insulating layer can be easily formed immediately above.

  FIG. 12 is a cross-sectional view showing a stacked state of via holes in a multilayer printed wiring board in which an outer surface overlaps with a concave via hole to form a directly upper via hole. (A) and (B) are cross-sectional views of a multilayer printed wiring board in which a via hole is formed directly by a hole filling method. FIG. (A) is a diagram showing a conductive resin filling the via hole, and FIG. Is an insulating resin. FIG. 3C is a cross-sectional view of a multilayer printed wiring board in which a via hole directly above is formed by a filled plating method.

  In the case of FIG. 3A, a copper foil wiring pattern 107 is first formed on the surface of the substrate 101. An inner insulating layer 123 is laminated on the surface of the substrate 101, and a via hole 124 is formed in the inner insulating layer 123 corresponding to the wiring pattern 107. Thereafter, the via hole wiring 125 is formed, and the concave portion is filled with the conductive hole filling resin 126 to flatten the outer surface of the via hole wiring 125. Further, an outer insulating layer 127 is stacked, and a via hole 128 is formed so as to overlap with the via hole wiring 125. By plating the surface of the via hole 128 to form copper plating, and patterning the copper plating, the via hole wiring 129 is formed. In this manner, a multilayer printed wiring board in which the wiring pattern 107 on the surface of the substrate 101 and the via hole wiring 129 on the surface of the outer insulating layer 127 are connected is manufactured.

  In the case of FIG. 6B, the concave portion of the via hole wiring 125 is filled with an insulating hole filling resin 126i, and a via hole wiring 125c as a land portion of the via hole wiring 125 is formed on the surface thereof. ) Is different. The other points are the same as in FIG. 5A, and detailed description thereof is omitted.

In the case of FIG. 10C, the point that the via hole 124 is filled by the filled plating method is different from FIGS. That is, after the via hole 124 is formed, the copper plating 130 is deposited so as to fill the concave portion of the via hole 124. The other points are the same as those in FIGS. 1A and 1B, and detailed description thereof is omitted.
JP-A-5-226838

  However, the conventional multilayer printed wiring board having a via hole structure directly above requires a complicated process for filling the via hole, and cannot provide an inexpensive and high design freedom. In other words, the conventional hole filling method increases the cost due to the increased number of processes, and the filled plating method complicates the control of copper plating, and when applied to via holes of different diameters, the filling of copper plating Copper plating by the fill plating method is thick in the recesses and thinly deposited on the protrusions, making it difficult to achieve both plating thickness at the corners of the through holes and via hole filling. There are problems such as being.

  The present invention has been made in view of such problems, and it is an object of the present invention to provide a multilayer printed wiring board that does not need to fill a via hole, has a simple via hole structure, and can easily form a via hole immediately above. And Another object of the present invention is to provide a method for manufacturing a multilayer printed wiring board that simplifies the wiring formation process in the via hole, can form the wiring in the via hole with few processes, and can easily form the via hole immediately above. .

  A multilayer printed wiring board according to the present invention includes a first wiring having a first insulating layer in which a first layer via hole is formed, and a wiring metal layer laminated on each of the first surface and the second surface of the first insulating layer. A multilayer printed wiring board in which a base material, a second insulating layer in which a second layer via hole is formed, and a second wiring base material having a wiring metal layer laminated on the first surface of the second insulating layer, The first surface of the first insulating layer and the second surface of the second insulating layer are opposed to each other, and the first layer via hole extends from the second surface of the first insulating layer to the first surface. A first-layer via hole wiring having a land portion is formed on the first surface of the first insulating layer.

  According to the present invention, the first layer via-hole wiring has a concave shape from the second surface of the first insulating layer toward the first surface, and has a planar land portion on the first surface of the first insulating layer. This eliminates the need for a hole filling process and a filled plating (filled plating) process for a via hole (first layer via hole) that is required in the prior art. Therefore, the connection between the first layer via hole wiring and the wiring metal layer laminated on the first surface of the second wiring substrate is made without the hole filling process or the filled plating process for the first layer via hole. The multilayer printed wiring board by the build-up method can be easily realized.

  In the multilayer printed wiring board according to the present invention, the second via hole has a concave shape from the first surface of the second insulating layer toward the second surface, and a land portion is formed on the second surface of the second insulating layer. A second-layer via-hole wiring is formed. According to the present invention, the interconnection between the wiring metal layer laminated on the first surface of the first wiring substrate and the wiring metal layer laminated on the first surface of the second wiring substrate is easy and reliable. And a multilayer printed wiring board by a build-up method can be easily realized.

  In the multilayer printed wiring board according to the present invention, the first layer via hole wiring and the second layer via hole wiring overlap each other in the stacking direction of the first wiring substrate and the second wiring substrate. And According to the present invention, since the second layer via hole wiring is arranged so as to overlap the first layer via hole wiring, the connection between the first layer via hole wiring and the second layer via hole wiring can be made the shortest distance. it can. It is possible to optimize the arrangement of via holes, simplify the formation of the via hole directly by the build-up method, stabilize the shape, and improve the reliability of interconnection.

  In the multilayer printed wiring board according to the present invention, the first layer via hole wiring and the second layer via hole wiring are connected to each other. According to the present invention, the first layer via hole wiring and the second layer via hole wiring can be connected to each other, and a multilayer printed wiring board having a high degree of design freedom can be obtained.

  In the multilayer printed wiring board according to the present invention, the film thickness of the first insulating layer is smaller than the film thickness of the second insulating layer. According to the present invention, the thickness of the multilayer printed wiring board as a whole can be reduced as compared with the case where a multilayer printed wiring board is formed by repeatedly laminating an insulating layer having the same thickness and a metal wiring layer having the same thickness. Can do. Further, the thin first insulating layer can be configured as a cable portion of the multilayer printed wiring board.

  In the multilayer printed wiring board according to the present invention, the first wiring substrate is a flexible printed wiring substrate. According to the present invention, a thin first wiring substrate having wiring metal layers on both sides can be easily realized, and a flexible multilayer printed wiring board can be easily realized with a thin total thickness of the wiring board.

  In the multilayer printed wiring board according to the present invention, the second wiring substrate is a resin-coated metal foil, the second insulating layer is a fiber-containing resin sheet, or the second insulating layer is a semi-cured resin sheet. It is characterized by being cured. According to the present invention, the second wiring substrate can be easily laminated on the first wiring substrate.

  In the multilayer printed wiring board according to the present invention, a rigid board region in which the first wiring base material and the second wiring base material are laminated, and the first wiring base material further extends from the second wiring base material. And a flex substrate region. According to the present invention, it is possible to provide a multilayer printed wiring board that can be easily incorporated into an electronic device by applying the flex substrate region as a cable portion, for example.

