JP2844832B2 - Manufacturing method of heat-resistant tape-shaped wiring material - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a heat-resistant tape-shaped wiring member which does not deteriorate even in high-temperature processing such as reflow and solder dipping.

(Prior art and problems to be solved) As an electric circuit which does not use individual single-coated electric wires, places emphasis on occupancy efficiency, simplification of connection, and the like, so-called tape electric wires and flexible electric wires are used. There is a printed wiring board (FPC).

Of these, the so-called tape electric wire is applied by applying a hot-melt adhesive to the base film, and then vertically attaching slit copper tape to the cover film with a hot-roll adhesive. And formed. Such a tape wire has the advantage that it can be manufactured inexpensively as a continuous long body, but has the drawback that it is difficult to make only a fixed shape, and the general product has low heat resistance.

In addition, FPC prints a resist material on a copper-clad substrate where a base film and copper foil are bonded together using a thermosetting adhesive, etches the copper foil, punches a B-stage adhesive coverlay, and presses it hot. And formed by thermocompression bonding. Such an FPC can be formed in an arbitrary shape and is excellent in heat resistance, but is expensive and has a drawback that the process from each material to a finished product is difficult to be converted into a continuous long line.

[Means for Solving the Problems] The present invention solves the above-mentioned problems and has a tape-like wiring excellent in heat resistance and workability similar to or higher than that in the case of manufacturing a tape electric wire. It provides a method of manufacturing a material, the feature of which is to form an electron beam cross-linkable adhesive layer made of a polyolefin resin containing a polyfunctional monomer on one surface of a heat-resistant insulating base film made of a polyimide film, Bonding a copper foil thereon, forming a resist film of an arbitrary shape on the copper foil, removing unnecessary copper foil by etching to form a circuit, and forming the circuit on the circuit with the polyfunctional monomer. By removing the terminal part from a heat-insulating coverlay film consisting of a polyimide film provided with an electron beam crosslinkable adhesive layer consisting of a polyolefin resin containing It is to cross-link the adhesive layer by irradiating electrons after the step of bonding.

(Example) FIGS. 1A to 1D are explanatory views showing the procedure of the manufacturing method of the present invention.

As shown in FIG. 1A, a heat-resistant insulating film made of a polyimide film formed by applying an electron beam crosslinkable adhesive layer (2) made of a polyolefin resin containing a polyfunctional monomer on one surface is used as a base film (1). Then, a copper foil (3) is stuck thereon and irradiated with an electron beam to produce a conductor base material. A resist film (4) is formed on this substrate in accordance with a general method of manufacturing a general-purpose FPC (b in the same figure), and then, one-sided electrical insulation is performed by a known method of removing unnecessary copper foil (3) by etching. A circuit conductor (3 ') having a coating is formed (FIG. 3C). And the base film (1)
Similarly to the above, a heat-insulating coverlay film (6) made of a polyimide film coated and formed with an electron beam crosslinkable adhesive layer (5) made of a polyolefin resin containing a polyfunctional monomer can be used without the need for terminals and the like. Then, the portion to be formed is punched into a predetermined pattern, and is continuously bonded on the circuit conductor portion (3 ') as shown in FIG.

 FIG. 2 is a perspective view of the obtained heat-resistant tape wiring member.

(Function) In the above-described production method of the present invention, both the base film and the coverlay film use conventional vinyl chloride, polyester, polyethylene, nylon, etc., and the present invention uses a polyimide film. . In addition, in the present invention, a polyfunctional resin containing 1 to 20% by weight of a hot-melt resin adhesive such as polyester, vinyl chloride, urethane, or polyolefin is used as the adhesive for the coverlay and the conductor. Using an electron beam-curable adhesive composed of monomer-containing polyolefin, coating the heat-resistant film and laminating, after lamination, cross-linking by irradiating 3 to 30 Mrad of electron beam,
Performs reliable adhesive curing in a short time. Examples of the polyfunctional monomer include trimethylpropane, trimethacrylate, triallyl isocyanurate, triallyl cyanurate, triacrylate formal, diacrylates such as ethylene glycol, pentaerythritol triacrylate, butoxyethyl acrylate, and the like. .

