KR20050059342A - Method for manufacturing flexible wiring circuit board - Google Patents

Abstract

A method for manufacturing a flexible wiring circuit board having an insulating support film and, formed thereon, a wiring circuit, which comprises the following steps (a) to (d) : (a) a step of adhering pressure-sensitively a laminate comprising the insulating support film and an electroconductive layer formed thereon to a transparent hard substrate by the use of a pressure-sensitive adhesive layer from the insulating support film side of the laminate; (b) a step of patterning the electroconductive layer of said laminate, to form the wiring circuit; (c) a step of reducing the adhesion strength of said pressure-sensitive adhesive layer; and (d) a step of peeling the laminate having the wiring circuit formed thereon from the transparent hard substrate so as for the pressure-sensitive adhesive layer to remain on the transparent hard substrate.

Description

Manufacturing method of flexible wiring circuit board {METHOD FOR MANUFACTURING FLEXIBLE WIRING CIRCUIT BOARD}

The present invention relates to a method for manufacturing a flexible wiring circuit board.

Background Art Conventionally, flexible wiring circuit boards obtained by patterning copper foils having a thickness of 35 μm or less laminated on one surface of a polyimide film having a thickness of 25 μm or less by a subtractive method to form a wiring circuit have been widely used.

As a method of manufacturing such a flexible wiring circuit board in a roll to roll, a method characterized by adhering a copper clad laminate with an adhesive whose adhesiveness is reduced by light irradiation on a carrier film has been proposed (patented). Document 1: See Japanese Patent Application Laid-Open No. 7-99379).

In this manufacturing method, the copper clad laminated board of the structure by which copper foil is affixed to the polyimide-type film is stuck together to the carrier film with which the adhesive whose adhesiveness falls by light irradiation is apply | coated from the polyimide-type film side surface, and is mutually bonded. After the wiring circuit was formed on the copper foil of the laminated board, the adhesive film was cured by irradiating ultraviolet rays from the carrier film side to lower the adhesive force, and the flexible wiring circuit board was peeled off by removing the carrier film at the interface between the adhesive and the polyimide film. Get

According to this manufacturing method, since the copper clad laminated board is held on the carrier tape, generation of bending and wrinkles can be suppressed during the wiring circuit forming processing, and the adhesive force of the pressure-sensitive adhesive can be reduced, so that even when the carrier film is peeled off. The occurrence of bending and bending can be suppressed.

However, with the recent trend of increasing the density of electronic devices, under the phenomenon that thinning and densification of flexible wiring circuit boards are progressing, in the case of the manufacturing method disclosed in Patent Document 1 using a carrier tape, the pattern pitch of the wiring circuit is 40. If the thickness is less than or equal to size, there is a problem that the patterning accuracy is lowered due to the surface warping and the unevenness of the carrier tape. In addition, there is also a problem that pattern defects are likely to occur due to cut debris on both end faces of the carrier tape, an adhesive exposed on the end face, and the like.

In addition, in the case of carrying out the manufacturing method disclosed in Patent Document 1, since the unwinding machine and the winding machine of the roll are required, it is difficult to cope with the miniaturization of the equipment, the operating cost of the auxiliary equipment is high, and the roll-to-roll is performed. Therefore, since the time for condition selection, the time for unwinding, etc. becomes long, there is a problem that the production lead time also becomes long.

In addition, when the extraction processing is performed on the copper clad laminate after patterning of the copper foil, a mold extraction processing method is applied. Therefore, burrs are formed at the cut end portions, and a change is likely to occur in the flexible wiring circuit board itself. there is a problem. In addition, since expensive molds must be prepared for each flexible wiring board having a different wiring circuit pattern, there is a problem that the extraction processing price cannot be suppressed.

In order to solve this problem, it is considered to apply a laser cutting method that can easily create various extraction patterns by changing the program. However, since the carrier tape is also cut at the same time in the laser cutting method, a flexible wiring circuit board is used. There is a problem that it cannot be maintained in the phase, the handleability is greatly reduced, and the incidence rate of defective products is also increased.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems of the prior art, and even when the pattern pitch of the flexible wiring circuit board becomes very small, the patterning accuracy does not decrease, no pattern defects occur, and the size of the manufacturing equipment is relatively easy, It is an object of the present invention to manufacture a flexible wiring circuit board manufacturing method which can shorten the lead time and can be subjected to extraction processing by a laser cutting method.