  In the multilayer printed wiring board according to the present invention, a wiring metal layer is laminated on only one of the first surface and the second surface of the first insulating layer in the flex substrate region. According to the present invention, the wiring metal layer is laminated on only one of the first surface and the second surface of the first insulating layer in the flex substrate region, thereby reducing the rigidity as the cable portion and bending repeatedly. It can be set as the multilayer printed wiring board which improved the durability with respect to.

  In the multilayer printed wiring board according to the present invention, the film thickness of the wiring metal layer laminated on only one of the first surface and the second surface of the first insulating layer in the flex substrate region is the rigid substrate region. It is thinner than the thickness of the wiring metal layer laminated on the second surface of the first insulating layer. According to the present invention, for example, even when a wiring metal layer (wiring pattern) is formed by laminating a plating layer on a wiring metal layer in the rigid board region, the plating layer is formed on the wiring metal layer in the flex board area. The flexibility of the flex substrate region can be maintained by maintaining the original thickness of the wiring metal layer without providing it.

  The multilayer printed wiring board according to the present invention is characterized in that two multilayer printed wiring boards according to the present invention are arranged to face each other with an intermediate body therebetween. In the multilayer printed wiring board according to the present invention, the first wiring substrate is arranged on the intermediate body side with respect to the second wiring substrate. According to the present invention, two multilayer printed wiring boards are laminated so as to face each other and are arranged in a mirror image relationship with each other. It can be a printed wiring board.

  In the multilayer printed wiring board according to the present invention, the intermediate body is composed of a protective film covering the second surface of the first wiring substrate and an adhesive sheet that bonds the protective film so as to oppose each other. It is characterized by. According to the present invention, by using the protective film, the wiring metal layer on the second surface of the first wiring base material that becomes the wiring portion of the flex substrate region (cable portion) can be reliably protected, and the adhesive sheet By using this, the rigidity of the rigid substrate region can be improved.

  In the multilayer printed wiring board according to the present invention, the adhesive sheet is arranged in a region corresponding to the rigid substrate region. According to the present invention, by using an adhesive sheet, a rigid substrate region can be defined and flexibility of the flex substrate region can be maintained.

  In the multilayer printed wiring board according to the present invention, the wiring metal layer on the first surface of the first insulating layer disposed on one side of the intermediate body and the first insulating layer disposed on the other side of the intermediate body. The wiring metal layer on the first surface is connected to each other through a hole wiring formed in a through hole penetrating the two first insulating layers and the intermediate body. According to the present invention, the wiring pattern formed by the wiring metal layer on the first surface formed on the first wiring base located at one position in the mirror image relation and the first wiring base located at the other position. The formed wiring pattern of the wiring metal layer on the first surface can be connected, and a multilayer printed wiring board having a wiring structure with a high degree of design freedom can be obtained.

  In the multilayer printed wiring board according to the present invention, the hole wiring is connected to the second layer via hole wiring. According to the present invention, the wiring pattern by the wiring metal layer formed on the second wiring substrate at one position in the mirror image relation and the wiring pattern by the wiring metal layer formed on the second wiring substrate at the other position. Can be connected via a hole wiring, and a multilayer printed wiring board having a wiring structure with a high degree of design freedom can be obtained.

  In the multilayer printed wiring board according to the present invention, the wiring metal layer on the first surface of the second insulating layer disposed on one side of the intermediate body and the second insulating layer disposed on the other side of the intermediate body. The wiring metal layer on the first surface is connected to each other via a hole wiring formed in a through hole penetrating the two first insulating layers, the two second insulating layers, and the intermediate body. And According to the present invention, the wiring pattern formed by the wiring metal layer formed on the second wiring base located at one position in the mirror image relation and the wiring formed on the second wiring base located at the other position. A wiring pattern made of a metal layer can be connected through a hole wiring, and a multilayer printed wiring board having a wiring structure with a high degree of freedom can be obtained.

  A method for manufacturing a multilayer printed wiring board according to the present invention includes: a first wiring substrate having a first insulating layer and a wiring metal layer laminated on the first surface and the second surface of the first insulating layer; A method of manufacturing a multilayer printed wiring board in which an insulating layer and a second wiring substrate having a wiring metal layer laminated on a first surface of the second insulating layer are laminated, and the second surface of the first insulating layer Forming a first layer via hole from the first surface to the first surface, and forming a concave shape in the first layer via hole from the second surface of the first insulating layer toward the first surface, the first surface of the first insulating layer Forming a first-layer via-hole wiring having a land portion on the surface, laminating a first surface of the first insulating layer and a second surface of the second insulating layer facing each other, and the second insulating layer Forming a second layer via hole from the first surface to the second surface, Characterized in that it comprises a step of forming a second layer via hole wiring serial second layer via holes.

  According to the present invention, when a wiring metal layer is connected between layers through via holes of a multilayer printed wiring board, a via hole filling process and a filled plating (filling plating) process required in the prior art are not required. .

  A method for manufacturing a multilayer printed wiring board according to the present invention includes: a first wiring substrate having a first insulating layer and a wiring metal layer laminated on the first surface and the second surface of the first insulating layer; A method for manufacturing a multilayer printed wiring board in which two multilayer printed wiring boards each having an insulating layer and a second wiring base material having a wiring metal layer laminated on the first surface of the second insulating layer are arranged to face each other A first layer via hole is formed from the second surface of the first insulating layer to the first surface, and the first layer via hole is directed from the second surface of the first insulating layer toward the first surface. Forming a first-layer via-hole wiring having a concave shape and having a land portion on a first surface of the first insulating layer; covering a second surface of the first wiring substrate with a protective film; and Two first wiring substrates coated with film are placed facing both sides of the adhesive sheet A step of bonding each of the protective films to the adhesive sheet, a step of laminating the first surface of the first insulating layer and the second surface of the second insulating layer, and a second step of the second insulating layer. Forming a second layer via hole from the first surface to the second surface, and forming a second layer via hole wiring in the second layer via hole.

  According to the present invention, when a wiring metal layer is connected between layers through via holes of a multilayer printed wiring board, a via hole filling process and a filled plating (filling plating) process required in the prior art are not required. . In addition, since two multilayer printed wiring boards are arranged to face each other in a mirror image relation, a multilayer printed wiring board having twice the number of layers can be easily manufactured.

  In the method for manufacturing a multilayer printed wiring board according to the present invention, the second layer via hole wiring has a concave shape from the first surface of the second insulating layer toward the second surface, and is formed on the second surface of the second insulating layer. It has a land part. According to the present invention, the interconnection between the wiring metal layer laminated on the first wiring substrate and the wiring metal layer laminated on the first surface of the second wiring substrate can be easily and reliably performed.