Conventionally, the circuit conductor part was already slit and elongated ribbon wire-shaped copper foil was longitudinally attached and integrated with the electric insulating coating.In the present invention, the circuit conductor is bonded on the base film as in the case of EPC manufacturing. While laminating 18 to 100 μm thick copper foil through the agent layer, in a series of steps, resist film printing, and continuously remove unnecessary metal foil by etching to form a circuit conductor part I have.

The tape-shaped wiring member manufactured by such a manufacturing method of the present invention has a greater degree of freedom in producing a circuit pattern as compared with a conventional so-called taped wire, and has a high degree of processing at the time of use such as reflow and solder dipping. It is clear from the results of the heat resistance of each material and the results of the heat resistance test of the prototype described later that the production method of the present invention has the heat resistance characteristic that can withstand the heat resistance.

The manufacturing method can perform continuous processing in which each processing step is arranged in tandem on a long material of a plastic film and a metal foil in the same manner as a conventional method of manufacturing a tape-shaped wiring material. Yes, efficient work can be performed.

(Experimental example 1) Polyimide film (Kapton, trade name: DuPont) having a thickness of 25 µm and a width of 125 mm was used as a base film, and on one side thereof, 85% by weight of ethylene ethyl acrylate resin containing 10% acrylic acid, 5% by weight of trimethylpropane, 10 parts by weight of butyl methacrylate were blended, and the kneaded ethylene ethyl acrylate copolymer was coated to a thickness of 20 μm.

Rolled copper foil having a thickness of 35 μm and a width of 125 mm is heated and laminated at 150 ° C. on this, completely fused, and then 6 Mrad using an electron beam accelerator.
Irradiated with an electron beam to obtain a crosslinked substrate. Subsequently, a circuit pattern was printed on the substrate with a resist material, unnecessary copper was etched with copper chloride, and the resist film was peeled off to continuously form predetermined circuit conductors.

Next, on the circuit conductor, a coverlay film using the same film and adhesive as above, a land portion and a terminal portion to be punched in advance by a mold, and bonded while being aligned with a predetermined portion, The adhesive between the circuits was completely removed by pressing with a 150 ° C heating and pressurizing roll to completely remove bubbles between the circuits.After that, the adhesive layer was irradiated with 12Mrad of electron beam using an electron beam accelerator to cure and crosslink the adhesive layer. A heat-resistant tape-shaped wiring member was obtained.

The obtained tape-shaped wiring member was punched at its outer periphery with a mold so as to have a predetermined shape, and turned into a test piece having a width of about 25 mm and a length of about 120 mm. The following performance evaluation was performed. For comparison, a commercially available
A normal tape-like wire made of PVC insulating film was tested.

In order to evaluate the heat resistance, first immerse each in a molten solder bath at 240 ° C, 260 ° C, and 280 ° C for 5 seconds to curl, blister,
Peeling was tested. As a result, although the present invention was not abnormal at all, the comparative product was dissolved at 240 ° C. The product was passed through a soldering furnace at a peak temperature of 240 ° C. for 1 minute. As a result, the product of the present invention showed no curling, blistering, peeling, and no dimensional shrinkage.

Furthermore, in order to examine the flexibility of the tape-shaped circuit, when the copper foil was wound around a 2.0R radius and bent 180 °, it was examined how many times the copper foil would break.As a result, the product of the present invention could withstand 30,000 or more bends. However, the commercial product broke after 700 to 1000 times.

(Experimental Example 2) An aromatic polyamide film having a thickness of 25 μm and a width of 125 mm (trade name: TX-film manufactured by Toray Co., Ltd.) was used as a base film, and on one side thereof, 80% by weight of ethylene vinyl acetate resin (containing 14% of vinyl acetate) was used. EV kneaded with 15% by weight of allyl cyanurate and 5% by weight of butoxyethyl acrylate and kneaded
The A-based copolymer was coated to a thickness of 25 μm.

