JP4233528B2 - Multilayer flexible circuit wiring board and manufacturing method thereof - Google Patents

Description

  The present invention relates to a manufacturing method and structure of a multilayer circuit wiring board, and more particularly to a multilayer flexible circuit wiring board having a flexible cable portion and a manufacturing method thereof.

  In recent years, downsizing and higher functionality of electronic devices have been promoted more and more, and therefore, there is an increasing demand for higher density of circuit boards. In view of this, the circuit board is made to be a multi-layer circuit board from one side to both sides or three or more layers to increase the density of the circuit board.

  As part of this, a multilayer flexible circuit with a flexible cable unit that integrates a multilayer circuit board on which various electronic components are mounted, a separate flexible wiring board that connects hard circuit boards via connectors, etc., and a flexible flat cable. Wiring boards are widespread mainly in small electronic devices such as mobile phones.

  A typical structure of a multilayer flexible circuit wiring board is such that a double-sided or single-sided flexible wiring board is used as an inner layer, and a flexible or hard base circuit board as an outer layer is laminated thereon, and through holes are connected by plating or the like. The structure is a multilayer flexible circuit wiring board having about one layer.

  However, as described in Patent Documents 3 and 4, in order to provide a flexible cable portion in the multilayer circuit wiring board, a polyimide resin cover film of the flexible cable portion and an adhesive for bonding the same The coefficient of thermal expansion is high, and there is a problem that cracks are likely to occur in the through-hole plating layer due to heat during solder reflow of about 220 to 240 ° C during component mounting. Since cracks can only be avoided by increasing the thickness, the conductor thickness of the surface layer is increased, and this is a serious problem as a product in a multilayer flexible circuit wiring board that requires high-density wiring and high-density mounting.

  Patent Document 1 describes a structure in which a polyimide resin cover film of a flexible cable part is retracted outward from a through-hole conduction hole. However, when the cover film with the end face retracted is misaligned, the through-hole crack resistance is not improved, and the above problem cannot be solved. In addition, an adhesive such as a prepreg for laminating a single-sided copper-clad laminate or the like serving as an outer layer on the flexible cable part dislikes flowing out from the end face of the flexible cable part, and suppresses fluidity. For this reason, it is difficult to fill the level difference of the cover film whose end face is retracted. When the filling property of an adhesive such as a prepreg is improved, as described above, it causes a flow out from the end face of the flexible cable portion and the like, so that it is difficult to apply.

  Patent Document 2 describes a method of manufacturing a multilayer substrate by through-hole connection in which laser processing is performed so that the hole diameter of the inner layer is larger than that of the outer layer, and the through-hole plating thickness is selectively thickened only on the inner layer. ing. However, since the control of the hole diameter must be controlled by the laser processing conditions, even if the inner layer hole diameter changes due to variations in the laser processing conditions, it is necessary to determine the conditions every time the constituent material changes, There is a concern that the detection cannot be performed, and the through hole processing cannot be performed by stacking the substrates as in the conventional NC drill, and there is a disadvantage that the productivity is significantly inferior to the conventional method. In addition, regarding the control of the plating thickness, it is difficult to selectively thicken only the inner layer stably, and it is difficult to set the contrast of the plating thickness within the range described in this document. It is impossible to achieve both the through-hole reliability of the flexible circuit wiring board and the formation of fine wiring on the surface layer.

  In Patent Documents 5 and 6, through-hole plating is performed in advance on the inner layer circuit, and after laminating the outer layer, a conduction hole is formed coaxially with the through-hole, and further through-hole plating is performed. A method of adding contrast is described. However, since these methods simplify the inner layer desmear process, it is difficult to apply to a multilayer flexible circuit wiring board in which the inner layer circuit desmear process having a cable is essential. In addition, in order to prevent cracks in the polyimide resin cover film layer and adhesive layer in the vicinity of the flexible cable portion having a high thermal expansion coefficient unique to the multilayer flexible circuit wiring board, these It is necessary to increase the thickness of the through-hole plating of this layer. However, in the range described in Patent Documents 5 and 6, since only the through-hole plating thickness up to the interlayer connection portion of the inner layer circuit is increased, the problem cannot be solved. Furthermore, it is necessary to perform a complicated plating process a plurality of times, and it is difficult to say that the method is highly productive.