  In the method for manufacturing a multilayer printed wiring board according to the present invention, the first layer via hole wiring and the second layer via hole wiring overlap each other in the stacking direction of the first wiring substrate and the second wiring substrate. It is characterized by that. According to the present invention, since the second layer via hole wiring is arranged on top of the first layer via hole wiring, the mutual connection can be made with the shortest distance. It is possible to optimize the arrangement of via holes, simplify the formation of the via hole directly by the build-up method, stabilize the shape, and improve the reliability of interconnection.

  In the method for manufacturing a multilayer printed wiring board according to the present invention, the first layer via hole wiring and the second layer via hole wiring are connected to each other. According to the present invention, the first layer via hole wiring and the second layer via hole wiring can be connected to each other, and a multilayer printed wiring board having a high degree of design freedom can be obtained.

  In the method for manufacturing a multilayer printed wiring board according to the present invention, the first layer via hole and the second layer via hole are formed by laser processing. According to the present invention, a highly accurate via hole can be formed.

  In the method for manufacturing a multilayer printed wiring board according to the present invention, the first layer via hole wiring and the second layer via hole wiring are formed by plating. According to the present invention, via-hole wiring can be formed easily and reliably.

  In the method for producing a multilayer printed wiring board according to the present invention, the first wiring substrate is a flexible printed wiring substrate. According to the present invention, the wiring metal layer can be easily laminated on both side surfaces of the first insulating layer.

  In the method for producing a multilayer printed wiring board according to the present invention, the second wiring substrate is a metal foil with a resin, the second wiring substrate is formed by laminating a fiber-containing resin sheet and a metal foil, or The two-wiring substrate is formed by laminating a semi-cured resin sheet and a metal foil and curing the semi-cured resin sheet. According to the present invention, the second wiring substrate can be easily laminated on the first wiring substrate.

  According to the multilayer printed wiring board and the method for manufacturing the multilayer printed wiring board according to the present invention, since the via hole (first layer via hole) does not need to be filled, the via hole structure is simple, and the formation of the via hole immediately above is possible. There is an effect that an easy multilayer printed wiring board and a method for producing such a multilayer printed wiring board can be provided. In addition, according to the present invention, the wiring forming process in the via hole (first layer via hole) can be simplified, and the wiring in the via hole can be easily formed with a small number of processes. There is an effect that a multilayer printed wiring board having a via hole directly above can be easily formed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1-7 is principal part sectional drawing which shows the outline of the manufacturing process of the multilayer printed wiring board based on Embodiment of this invention. Note that hatching indicating a cross-sectional portion is basically omitted in consideration of the visibility of the drawing.

  FIG. 1A shows a cross section of the first wiring substrate 1. The first wiring substrate 1 is bonded and stacked on the first insulating layer 2, the wiring metal layer 3 f bonded and stacked on the first surface of the first insulating layer 2, and the second surface of the first insulating layer 2. The wiring metal layer 3s. In the following description, when it is not necessary to distinguish between the wiring metal layer 3f and the wiring metal layer 3s, the wiring metal layer 3 is described. The first wiring substrate 1 is, for example, a flexible printed wiring substrate (hereinafter also referred to as an FPC substrate. FPC: Flexible Printed Circuit). The first insulating layer 2 is, for example, a resin layer such as polyimide, and serves as a base material for the FPC base material. A copper foil is generally suitable as the wiring metal layer 3, and is bonded to the surface of the first insulating layer 2 using an appropriate adhesive. That is, a double-sided copper-clad FPC substrate can be used as the first wiring substrate 1.

  The thickness of the base material (first insulating layer 2) of the FPC base material (first wiring base material 1) can usually be about 12.5 to 25 μm, for example, a copper foil with resin (hereinafter referred to as RCC (Resin). The resin thickness of the resin-coated metal foil is usually about 60 to 70 μm, so that the FPC substrate (for example, double-sided copper-clad FPC having a wiring metal layer on both sides as the first wiring substrate 1 is used. By using the base material, the thickness of the first wiring base material 1 can be significantly reduced as compared with the case where two layers of metal foil with resin are laminated to form a two-layer wiring board. The total thickness of the multilayer printed wiring board can be reduced.

  FIG. 1B shows a cross section in a state where the opening 4 is formed in the wiring metal layer 3 s of the first wiring substrate 1. A portion of the wiring metal layer 3s corresponding to the hole diameter of the first-layer via hole 5 (see FIG. 1C) to be formed in a later process is removed by using a known technique such as etching to form the wiring metal layer 3s. Opening 4 is formed.

  FIG. 1C shows a cross section in a state in which the first layer via hole 5 is formed in the first insulating layer 2 of the first wiring substrate 1. By irradiating the opening 4 of the wiring metal layer 3 s with a laser beam and using the wiring metal layer 3 s as an etching mask, the first insulating layer 2 corresponding to the opening 4 is removed by etching, thereby forming a first layer via hole (laser via hole). ) 5 is formed. That is, the first layer via hole is formed from the second surface (wiring metal layer 3s side) of the first insulating layer 2 to the first surface (wiring metal layer 3f side). Since the first layer via hole 5 is formed by laser, the first layer via hole 5 can be formed with high accuracy.

  The first layer via hole 5 has a concave surface on the surface irradiated with the laser beam (second surface of the first insulating layer 2), and a wiring metal layer 3f on the opposite surface (first surface of the first insulating layer 2). It becomes flat from. As the laser beam generating means, for example, a carbon dioxide laser can be applied. After the first layer via hole 5 is formed, if necessary, a minute residue of the first insulating layer 2 is removed by a known technique such as desmear, and the back surface of the wiring metal layer 3f (adhered to the first insulating layer 2). The exposed surface) is completely exposed to the first layer via hole 5 side. Needless to say, the first-layer via hole 5 is not limited to the method of etching by irradiating the laser beam, but may be formed by using other etching techniques.

  FIG. 1D shows a cross section in a state in which the plating layers 6 f and 6 s are formed on the wiring metal layer 3 of the first wiring substrate 1. After forming the first layer via hole 5, a plating layer 6f (plating layer on the surface of the wiring metal layer 3f) and a plating layer 6s (plating layer on the surface of the wiring metal layer 3s) are formed on the entire surface of the first wiring substrate 1. ). In the following description, when it is not necessary to distinguish between the plated layer 6f and the plated layer 6s, the plated layer 6 is described. In consideration of conductivity, reliability, adhesion to the wiring metal layer 3, and the like, the plating layer 6 is preferably copper plated when the wiring metal layer 3 is a copper foil.

