JP2004063725A - Multilayer interconnection circuit board incorporating coaxial line and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayer interconnection circuit board that prevents the crosstalk noise between adjacent signal wiring layers, maintains the degree of wiring freedom in the signal wiring layers, and has excellent connection reliability, and to provide a method for manufacturing the multilayer interconnection circuit board. <P>SOLUTION: A ground layer 41 and a power supply layer 42 are formed via an insulating layer 31 on one surface and the other of a wiring circuit board 10 where wiring layers 21a and 21b are formed on both the surfaces of an insulating base 11, respectively. A covering signal conductor 50 is provided on the ground layer 41, the periphery of the covering signal conductor 50 is covered with a conductor layer for forming a coaxial line with a coaxial structure as a signal wiring layer. Additionally, a connection section is provided, where the connection section electrically connects a signal conductor 51 of the coaxial line to the wiring layer, or electrically connects the signal conductor 51 each other when the coaxial line and the wiring layer are formed, thus easily, electrically connecting signal conductors when the coaxial line (signal wiring layer) is set to be in a multilayer structure. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a multilayer wiring circuit board having a built-in coaxial line and a method for manufacturing the same.
[0002]
[Prior art]
In a conventional multilayer wiring circuit board, the density of wiring layers is increased, so that signal lines come close to each other, so that crosstalk noise occurs between the signal wirings of each other, thereby causing a malfunction in a driving element of the circuit. Have a problem. In addition, this is noticeable in a circuit having an operating frequency of 100 MHz or more. To prevent this, conventionally, a ground pattern is arranged between left and right signal lines or a ground layer is formed between upper and lower signal lines. However, the measures are not sufficient.
[0003]
[Problems to be solved by the invention]
An object of the present invention is to provide a multilayer wiring circuit board with a built-in coaxial line, which prevents crosstalk noise between adjacent signal wiring layers, maintains the wiring flexibility of the signal wiring layers, and has excellent connection reliability, and a method for manufacturing the same. Aim.
[0004]
[Means for Solving the Problems]
To achieve the above object in the present invention, first, according to claim 1, a multilayer wiring circuit board comprising a ground layer, a power supply layer, and at least one or more wiring layers formed on an insulating base material In the above, a covered signal conductor in which the periphery of the signal conductor is covered with an insulating layer is disposed on the ground layer, and the periphery of the insulating layer of the covered signal conductor is covered with a conductor layer, and the conductor layer is electrically connected to the ground layer. And a connecting portion for electrically connecting the signal conductor of the coaxial cable and the wiring layer or the signal conductor of the coaxial cable is formed at a predetermined position of the coaxial cable. This is a multi-layer wiring circuit board with a built-in coaxial line.
[0005]
Further, in claim 2, the connection portion forms a hole in which a part of the signal conductor of the covered signal conductor is exposed by perforating the insulating layer on the covered signal conductor. A conductor is formed in the opening by filling or plating, or the like, and the signal conductor of the coaxial line and the wiring layer or the signal conductor of the coaxial line are electrically connected to each other. Item 10 is a multilayer wiring circuit board with a built-in coaxial line according to Item 1.
[0006]
According to a third aspect of the present invention, when the plurality of coaxial lines are formed, the coaxial lines have the same length. It was done.
[0007]
According to a fourth aspect of the present invention, there is provided a method of manufacturing a multilayer wiring circuit board with a built-in coaxial line, comprising at least the following steps.
(A) A wiring circuit board (base substrate) 10 having wiring layers 21a and 21b formed on both surfaces of an insulating base material 11 has a ground layer 41 on one surface via an insulating layer 31, and an insulating layer 31 on the other surface. Forming a hole by performing photo-etching processing on a predetermined position of the ground layer 41 of the printed circuit board on which the power supply layer 42 is formed, and burying an insulating material such as resin to form a buried layer 41a.
(B) forming an adhesive layer 32 having a predetermined thickness on the ground layer 41 and the buried layer 41a;
(C) A step of disposing the covered signal conductor 50 in which the periphery of the signal conductor 51 is covered with the insulating layer 52 on the adhesive layer 32.
(D) a step of removing the adhesive layer 32 except for a portion where the covered signal conductor 50 is fixed.
(E) forming a thin-film conductor layer around the insulating layer 52 of the covered signal conductor 50 and on the ground layer 41;
(F) a step of forming a resist pattern 37 for forming a connection portion at a predetermined position of the covered signal conductor 50 on which the thin film conductor layer is formed.
(G) Electrolytic copper plating is performed using the thin film conductor layer as a cathode, a conductor layer 44 having a predetermined thickness is formed around the insulating layer 52 of the covered signal conductor 50, the coaxial line 60 is formed, and the conductor layer 44 is formed on the ground layer 41. Forming step.
(H) a step of stripping the resist pattern 37 with a dedicated stripper to form an insulating layer 33 having a predetermined thickness on the coaxial line 70, the covered signal conductor 50 on which the thin film conductor layer is formed, and the conductor layer 44.
(I) a step of forming a hole 33a in which the signal conductor 51 of the covered signal conductor 50 is partially exposed by boring the insulating layer 33;
(J) A thin-film conductor layer is formed on the insulating layer 33 and in the opening 33a, electrolytic copper plating is performed using the thin-film conductor as a cathode, and a conductor layer 45 having a predetermined thickness is formed on the insulating layer 33. A step of forming a filled via 45c in 33a.
