JPH06310864A - Manufacture of multiwired board - Google Patents

Abstract

PURPOSE:To prevent generation of floating and movement of an insulated wire, by a method wherein light-setting type resin is applied to a not-yet cured state resin layer of the outermost layer of the insulated wire, and a board is heated after the light-setting type resin layer of the insulated wire is completely cured by irradiating the front surface of a board surface after wiring with light. CONSTITUTION:An insulated wire having a light-setting type resin layer in a not-yet cured state outside the insulating layer is used as an insulated wire. After the insulated wire is wired on a board, the front surface of the wired board surface is irradiated with light, and the light-setting type resin layer of the insulated wire is completely cured. Further the board is heated and a thermosetting type adhesive resin layer is cured. As the core conductor, copper and copper alloy can be used. As the lead wire plated with gold, silver, tin, etc., or an aluminum wire or an aluminum alloy wire or a twisted wire of them also can be used. As the insulative material for coating, polyimide resin, polyamid-imide resin, fluororesin, polyester resin, etc., can be used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a multi-wire wiring board using insulated wires for a required wiring pattern.

[0002]

2. Description of the Related Art In a multi-wire wiring board, a thermosetting adhesive resin layer is formed on an insulating substrate on which inner layer circuits such as power supply and ground are formed, and at the same time an insulated electric wire is laid by a numerical control wiring machine. After the adhesive resin layer is bonded (hereinafter referred to as wiring) by heating and melting the adhesive resin layer by ultrasonic vibration, it is heated (hereinafter referred to as precure) to increase the viscosity of the adhesive resin layer, and further. In order to remove bubbles generated in the vicinity of the insulated wire and to embed the insulated wire in the adhesive resin layer, heating / pressurization (hereinafter referred to as flash press) is performed. After that, prepregs are arranged on both sides of the insulating substrate, laminated with a press or the like to fix the insulated electric wire, a hole is formed across the insulated electric wire, and a metal layer is formed by plating in the hole to manufacture. As the adhesive resin layer, a phenoxy adhesive sheet described in JP-A 1-166089 is used, and as an insulated wire (hereinafter referred to as a wire), copper having a diameter of 0.06 to 0.16 mm is used. After the wire is coated with a polyimide resin, a phenoxy resin is applied as an adhesive layer in order to increase the adhesive strength of the wire.

With the increasing density of electronic devices, it has become necessary to improve the wiring density and hole density of multi-wire wiring boards more than ever before. That is, in the conventional multi-wire wiring board, the diameter is 1.0 mm on the grid of 2.54 mm.
There was a through hole, but now it is 1.27mm.
It has become necessary to provide through holes with a diameter of about 0.3 mm on the grid. Therefore, the conventional diameter 1.
In the case of a 0 mm through hole, there was a margin of wire positioning accuracy of 0.45 mm with respect to the through hole as shown in FIG. 3, but when the through hole diameter became 0.3 mm,
As shown in FIG. 4, it is necessary to suppress the positional accuracy of the wire to 0.1 mm or less, and it is necessary to prevent the wire from moving in the process after wiring. In order to meet such a demand, Japanese Patent Laid-Open No. 2-169364 proposes a method of gradually reducing the pressure during the flash press to reduce the movement of the wire during the flash press. Japanese Patent Laid-Open No. 3-79949 proposes a method of using a dummy plate to reduce the movement of the wire during flash press.

[0004]

However, wire movement occurs not only in the flash press step but also in the precure step. That is, as shown in FIG. 1, the wire may be bent and laid (hereinafter, referred to as a corner) before the through hole. In this case, the wire has a polyimide insulating coating layer, and thus the wire is not completely plastically deformed. However, the residual stress, that is, the restoring force acts on the wire corner portion, and the wire cannot be held and moved by the adhesive resin layer at normal temperature, but temporarily when the adhesive resin layer is heated by the precure. Since the viscosity of the wire suddenly decreases, the holding force of the adhesive resin layer against the wire decreases, and the wire's restoring force cannot be resisted, and the wire may move 0.1 mm or more as shown in FIG. Yes,
There is a problem that some wires are not connected to the through holes. As a method of reducing the movement of the wire due to this precure, a method of increasing the melt viscosity of the adhesive resin layer can be considered, but the adhesive strength with the wire during wiring is reduced, and wiring becomes difficult. The present invention provides a method for manufacturing a multi-wire wiring board that can reduce the movement of wires after wiring without lowering the wiring property.