  For these reasons, there has been a demand for a method of effectively preventing through-hole cracks in a multilayer flexible circuit wiring board by a method with good productivity without increasing the surface conductor thickness.

  11 to 13 are process diagrams showing a conventional method for manufacturing a multilayer flexible circuit wiring board. First, as shown in FIG. 11 (1), both surfaces of a flexible insulating base material 71 such as polyimide are provided. A so-called double-sided copper-clad laminate 74 having conductive layers 72 and 73 such as copper foil is prepared.

  Next, as shown in FIG. 2B, a circuit pattern 75 such as a cable is formed on the copper foil layers 72 and 73 of the double-sided copper-clad laminate 74 using an etching method by a normal photofabrication method. To form an inner layer circuit 76.

  Next, as shown in FIG. 3 (3), a cover 79 is formed by bonding a polyimide film 77 to a circuit pattern 75 such as a cable via an adhesive 78, thereby forming a cable portion 80.

  Next, as shown in FIG. 4 (4), a so-called single-sided copper-clad laminate 83 having a conductive layer 82 such as a copper foil on one side of an insulating base material 81, and this is punched into a desired shape by a mold or the like. An adhesive 84 for bonding to the processed cable portion 80 in FIG. The thickness of the conductive layer 82 at this time is 50 μm or less, and particularly preferably 35 μm or less.

  Next, as shown in FIG. 5 (5), the single-sided copper-clad laminate 83 and the adhesive 84 are bonded together, and this is punched into a desired shape using a mold or the like to form a single-sided copper-clad laminate 85.

  Next, as shown in FIG. 12 (1), the single-sided copper-clad laminate 85 of FIG. 11 (5) is laminated on the cable portion 80 of FIG. 11 (3) via an adhesive 84.

  Next, as shown in FIG. 12 (2), a conduction hole 86 is formed by an NC drill or the like. At this time, the polyimide film 77 and the adhesive 78 of the inner layer cover 79 cause heat sagging during drilling, and the periphery of the inner layer circuit 76 with the through-hole plating on the copper foil layers 72 and 73 is deteriorated, so that desmear processing is performed. .

  Next, as shown in FIG. 13 (1), the electroconductive plating 86 is subjected to electroless plating or conductive treatment, and then a through hole 87 is formed by electroplating. At this time, the plating thickness of the through hole 87 is preferably about 30 to 50 μm in order to ensure reliability.

Next, as shown in FIG. 13B, a circuit pattern 88 is formed on the through-hole surface by using an etching method based on a normal photofabrication method. Thereafter, a surface treatment such as formation of a photo solder resist layer, solder plating, nickel plating, gold plating or the like is performed on the surface of the substrate as necessary, and outer shape processing is performed to obtain the multilayer flexible circuit wiring board 89.
JP-A-6-21653 JP 2001-210953 A Japanese Patent No. 2631287 Japanese Patent No. 3427011 JP-A-62-190797 JP-A-8-264952 JP 2002-141629 A JP 2003-129259 A

  It is an object of the present invention to provide a multilayer flexible circuit wiring board and a method for manufacturing the multilayer flexible circuit wiring board capable of ensuring both through-hole connection reliability and forming a fine pattern on the surface layer in the production of the multilayer flexible circuit wiring board.

  According to the invention to solve the above-mentioned problem, in the multilayer flexible circuit wiring board having through-hole connection, the outer periphery of the hole for conducting the cover serving as the cable protection layer of the inner layer board having the cable structure is made of a conductive protrusion, A multilayer flexible circuit wiring board is employed in which the inner periphery is reinforced with a plating film continuous with through-hole plating of the outer layer.