(K) a step of patterning the conductor layer 45 on the insulating layer 33 to form the wiring layer 45a and the connection portion 45b.
[0008]
Furthermore, a fifth aspect of the present invention is a method for manufacturing a multilayer wiring circuit board with a built-in coaxial line, comprising at least the following steps.
(A) A wiring circuit board (base substrate) 10 having wiring layers 21a and 21b formed on both surfaces of an insulating base material 11 has a ground layer 41 on one surface via an insulating layer 31, and an insulating layer 31 on the other surface. Forming a hole by photo-etching a predetermined position of the ground layer 41 of the printed circuit board on which the power supply layer 42 is formed, and filling the hole with an insulating material such as resin to form a buried layer 41a.
(B) forming a resist pattern 34 having a predetermined shape at a predetermined position on the ground layer 41;
(C) A step of forming a thin-film conductor layer on the resist pattern 34 and the ground layer 41 and performing electrolytic copper plating using the resist pattern 38 as a plating mask to form a conductor pattern layer 46 having a predetermined thickness.
(D) a step of subjecting the resist pattern 38 to a stripping treatment with a dedicated stripping solution to form a groove 61 having a predetermined shape between the conductor pattern layers 46;
(E) A resist for disposing the covered signal conductor 50 in the groove 61, forming a thin-film conductor layer on the insulating layer 52 around the covered signal conductor 50, and forming a connection portion at a predetermined position on the covered signal conductor 50. Forming a pattern 38;
(F) A step of forming a conductor layer 47 having a predetermined thickness on the conductor pattern layer 46 by performing electrolytic copper plating using the thin film conductor layer as a cathode to form a coaxial wire 70 in which the periphery of the covered signal conductor 50 is filled with a conductor.
(G) a step of stripping the resist pattern 38 with a dedicated stripper to form the insulating layer 35 having a predetermined thickness on the covered signal conductor 50 and the conductor layer 47 on which the thin film conductor layer is formed.
(H) forming a hole 35a in which a part of the signal conductor 51 of the covered signal conductor 50 is exposed by punching the insulating layer 35;
(I) A thin-film conductor layer is formed on the insulating layer 35 and in the opening 35a, electrolytic copper plating is performed using the thin-film conductor layer as a cathode, and a conductor layer 48 is formed on the insulating layer 35 and the opening 35a is formed in the opening 35a. Forming a filled via 48c;
(J) a step of patterning the conductor layer 48 on the insulating layer 35 to form the wiring layer 48a and the connection portion 48b.
[0009]
In the multilayer wiring circuit board with a built-in coaxial cable of the present invention, in order to prevent noise generated between signal wiring layers of the high-density multilayer wiring circuit board, a covered signal conductor covered with an insulating layer is electrically connected to a ground layer. By covering with a conductor layer, a coaxial line having a coaxial structure is formed and used as a signal wiring layer. In addition, a connection portion is provided in an insulating layer on the coaxial line to electrically connect the signal conductor of the coaxial line with the wiring layer and the signal conductor of the coaxial line. In addition, it is possible to form a coaxial line by laminating the covered signal conductors by routing the covered signal conductors, thereby increasing the degree of freedom in designing the coaxial line (signal wiring layer) and maintaining the conventional building-up method. A high-density multilayer wiring circuit board with a built-in coaxial line can be manufactured.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a multilayer wiring circuit board with a built-in coaxial line according to the present invention will be described.
FIGS. 1, 2 and 3 are partial cross-sectional views schematically showing an embodiment of the multilayer wiring circuit board with a built-in coaxial cable of the present invention.
The multi-layer printed circuit board with a built-in coaxial cable according to the present invention according to claim 1, wherein the wiring layer 21 a and the wiring layer 21 b are formed on both surfaces of the insulating base 11 on one side of the printed circuit board 10 via the insulating layer 31 via the ground layer. 41, the power supply layer 42 is formed on the other surface via the insulating layer 31, the covered signal conductor 50 is provided on the ground layer 41, and the periphery of the covered signal conductor 50 is covered with a conductor layer. To form a coaxial line having a coaxial structure, thereby forming a signal wiring layer. Further, when forming the coaxial line and the wiring layer, a connecting portion for electrically connecting the signal conductor 51 of the coaxial line and the wiring layer or the signal conductors 51 is provided.
This has a coaxial structure in which the conductor layers 44 and 48 of the coaxial lines are electrically connected to the ground layer 41, thereby preventing noise generated between adjacent signal wiring layers in the high-density multilayer wiring circuit board. be able to.
[0011]
In the multilayer wiring circuit board with a built-in coaxial cable according to the present invention, when forming an opening in the insulating layer on the covered signal conductor 50 by laser processing or the like, the signal conductor 51 of the covered signal conductor is partially exposed. A conductor is buried by plating or filling to form a filled via, and a connection portion for electrically connecting the signal conductor of the coaxial line and the wiring layer or the signal conductor of the coaxial line is provided, and the coaxial line (signal wiring layer) is provided. In a multi-layer structure, the electrical connection between the signal conductors or the electrical connection between the coaxial signal conductor and the wiring layer is facilitated, increasing the degree of freedom in the wiring layer design and providing excellent cross-connection reliability. It is possible to obtain a multilayer wiring circuit board with a built-in high-density coaxial line without any talk.