  Along with the formation of the plated layer 6, the first layer via hole wiring 6v is formed in the first layer via hole 5 with the plated layer 6s extending. That is, the first layer via hole wiring 6v is formed in a concave shape from the second surface of the first insulating layer 2 toward the first surface along the first layer via hole 5, and is formed on the first surface of the first insulating layer 2. It has a land part. Since the land portion of the first layer via hole wiring 6v is directly connected to the wiring metal layer 3f formed on the first surface of the first insulating layer 2, the portion of the wiring metal layer corresponding to the first layer via hole wiring 6v. 3f can act as a substantial land portion (see the wiring pattern 26a in FIG. 4K), and can be used as a connection surface in subsequent steps.

  Further, before the plating process is performed, a plating resist 7 is formed by a well-known technique in an area corresponding to the flex board area 21 (see FIG. 2G), and then the plating process is performed, so that the flex board area 21 The wiring metal layer 3s can be kept thin. Thereby, durability of the repeated bending property in the flex board | substrate area | region 21 can be improved, and workability | operativity at the time of incorporating in an electronic device can be improved. On the other hand, in the region corresponding to the rigid substrate region 20 (see FIG. 2G), the plating layer 6 is formed by being laminated on the wiring metal layer 3, so that the thickness of the wiring metal layer 3 can be substantially increased. The rigidity of the rigid substrate region 20 can be improved. Although the wiring metal layer 3 and the plating layer 6 will be described as separate layers for the convenience of explaining the manufacturing process, a laminate of the wiring metal layer 3 and the plating layer 6 can be treated as a substantial wiring metal layer 3. Needless to say, you can.

  FIG. 1E shows a cross section in a state where predetermined wiring patterns 8 a, 8 b, 8 c are formed on the second surface of the first insulating layer 2. After the plating layer 6 is formed, the wiring metal layer 3s and the plating layer 6s formed on the second surface of the first insulating layer 2 are processed into a predetermined pattern shape by a known technique such as etching, for example, the first layer. A wiring pattern 8a including the via hole wiring 6v, a wiring pattern 8b connected to the hole wiring 23h (see FIG. 3I), and a wiring pattern 8c as a single layer wiring are formed. In the following description, when it is not necessary to distinguish between the wiring pattern 8a, the wiring pattern 8b, and the wiring pattern 8c, the wiring pattern 8 is described. Further, the wiring metal layer 3f and the plating layer 6f formed on the first surface of the first insulating layer 2 are appropriately subjected to an etching mask to maintain the state as it is.

  FIG. 2F shows a cross section in a state in which the protective film 9 is formed on the second surface of the first insulating layer 2 (the second surface of the first wiring substrate 1). In order to improve the adhesion of the surface on which the wiring pattern 8 is formed (the second surface of the first wiring substrate 1), a known technique is used for the second surface of the first wiring substrate 1 including the surface of the wiring pattern 8. Roughening treatment, acid treatment, etc. are performed. Then, the protective film 9 is affixed on the surface on which the wiring pattern 8 of the first wiring substrate 1 is formed, and an intermediate processed wiring substrate 10U is formed. Although the film-like thing which provided the adhesive layer in the polyimide film was used as the protective film 9, it is not restricted to this, Other materials may be used if it is compatible.

  Furthermore, in the same figure, the intermediate processed wiring base material 10D manufactured in the same process as the intermediate processed wiring base material 10U is disposed opposite to the intermediate processed wiring base material 10U with the adhesive sheet 11 interposed therebetween, for the subsequent processes. Shows the prepared state. In the following description, when it is not necessary to distinguish between the intermediate processed wiring base 10U and the intermediate processed wiring base 10D, the intermediate processed wiring base 10 is described. The opposing direction of the intermediate processed wiring substrate 10U and the intermediate processed wiring substrate 10D is such that each protective film 9 of the intermediate processed wiring substrate 10U, 10D faces (faces) the adhesive sheet 11. That is, the first layer via-hole wiring 6v is disposed so that the concave surfaces face each other. Note that the intermediate processed wiring base material 10D has the same configuration as the intermediate processed wiring base material 10U, and therefore the reference numerals in the drawings are omitted as appropriate (the same applies to the drawings subsequent to FIG. 2G). . Further, the adhesive sheet 11 is subjected to a hole processing or a notch process in advance so that the intermediate processed wiring base material 10 has an area that adheres to the adhesive sheet 11 and an area that does not adhere.

  FIG. 2G shows a cross section of the multilayer printed wiring board in a state in which the intermediate processed wiring base materials 10U and 10D are integrally formed with the adhesive sheet 11 interposed therebetween. As shown in FIG. 2 (F), the intermediate processed wiring base materials 10U and 10D arranged to face both surfaces of the adhesive sheet 11 are integrally formed by a known technique such as a laminating press. That is, the two first wiring substrates 1 coated with the protective film 9 are arranged opposite to both surfaces of the adhesive sheet 11, and each of the protective films 9 is bonded to the adhesive sheet 11. The region where the intermediate processed wiring substrate 10U and the intermediate processed wiring substrate 10D are bonded by the adhesive sheet 11 has the structure of a multilayer printed wiring board, and constitutes a rigid substrate region 20 with further improved rigidity. Moreover, since there is no adhesive sheet and the region where the intermediate processed wiring substrate 10U and the intermediate processed wiring substrate 10D exist individually maintains the characteristics of the first wiring substrate 1, the FPC substrate is used. Constitutes a flex substrate region 21 that can be made into a cable portion (FPC cable portion) by utilizing excellent flexibility. That is, the intermediate processed wiring base materials 10U and 10D can be multilayer printed wiring boards (flex rigid multilayer printed wiring boards) each including a rigid substrate region 20 and a flex substrate region 21.

  The intermediate processed wiring base materials 10U and 10D may be formed as a rigid substrate region 20 as a region having a multilayer printed wiring board structure, and a flex substrate region 21 as a region where the wiring base material 1 exists in a single layer, for example. A flex-rigid multilayer printed wiring board can be formed even when the sheets 11 are not bonded to each other (when the intermediate processed wiring substrate 10 is not disposed facing each other and is formed as a multilayer printed wiring board alone). At this time, the protective film 9 can reliably protect the wiring metal layer 3s in the flex substrate region 21 and the wiring pattern 8 in the rigid substrate region 20 from the outside.

  In the figure, the right end is the flex substrate region 21, but the present invention is not limited to this, and the right end can be further extended to make the extended portion a rigid substrate region. In addition, as a representative example, a configuration as a flex-rigid multilayer printed wiring board is shown, but it is of course possible to provide a multilayer printed wiring board having only the rigid board area 20 without the flex board area 21.