  As a manufacturing method of the present invention for solving the above-mentioned problem, in the method for manufacturing a multilayer flexible circuit wiring board, a cable structure cover is provided on the surface on which the conductive protrusion of the conductive layer is erected on one surface. A circuit base material on which a flexible insulating layer is formed is prepared, and the conductive protrusion and the circuit base are formed in a cable structure in which a first conduction hole having a diameter larger than that of the conductive protrusion is previously formed on the circuit base material. The first hole for conduction is aligned to form a laminated inner layer substrate, and a single-sided copper-clad laminate and an adhesive that have been pre-cut are aligned and laminated on the inner layer substrate, and the conductive projections are arranged on the same axis. Forming a second conduction hole for forming a through-hole having a diameter smaller than that of the conductive projection in which the conductive projection remains concentrically, and electroless plating or / and conducting to the second conduction hole; Treatment and electrolysis A method of manufacturing a multilayer flexible circuit wiring board is employed, wherein a through hole is formed on the same axis as the conductive protrusion by applying a plating.

  As another manufacturing method of the present invention for solving the above-mentioned problem, in the method for manufacturing a multilayer flexible circuit wiring board, a cable structure is provided on the surface where the conductive protrusions of the conductive layer are erected on one surface. A single-sided copper-clad laminate that has been prepared by preparing a circuit base material on which a flexible insulating layer is formed to serve as a cover, and pasting the circuit base material onto a flexible circuit having a cable structure that has been formed in advance, as an inner layer substrate And an adhesive for positioning on the inner layer substrate and laminating, and forming a through hole having a diameter smaller than that of the conductive protrusion on which the conductive protrusion remains concentrically on the same axis of the conductive protrusion Forming a through hole, and forming a through hole on the same axis as the conductive protrusion by performing electroless plating or / and conducting treatment and electrolytic plating on the conductive hole. A method for manufacturing a sibling circuit wiring board is employed.

  Due to these features, the present invention has the following effects.

  In the multilayer flexible circuit wiring board having through-hole connection according to the present invention, the outer periphery of the conduction hole of the cover serving as the cable protection layer of the inner layer board having the cable structure is made of conductive protrusions, and the inner circumference is the outer layer through-hole plating. Multilayer flexible circuit wiring board, which is reinforced with a continuous plating film, is used, so the inner layer board has conductive protrusions and has sufficient strength at the interlayer connection compared to the conventional method However, since the through-hole plating thickness of the surface layer can be reduced, a fine pattern can be formed on the surface layer while ensuring connection reliability. In addition, since the plating thickness of the surface layer can be reduced, the flatness of the surface layer caused by the variation in plating thickness is improved, and the mountability is also improved.

  Furthermore, as a manufacturing method of the present invention, in the manufacturing method of a multilayer flexible circuit wiring board, the flexibility that becomes a cover of the cable structure on the surface where the conductive protrusion of the conductive layer is erected on one surface and the conductive protrusion is erected A circuit base material on which an insulating layer is formed is prepared, and the conductive protrusion and the first conductive conductor are formed in a cable structure in which the first conductive hole having a diameter larger than the conductive protrusion is previously formed on the circuit base material. The holes are aligned to form a laminated inner layer substrate, a pre-die-cut single-sided copper-clad laminate and an adhesive are aligned and laminated on the inner layer substrate, and the conductive protrusions are concentric on the same axis as the conductive protrusions. Forming a second conduction hole for forming a through hole having a diameter smaller than that of the conductive protrusion remaining in a shape, and subjecting the second conduction hole to electroless plating and / or conductive treatment and electrolytic plating. By applying A method for manufacturing a multilayer flexible circuit wiring board, wherein a through hole is formed on the same axis as the conductive protrusion, is adopted, and as another manufacturing method of the present invention, a method for manufacturing a multilayer flexible circuit wiring board is provided. Preparing a circuit base material on which a flexible insulating layer serving as a cable structure cover is formed on the surface of the conductive layer on which the conductive protrusion is erected on one surface, A flexible circuit having a formed cable structure is bonded to an inner layer substrate, a pre-die-cut single-sided copper-clad laminate and an adhesive are aligned and stacked on the inner layer substrate, and the conductive layer is coaxially connected to the conductive protrusion. A conductive hole for forming a through-hole having a diameter smaller than that of the conductive protrusion in which the conductive protrusion remains concentrically, and electroless plating and / or conductive treatment is performed on the conductive hole; Since a method for manufacturing a multilayer flexible circuit wiring board is employed, in which a through hole is formed on the same axis as the conductive protrusion by applying electrolytic plating, the through hole processing is performed by stacking the substrates as in the conventional method. In addition to being able to process with good productivity, the second manufacturing method does not require a complicated desmear process with many man-hours. For these reasons, it is possible to provide a multilayer flexible circuit wiring board, which has been difficult with the conventional method, at low cost and stably without impairing productivity.