[0012]
The multi-layer printed circuit board with a built-in coaxial line of the present invention according to the third aspect of the present invention is configured such that the coaxial lines provided in the printed circuit board have the same length, so that the coaxial line (signal The signal propagation speeds of the wiring layers are the same to prevent a phase shift between signals.
[0013]
Hereinafter, a method of manufacturing the multilayer wiring circuit board with a built-in coaxial line of the present invention will be described.
FIGS. 4 and 5 (a) to 5 (j) show one embodiment of a method of manufacturing the coaxial-line built-in multilayer wiring circuit board shown in FIGS. 1 (a) and 1 (b) in the order of steps.
First, insulation is performed by attaching a resin film or the like to both sides of a printed circuit board (base substrate) 10 (see FIG. 4A) in which the wiring layers 21a and 21b are formed on both sides of the insulating base material 11. A layer 31 is formed, and further, a copper foil or the like is bonded thereto, and a ground layer 41 is formed on one surface via the insulating layer 31 and a power supply layer 42 is formed on the other surface via the insulating layer 31. Is patterned by photo-etching or the like to form an opening, and an insulating material such as resin is buried by screen printing or the like, and the surface is polished to form a buried layer 41a (see FIG. 4B).
The buried layer 41a is used to form a region that is electrically insulated from the ground layer 41 when a connection portion is formed in this region, and the covered signal conductor 50 is always disposed on the buried layer 41a. So that
[0014]
Next, a heat-curable adhesive film is attached on the ground layer 41 and the buried layer 41a to form the adhesive layer 32 (see FIG. 4C).
Next, a covered signal conductor 50 in which a signal conductor 51 made of a copper wire is covered with an insulating layer 52 is disposed at a predetermined position on the adhesive layer 32, and heated at a predetermined temperature, so that the covered signal conductor 50 is attached to the adhesive layer 32. Is fixed on the ground layer 41 (see FIG. 4D).
[0015]
Next, the adhesive layer 32 other than the portion where the covered signal conductor 50 is fixed on the ground layer 41 is removed by etching or the like, and the covered signal conductor 50 is fixed to the ground layer 41 by the processed adhesive layer 32a. You. Further, a thin film conductor layer (not particularly shown) having a thickness of about 0.5 μm is formed around the covered signal conductor 50 and on the ground layer 41 by electroless plating or the like. Further, a photosensitive layer is formed on the ground layer 41 on which the thin film conductor layer is formed and the covering signal conductor 50, and patterning processing such as pattern exposure and development is performed, so that a predetermined position on the buried layer 41a and the covering signal conductor 50 is formed. A resist pattern 37 for forming a connection portion is formed (see FIG. 4E).
[0016]
Next, electrolytic copper plating is performed using the thin film conductor layer as a cathode to form the conductor layer 44 on the coaxial wire 60 having the conductor layer 44 of a predetermined thickness formed around the covered signal conductor 50 and the ground layer 41 (FIG. 5 (f)).
Here, a thickness of the conductor layer 44 of 10 μm or more is sufficient as an effect of preventing noise. In addition, since the conductor layer 44 is also formed on the ground layer 41, the coaxial line 60 electrically connected to the ground layer 41 can be obtained.
[0017]
Next, the resist pattern 37 is stripped with a dedicated stripping solution, the thin film conductor layer under the resist pattern 37 is removed by soft etching, and a resin solution is applied on the conductor layer 44, the coaxial line 60 and the covered signal conductor 50. Alternatively, the insulating layer 33 is formed by a method such as bonding a resin film (see FIG. 5G).
Next, a predetermined position of the insulating layer 33 on the covered signal conductor 50 is drilled by laser processing or the like to form an opening 33a that partially exposes the signal conductor 51 of the covered signal conductor 50 (FIG. 5). (H)).
[0018]
Next, a thin film conductor layer (not particularly shown) having a thickness of about 0.5 μm is formed on the insulating layer 33 and in the opening 33a by electroless copper plating or the like, and electrolytic copper plating is performed using the thin film conductor layer as a cathode. Then, a conductor layer 45 having a predetermined thickness is formed on the insulating layer 33, a filled via 45c is formed in the opening 33a, and a connection portion where the conductor layer 45 and the coaxial signal line 51 are electrically connected by the filled via 45c. (See FIG. 5 (i)).
[0019]
Next, the conductor layer 45 on the insulating layer 33 is patterned by photo-etching to form a wiring layer 45a and a connection portion 45b, and the signal conductor 51 of the coaxial line 60 and the wiring layer 45a are electrically connected by a filled via 45c. The multilayer wiring circuit board 100 with a built-in coaxial line having the connected connection portion 45b can be obtained (see FIG. 5 (j)).
[0020]
FIGS. 6 and 7A to 7J show another embodiment of the method of manufacturing the multi-layer wiring circuit board with a built-in coaxial cable shown in FIGS. 2A and 2B in the order of steps.
First, a resin film or the like is attached to both sides of a wiring circuit board (base substrate) 10 (see FIG. 6A) in which the wiring layers 21a and 21b are formed on both sides of the insulating base material 11. A layer 31 is formed, and further, a copper foil or the like is bonded thereto, and a ground layer 41 is formed on one surface via the insulating layer 31 and a power supply layer 42 is formed on the other surface via the insulating layer 31. A ring-shaped opening 41b is formed by photo-etching or the like, and a metal layer 41c that is electrically insulated from the ground layer 41 is formed (see FIG. 6B).