(A)-(d) is a manufacturing process drawing of embodiment of this invention.

2 and 3 are additional process diagrams of the present invention. 4 (a)-(b4) and 5 (c)-(d) are manufacturing process drawings of another embodiment of the present invention. 6 (a) to 6 (d) are manufacturing process drawings of another embodiment of the manufacturing method of the present invention. 7 is an additional process diagram of the present invention.

In the drawings, (1) is an insulating support film, (2,42) is a conductor layer, (2a, 42a) is a wiring circuit, (3) is a laminate, (4) is an adhesive layer, and (5) is a double-sided adhesive Film (5a) is a plastic film, (5b) is an adhesive layer, (6) is a plating resist pattern, (10, 40) is a flexible wiring circuit board, (41) is a polyimide precursor-based adhesive layer, (43) Polyimide support film, (G) is a transparent hard substrate, UV is an ultraviolet-ray, L is laser light.

The present invention uses a transparent hard substrate such as a glass substrate or an acrylic substrate excellent in planarity instead of a carrier tape so that a flexible wiring circuit board can be manufactured by a sheet type rather than a roll-to-roll, and irradiates ultraviolet rays to the transparent rigid substrate. A pressure-sensitive adhesive layer capable of lowering the adhesive force by, for example, a laminate in which a conductor layer is formed on the insulating support film is adhered on the insulating support film side, and after patterning the conductor layer, the adhesive force of the adhesive layer is reduced to be laminated on a transparent hard substrate. By peeling the sieve or on a transparent hard substrate, the conductor layer is directly adhered to the polyimide precursor-based pressure-sensitive adhesive layer, and the polyimide precursor-based pressure-sensitive adhesive layer is imidized after or before the conductor layer is patterned, thereby having insulating properties. At the same time as the polyimide support film, its adhesive force is lowered, and then the polyimide is By peeling a de support film, it discovered that the said objective was achieved and completed this invention.

The first invention based on this knowledge is a manufacturing method of a flexible wiring circuit board having wiring circuits formed on an insulating support film, and the following steps (a) to (d):

(a) adhering a laminate having a conductor layer formed on the insulating support film to the transparent rigid substrate with an adhesive layer on the insulating support film side;

(b) forming a wiring circuit by patterning the conductor layer of the laminate;

(c) reducing the adhesive force of the pressure-sensitive adhesive layer; and

(d) It has a process of peeling from the transparent hard board the laminated body in which the wiring circuit was formed so that an adhesive layer might remain on the transparent hard board side.

Moreover, 2nd invention is the manufacturing method of the flexible wiring circuit board with which the wiring circuit was formed on the polyimide support film which has insulation, The following process (aa)-(dd):

(aa) a step of laminating a conductor layer on a transparent hard substrate via a polyimide precursor-based pressure-sensitive adhesive layer;

(bb) forming a wiring circuit by patterning the conductor layer;

(cc) imidating the polyimide precursor-based pressure-sensitive adhesive layer to obtain a polyimide support film having insulation; and

and (dd) the polyimide support film on which the wiring circuit is formed is peeled off from the transparent hard substrate.

In the first aspect of the present invention, when the extraction processing is performed by laser cutting, the step (e) is performed between the step (b) and the step (c) or between the step (c) and the step (d). :

(e) It is preferable to further provide the process of extracting and processing by the laser cutting method with respect to the laminated body in which the wiring circuit was formed.

Similarly, in the second aspect of the present invention, between the step (bb) and the step (cc) or between the step (cc) and the step (dd), the step (ee):

(ee) It is preferable to further include the step of performing extraction processing by the laser cutting method with respect to the laminated board in which the wiring circuit was formed.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of the manufacturing method of the flexible wiring circuit board with which a wiring circuit was formed on the insulating support film of this invention is demonstrated in detail, referring drawings.

In the first aspect of the present invention, each step will be described with reference to FIGS. 1A to 1D.