  The first wiring substrate 1 of the intermediate processed wiring substrate 10U and the first wiring substrate 1 of the intermediate processed wiring substrate 10D are opposed to each other through an intermediate body made of the protective film 9 and the adhesive sheet 11. However, the wiring pattern of each layer does not need to be the same. For example, the wiring pattern 8 of the intermediate processing wiring substrate 10U and the wiring pattern 8 of the intermediate processing wiring substrate 10D are different. It may be a pattern. Further, the configuration of the intermediate is not limited to the protective film 9 and the adhesive sheet 11.

  Hereinafter, a form in which the first wiring base 1 of the pre-processed wiring base 10U and the first wiring base 1 of the pre-processed wiring base 10D are arranged to face each other via an intermediate (a form having a mirror image relationship). However, it is needless to say that a multilayer printed wiring board having a form similar to that shown in the following steps can be applied to the single prefabricated wiring substrate 10. In the following, since the configuration of the pre-processed wiring substrate 10U and the pre-processed wiring substrate 10D is basically the same, only one of them will be described, and the description of the other will be omitted as appropriate.

  FIG. 3H shows a cross section in a state in which the through hole 22 penetrating the preliminary processed wiring base material 10U, the adhesive sheet 11, and the preliminary processed wiring base material 10D is formed in the rigid board region 20. The wiring metal layer 3f on the first surface of the first insulating layer 2 arranged on one side of the intermediate body (preliminary processing wiring base material 10U side) and the other side of the intermediate body (preliminary processing wiring base material 10D side) In order to connect the wiring metal layer 3f on the first surface of a certain first insulating layer 2 to each other, a through hole that becomes an inner via hole using a known technique such as a drill for the two first insulating layers 2 and the intermediate body 22 is formed.

  FIG. 3I shows a cross section in a state in which the hole wiring 23 h is formed in the through hole 22. After the through hole 22 is formed, the entire surface of the multilayer printed wiring board is subjected to a plating process, so that the plating layer 23 is further overlapped on the surface of the plating layer 6f. That is, the plating layer 23 is formed on the surfaces of the prefabricated wiring substrates 10U and 10D. At this time, since the plating layer 23 is simultaneously formed on the side wall of the through hole 22, the hole wiring 23h can be formed. As described above, the plating material is preferably made of copper plating in accordance with the material of the wiring metal layer 3. By the hole wiring 23h, the wiring metal layer 3f of the prefabricated wiring base material 10U in one of the mirror image relations and the wiring metal layer 3f of the preliminary processing wiring base material 10D in the other of the mirror image relations are connected to each other.

  Since the wiring metal layer 3f of the prefabricated wiring substrate 10U and the wiring metal layer 3f of the prefabricated wiring substrate 10D are connected to each other, the wiring pattern 26b (FIG. K)) is connected to the wiring pattern 26b of the wiring metal layer 3f of the prefabricated wiring substrate 10D, and a multilayer printed wiring board having a wiring structure with a high degree of design freedom can be obtained. Note that the wiring metal layer 3f laminated with the plating layer 6f and the plating layer 23 can be handled as a substantial wiring metal layer. Further, since the wiring metal layer 3s and the plating layer 6s do not exist on the surface of the protective film 9 in the flex substrate region 21 (the surface of the region where the adhesive sheet 11 does not exist), the plating layer 23 is not formed.

  FIG. 4J shows a cross section in a state in which the through hole 22 in which the hole wiring 23 h is formed is filled with the embedding resin 24 and the plating layer 25 is formed on the surface of the preliminary processed wiring base material 10. After filling the through hole 22 with an embedding resin 24 made of an insulating resin, and flattening the outer surface of the embedding resin 24, a plating layer 25 is formed by performing a plating process such as copper plating on the entire surface of the multilayer printed wiring board. To do.

  FIG. 4K shows a cross section in a state in which the wiring patterns 26a, 26b, and 26c are formed on the outer surface of the prefabricated wiring substrate 10 (the first surface of the first wiring substrate 1). After forming the plating layer 25, the wiring metal layer 3f and the plating layers 6f, 23, 25 formed on the first surface of the first insulating layer 2 are processed into a predetermined pattern shape by a known technique such as etching, For example, a wiring pattern 26a connected to the first layer via hole wiring 6v, a wiring pattern 26b connected to the hole wiring 23h, and a wiring pattern 26c as a single layer wiring are formed. In the following description, when it is not necessary to distinguish between the wiring pattern 26a, the wiring pattern 26b, and the wiring pattern 26c, the wiring pattern 26 is described.

  With such a configuration, the two wiring patterns 8b having the mirror image relation can be connected to each other via the hole wiring 23h, and the two wiring patterns 26b can be connected to each other. Can be connected. Since the combination of connections can be freely set by appropriately changing the pattern shapes of the wiring pattern 8b and the wiring pattern 26b, a multilayer printed wiring board with a higher degree of design freedom can be obtained.

  The first-layer via-hole wiring 6v has a concave shape from the wiring pattern 8a toward the wiring pattern 26a, and the land portion of the first-layer via-hole wiring 6v formed in a planar shape is laminated on the surface in a planar shape. Since it is directly connected to the wiring pattern 26a, an embedding step for the first layer via-hole wiring 6v is not required. Therefore, the manufacturing process can be simplified, the manufacturing cost can be reduced, and the reliability of interlayer connection can be improved.

  When the wiring pattern 26 is formed, at the same time, the wiring metal layer 3f, the plating layer 6f, and the plating layers 23 and 25 formed in the flex substrate region 21 are removed, and the wiring in the flex substrate region 21 is connected to the wiring metal layer 3s. By making it only, the flexibility of the flex board | substrate area | region 21 can further be improved. In order for the flex substrate region 21 to function as an FPC cable portion, the wiring metal layer 3 only needs to be laminated on either the first surface or the second surface of the first insulating layer 2. A multilayer printed wiring board in which the (FPC cable portion) is a single-sided wiring and has a double structure (a double structure of pre-processed wiring base materials 10U and 10D) can be formed. Further, since the thickness of the wiring metal layer 3s in the flex substrate region 21 is made thinner than the thickness of the wiring pattern 8 formed on the same surface (the second surface of the first insulating layer 2), a larger flexibility. Can be realized.

  FIG. 5L shows a cross section in a state where the second wiring base material 31 is laminated on the outer surface of each of the prefabricated wiring base materials 10U and 10D on which the wiring pattern 26 is formed. The first wiring substrate 1 including the surface of the wiring pattern 26 in order to improve the adhesion of the surface on which the wiring pattern 26 is formed (the first surface of the first wiring substrate 1: the outer surface of the prefabricated wiring substrate 10). The first surface is subjected to a surface roughening treatment, an acid treatment or the like using a known technique. Thereafter, the second wiring substrate 31 is laminated on the first surface of the first wiring substrate 1. Thereby, the wiring pattern 26 is covered with the second insulating layer 32, and the first surface of the first insulating layer 2 and the second surface of the second insulating layer 32 are in contact with each other. Further, the first wiring substrate 1 is arranged on the intermediate body side with respect to the second wiring substrate 31. The second wiring substrate 31 is composed of a second insulating layer 32 and a wiring metal layer 33 laminated on the first surface of the second insulating layer 32.