  Hereinafter, the present invention will be further described with reference to the illustrated embodiments.

  FIG. 1 is a process diagram showing a method for producing a multilayer flexible circuit wiring board according to the present invention. First, as shown in FIG. 1 (1), copper foil is provided on both sides of a flexible insulating base material 1 such as polyimide. A so-called double-sided copper-clad laminate 4 having conductive layers 2 and 3 such as these is prepared.

  Next, as shown in FIG. 2 (2), a circuit pattern 5 such as a cable is formed on the copper foil layers 2 and 3 of the double-sided copper-clad laminate 4 by using an etching method based on a normal photofabrication method. To form an inner layer circuit 6.

  Next, as shown in FIG. 3C, a conduction hole 7 is formed in the inner layer circuit 6 with an NC drill or the like. As the diameter of the conduction hole 7, for example, a diameter of 300 μm is applicable.

  Next, a copper foil 8 is prepared as shown in FIG. Since this copper foil will later form conductive protrusions, its thickness is preferably about 50 μm to 200 μm.

  Next, as shown in FIG. 5 (5), a resist layer 9 for forming conductive protrusions on the copper foil 8 by a photofabrication method is formed.

  Next, as shown in FIG. 2 (1), the conductive protrusions 10 are raised from the copper foil 8 by the photofabrication method using the resist layer 9 by the method described in Patent Documents 7 and 8. The base material 11 to be provided is formed. Thereafter, the conductive protrusion 10 is desirably smaller than the conduction hole 7 of the inner layer circuit 6 formed in FIG. 1 (3). Here, the top diameter of the conductive protrusion 10 is 200 μm, and the bottom diameter is 200 μm. A film having a thickness of 350 μm and a height of 50 μm was formed. In a subsequent process, a polyimide film and an adhesive layer are formed on the base material 11 on which the conductive protrusions 10 are erected, and the conductive protrusions 10 need to be higher than the cover thickness. The conductive protrusions 10 can be formed at a pitch of 500 μm or less and can sufficiently cope with the formation of high-density through holes.

  Next, as shown in FIG. 2 (2), a polyimide film 13 that becomes the cover 12 of the inner layer circuit 6 such as a cable formed in FIG. 1 (2) on the base material 11 on which the conductive protrusions 10 are erected, and The adhesive material 14 is formed. A method such as a laminating method or a casting method can be selected as the method for forming the cover 12, and the laminating method is selected here.

  Next, as shown in FIG. 2 (3), a polishing process such as CMP is performed to expose the top and side walls of the conductive protrusion 10, and the top and side walls of the conductive protrusion 10 are exposed to remove the conductive protrusion. The cover base material 15 having is formed.

  Next, as shown in FIG. 2 (4), the conductive protrusion 10 is aligned with the conduction hole 7 of the inner layer circuit 6, and the cover base material 15 having the conductive protrusion on the circuit pattern such as the cable of the inner layer circuit 6. Are bonded together with an adhesive 14.