Process (a)

First, as shown in FIG. 1 (a), the laminated body 3 having the conductor layer 2 formed on the insulating support film 1 is placed on the transparent hard substrate G from the insulating support film 1 side. It sticks by the adhesive layer 4. In this case, specifically, the pressure-sensitive adhesive is applied onto the transparent hard substrate G by a known method, for example, a spin coater method, and dried to form the pressure-sensitive adhesive layer 4, and onto the pressure-sensitive adhesive layer 4 The laminated body 3 is pressed by using a rubber roller or the like on the insulating support film 1 side.

Here, as the transparent hard substrate (G), although an acrylic substrate, a glass substrate, etc. are enumerated, it is preferable to use a glass substrate which is more excellent in flatness and also excellent in heat resistance. The pressure-sensitive adhesive layer 4 may be formed on one entire surface of the transparent hard substrate G. As shown in FIG.

In this process (a), it is important to use a transparent hard substrate (G) having excellent flatness in a single sheet type, and to have a good relation with the insulating support film (1) and the transparent hard substrate (G) during processing such as a patterning process. While maintaining the adhesiveness, by performing certain treatments (for example, ultraviolet irradiation treatment, heat treatment, cooling treatment, ultrasonic irradiation treatment, electron beam irradiation treatment, etc.), the insulation is relatively insulated as compared with the case of the transparent hard substrate (G). The adhesive layer 4 which the adhesiveness with respect to the film 1 falls large can be used.

According to the present embodiment, even when the patterned pitch of the flexible wiring circuit board is very small by using the transparent hard board G having excellent flatness as a single sheet type, the patterning accuracy does not decrease, and no pattern defect occurs. The downsizing of the manufacturing equipment is also relatively easy, and the lead time can be relatively short. In addition, the conductive layer 2 may be formed by performing an ultraviolet irradiation treatment or the like, and using the pressure-sensitive adhesive layer 4 which is inferior in adhesion to the insulating support film 1 as compared with the case of the transparent hard substrate G. In the case of patterning), the laminate 3 can be reliably held on the transparent hard substrate G, and furthermore, the laminate 3 can be easily separated from the transparent hard substrate G after patterning. .

In the case of this invention, as the insulating support film 1, the thing similar to the insulating film of a conventional copper clad laminated board can be used, For example, a polyimide film can be used preferably. Although the thickness of the insulating support film 1 is not restrict | limited, Usually, it is 50 micrometers or less, Preferably it is 20-25 micrometers.

Moreover, as the conductor layer 2, electrolytic copper foil, SUS304 foil, SUS430 foil, aluminum foil, beryllium foil, phosphorus bronze foil, etc. can be used preferably. Moreover, a copper- nickel alloy plating layer can also be used preferably. Although there is no restriction | limiting in particular also in the thickness of the conductor layer 2, Usually, it is 35 micrometers or less, Preferably it is 8-12 micrometers.

If the thickness of the transparent rigid substrate G is too thin, it is easily deformed or destroyed by external stress, and the workability at the time of manufacture is reduced, or if the thickness is too thick, the weight becomes heavy, and the load on the manufacturing equipment increases. Since stability of equipment falls, Preferably it is 1.0 mm-5.0 mm, More preferably, it is 1.5-2.5 mm.

When the thickness non-uniformity of the transparent hard substrate G (the result of measurement by the flatness 1: TTV (Total Thickness Valuation) method) becomes large, when the fine pattern is exposed, the focus during exposure becomes unfocused. Since a defect may arise, it is preferable to suppress thickness nonuniformity to 0.02 mm or less.

Here, the TTV method is a method of measuring the surface roughness of the entire measurement object, and represents a difference between the maximum value and the minimum value of the roughness measured when the measurement object is adsorbed and fixed.

In addition, when the luminance of the transparent hard substrate G (the result measured by the flatness 2: Local Thickness Valuation (LTV) method) becomes large, exposure in the case of patterning the conductor layer 2 in the step (b) described later At the time, since the transparent hard substrate G is hard to be fixed by the vacuum chuck and there is a possibility that pattern defects may occur, it is preferable to suppress the thickness to 0.1 mm or less.