[0021]
Hereinafter, processing is performed in the same steps as in the method of manufacturing a multilayer wiring circuit board with a built-in coaxial line according to claim 4, and a filled via is formed on the metal layer 41c which is electrically insulated from the coaxial line 60, the wiring layer 45a and the ground layer 41. A connection portion 45b made of the coaxial line 45c is formed, and the coaxial line built-in multilayer wiring circuit board 200 having the connection portion 45b in which the signal conductor 51 of the coaxial line 60 and the wiring layer 45a are electrically connected by the filled via 45c can be obtained. (See FIG. 7 (j)).
In this method, a metal layer 41b that is electrically insulated from the ground layer 41 is provided instead of the buried layer 41 of the ground layer 41 in the above-described manufacturing method, and the insulating layer 33 formed on the covered signal conductor 50 is provided. Is formed by laser processing or the like to form an opening 33a (see FIG. 7 (h)), the metal layer 41c functions as a stopper layer, and a wide range of processing conditions during laser processing can be set. Etc.
[0022]
FIGS. 8, 9 and 10 (a) to 10 (k) show an embodiment of the method of manufacturing the multilayer wiring circuit board with a built-in coaxial line shown in FIGS. 3 (a) and 3 (b) in the order of steps. Show.
First, a resin film or the like is attached to both sides of a printed circuit board (base substrate) 10 (see FIG. 8A) in which the wiring layer 21a and the wiring layer 21b are formed on both sides of the insulating base material 11. A layer 31 is formed, and further, a copper foil or the like is bonded thereto, and a ground layer 41 is formed on one surface via the insulating layer 31 and a power supply layer 42 is formed on the other surface via the insulating layer 31. The opening is formed by patterning the film with an etching process or the like, and an insulating material such as a resin is buried by screen printing or the like, and the surface is polished to form a buried layer 41a (see FIG. 8B).
[0023]
Next, a photosensitive layer is formed by a method such as laminating a dry film on the ground layer 41 and the buried layer 41a, and a series of patterning processes such as pattern exposure and development are performed to form a resist pattern 34 having a predetermined shape. (See FIG. 8 (c)). The resist pattern 34 serves as a plating mask for forming a groove for arranging the conductor pattern layer and the covering signal line in a semi-additive process.
[0024]
Next, a thin film conductor layer (not shown) having a thickness of about 0.5 μm is formed on the resist pattern 34 and the ground layer 41 by electroless plating or the like, and electrolytic copper plating is performed using the thin film conductor layer as a cathode. A conductor pattern layer 46 having a predetermined thickness is formed between the patterns 34 (see FIG. 8D).
Next, the resist pattern 34 is peeled off with a dedicated peeling liquid, and a groove 61 having a predetermined shape for arranging the covering signal conductor 50 is formed between the conductor pattern layers 46 (see FIG. 8E).
[0025]
Next, a covering signal conductor 50 having a thermoplastic resin layer formed on the outer peripheral portion is disposed in the groove 61, and is heated at a predetermined temperature to fix the covering signal conductor 50 in the groove 61, and the covering signal conductor 50 is fixed. A thin conductor layer (not shown) having a thickness of about 0.3 μm is formed around the conductor 50 and on the ground layer by electroless plating or the like. Further, a photosensitive resin solution is applied on the covered signal conductor 50 and the conductor pattern layer 46, dried to form a photosensitive layer, and subjected to a patterning process such as pattern exposure and development to form a covered signal conductor on the buried layer 41a. A resist pattern 38 for forming a connection portion at a predetermined position 50 is formed (see FIG. 9F).
[0026]
Next, electrolytic copper plating is performed using the thin film conductor layer as a cathode to form a coaxial wire 70 in which the periphery of the covered signal conductor 50 is embedded with a conductor made of copper, and a conductor layer 47 is formed on the conductor pattern layer 46 (FIG. 9 (g)).
Here, if the film thickness of the conductor layer 47 is 10 μm or more, the effect of preventing noise is sufficient.
[0027]
Next, the resist pattern 38 is peeled off with a dedicated peeling liquid, the thin film conductor layer under the resist pattern 38 is removed by soft etching, and a resin solution is applied on the conductor layer 47, the coaxial wire 70 and the covered signal conductor 50. Alternatively, the insulating layer 35 is formed by a method such as bonding a resin film (see FIG. 9H).
Next, a predetermined position of the insulating layer 35 on the covered signal conductor 50 is drilled by laser processing or the like to form an opening 35a where the signal conductor 51 of the covered signal conductor 50 is partially exposed (FIG. 9 ( i)).
[0028]
Next, a thin film conductor layer (not particularly shown) having a thickness of about 0.5 μm is formed on the insulating layer 35 and in the opening 35 a by electroless copper plating or the like, and electrolytic copper plating is performed using the thin film conductor layer as a cathode. Then, the conductor layer 48 having a predetermined thickness is formed on the insulating layer 35, and a filled via 48c is formed in the opening 35a, so that the conductor layer 48 and the coaxial signal line 51 are electrically connected by the filled via 48c. A part is formed (see FIG. 10 (j)).
[0029]
Next, the conductor layer 45 is patterned by photo-etching or the like to form a wiring layer 48a and a connection portion 48b, and the connection portion where the signal conductor 51 of the coaxial line 70 and the wiring layer 48a are electrically connected by a filled via 48c. Thus, a coaxial line built-in multilayer wiring circuit board 300 having 48b can be obtained (see FIG. 10 (k)).