On top of this, an electrolytic copper foil with a thickness of 35 μm and a width of 125 mm is laminated by heating at 140 ° C., and after complete fusion, 6Mra is applied using an electron beam accelerator.
The crosslinked substrate was obtained by irradiating the electron beam of d. Subsequently, a circuit pattern was printed on the substrate with a resist material, unnecessary copper was etched with copper chloride, and the resist film was peeled off to continuously form predetermined circuit conductors.

Next, on the circuit conductor, a coverlay film using the same film and adhesive as above, a land portion and a terminal portion to be punched in advance by a mold, and bonded while being aligned with a predetermined portion, Pressure is applied by a 140 ° C heating and pressing roll to completely remove air bubbles between circuits.After that, the adhesive layer is cured and cross-linked by irradiating 18Mrad of electron beam using an electron beam accelerator, resulting in a long heat-resistant material. A tape-shaped wiring member was obtained.

The outer periphery of the obtained tape-shaped wiring material was punched out with a mold so as to be in a predetermined prison, and a test piece having a width of about 25 mm and a length of about 120 mm was formed. The following performance evaluation was performed. For comparison, a conventional tape-shaped wire made of a commercially available PE insulating film was tested.

To evaluate heat resistance, first immerse each in a molten solder bath at 220 ° C, 240 ° C, and 260 ° C for 5 seconds to curl, blister,
Peeling was tested. As a result, the present invention was completely normal, but the commercial product was dissolved at 220 ° C. In addition, the sample was passed through a soldering furnace at a peak temperature of 230 ° C. for 1 minute, but the present invention showed no curling, blistering, peeling, and no dimensional shrinkage.

Furthermore, in order to examine the flexibility of the tape-shaped circuit, when the copper foil was bent 180 ° when wound around a radius of 2.0R and examined how many times the copper foil broke, the product of the present invention withstood 15.000 or more bends. However, the commercial product broke after 300 to 400 times.

(Effect of the Invention) As described above, according to the production method of the present invention, an electron beam made of a polyolefin resin containing a polyfunctional monomer is used for bonding a base film and a copper foil and bonding a coverlay film. Since a cross-linking adhesive is used, the adhesive strength is not deteriorated even at a high temperature, and the time required for bonding can be significantly reduced.

Furthermore, the circuit conductor is formed by printing and etching a wide copper foil in a series of manufacturing processes, instead of vertically attaching a ribbon-shaped conductor that has been separately slit as in the past, so that the circuit shape is free. As the degree increases,
The dimensional accuracy is improved, and fine and high-density products can be manufactured.

[Brief description of the drawings]

1 (a) to 1 (d) are explanatory views of the procedure of the manufacturing method of the present invention, and FIG. 2 is a perspective view of an example of the obtained tape-shaped wiring member. DESCRIPTION OF SYMBOLS 1 ... Base film, 2 and 5 ... Electron beam crosslinking type adhesive layer, 3 ... Copper foil, 3 '... Circuit conductor part, 4 ... Resist film, 6 ... Coverlay film.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01B 13/00

Claims (1)

(57) [Claims] A step of forming an electron beam cross-linkable adhesive layer made of a polyolefin resin containing a polyfunctional monomer on one surface of a heat-resistant insulating base film made of a polyimide film, and laminating a copper foil thereon; A step of forming a resist film of an arbitrary shape on the copper foil, a step of forming a circuit by removing unnecessary copper foil by etching, and an electron beam comprising a polyolefin resin containing the polyfunctional monomer on the circuit Through a step of bonding a heat-resistant insulating coverlay film made of a polyimide film provided with a cross-linkable adhesive layer by removing the terminal portion, and then irradiating an electron beam to cross-link the adhesive layer. Manufacturing method of heat-resistant tape-shaped wiring material.