Here, the LTV method is a method of partially measuring the surface roughness of a measurement object, and when the measurement object is fixed to adsorption, the difference between the maximum value and the minimum value of the measured roughness in a predetermined area (for example, 15 mm x 15 mm square) is measured. To indicate.

In addition, in order to harden an ultraviolet curable adhesive as the adhesive layer 4 in the process (c) mentioned later, transparent hard board | substrate G uses an ultraviolet curable adhesive at the time of irradiating an ultraviolet-ray from the transparent hard board | substrate G side. It is preferable to have the property which permeate | transmits an ultraviolet-ray so that it may fully harden | cure.

In this case, when the UV transmittance of the transparent hard substrate G is too low, since the irradiation time must be increased or the irradiation amount must be increased to cure the UV-curable pressure-sensitive adhesive 4, at least 30% (250-450 nm). Measurement results in the case of using an ultraviolet spectrophotometer in the wavelength range of?).

As an example of the adhesive layer 4, although an ultraviolet curable adhesive layer, a thermosetting adhesive layer, etc. are mentioned, an ultraviolet curable adhesive layer is especially preferable from a viewpoint of realizing favorable thermal stability.

As such an ultraviolet curable adhesive layer, there exists a certain adhesive strength before ultraviolet irradiation, and hardens | cures by ultraviolet irradiation, and the adhesive force falls. In this case, it is necessary that the adhesive force (peel strength) of the laminated body 3 to the insulating support film 1 is relatively small compared with the case of the transparent hard substrate G.

As such an ultraviolet light-type adhesive layer, it is preferable to use what formed the ultraviolet curable adhesive so that the initial stage peel strength (JIS K6854) before ultraviolet irradiation may be 3 N / cm or more, and the peel strength after ultraviolet irradiation may be 1 N / cm or more. . In this case, as the ultraviolet curable pressure sensitive adhesive, an optical ultraviolet curing type acrylic ultraviolet curable pressure sensitive adhesive or the like can be used.

Process (b)

Subsequently, as shown in FIG. 1 (b), the wiring circuit 2a is formed by patterning the conductor layer 2 of the laminate 3 using, for example, a conventional photolithography technique. In this case, specifically, the photosensitive resist film is adhered on the conductor layer 2 using the adhesive force, exposed through a mask for patterning (not shown), and developed to develop the resist pattern for etching the conductor layer 2. After the formation, the conductor layer 2 is etched and patterned, and then the wiring circuit 2a is formed by removing the photosensitive resist pattern.

In the present invention, only one wiring circuit 2a may be formed on the insulating support film 1 of the laminate 3, but usually a plurality of wiring circuits 2a are formed. When a plurality of wiring circuits 2a are formed, they are separated from each flexible wiring circuit board by extraction processing as described later.

Process (c)

Next, the adhesive force of the adhesive layer 4 is reduced. For example, when the ultraviolet curing type gradually increasing agent layer is used as the adhesive layer 4, as shown in FIG. 1 (c), ultraviolet-ray UV is irradiated from the transparent hardening board G side, and an ultraviolet curing adhesive layer is hardened, The adhesive force is lowered so that the adhesion strength to the insulating support film 1 is lower than that of the transparent hard substrate G.

In the case of this invention, as another means of reducing the adhesive force of the adhesive layer 4, the atmospheric temperature is reduced and the temperature of the adhesive layer 4 is made lower than the temperature at the time of adhesion | attachment. Thereby, the adhesive layer 4 hardens | cures and adhesive force can be reduced.

Process (d)

Subsequently, as shown in FIG. 1 (d), the laminate in which the wiring circuit 2a is formed on the transparent hard substrate G so that the pressure-sensitive adhesive layer 4 whose adhesive strength is lowered by curing remains on the transparent hard substrate G side. (3) is peeled off. Thereby, the flexible wiring circuit board 10 can be obtained.

By the way, in the case where a plurality of wiring circuits 2a are formed for one laminate 3, it is necessary to extract and process them on each of the flexible wiring circuit boards, but in this case, the plurality of wiring circuits 2a are peeled off from the transparent hard board G. Although the laminated body 3 in which the some wiring circuit 2a was formed may be isolate | separated into each flexible wiring circuit board by the metal mold extraction process, in this invention, a variety of punching patterns are easily carried out without a burr or deformation | transformation. It is preferable to apply the process (e) by the laser cutting method which can be prepared.