  In the case where the second wiring base 31 is a resin-coated metal foil, the second wiring base 31 can be easily stacked on the pre-processed wiring bases 10U and 10D by a stacking press. As the metal foil with resin, for example, RCC (Resin Coated Copper) is preferably used. When a fiber-containing resin sheet or a semi-cured resin sheet is used as the second insulating layer 32, the second wiring substrate 31 can be easily laminated by simultaneously laminating the second insulating layer 32 and the wiring metal layer 33. It is possible to achieve the same configuration and operation as the RCC. For example, a glass fiber-containing resin sheet (prepreg) is preferably used as the fiber-containing resin sheet, and a copper foil is preferably used as the wiring metal layer 33. In the case of a semi-cured resin sheet (bonding sheet), the second wiring substrate 31 can be easily formed by heating and curing simultaneously with the lamination.

  FIG. 5M shows a cross section in a state in which openings 34 a and 34 b are formed in the wiring metal layer 33 laminated on the first surface of the second insulating layer 32. A portion of the wiring metal layer 33 corresponding to the hole diameter of the second layer via holes 35a and 35b (see FIG. 6 (N)) to be formed in a later step is removed by using a known technique such as etching to thereby form a wiring metal layer. Openings 34 a and 34 b are formed in 33. Here, the opening 34a is aligned with the wiring pattern 26a, and the opening 34b is aligned with the wiring pattern 26b. In the following description, when it is not necessary to distinguish between the opening 34a and the opening 34b, they are referred to as the opening 34.

  FIG. 6N shows a cross section in a state in which the second layer via holes 35a and 35b are formed in the second insulating layer 32, and then the plated layer 36 is further formed. Similarly to the case of FIG. 1C, the opening 34 of the wiring metal layer 33 is irradiated with a laser beam, and the second insulating layer 32 corresponding to the opening 34 is etched away using the wiring metal layer 33 as an etching mask. Thus, second layer via holes (laser via holes) 35a and 35b are formed. In the following description, when it is not necessary to distinguish between the second layer via hole 35a and the second layer via hole 35b, they are referred to as a second layer via hole 35. After forming the second layer via hole 35, if necessary, a minute residue of the second insulating layer 32 is removed by a known technique such as desmear, and the surface of the wiring pattern 26 (the surface of the plating layer 25) is changed to the second. The layer via hole 35 is completely exposed.

  Thereafter, similarly to the case of FIG. 1D, a plating layer 36 is formed on the entire surface of the multilayer printed wiring board by performing a plating process such as copper plating. Along with the formation of the plated layer 36, the second layer via hole wiring 36v is formed in the second layer via hole 35 in a form in which the plated layer 36 extends. That is, the second layer via hole wiring 36v is formed in a concave shape along the second layer via hole 35 from the first surface of the second insulating layer 32 toward the second surface, and is formed on the second surface of the second insulating layer 32. It has a land part. Since the land portion of the second layer via-hole wiring 36v is directly connected to the wiring pattern 26 formed on the first surface of the first insulating layer 2, the plated layer 25 of the wiring pattern 26 acts as a substantial land portion. And can be a connecting surface for the previous step.

  FIG. 6O shows a cross section in a state in which the wiring patterns 38a, 38b, and 38c are formed. After the plating layer 36 is formed, the wiring metal layer 33 formed on the first surface of the plating layer 36 and the second insulating layer 32 is processed into a predetermined pattern shape by a known technique such as etching, for example, the wiring pattern 26a. A wiring pattern 38a connected to the wiring pattern 38b, a wiring pattern 38b connected to the wiring pattern 26b, and a wiring pattern 38c as a single-layer wiring are formed. In the following description, when it is not necessary to distinguish the wiring pattern 38a, the wiring pattern 38b, and the wiring pattern 38c, they are referred to as a wiring pattern 38. The wiring pattern 38a and the wiring pattern 38b are each formed integrally with the second layer via hole wiring 36v. Thereafter, a multilayer printed wiring board is completed through a known solder resist, pattern surface treatment, external shape processing, and inspection process.

  The second layer via hole wiring 36v formed in the second layer via hole 35a is superimposed on the wiring pattern 26a. Therefore, the first layer via hole wiring 6v and the second layer via hole wiring 36v overlap in the stacking direction of the first wiring substrate 1 and the second wiring substrate 31. Since the wiring pattern 26a serves as a connection surface connecting the first layer via hole wiring 6v and the second layer via hole wiring 36v, the first layer via hole wiring 6v and the second layer via hole wiring 36v are overlapped with each other. Since direct connection is possible and the interconnection between the first layer via hole wiring 6v and the second layer via hole wiring 36v is the shortest distance, the wiring resistance can be reduced. In addition, since the first layer via hole wiring 6v and the second layer via hole wiring 36v can be overlapped, it becomes possible to optimize the arrangement of the via holes, and simplification of the formation of the via hole directly by the build-up method, It is possible to stabilize the shape and improve the reliability of interconnection.

  Note that the first-layer via hole wiring 6v and the second-layer via hole wiring 36v do not necessarily overlap each other, and are appropriately set according to the designed wiring pattern. Needless to say, the first-layer via-hole wiring 6v and the second-layer via-hole wiring 36v may be formed as independent wirings without being connected to each other.

  A second layer via hole wiring 36v formed in the second layer via hole 35b is connected to the wiring pattern 26b. As a result, the second-layer via-hole wiring 36v is connected to the hole wiring 23h. In other words, one second-layer via hole wiring 36v in the mirror image relationship can be connected to the other second layer via hole wiring 36v in the mirror image relationship via the hole wiring 23h, and the degree of freedom in designing the multilayer printed wiring board Can be improved.

  With one wiring pattern 8, wiring pattern 26, and wiring pattern 38 having a mirror image relationship, a three-layer multilayer printed wiring board can be formed on one side of the adhesive sheet 11. Accordingly, a total of 6 layers of multilayer printed wiring boards can be formed on both surfaces of the adhesive sheet 11 having a mirror image relationship. Needless to say, the wiring pattern itself can be freely designed in each layer, and the pattern shape of the wiring pattern in each layer does not need to have a mirror image relationship.