[0005]

A method of manufacturing a multi-wire wiring board according to the present invention comprises providing a thermosetting adhesive resin layer on a substrate or an insulating substrate on which a conductor circuit is formed in advance, and then applying an insulated wire to the adhesive resin layer. In the method for producing a multi-wire wiring board, in which a wiring pattern is formed on the conductive resin layer, a hole is formed across the insulated electric wire, and the inner wall of the hole is metallized, the insulated electric wire is not formed on the outside of the insulating layer. Using an insulated electric wire having a cured photocurable resin layer, after laying the insulated electric wire,
The entire surface of the wired substrate is irradiated with light to completely cure the photocurable resin layer of the insulated wire, and the substrate is heated to cure the thermosetting adhesive resin layer. It is characterized by

In the insulated wire used in the present invention, copper or a copper alloy can be used as the conductor of the core wire, and a copper wire plated with gold, silver, tin or the like, an aluminum wire, an aluminum alloy wire, or these wires is used. A twisted product can also be used.

As the insulating material for coating, polyimide resin, polyamide-imide resin, fluororesin, polyester resin or the like can be used.

The photocurable resin applied to the outermost layer of the insulated wire is a composition in which an epoxy resin or an epoxy compound is cured with a cationic polymerization type photoinitiator, or an acrylate epoxy resin or an acrylate compound is radical polymerization type photoinitiator. It is possible to use a composition which is cured with an agent, and further, a flexible agent such as polyvinyl butyral for improving the wireability and flexibility, and a phenoxy resin for improving the film forming property. Polymeric materials can be added.
As a method for forming such a photocurable resin layer on the surface of the insulated wire, dip coating or die coating can be used.

[0009]

According to the present invention, a photo-curable resin is used for the uncured resin layer of the insulated wire which is the outermost layer, and the entire surface of the substrate after wiring is irradiated with light to provide the photo-curable resin of the insulated wire. After completely curing the resin layer, by heating the substrate,
Even if the viscosity of the thermosetting adhesive resin layer is temporarily reduced, the insulated electric wire does not float or move because the wiring shape of the insulated electric wire is retained by the cured photocurable resin layer.

[0010]