Process (e)

As shown in FIG. 2, this process (e) performs extraction processing by irradiating the laminated body 3 in which the wiring circuit 2a was formed by irradiating the well-known high-output laser light L for cutting according to an extraction pattern. As a used laser apparatus and laser irradiation conditions, it can determine suitably from a well-known thing according to the material to be cut | disconnected.

In the case of the present invention, step (e) may be provided between step (b) and step (c) described above or between step (c) and step (d), but from the viewpoint of preventing contamination by the uncured adhesive In the case, it is preferable to provide between the step (c) and the step (d).

In addition, although the transparent hard board | substrate G and the laminated body 3 are laminated | stacked by the single-layered adhesive layer 4 in the aspect of FIG. 1, as shown in FIG. 3, the above-mentioned adhesive on both surfaces of the plastic film 5a is shown. Even if the transparent rigid substrate G and the laminated body 3 are laminated | stacked through the double-sided adhesive film 5 in which the adhesive layer 5b (for example, an ultraviolet curable adhesive layer) which shows the same characteristic as the layer 4 was formed. good. Also in this case, the process similar to the said FIG. 1 (a)-(d) is performed, and finally, between the insulating support film 1 of the laminated body 3, and the adhesive layer 5b of the double-sided adhesive film 5 is carried out. Peeling is performed in between.

As the plastic film 5a, for example, a polyester film having a thickness of 50 to 125 µm can be preferably used. Moreover, as a material of the adhesive layer 5b, what shows the same characteristic as the adhesive layer 4 mentioned above can be used preferably, The thickness is 10-30 micrometers preferably.

In addition, although the aspect of FIG. 1 is the example which patterned the conductor layer 2 by the subtractive method, you may pattern in this invention by the buildup method. Also in this case, similarly to the example shown in FIG. 1, a flexible wiring circuit board can be obtained through the following steps (a ') to (d'). In this case, extraction processing can be performed further by applying the laser cutting method as a process (e ') as needed.

Process (a ')

As shown in Fig. 4 (a), in the same manner as the step (a) described in Fig. 1, the laminated body 3 on which the thin conductor layer 2 is formed on the insulating support film 1 is formed by the insulating support film ( On the 1) side, it is made to adhere to the transparent hard substrate G with the adhesive layer 4 formed by a well-known method. Alternatively, the insulating support film 1 is attached to the transparent hard substrate G with the adhesive layer 4, and then a metal thin film is formed as a thin conductor layer 2 on the surface of the insulating support film 1 by electroless plating. It may be sufficient (FIG. 4 (a)).

Here, it is preferable that the adhesive layer 4 is formed in one whole surface of the transparent hard board | substrate G. As shown in FIG. Thereby, adhesiveness with respect to the transparent hard board | substrate G of the plating resist pattern 6 mentioned later can be improved.

Process (b ')

As shown in Fig. 4 (b1), after the plating resist pattern 6 is formed on the thin conductor layer 2 of the laminate 3, for example, by a conventional photolithography technique, As shown in b2), the plating metal 2 'is deposited on the thin conductor layer 2 by the electroplating method using copper, for example.

As shown in Fig. 4 (b3), after removing the plating resist pattern 6 by etching, as shown in Fig. 4 (b4), soft etching is performed on the thin conductor layer 2 to form a wiring circuit pattern ( 2a).

Process (c ')

As shown in FIG. 5 (c), similarly to the process (c) described in FIG. 1, for example, ultraviolet ray UV is irradiated on the transparent hard substrate G side to lower the adhesive force of the pressure-sensitive adhesive layer 4.

Process (d ')

As shown in FIG. 5 (d), in the same manner as the process (d) described in FIG. 1, the wiring circuit 2a is formed on the transparent hard substrate G such that the pressure-sensitive adhesive layer 4 remains on the transparent hard substrate G side. The laminated body 3 in which the was formed is peeled. As a result, the flexible wiring circuit board 10 can be obtained.