[0030]
【Example】
Hereinafter, the present invention will be described in detail with reference to examples.
<Example 1>
First, a conductive layer is formed by laminating a 12 μm thick copper foil on both sides of an insulating base material 11 made of a 50 μm polyimide film, and the conductive layer is patterned to form a wiring layer 21a and a wiring layer 21b. A substrate (base substrate) 10 was produced (see FIG. 4A).
[0031]
Next, copper foil with a resin film for build-up is attached to both sides of the printed circuit board (base substrate) 10 with a laminator, heated and cured to form an insulating layer 31 and a conductor layer, and then subjected to patterning processing. A ground layer 41 is formed on one surface of the substrate (base substrate) 10 via an insulating layer 31 and a power supply layer 41 is formed on the other surface via the insulating layer 31. A predetermined position of the ground layer 41 is formed by photo-etching. Then, an opening was formed, an insulating material such as a resin was embedded by screen printing, and the surface was polished to form an embedded layer 41a (see FIG. 4B).
[0032]
Next, a thermosetting epoxy-based double-sided adhesive film was laminated on the ground layer 41 and the buried layer 41a to form an adhesive layer 32 (see FIG. 4C). Next, a covered signal conductor 50 covered with a 10 μm epoxy insulating layer 52 is disposed on a signal conductor 51 made of a 30 μm core wire (copper) at a predetermined position on the adhesive layer 32, and is placed in an oven at 120 ° C. for 45 minutes. By heating, the covered signal conductor 50 was fixed on the ground layer 41 (see FIG. 4D).
[0033]
Next, the adhesive layer 32 excluding the portion where the covering signal conductor 50 is fixed on the ground layer 41 is treated with an alkaline etching solution (permanganic acid 60 g / l, sodium hydroxide 35 g / l) heated to 70 ° C. , Etching and the like. Further, a 0.5 μm thick thin-film conductor layer (not particularly shown) is formed around the covered signal conductor 50 and on the ground layer by electroless plating or the like, and the ground layer 41 on which the thin-film conductor layer is formed and the covered signal conductor are formed. A resist pattern is formed on the buried layer 41a by forming a photosensitive layer by applying a resist thereon, performing patterning processing such as pattern exposure and development, and forming a connection portion at a predetermined position on the covered signal conductor 50 on the buried layer 41a. 37 was formed (see FIG. 4E).
[0034]
Next, electrolytic copper plating is performed using the thin-film conductor layer as a cathode to form a 12 μm-thick conductor layer 44 on the coaxial line 60 and the ground layer 41 in which the 12 μm-thick conductor layer 44 is formed around the covered signal conductor 50. (See FIG. 5 (f)).
[0035]
Next, the resist pattern 37 was removed with a 10% sodium hydroxide solution, and the thin film conductor layer under the resist pattern 37 was dissolved and removed with an etching solution containing a 200 g / l ammonium persulfate solution. Further, an insulating sheet (ABF-50: made of Ajinomoto) having a thickness of 50 μm is laminated on the conductor layer 44, the coaxial line 60 and the covered signal conductor 50 with a vacuum laminator at 140 ° C., heated and cured at 170 ° C. for 30 minutes. An insulating layer 33 was formed (see FIG. 5G).
Next, a predetermined position of the insulating layer 33 on the covered signal conductor 50 is perforated by using a UV-YAG laser processing machine (manufactured by Mitsubishi Electric Corporation), and a 50 μmφ part of the signal conductor 51 of the covered signal conductor 50 is partially exposed. An opening 33a was formed (see FIG. 5 (h)).
[0036]
Next, a 0.5 μm-thick thin-film conductor layer (not particularly shown) is formed on the insulating layer 33 and in the opening 33 a by electroless copper plating, and electrolytic copper plating is performed using the thin-film conductor layer as a cathode. A conductive layer 45 having a thickness of 12 μm is formed on the insulating layer 33 and a filled via 45c is formed in the opening 33a to form a connection portion where the conductive layer 45 and the coaxial signal line 51 are electrically connected by the filled via 45c. (See FIG. 5 (i)).
[0037]
Next, a photosensitive dry film (RY3215: manufactured by Hitachi Chemical Co., Ltd.) having a thickness of 15 μm is attached on the conductor layer 45 with a laminator at 110 ° C. to form a photosensitive layer. The solution is spray-developed to form a resist pattern. Using the resist pattern as a mask, the conductor layer 45 is etched with a ferric chloride solution to form a wiring layer 45a and a connection portion 45b. The multilayer wiring circuit board 100 with a built-in coaxial line having a connection portion 45b where the wiring layer 45a and the wiring layer 45a are electrically connected by the filled via 45c was obtained (see FIG. 5 (j)).
[0038]
<Example 2>
First, a conductive layer is formed by laminating a 12 μm thick copper foil on both sides of an insulating base material 11 made of a 50 μm polyimide film, and the conductive layer is patterned to form a wiring layer 21a and a wiring layer 21b. A substrate (base substrate) 10 was produced (see FIG. 6A).