  Next, as shown in FIG. 2 (5), unnecessary copper foil on the side where the conductive protrusions 10 are not erected is removed by a normal photofabrication technique. At this time, the end face of the polyimide film 13 of the cover 12 is removed. In order to ensure that the conductive protrusions 10 are brought into close contact with each other, it is preferable to form a concentric land larger than the bottom of the conductive protrusions 10, so the lands 16 of the conductive protrusions 10 are formed as shown in the figure. Through the steps so far, the inner layer circuit 17 including the cable portion having the conductive protrusion 10 is formed.

  Next, as shown in FIG. 3A, a so-called single-sided copper-clad laminate 20 having a conductive layer 19 such as a copper foil on one side of an insulating base material 18 and this is punched into a desired shape by a mold or the like. An adhesive 21 is prepared for bonding to the inner layer circuit 17 including the cable portion having the processed conductive protrusion 10 of FIG.

  Next, as shown in FIG. 3 (2), the single-sided copper-clad laminate 20 and the adhesive 21 are bonded together, punched into a desired shape with a mold or the like, and the die-cut one-sided copper-clad laminate 22 Form.

  Next, as shown in FIG. 3 (3), the single-sided copper of FIG. 3 (2) is punched into the inner layer circuit 17 including the cable portion having the conductive protrusions 10 of FIG. 2 (5) through the adhesive 21. The tension laminate 22 is laminated.

  Next, as shown in FIG. 4A, the conduction hole 23 is formed by an NC drill or the like. The diameter of the conduction hole 23 is smaller than the diameter of the conduction hole 7 formed in FIG. 1 (3), and a diameter that can secure a sufficient layer thickness of the conductive protrusion 10, for example, a diameter of 150 to 200 μm can be selected. . If the hole diameter is too small, the drill blade is likely to be broken, leading to a decrease in yield, and a risk of worsening the contact with the subsequent through-hole plating. When the hole diameter is large, there is a risk that defects such as cracks and chippings may be imparted to the conductive protrusion 10 when forming the conduction hole 23 due to problems such as alignment.

  Next, as shown in FIG. 4 (2), for the purpose of improving the plating coverage in the subsequent through-hole plating step, the drilled conductive protrusion 10 is softened as necessary. Etching is performed to remove burrs and the like. Further, when the single-sided copper-clad laminate 22 is laminated in FIG. 3 (3), the adhesive 21 may flow, and therefore desmear treatment is performed as necessary.

  Next, as shown in FIG. 5A, after conducting the conductive treatment to the conduction hole 23, the through hole 24 is formed by electroplating. The plating thickness of the through hole 24 at this time may be relatively thin, and for example, connection reliability can be ensured at about 15 μm.

  Next, as shown in FIG. 5B, a circuit pattern 25 is formed on the through-hole surface by using an etching method based on a normal photofabrication method. Thereafter, the multilayer flexible circuit wiring board 26 is obtained by subjecting the surface of the substrate to surface treatment such as formation of a photo solder resist layer, solder plating, nickel plating, gold plating, and the like, as necessary, and performing external processing.

  6 to 9 are process diagrams showing another method for manufacturing the multilayer flexible circuit wiring board of the present invention. First, as shown in FIG. 6A, a flexible insulating base material 31 such as polyimide is used. A so-called double-sided copper-clad laminate 34 having conductive layers 32 and 33 such as copper foil on both sides is prepared.

  Next, as shown in FIG. 2B, a circuit pattern 35 such as a cable is formed on the copper foil layers 32 and 33 of the double-sided copper-clad laminate 34 by using an etching method based on a normal photofabrication method. To form the inner layer circuit 36.

  Next, a copper foil 37 is prepared as shown in FIG. Since this copper foil will later form conductive protrusions, its thickness is preferably about 50 μm to 200 μm.

  Next, as shown in FIG. 4 (4), a resist layer 38 for forming conductive protrusions on the copper foil 37 by a photofabrication technique is formed.