Even in the case of the present invention, if necessary, between steps (b ') and (c') or between steps (c ') and (d') (preferably between steps (c ') and (d')). In the same manner as the step (e) described in FIG. 2, the extraction process can be performed by applying the laser cutting method as the step (e ').

Next, each process is demonstrated, referring FIG. 6 for the example of 2nd invention.

Process (aa)

First, as shown in FIG. 6 (a), the conductor layer 42 is laminated on the transparent hard substrate G via the polyimide precursor-based pressure-sensitive adhesive layer 41. Specifically, a polyimide precursor-based pressure-sensitive adhesive is applied to a transparent hard substrate (G), dried to form a polyimide precursor-based pressure-sensitive adhesive layer 41, and a conductor layer 42 such as copper foil is pressed thereon with a pressure roll. It is good to stick.

Here, as a polyimide precursor adhesive layer 41, what has a property to become a polyimide film which has insulation by the imidation process heated at 250 degreeC-350 degreeC is used, for example.

The polyimide precursor-based pressure-sensitive adhesive layer 41 is formed by forming a polyimide precursor-based pressure-sensitive adhesive as described above. As such polyimide precursor-based adhesives, polyamic acids obtained from acid dianhydrides and diamines (Japanese Patent Application Laid-Open No. 60-157286, Japanese Patent Laid-Open No. 60-243120, Japanese Patent Application Laid-Open No. 63-239998, Japanese Patent Application Laid-Open No. 1-245586). (See Japanese Patent Application Laid-Open No. 3-123093, Japanese Patent Laid-Open Publication No. HEI 5-139027), and the terminal synthesized from the excess acid dianhydride and diamine is partially imidized from the polyamic acid prepolymer and diisocyanate compound, which are acid dianhydrides. Polyamic acids (polyamide resin handbook, the Daily Industrial Newspaper Co., Ltd. (536, 1988); Polymer Debate, 47 (6), 1990) and the like can be used. Among these, polyamic acids obtained from acid dianhydride and diamine can be preferably used.

Preferred examples of acid dianhydrides include pyromellitic dianhydride (PMDA), 3,4,3 ', 4'-biphenyltetracarboxylic dianhydride (BPDA), 3,4,3', 4'-benzophenonetetra Carboxylic acid dianhydride (BTDA), 3,3 ', 4,4'- diphenylsulfontetracarboxylic dianhydride (DSDA) is mentioned. Further preferred examples of the diamine include 4,4'-diaminodiphenyl ether (DPE), paraphenylenediamine (PDA), 4,4'-diaminobenzanilide (DABA), 4,4'-bis (p -Aminophenoxy) diphenylsulfone (BAPS).

In addition, the transparent hard board | substrate G and the conductor layer 42 are the same as what was demonstrated by process (a) regarding FIG.

Process (bb)

Subsequently, as shown in FIG. 6 (b), the conductor layer 42 is patterned by the same method as the process (b) described in FIG. 1 to form the wiring circuit 42a.

Process (cc)

As shown in FIG. 6 (c), the polyimide precursor-based pressure-sensitive adhesive layer 41 is imided to obtain a polyimide support film 43 having insulation.

In this case, as imidation conditions, it can set suitably according to the kind of polyimide precursor type adhesive layer to be used.

This polyimide support film 43 functions as a support for the conductor layer 42 and has a lower adhesive force to the transparent hard substrate G than the case for the conductor layer 42 (wiring circuit 42a). As a result, the transparent hard substrate G and the polyimide support film 43 can be easily peeled off.

In addition, this process (cc) may be performed between the process (aa) and the process (bb) in addition to performing between the process (bb) and the process (dd) like the present example.

Process (dd)

Subsequently, as shown in FIG. 6 (d), the polyimide support film 43 having the wiring circuit 42a formed thereon is peeled off from the transparent hard substrate. As a result, the flexible wiring circuit board 40 can be obtained.

Also in this case, although the mold extraction processing may be performed with respect to the obtained flexible wiring circuit board 40 as needed, extraction processing is performed by the laser cutting method similarly to process (e) demonstrated in FIG. It is preferable.

In this case, specifically, it is preferable to provide the following steps (ee) between the step (bb) and the step (cc) or between the step (cc) and the step (dd).