[0039]
Next, copper foil with a resin film for build-up is attached to both sides of the printed circuit board (base substrate) 10 with a laminator, heated and cured to form an insulating layer 31 and a conductor layer, and then subjected to patterning processing. A ground layer 41 is formed on one surface of the substrate (base substrate) 10 via an insulating layer 31 and a power supply layer 41 is formed on the other surface via the insulating layer 31. A predetermined position of the ground layer 41 is formed by photo-etching. Then, a ring-shaped opening 41b was formed, and a metal layer 41c electrically insulated from the ground layer 41 was formed (see FIG. 6B).
[0040]
Hereinafter, in the same process as in the first embodiment, the connection portion 45b is formed on the metal layer 41c electrically insulated from the coaxial line 60, the wiring layer 45a, and the ground layer 41, and the signal line 51 of the coaxial line 60 is connected to the wiring. A multilayer wiring circuit board 200 with a built-in coaxial line having a connection portion 45b in which the layer 45a was electrically connected by the filled via 45c was obtained (see FIG. 7 (j)).
[0041]
<Example 3>
First, a wiring circuit in which a copper layer having a thickness of 12 μm is laminated on both surfaces of an insulating substrate 11 made of a 50 μm polyimide film to form a conductor layer, and the conductor layer is patterned to form a wiring layer 21a and a wiring layer 21b. A substrate (base substrate) 10 was produced (see FIG. 8A).
[0042]
Next, copper foil with a resin film for build-up is attached to both sides of the printed circuit board (base substrate) 10 with a laminator, heated and cured to form an insulating layer 31 and a conductor layer, and patterning is performed. A ground layer 41 is formed on one surface of the substrate (base substrate) 10 via an insulating layer 31 and a power supply layer 41 is formed on the other surface via the insulating layer 31. A predetermined position of the ground layer 41 is formed by photo-etching. Then, an opening was formed, and an insulating material such as a resin was embedded by screen printing, and the surface was polished to form an embedded layer 41a (see FIG. 8B).
[0043]
Next, a photosensitive dry film (RY3215: manufactured by Hitachi Chemical) is laminated on the ground layer 41 and the buried layer 41a to form a photosensitive layer, and a series of patterning processes such as pattern exposure and development are performed. Then, a resist pattern 34 having a predetermined shape was formed (see FIG. 8C).
[0044]
Next, a 0.5 μm thick thin-film conductor layer (not particularly shown) is formed on the resist pattern 34 and the ground layer 41 by electroless plating or the like, and electrolytic copper plating is performed using the thin-film conductor layer as a cathode. A conductor pattern layer 46 having a thickness of 20 μm was formed between the conductor patterns 34 (see FIG. 8D).
Next, the resist pattern 34 was stripped with a 10% sodium hydroxide solution to form a groove 61 having a predetermined shape between the conductor pattern layers 46 for disposing the covering signal conductor. (See FIG. 8E).
[0045]
Next, a covered signal conductor 50 in which a signal conductor 51 made of a 30 μm core wire (copper) is covered with a 10 μm epoxy insulating layer 52 in a groove 61 and a thermoplastic resin layer is formed on an outer peripheral portion is provided. Then, it was heated and temporarily bonded to the ground layer 41 in the groove 61, and heated in an oven at 120 ° C. for 45 minutes to fix the covered signal conductor 50 on the ground layer 41. Further, a 0.5 μm-thick thin-film conductor layer (not particularly shown) is formed around the covered signal conductor 50 and on the ground layer by electroless copper plating, and a 25 μm-thick conductor layer is formed on the covered signal conductor 50 and the conductor pattern layer 46. A photosensitive dry film (RY3215: manufactured by Hitachi Chemical Co., Ltd.) is laminated to form a photosensitive layer, and a series of patterning processes such as pattern exposure and development are performed to form a covering signal in which the thin film conductor layer on the buried layer 41a is formed. A resist pattern 38 for forming a connection portion at a predetermined position of the conductive wire 50 was formed (see FIG. 9F).
[0046]
Next, electrolytic copper plating is performed using the thin film conductor layer as a cathode, and a 12 μm thick conductor layer 47 is formed on the coaxial wire 70 and the ground layer 41 in which the periphery of the covered signal conductor 50 in the groove 61 is embedded with a conductor made of copper. It was formed (see FIG. 9 (g)).
[0047]
Next, the resist pattern 38 was removed with a 10% sodium hydroxide solution, and the thin film conductor layer under the resist pattern 38 was dissolved and removed with an etching solution containing a 200 g / l ammonium persulfate solution. Further, an insulating sheet (ABF-50: made of Ajinomoto) having a thickness of 50 μm is adhered on the conductor layer 47, the coaxial line 70 and the covered signal conductor 50 with a vacuum laminator at 140 ° C. and heated at 170 ° C. for 30 minutes to form an insulating layer. 35 (see FIG. 9H).
Next, a predetermined position of the insulating layer 35 on the covered signal conductor 50 was laser-drilled to form an opening 35a of 50 μmφ where the signal conductor 51 of the covered signal conductor 50 was partially exposed (FIG. 9). (See (i)).
[0048]
Next, a 0.5 μm-thick thin-film conductor layer (not particularly shown) is formed on the insulating layer 35 and in the opening 35 a by electroless copper plating, and electrolytic copper plating is performed using the thin-film conductor layer as a cathode. A conductor layer 48 having a thickness of 12 μm is formed on the insulating layer 35, and a filled via 48 c is formed in the opening 35 a to form a connection portion where the conductor layer 48 and the coaxial signal line 51 are electrically connected by the filled via 48 c. It was formed (see FIG. 10 (j)).