  Next, as shown in FIG. 7 (1), the conductive protrusions 39 are raised from the copper foil 37 by the photofabrication method using the resist layer 38 by the method described in Patent Documents 7 and 8. The base material 40 to be provided is formed. The conductive protrusion 39 is preferably smaller than the conductive hole to be formed later. Here, the conductive protrusion 39 has a top diameter of 200 μm, a bottom diameter of 350 μm, and a height of 50 μm. In a subsequent process, a polyimide film and an adhesive layer are formed on the base material 40 on which the conductive protrusions 39 are erected, and the conductive protrusions 39 need to be higher than the cover thickness. The conductive protrusions 39 can be formed at a pitch of 500 μm or less and can sufficiently cope with the formation of high-density through holes.

  Next, as shown in FIG. 7 (2), the polyimide film 42 which becomes the cover 41 of the inner layer circuit 36 such as the cable formed in FIG. 6 (2) on the base material 40 on which the conductive protrusions 39 are erected, and An adhesive 43 is formed. As a method for forming the cover 41, a method such as a laminating method or a casting method can be selected. Here, the laminating method is selected.

  Next, as shown in FIG. 7 (3), a polishing process such as CMP is performed to expose the top and side walls of the conductive protrusions 39, and the top and side walls of the conductive protrusions 39 are exposed to remove the conductive protrusions. The cover base material 44 having is formed.

  Next, as shown in FIG. 7 (4), a cover substrate 44 having conductive protrusions is bonded to a circuit pattern such as a cable of the inner layer circuit 36 through an adhesive 43.

  Next, as shown in FIG. 7 (5), unnecessary copper foil on the side where the conductive protrusions 39 are not erected is removed by a normal photofabrication technique. At this time, the polyimide film 42 of the cover base 44 is removed. A concentric land larger than the bottom of the conductive protrusion 39 is preferably formed in order to ensure that the conductive protrusion 39 is in close contact with the end face. Therefore, the land 45 of the conductive protrusion 39 is formed as shown in the figure. Through the steps so far, the inner layer circuit 46 including the cable portion having the conductive protrusions 39 is formed.

  Next, as shown in FIG. 8 (1), a so-called single-sided copper-clad laminate 49 having a conductive layer 48 such as copper foil on one side of an insulating base material 47, and this is punched into a desired shape by a mold or the like. An adhesive 50 is prepared for bonding to the inner layer circuit 46 including the cable portion having the processed conductive protrusion 39 of FIG. 7 (5).

  Next, as shown in FIG. 8 (2), the single-sided copper-clad laminate 51 and the adhesive 50 are bonded together and punched into a desired shape with a mold or the like, and the die-cut one-sided copper-clad laminate 51 Form.

  Next, as shown in FIG. 8 (3), the single-sided copper of FIG. 8 (2) is punched into the inner layer circuit 46 including the cable portion having the conductive protrusions 39 of FIG. 7 (5) through the adhesive 50. The tension laminate 51 is laminated.

  Next, as shown in FIG. 9A, the conduction hole 52 is formed by an NC drill or the like. As the diameter of the conduction hole 52, a diameter capable of ensuring the layer thickness of the conductive protrusion 39 formed in FIG. 7A, for example, a diameter of 150 μm can be selected. If the hole diameter is too small, the drill blade is likely to be broken, leading to a decrease in yield, and a risk of worsening the contact with the subsequent through-hole plating. When the hole diameter is large, there is a possibility that a defect such as cracking or chipping may be given to the conductive protrusion 39 when the conduction hole 52 is formed due to problems such as alignment. Since the inner layer cover base 44 is not directly drilled, there is no risk of thermal sagging during drilling, and there is no need to perform desmear treatment.

  Next, as shown in FIG. 9 (2), after conducting the conductive treatment to the conduction hole 52, a through hole 53 is formed by electroplating. At this time, the plating thickness of the through hole 53 may be relatively thin. For example, connection reliability can be ensured at about 15 μm.