Ee

As shown in Fig. 7, according to the extraction pattern, a known high-output laser light L for cutting the polyimide support film 43 in which the wiring circuit 42a is formed is applied in the same manner as in step (e) described in Fig. 2. Irradiation is performed by irradiation. As used laser apparatus and laser irradiation conditions, it can determine suitably from a well-known thing according to the material to be cut | disconnected.

Moreover, it is more preferable to arrange this process (ee) between a process (cc) and a process (dd) from a viewpoint of preventing contamination by the scattering of an adhesive.

Hereinafter, the present invention will be described in detail by way of examples.

Example 1

UV-curable acrylic adhesive (solid content 20%) is applied to one side of glass substrate with a thickness of 1mm with a UV transmittance of 98% so as to have a dry thickness of 20 to 30 μm, and dried in two steps of 60 ° C. and 100 ° C. An adhesive layer was installed.

Subsequently, a copper-clad laminate (copper foil 12 µm thickness / polyimide 25 µm thickness) was pressure-adhered to the UV curable pressure-sensitive adhesive layer on a glass substrate using a rubber roller from the polyimide surface, and the copper foil of the copper-clad laminate was added to a mixture of hydrogen peroxide and sulfuric acid. Soft etching was used to clean the copper foil surface.

Subsequently, a liquid resist (PMER-P, manufactured by Tokyo Okago Kogyo Co., Ltd.) was applied to the copper foil surface by spin coating method, dried to form an etching resist layer having a thickness of 7 μm, and a pattern mask was applied to the etching resist layer. After exposure through light, and developed with a dedicated developer (manufactured by Tokyo-Kagokyo Co., Ltd.) of the used liquid resist, the copper foil was further etched with an aqueous ferric chloride solution to form a wiring circuit pattern on the copper foil, and then the etching resist layer was removed. A solder resist layer is provided and solder plating is performed on the pattern terminal portion.

Subsequently, ultraviolet rays were irradiated on the glass substrate side to the ultraviolet curable gradually increasing agent layer at an energy amount of 400mj to cure the ultraviolet curable pressure sensitive adhesive layer.

Finally, the cured ultraviolet curable pressure sensitive adhesive layer on the glass substrate and the polyimide surface of the copper clad laminate were peeled off to obtain a flexible wiring circuit board. At this time, the peel force is 0.2 N / cm, the product is not curled, the pressure-sensitive adhesive is not electrodeposited on the polyimide surface can be easily peeled off the glass substrate.

Example 2

A 50-micrometer-thick polyethylene terephthalate film was prepared on both sides of an ultraviolet-curable acrylic pressure-sensitive adhesive layer (D-203DF, manufactured by Linetec Co., Ltd.) having a thickness of 15 micrometers, respectively. One side of a glass substrate having a thickness of 95% and a thickness of 2mm was pressure-adhered by using a rubber roller under the condition of a temperature of 80 ° C.

On the double-sided adhesive film adhered to the glass substrate, a laminate in which a seed layer (nickel-copper alloy layer) having a thickness of 0.25 μm was provided on one side of a 25 μm thick polyimide film was laminated with a rubber roller on the polyimide film side.

Subsequently, ultraviolet rays were irradiated with an energy amount of 400mj on the glass substrate side to cure the ultraviolet curable acrylic pressure-sensitive adhesive layer. Subsequently, a liquid resist (PMER-P, manufactured by Tokyo Okagyo Co., Ltd.) is applied to the seed layer surface of the laminate by a spin coater method, dried to form a plating resist layer having a thickness of 8 μm, and the plating resist layer After exposing through a pattern mask, developing with a dedicated developer (manufactured by Tokyo-Kagokyo Co., Ltd.) of the used liquid resist to form a plating resist pattern, copper having a thickness of 7 μm was deposited on the seed layer by electrolytic copper plating. Accumulated.

Next, after removing the plating resist pattern, the seed layer exposed by soft etching with a mixture of hydrogen peroxide and sulfuric acid was removed. And a soldering resist layer was provided and the soldering plating was performed to the pattern terminal part.