  FIG. 7 shows that the hole wiring 36h is formed in the through hole 42 penetrating the preliminary processing wiring base materials 10U and 10D, the adhesive sheet 11, and the two second wiring base materials 31 arranged in a mirror image relation in the rigid board region 20. Furthermore, the cross section of the state which formed wiring pattern 38a, 38b, 38c, 38d is shown. The same parts as those in FIGS. 1 to 6 are denoted by the same reference numerals, and detailed description thereof is omitted. First, for the multilayer printed wiring board in the state shown in FIG. 5 (M), the second wiring base 31 (the second insulating layer 32 of the second insulating layer 32) laminated on the first wiring base 1 disposed on one of the intermediate bodies. The wiring metal layer of the second wiring substrate 31 (the first surface of the second insulating layer 32) laminated on the wiring metal layer 33 of the first surface and the first wiring substrate 1 disposed on the other of the intermediates. 33, two second wiring base materials 31 (second insulating layer 32) having a mirror image relationship, two first wiring base materials 1 (first insulating layer 2) having a mirror image relationship, and A through hole 42 serving as an outer via hole is formed in the intermediate body using a known technique such as a drill.

  Thereafter, second layer via holes 35a and 35b are formed as shown in FIG. 6 (N), and further, a plating process such as copper plating is performed on the entire surface of the multilayer printed wiring board to form a plated layer 36. The hole wiring 36h is formed in the through hole 42. Thus, the wiring metal layer 33 on the first surface of the second insulating layer 32 at one position in the mirror image relation and the wiring metal layer 33 on the first surface of the second insulating layer 32 in the other position in the mirror image relation are obtained. The first insulating layer 2, the second insulating layer 32, and the intermediate body (the protective film 9, the adhesive sheet 11) are connected to each other via a hole wiring 36 h formed in the through hole 42.

  Further, as shown in FIG. 6 (O), a wiring pattern 38a connected to the wiring pattern 26a, a wiring pattern 38b connected to the wiring pattern 26b, and a single-layer wiring are processed into a predetermined pattern shape by a known technique such as etching. As a wiring pattern 38c, a wiring pattern 38d connected to the hole wiring 36h is formed. Thereafter, a multilayer printed wiring board is completed through a known solder resist, pattern surface treatment, external shape processing, and inspection process.

  With such a configuration, a connection effect similar to that of the hole wiring 23h can be realized. That is, the two wiring patterns 38d having a mirror image relation can be connected to each other via the hole wiring 36h, and the wiring pattern 8c, the wiring pattern 26c, and the wiring pattern 38d can be connected. Furthermore, it can be set as a multilayer printed wiring board with a big design freedom.

It is principal part sectional drawing which shows the outline of the manufacturing process of the multilayer printed wiring board which concerns on embodiment of this invention. It is principal part sectional drawing which shows the outline of the manufacturing process of the multilayer printed wiring board which concerns on embodiment of this invention. It is principal part sectional drawing which shows the outline of the manufacturing process of the multilayer printed wiring board which concerns on embodiment of this invention. It is principal part sectional drawing which shows the outline of the manufacturing process of the multilayer printed wiring board which concerns on embodiment of this invention. It is principal part sectional drawing which shows the outline of the manufacturing process of the multilayer printed wiring board which concerns on embodiment of this invention. It is principal part sectional drawing which shows the outline of the manufacturing process of the multilayer printed wiring board which concerns on embodiment of this invention. It is principal part sectional drawing which shows the outline of the manufacturing process of the multilayer printed wiring board which concerns on embodiment of this invention. It is a schematic sectional drawing which shows the example of the manufacturing process in the conventional multilayer printed wiring board. It is a schematic sectional drawing which shows the example of the manufacturing process in the conventional multilayer printed wiring board. It is a schematic sectional drawing which shows the example of the manufacturing process in the conventional multilayer printed wiring board. It is a schematic sectional drawing which shows the example of the manufacturing process in the conventional multilayer printed wiring board. It is a schematic sectional drawing which shows the example of the manufacturing process in the conventional multilayer printed wiring board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st wiring base material 2 1st insulating layer 3, 3f, 3s wiring metal layer 4 opening part 5 1st layer via hole 6, 6f, 6s plating layer 6v 1st layer via hole wiring 7 plating resist 8, 8a, 8b 8c Wiring pattern 9 Protective film 10, 10U, 10D Prefabricated wiring substrate 11 Adhesive sheet 20 Rigid board area 21 Flex board area 22 Through hole 23 Plating layer 23h Hole wiring 24 Embedded resin 25 Plating layer 26, 26a, 26b, 26c Wiring pattern 31 Second wiring substrate 32 Second insulating layer 33 Wiring metal layer 34, 34a, 34b Opening 35, 35a, 35b Second layer via hole 36 Plating layer 36h Hole wiring 36v Second layer via hole wiring 38a, 38b 38c Wiring pattern 42 Through hole

Claims (39)