  Next, as shown in FIG. 9 (3), a circuit pattern 54 is formed on the through-hole surface by using an etching method by a normal photofabrication method. Thereafter, surface treatment such as formation of a photo solder resist layer, solder plating, nickel plating, gold plating or the like is performed on the substrate surface as necessary, and external processing is performed to obtain the multilayer flexible circuit wiring board 55.

  FIG. 10 is a cross-sectional view showing a structure manufactured by the method for manufacturing a multilayer flexible circuit wiring board according to the present invention. As shown in the drawing, in the manufacturing process of the multilayer flexible circuit wiring board, a cable having conductive protrusions When manufacturing the inner layer circuit including the portion, it is also possible to form the wiring in the step of forming the land of the conductive protrusion, and thereby the multilayer flexible circuit wiring board 61 having the wiring 62 is obtained.

The manufacturing process figure of the multilayer flexible circuit wiring board by this invention. The manufacturing process figure following FIG. The manufacturing process figure following FIG. Manufacturing process figure following FIG. The manufacturing process figure following FIG. The manufacturing process figure of the multilayer flexible circuit wiring board by the other manufacturing method of this invention. Manufacturing process figure following FIG. Manufacturing process figure following FIG. The manufacturing process figure following FIG. The conceptual cross-sectional block diagram of the multilayer flexible circuit wiring board by this invention. The manufacturing process figure of the multilayer flexible circuit wiring board by the conventional method. The manufacturing process figure following FIG. The manufacturing process figure following FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Flexible insulating base material 2 Copper foil layer 3 Copper foil layer 4 Double-sided copper clad laminated board 5 Circuit pattern 6 Inner layer circuit 7 Conductive hole 8 Copper foil 9 Resist layer 10 Conductive protrusion 11 Conductive protrusion standing base Material 12 Cover 13 Polyimide film 14 Adhesive 15 Cover base material having conductive protrusion 16 Land of conductive protrusion 17 Inner layer circuit including cable portion having conductive protrusion 18 Insulating base material 19 Conductive layer 20 Single-sided copper-clad laminate 21 Adhesive 22 Die-cut single-sided copper-clad laminate 23 Conductive hole 24 Through hole 25 Circuit pattern

Claims (3)

  In a multilayer flexible circuit wiring board having through-hole connection, the outer periphery of the conductive hole of the cover serving as the cable protection layer of the inner-layer board having the cable structure is made of conductive protrusions, and the inner periphery is continuous with the through-hole plating of the outer layer. A multilayer flexible circuit wiring board characterized by being reinforced with a film.   A circuit base material is prepared in which a flexible insulating layer serving as a cable structure cover is formed on the surface of the conductive layer on which the conductive protrusion is erected on one side, and the circuit base is previously A single-sided copper-clad laminate in which the conductive protrusions and the first conductive holes are aligned and bonded to a cable structure in which a first conductive hole having a diameter larger than the conductive protrusion is formed, and is die-cut in advance. A second plate for aligning and laminating a plate and an adhesive on the inner layer substrate to form a through hole having a diameter smaller than that of the conductive protrusion on which the conductive protrusion remains concentrically on the conductive protrusion. A through hole is formed on the same axis as the conductive protrusion by performing electroless plating and / or conductive treatment and electrolytic plating on the second conductive hole. Multilayer flexible circuit arrangement A method of manufacturing a wire substrate.   Prepare a circuit board with a flexible insulating layer that will be the cover of the cable structure on the surface of the conductive layer where the conductive protrusion is erected on one side, and pre-form the circuit base The inner layer substrate is laminated to a flexible circuit having a cable structure, and a single-sided copper-clad laminate and an adhesive previously punched are aligned and laminated on the inner layer substrate, and the conductive layer is coaxially connected to the conductive protrusion. By forming a conduction hole for forming a through hole having a diameter smaller than that of the conductive protrusion in which the protrusions remain concentrically, and subjecting the conduction hole to electroless plating and / or conductive treatment and electrolytic plating. A method of manufacturing a multilayer flexible circuit wiring board, wherein a through hole is formed on the same axis as the conductive protrusion.

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