Finally, peeling was performed between the double-sided adhesive film on the glass substrate and the polyimide film of the laminate to obtain a flexible wiring circuit board. At this time, the peeling force was 0.4 N / cm, the product did not produce curl, and the adhesive was not electrodeposited on the polyimide surface.

As described above, according to the manufacturing method of the flexible wiring circuit board of the present invention, since the process operation is performed on the transparent rigid substrate having excellent flatness, the flatness is maintained throughout the entire process and the quality is uneven even if the wiring circuit is refined. The yield is remarkably improved. In particular, stable precision can be achieved even in the pattern formation by the subtractive method, and the impedance control of a product becomes easy. In addition, since the carrier film is not used, pattern defects due to adhesion of foreign matter such as dust due to the use of the carrier film can be eliminated. In addition, since the sheet can be produced on a transparent hard substrate in a sheet type, the production can be made with a very simple facility. As a result, the manufacturing space and the auxiliary equipment space can be reduced, and the resources such as electric power, chemical liquid and water can be reduced, and the lead time can be shortened. In addition, since the extraction processing can be performed by the laser cutting method, it is possible to eliminate various problems caused by the mold extraction processing.

Claims (8)

A method of manufacturing a flexible wiring circuit board having wiring circuits formed on an insulating support film, the method of manufacturing a flexible wiring circuit board having the following steps (a) to (d): (a) adhering a laminate having a conductor layer formed on the insulating support film to the transparent rigid substrate with an adhesive layer on the insulating support film side; (b) forming a wiring circuit by patterning the conductor layer of the laminate; (c) reducing the adhesive force of the pressure-sensitive adhesive layer; and (d) Process of peeling the laminated body in which the wiring circuit was formed in the transparent hard board so that an adhesive layer might remain on the transparent hard board side. The pressure-sensitive adhesive layer according to claim 1, wherein the pressure-sensitive adhesive layer used in the step (b) is an ultraviolet curable pressure-sensitive adhesive layer, and in the step (c), in order to reduce the adhesive force of the pressure-sensitive adhesive layer, ultraviolet rays are applied to the pressure-sensitive adhesive layer on the transparent hard substrate side. A method of manufacturing a flexible wiring circuit board which is cured by irradiating with light. The adhesive layer used in a process (b) is a double-sided adhesive film in which the ultraviolet curable adhesive layer was formed in both surfaces of a plastic film, In a process (c), in order to reduce the adhesive force of the said adhesive layer, A method for manufacturing a flexible wiring circuit board which irradiates ultraviolet light to the pressure-sensitive adhesive layer on the transparent hard board side to cure the adhesive layer. The method of manufacturing a flexible wiring circuit board according to claim 1, further comprising step (e) between step (b) and step (c) or between step (c) and step (d): (e) A step of performing extraction processing on the laminated body on which the wiring circuit is formed by the laser cutting method. The method of manufacturing a flexible wiring circuit board according to claim 2, further comprising step (e) between step (b) and step (c) or between step (c) and step (d): (e) A step of performing extraction processing on the laminated body on which the wiring circuit is formed by the laser cutting method. The method of manufacturing a flexible wiring circuit board according to claim 3, further comprising step (e) between step (b) and step (c) or between step (c) and step (d): (e) A step of performing extraction processing on the laminated body on which the wiring circuit is formed by the laser cutting method. A method of manufacturing a flexible wiring circuit board having wiring circuits formed on an insulating polyimide support film, the method of manufacturing a flexible wiring circuit board having the following steps (aa) to (dd): (aa) a step of laminating a conductor layer on a transparent hard substrate via a polyimide precursor-based pressure-sensitive adhesive layer; (bb) forming a wiring circuit by patterning the conductor layer; (cc) imidating the polyimide precursor-based pressure-sensitive adhesive layer to obtain a polyimide support film having insulation; and (dd) A step of peeling a polyimide support film having a wiring circuit formed from a transparent hard substrate. The method of manufacturing a flexible wiring circuit board according to claim 7, further comprising step (ee) between step (bb) and step (cc) or between step (cc) and step (dd). (ee) A step of performing an extraction processing method by a laser cutting method on a polyimide support film having a wiring circuit formed thereon.