[0049]
Next, a photosensitive dry film (RY3215: manufactured by Hitachi Chemical Co., Ltd.) having a thickness of 15 μm is attached on the conductor layer 48 with a laminator heated to 110 ° C. to form a photosensitive layer. A sodium carbonate solution is spray-developed to form a resist pattern. Using the resist pattern as a mask, the conductor layer 48 is etched with a ferric chloride solution to form a wiring layer 48a and a connection portion 48b. A coaxial-line built-in multilayer wiring circuit board 300 having a connection portion 48b in which the signal conductor 51 and the wiring layer 48a are electrically connected by the filled via 48c was obtained (see FIG. 10 (k)).
[0050]
As a result of measuring the crosstalk noise between the coaxial lines (signal wiring layers) of the multilayer wiring circuit board with a built-in coaxial line obtained in the above embodiment, the crosstalk noise can be reduced to 1/10 of the conventional crosstalk noise. The crosstalk noise reduction effect of the multilayer wiring circuit board with a built-in coaxial line was confirmed.
[0051]
【The invention's effect】
The multi-layer wiring circuit board with a built-in coaxial line of the present invention is configured such that a covered signal conductor is disposed on a ground layer, and a coaxial line having a coaxial structure is formed by covering with a conductor layer electrically connected to the ground layer. Therefore, noise generated between adjacent signal wiring layers in a high-density multilayer wiring circuit board can be prevented.
In addition, since a connection portion for electrically connecting the signal conductor and the wiring layer or the signal conductor is provided at a predetermined position of the coaxial line, the electric connection between the signal conductors when the coaxial line has a multilayer structure is provided. In addition, the electrical connection between the signal conductor of the coaxial cable and the wiring layer is facilitated, the degree of freedom in designing the wiring layer is increased, and a high-density coaxial-line-incorporated multilayer wiring circuit board with excellent cross-talk and excellent connection reliability is obtained. be able to.
[Brief description of the drawings]
FIG. 1A is a partial perspective view showing a configuration of an embodiment of a multilayer wiring circuit board with a built-in coaxial line of the present invention. (B) is a schematic configuration partial cross-sectional view of the partial perspective view of (a) cut along line AA '.
FIG. 2 (a) is a partial perspective view showing a configuration of another embodiment of a multilayer wiring circuit board with a built-in coaxial line of the present invention. (B) is a schematic configuration partial cross-sectional view of the partial perspective view of (a) cut along line AA '.
FIG. 3 (a) is a partial perspective view showing the configuration of another embodiment of the multilayer wiring circuit board with a built-in coaxial line of the present invention. (B) is a schematic configuration partial cross-sectional view of the partial perspective view of (a) cut along line AA '.
FIGS. 4A to 4E are partial cross-sectional views schematically showing a part of a manufacturing process of an embodiment of a method for manufacturing a multilayer wiring circuit board with a built-in coaxial cable according to claim 4;
FIGS. 5 (f) to (j) are partial cross-sectional views schematically showing a part of the manufacturing process of an embodiment of the method for manufacturing a multilayer wiring circuit board with a built-in coaxial cable according to claim 4;
FIGS. 6A to 6E are partial cross-sectional views schematically showing a part of the manufacturing process of another embodiment of the method for manufacturing a multilayer wiring circuit board with a built-in coaxial cable according to claim 4;
FIGS. 7 (f) to 7 (j) are partial cross-sectional views schematically showing a part of the manufacturing process of another embodiment of the method for manufacturing a coaxial-line built-in multilayer wiring circuit board according to claim 4;
FIGS. 8A to 8E are partial cross-sectional views schematically showing a part of the manufacturing process of an embodiment of the method for manufacturing a multilayer wiring circuit board with a built-in coaxial cable according to claim 5;
9 (f) to 9 (i) are partial cross-sectional views schematically showing a part of the manufacturing process of an embodiment of the method for manufacturing a coaxial-line built-in multilayer wiring circuit board according to claim 5;
10 (j) to 10 (k) are partial cross-sectional views schematically showing a part of the manufacturing process of an embodiment of the method for manufacturing a multilayer wiring circuit board with a built-in coaxial cable according to claim 5. FIG.
[Explanation of symbols]
10 ... Wiring circuit board (base board)
11 ... insulating base material
21a, 21b ... wiring layer
31, 33, 35 ... insulating layer
32 ... adhesive layer
32a .... Adhesive layer after processing
33a, 35a ... hole opening
34, 37, 38 ... resist pattern
41 ... Ground layer
41a: embedded layer
41b: Ring-shaped opening
41c: Metal layer
42 Power supply layer
44, 45, 48 ... conductor layer
45a, 48a ... wiring layer
45b, 48b ... connection part
45c, 48c ... filled via
46: Conductive pattern layer
50 ... Coated signal conductor
51 ... signal conductor
52 ... insulating layer
60, 70 ... coaxial line
61 ... groove
100, 200, 300 ... Multilayer wiring circuit board with built-in coaxial

Claims (5)

In a multilayer wiring circuit board having a ground layer, a power supply layer, and at least one or more wiring layers formed on an insulating base material, a covered signal conductor in which a signal conductor is covered with an insulating layer on the ground layer. Disposed, the periphery of the insulating layer of the covered signal conductor is covered with a conductor layer to form a coaxial cable of a coaxial cable structure in which the conductor layer is electrically connected to and embedded in the ground layer. A multilayer wiring circuit board with a built-in coaxial line, wherein a connecting portion for electrically connecting the signal conductor of the coaxial line and the wiring layer or the signal conductor of the coaxial line is formed. The connection portion is formed by perforating the insulating layer on the covered signal conductor to form an opening where a part of the signal conductor of the covered signal conductor is exposed, and filling or plating the opening. The multi-layer wiring with a built-in coaxial line according to claim 1, wherein a conductor is formed by a method such as the above, and the conductive line of the coaxial line and the wiring layer or the conductive line of the coaxial line are electrically connected to each other. Circuit board. 3. The multilayer wiring circuit board with a built-in coaxial line according to claim 1, wherein when a plurality of the coaxial lines are formed, the line lengths of the coaxial lines are set to the same length. A method for manufacturing a multilayer wiring circuit board with a built-in coaxial line, comprising at least the following steps.