EXAMPLES Example 1 (1) φ0.08,1IMW (manufactured by Hitachi Cable, Ltd.) which is a polyimide-coated wire with a core wire diameter of 0.08 mm
In addition, a photocurable resin having the following composition was used, with a furnace length of 3 m and a furnace temperature of 270
℃, baking speed 35m / min, about 15μm after 12 bakings
It was applied to produce an insulated electric wire. Epoxy acrylate LS-51P (manufactured by the company, trade name)
・ ・ ・ ・ 40 parts by weight ・ Phenoxy resin YP-50 (product name, manufactured by the company)
・ ・ ・ ・ 10 parts by weight ・ Epoxy resin EP-828 (manufactured by Yuka Shell Epoxy Co., Ltd., product name) ・ ・ ・ 30 parts by weight ・ Epoxy resin ESB-400T (manufactured by company, product name) ・ ・ ・ ・
··· 20 parts by weight · Polyvinyl butyral # 5000A (manufactured by the company, product name) ···
・ ・ ・ 5 parts by weight ・ Cationic photopolymerization initiator UVI-6970 (manufactured by the company, trade name) ・ ・ ・ ・
5 parts by weight Photoinitiator I-651 (manufactured by the company, trade name)
6 parts by weight Palladium chloride
... 0.01 parts by weight (2) A circuit was formed on a double-sided copper-clad laminate MCL-E-168 (trade name, manufactured by Hitachi Chemical Co., Ltd.) by a usual etching method. Next, glass cloth epoxy resin prepreg GEA-168 (manufactured by Hitachi Chemical Co., Ltd., trade name)
2 pieces on each side of the board, 175 ℃, 45kgf /
The layers were integrated by heating and pressing under the conditions of cm ² and 60 minutes. (3) Next, a thermosetting adhesive sheet A having a thickness of 80 μm
S-102 (manufactured by Hitachi Chemical Co., Ltd., trade name) was placed on both sides and laminated using a hot roll laminator. (4) The insulated electric wires produced in (1) were laid one by one while applying ultrasonic heating with an NC wiring machine. (5) Following the wiring, the ultraviolet irradiation device M-2082-A
-Using R2 (Oak Seisakusho, trade name),
Both sides were irradiated with light of 3 J / cm ² to cure the photocurable resin contained in the insulated wire. (6) Precure was performed by heating at 120 ° C. for 60 minutes using a dryer. (7) Next, the substrate was subjected to flash pressing by heating and pressurizing the substrate at 130 ° C. and 20 kgf / cm ² for 20 minutes using silicon rubber as a cushioning material. (8) The adhesive sheet was cured by heating at 170 ° C. for 60 minutes using a dryer. (9) Next, glass cloth cloth epoxy resin prepreg GE
A-168 (manufactured by Hitachi Chemical Co., Ltd., trade name) was placed on each of the two surfaces of the substrate obtained in (8), 175 ° C.
A layer was formed by heating and pressing under the conditions of 45 kgf / cm ² and 60 minutes. (10) Subsequently, a polyethylene film H-5310 with adhesive (trade name, manufactured by Hitachi Chemical Co., Ltd.) as a plating mask was laminated on both sides of the substrate obtained in (9), and a 0.3 mm diameter was obtained at a necessary place. After making a hole with a drill, pretreatment such as hole cleaning was performed, and the hole was further immersed in an electroless copper plating solution. After performing 30 μm through-hole plating, the polyethylene film was peeled off to manufacture a multi-wire wiring board.

Comparative Example 1 In place of the polyimide-coated wire having the uncured photocurable resin layer as the outermost layer in (1) of Example 1, a film thickness of 15
A polyimide-coated wire HAW (trade name, manufactured by Hitachi Cable, Ltd.) with a core wire diameter of 0.08 mm having a thermosetting resin layer in the uncured state of μm as the outermost layer was used, and the step (5) was omitted. Manufactured a multi-wire wiring board in the same process as in Example 1.

As described above, the positions of the insulated electric wires laid in the multi-wire wiring boards manufactured in Example 1 and Comparative Example 1 and the connection state between the insulated wires and the through holes were investigated. As a result, in Example 1, the positional deviation amount of the wired insulated electric wire is 70.
It was less than μm, and there was no occurrence of unconnection between the through hole and the insulated wire. On the other hand, in Comparative Example 1, there was a portion where the amount of positional deviation of the wired insulated electric wire exceeded 100 μm, and disconnection between the through hole and the insulated electric wire occurred.

[0013]

As described above, according to the present invention, it is possible to improve the positional accuracy of wires without reducing the wiring property, and to provide a method of manufacturing a multi-wire wiring board excellent in high density. You can

[Brief description of drawings]

FIG. 1 is a plan view showing a positional relationship between wires and through holes according to an embodiment of the present invention.

FIG. 2 is a plan view for explaining a problem of a conventional example.

FIG. 3 is a plan view showing a positional relationship between a wire and a through hole in a conventional example.

FIG. 4 is a plan view showing a positional relationship between wires and through holes of a high-density multi-wire wiring board.

[Explanation of symbols]

1. Wire 2. Small diameter through hole 3. Through hole

Claims (1)

[Claims] 1. A thermosetting adhesive resin layer is provided on a substrate or an insulating substrate on which a conductor circuit has been formed in advance, and then an insulated wire is laid on the adhesive resin layer to form a wiring pattern, followed by insulation. In the method for producing a multi-wire wiring board in which a hole is formed across an electric wire and the inner wall of the hole is metallized, an insulated electric wire having an uncured photocurable resin layer outside the insulating layer is used as the insulated electric wire, After laying the insulated wire, the entire surface of the laid substrate is irradiated with light to completely cure the photocurable resin layer of the insulated wire, and the substrate is further heated to the thermosetting property. A method for manufacturing a multi-wire wiring board, which comprises curing the adhesive resin layer of.