A first insulating layer having a first layer via hole, a first wiring substrate having a wiring metal layer laminated on the first surface and the second surface of the first insulating layer, and a second layer via hole; A multilayer printed wiring board in which a formed second insulating layer and a second wiring substrate having a wiring metal layer laminated on the first surface of the second insulating layer are laminated,
The first surface of the first insulating layer and the second surface of the second insulating layer are opposed to each other,
The first layer via hole is formed with a first layer via hole wiring having a concave shape from the second surface of the first insulating layer toward the first surface and having a land portion on the first surface of the first insulating layer. A multilayer printed wiring board characterized by   In the second layer via hole, a second layer via hole wiring having a concave shape from the first surface of the second insulating layer toward the second surface and having a land portion on the second surface of the second insulating layer is formed. The multilayer printed wiring board according to claim 1, wherein the multilayer printed wiring board is provided.   3. The multilayer print according to claim 2, wherein the first layer via hole wiring and the second layer via hole wiring are overlapped in a stacking direction of the first wiring base and the second wiring base. Wiring board.   4. The multilayer printed wiring board according to claim 2, wherein the first layer via hole wiring and the second layer via hole wiring are connected.   5. The multilayer printed wiring board according to claim 1, wherein a thickness of the first insulating layer is smaller than a thickness of the second insulating layer.   The multilayer printed wiring board according to claim 5, wherein the first wiring substrate is a flexible printed wiring substrate.   The multilayer printed wiring board according to claim 5 or 6, wherein the second wiring substrate is a metal foil with resin.   The multilayer printed wiring board according to claim 5, wherein the second insulating layer is a fiber-containing resin sheet.   The multilayer printed wiring board according to claim 5 or 6, wherein the second insulating layer is obtained by curing a semi-cured resin sheet. A rigid substrate region in which the first wiring substrate and the second wiring substrate are laminated;
The multilayer printed wiring board according to any one of claims 1 to 9, wherein the first wiring substrate includes a flex substrate region further extending from the second wiring substrate.   11. The multilayer printed wiring board according to claim 10, wherein a wiring metal layer is laminated on only one of the first surface and the second surface of the first insulating layer in the flex substrate region.   The thickness of the wiring metal layer laminated on only one of the first surface and the second surface of the first insulating layer in the flex substrate region is equal to the second surface of the first insulating layer in the rigid substrate region. The multilayer printed wiring board according to claim 11, wherein the multilayer printed wiring board is thinner than a thickness of the laminated wiring metal layer.   A multilayer printed wiring board, wherein two of the multilayer printed wiring boards according to any one of claims 1 to 12 are arranged to face each other via an intermediate.   The multilayer printed wiring board according to claim 13, wherein the first wiring substrate is disposed on the intermediate body side with respect to the second wiring substrate.   The said intermediate body is comprised by the adhesive film which adhere | attaches the protective film which coat | covers the 2nd surface of the said 1st wiring base material, and this protective film mutually opposed. Multilayer printed wiring board.   The multilayer printed wiring board according to claim 15, wherein the adhesive sheet is disposed in a region corresponding to the rigid substrate region.   The wiring metal layer on the first surface of the first insulating layer arranged on one side of the intermediate body and the wiring metal layer on the first surface of the first insulating layer arranged on the other side of the intermediate body are 2 The multilayer according to any one of claims 14 to 16, wherein the multilayers are connected to each other through a hole wiring formed in a through hole penetrating the first insulating layer and the intermediate body. Printed wiring board.   The multilayer printed wiring board according to claim 17, wherein the hole wiring is connected to the second layer via hole wiring.   The wiring metal layer on the first surface of the second insulating layer disposed on one side of the intermediate body and the wiring metal layer on the first surface of the second insulating layer disposed on the other side of the intermediate body are 2 19. The device according to claim 14, wherein the first insulating layer, the two second insulating layers, and the intermediate body are connected to each other via a hole wiring formed in a through hole. The multilayer printed wiring board as described in any one. A first wiring substrate having a first insulating layer and a wiring metal layer laminated on each of the first surface and the second surface of the first insulating layer; and a second insulating layer and a first surface of the second insulating layer. A method for producing a multilayer printed wiring board in which a second wiring substrate having a laminated wiring metal layer is laminated,
Forming a first layer via hole from the second surface of the first insulating layer to the first surface;
Forming a first layer via hole wiring having a concave shape in the first layer via hole from the second surface of the first insulating layer toward the first surface and having a land portion on the first surface of the first insulating layer; ,
Laminating the first surface of the first insulating layer and the second surface of the second insulating layer facing each other;
Forming a second layer via hole from the first surface to the second surface of the second insulating layer;
Forming a second layer via hole wiring in the second layer via hole. A method for manufacturing a multilayer printed wiring board, comprising:   21. The second-layer via-hole wiring according to claim 20, wherein the second-layer via-hole wiring has a concave shape from the first surface of the second insulating layer toward the second surface, and has a land portion on the second surface of the second insulating layer. The manufacturing method of the multilayer printed wiring board as described.   The multilayer print according to claim 21, wherein the first layer via-hole wiring and the second layer via-hole wiring overlap each other in the stacking direction of the first wiring substrate and the second wiring substrate. A method for manufacturing a wiring board.   23. The method for manufacturing a multilayer printed wiring board according to claim 21, wherein the first layer via hole wiring and the second layer via hole wiring are connected to each other.   The method of manufacturing a multilayer printed wiring board according to any one of claims 20 to 23, wherein the first layer via hole and the second layer via hole are formed by laser processing.   The method for manufacturing a multilayer printed wiring board according to any one of claims 20 to 24, wherein the first layer via hole wiring and the second layer via hole wiring are formed by plating.   The method for producing a multilayer printed wiring board according to any one of claims 20 to 25, wherein the first wiring substrate is a flexible printed wiring substrate.   The method for producing a multilayer printed wiring board according to claim 26, wherein the second wiring substrate is a metal foil with resin.   27. The method for producing a multilayer printed wiring board according to claim 26, wherein the second wiring substrate is formed by laminating a fiber-containing resin sheet and a metal foil.   27. The method for producing a multilayer printed wiring board according to claim 26, wherein the second wiring substrate is formed by laminating a semi-cured resin sheet and a metal foil and curing the semi-cured resin sheet. A first wiring substrate having a first insulating layer and a wiring metal layer laminated on each of the first surface and the second surface of the first insulating layer; and a second insulating layer and a first surface of the second insulating layer. A method for producing a multilayer printed wiring board in which two multilayer printed wiring boards laminated with a second wiring substrate having a laminated wiring metal layer are disposed facing each other,
Forming a first layer via hole from the second surface of the first insulating layer to the first surface, and forming a concave shape in the first layer via hole from the second surface of the first insulating layer toward the first surface; Forming a first layer via hole wiring having a land portion on a first surface of the first insulating layer;
Covering the second surface of the first wiring substrate with a protective film;
Arranging the two first wiring substrates coated with the protective film opposite to both surfaces of the adhesive sheet, and bonding each of the protective films to the adhesive sheet;
Laminating the first surface of the first insulating layer and the second surface of the second insulating layer facing each other;
Forming a second layer via hole from the first surface to the second surface of the second insulating layer, and forming a second layer via hole wiring in the second layer via hole. A method for manufacturing a wiring board.   32. The second layer via hole wiring according to claim 30, wherein the second layer via hole wiring has a concave shape from the first surface of the second insulating layer toward the second surface, and has a land portion on the second surface of the second insulating layer. The manufacturing method of the multilayer printed wiring board as described.   32. The multilayer print according to claim 31, wherein the first layer via-hole wiring and the second layer via-hole wiring overlap each other in the stacking direction of the first wiring substrate and the second wiring substrate. A method for manufacturing a wiring board.   33. The method for manufacturing a multilayer printed wiring board according to claim 31, wherein the first layer via hole wiring and the second layer via hole wiring are connected to each other.   34. The method of manufacturing a multilayer printed wiring board according to claim 30, wherein the first layer via hole and the second layer via hole are formed by laser processing.   35. The method of manufacturing a multilayer printed wiring board according to claim 30, wherein the first layer via hole wiring and the second layer via hole wiring are formed by plating.   36. The method for producing a multilayer printed wiring board according to any one of claims 30 to 35, wherein the first wiring substrate is a flexible printed wiring substrate.   The method for producing a multilayer printed wiring board according to claim 36, wherein the second wiring substrate is a metal foil with resin.   37. The method for producing a multilayer printed wiring board according to claim 36, wherein the second wiring substrate is formed by laminating a fiber-containing resin sheet and a metal foil.   The method for producing a multilayer printed wiring board according to claim 36, wherein the second wiring substrate is formed by laminating and curing a semi-cured resin sheet and a metal foil.

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