(A) On one surface of a printed circuit board (base substrate) (10) in which wiring layers (21a and 21b) are formed on both surfaces of an insulating base material (11), a ground layer (41) via an insulating layer (31). ) Forms a hole by photoetching a predetermined position of the ground layer (41) of the printed circuit board on which the power supply layer (42) is formed on the other surface via the insulating layer (31). Forming an embedded layer (41a) by embedding an insulating material such as
(B) forming an adhesive layer (32) having a predetermined thickness on the ground layer (41) and the buried layer (41a);
(C) A step of disposing a covered signal conductor (50) in which the periphery of the signal conductor (51) is covered with an insulating layer (52) on the adhesive layer (32).
(D) removing the adhesive layer (32) except for the portion where the covered signal conductor (50) is fixed.
(E) forming a thin-film conductor layer around the insulating layer (52) of the covered signal conductor (50) and on the ground layer (41);
(F) forming a resist pattern (37) for forming a connection portion at a predetermined position of the covered signal conductor (50) on which the thin film conductor layer is formed;
(G) Electrolytic copper plating is performed using the thin film conductor layer as a cathode, a conductor layer (44) having a predetermined thickness is formed around the insulating layer (52) of the covered signal conductor (50), and the coaxial line (60) is grounded. Forming a conductor layer (44) on the layer (41);
(H) The resist pattern (37) is peeled off with a dedicated peeling liquid, and a predetermined thickness of an insulating layer (50) is formed on the coaxial line (70), the covered signal conductor (50) on which the thin film conductor layer is formed, and the conductor layer (44). Forming step 33).
(I) forming a hole (33a) in which the signal conductor (51) of the covered signal conductor (50) is partially exposed by perforating the insulating layer (33);
(J) A thin-film conductor layer is formed on the insulating layer (33) and in the opening (33a), electrolytic copper plating is performed using the thin-film conductor layer as a cathode, and a conductor layer having a predetermined thickness is formed on the insulating layer (33). (45) forming a filled via (45c) in the opening (33a);
(K) a step of patterning the conductor layer (45) on the insulating layer (33) to form a wiring layer (45a) and a connection portion (45b). A method for manufacturing a multilayer wiring circuit board with a built-in coaxial line, comprising at least the following steps.
(A) On one surface of a printed circuit board (base substrate) (10) in which wiring layers (21a and 21b) are formed on both surfaces of an insulating base material (11), a ground layer (41) via an insulating layer (31). ) Forms a hole by photoetching a predetermined position of the ground layer (41) of the printed circuit board on which the power supply layer (42) is formed on the other surface via the insulating layer (31). Forming a buried layer (41a) by embedding with an insulating material such as
(B) forming a resist pattern (34) having a predetermined shape at a predetermined position on the ground layer (41);
(C) A thin-film conductor layer is formed on the resist pattern (34) and the ground layer (41), and electrolytic copper plating is performed using the resist pattern (38) as a plating mask to form a conductor pattern layer (46) having a predetermined thickness. Process.
(D) a step of stripping the resist pattern (38) with a dedicated stripper to form a groove (61) having a predetermined shape between the conductor pattern layers (46).
(E) disposing a covered signal conductor (50) in the groove (61), forming a thin film conductor layer on an insulating layer (52) around the covered signal conductor (50), and forming a predetermined conductor on the covered signal conductor (50); Forming a resist pattern (38) for forming a connection portion at a position;
(F) Electrolytic copper plating is performed using the thin film conductor layer as a cathode, and a coaxial wire (70) in which the periphery of the covered signal conductor (50) is filled with a conductor is placed on the conductor pattern layer (46) by a conductor layer having a predetermined thickness. A step of forming (47).
(G) Stripping the resist pattern (38) with a dedicated stripper to form an insulating layer (35) having a predetermined thickness on the covered signal conductor (50) on which the thin film conductor layer is formed and the conductor layer (47). Process.
(H) forming a hole (35a) in which a part of the signal conductor (51) of the covered signal conductor (50) is exposed by boring the insulating layer (35);
(I) A thin film conductor layer is formed on the insulating layer (35) and in the opening (35a), electrolytic copper plating is performed using the thin film conductor layer as a cathode, and the conductor layer (48) is formed on the insulating layer (35). Forming a filled via (48c) in the opening (35a).
(J) a step of patterning the conductor layer (48) on the insulating layer (35) to form a wiring layer (48a) and a connecting portion (48b).

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