JPH07105174B2 - Method for manufacturing anisotropic conductive film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a method for producing an anisotropic conductor, particularly a glass substrate of a liquid crystal display panel and a flexible printed circuit as its driving circuit, or an IC on the printed circuit board. The present invention relates to a method for manufacturing an anisotropic conductive film used for connection with a mounted film carrier and further for chip-on-glass connection for directly mounting an IC.

[Prior Art] A glass substrate of a liquid crystal display panel (hereinafter abbreviated as LCD) used as a display device of a desktop electronic computer or a clock, and a flexible printed circuit board (hereinafter abbreviated as FPC) that is a driving circuit thereof. Electrical connection was conventionally made with a conductive rubber connector, but the connection pitch between the glass substrate and FPC, which was 0.4 mm or more, has recently increased to 0.3 mm due to the increase in the number of display pixels due to the large size of LCD. Since it has become the following, for this electrical connection, it is becoming mainstream to use a dispersion type anisotropic conductive film in which conductive particles are uniformly dispersed in a heat-meltable adhesive. As the anisotropic conductive film, for example, a styrene-butadiene-styrene block copolymer in a hot-melt adhesive obtained by adding a tackifier, an antioxidant, a latent curing agent, etc. to a thermoplastic resin, a diameter of 10 Approximately 30 μm in diameter, approximately spherical metal-plated resin particles and solder particles are evenly dispersed on the release film to form a film with a thickness of 20 to 30 μm, and then ribbon-shaped with a width of 2 to 3 mm is generally used. This is peeled off from the release film at the time of use and heat-sealed at 130 to 190 ° C. for 10 to 20 seconds.

[Problems to be Solved by the Invention] However, in an anisotropic conductive film in which conductive particles are dispersed in a conventionally known hot-melt adhesive, 1) the conductive particles are dispersed in an arbitrary state, so When the electrodes (hereinafter, simply referred to as electrodes) have a low pitch, as shown in FIG. 4 a), a secondary aggregate of several conductive particles causes a leak failure between adjacent electrodes, and As shown in FIG. 4 b), a chain of conductive particles is formed in the pool of adhesive that has flowed around the heat-sealed portion along with the flow of the hot-melt adhesive during heat-sealing when these conductive particles are connected. Therefore, leakage failure may occur between adjacent electrodes. 2) If the particles of the conductive particles are not uniform, good connection resistance can be obtained between the electrodes of large particles as shown in FIG. 4c). , Between the electrodes of small particles If the connection resistance is remarkably increased due to interference with the connection, or conduction failure occurs, 3) if the amount of conductive particles blended in the adhesive is reduced in order to eliminate leakage failure between adjacent electrodes, However, there is a defect that conduction failure occurs due to the absence of particles between opposed electrodes, and the connection pitch between the glass substrate of the LCD and the FPC that can be connected to this is 0.
2mmp is the limit, and this will accompany future colorization etc.
Due to the increase in the number of pixels in the LCD panel, it is said to be 0.2 mm or less, which is disadvantageous in that it cannot cope with this.

[Means for Solving the Problems] The present invention relates to a method for producing an anisotropic conductive film capable of solving such disadvantages, which is a method of forming an electrically insulating polymer film in the thickness direction thereof. A method of manufacturing an anisotropic conductive film, comprising piercing rivet-shaped metal conductors having both ends enlarged and protruding on the upper and lower surfaces thereof independently of each other in the order of 1) to 5) below. A method for producing an anisotropic conductive film, comprising:

1) An electrically insulating polymer film is formed on a flat metal support, 2) The polymer film is perforated by a predetermined patterning, and 3) From the perforated polymer film side. Etching the metal support, and 4) after the etching, forming a rivet-shaped metal conductor with enlarged ends at the holes of the polymer film by electroforming, and 5) filling the rivet-shaped metal conductor with the metal conductor. The polymer film is peeled off from the metal support.

Is the gist.

This will be described in more detail below.

[Operation] The present invention relates to a method for producing a novel anisotropic conductive film which is useful for electrical connection between an LCD glass substrate and an FPC or IC.

The anisotropic conductive film obtained by the production method of the present invention is an electrically insulating polymer film, which is formed by electroforming a rivet-shaped metal conductor with both ends enlarged, which penetrates the film in the thickness direction and projects on the upper and lower surfaces thereof. It is supposed to be arranged in a dot shape by the method.

3a) and 3c) are perspective views of anisotropic conductive films having different arrangement patterns, which show an enlarged metal conductor on the surface of an electrically insulating polymer film as shown. The both ends of the metal conductor are arranged so as to project in a dot shape, but the metal conductors are independent from each other in the thickness direction of the electrically insulating polymer film as shown in the longitudinal sectional view of FIG. 3b). It is arranged so as to penetrate therethrough and project to the upper and lower surfaces thereof.

The anisotropic conductive film according to the present invention is used as an LCD glass substrate and an FPC.
Or placed between IC and glass substrate and FPC or IC
And is kept insulating by this polymer film,
A rivet-shaped metal conductor with enlarged ends (hereinafter simply referred to as a conductor) protrudes from this anisotropic conductive film, so that the electrodes of the glass substrate and the electrodes of the FPC and IC to be connected are in contact with this conductor. The electrical connection is ensured, the insulation from other electrodes is ensured, and the spacing and arrangement position of the conductors can be set by patterning.

The electrically insulating polymer film constituting the anisotropic conductive film obtained by the present invention can be handled as a film because it is supported by a metal support and peeled off as described later. It is necessary to have sufficient strength and toughness, and it is necessary not to be attacked by etching or electroforming processing bath. In the case of the anisotropic conductive film formed, since it is required not to be thermally deformed even at high temperature during heat sealing, as the polymer film, a polyimide film, a polyamideimide film, a polycarbonate film, a polyester film, Polyetherimide film, polyarylate film, polyphenylene oxide film, polyphenylene Alpha Id films, polysulfone films, poly-4-methylpentene films, polyparabanic acid films, polyether sulfone films,
Examples of polyether ether ketone film,
Further, as will be described later, using a photoresist for the polymer film, in the case of punching with an alkali or a solvent, it is necessary to use a film having alkali solubility or organic solvent solubility. The film may be selected from a polyimide film, a polyamideimide film, a polycarbonate film, a polyetherimide film, a polysulfone film, a poly-4-methylpentene film, a polyparabanic acid film and the like, but the thickness thereof is different when it is too thin. The conductive film becomes difficult to handle, and if it is too thick, it becomes difficult to obtain a hole without a taper in the later-described drilling, the etching solution does not easily enter the hole, and it takes a long time to perform electroforming. 10 to 50 as required
The thickness may be in the range of 0 μm, preferably in the range of 20 to 200 μm.

Also, perforate this polymer film as described below,
After etching, the conductor that forms this anisotropic conductive film is required to have good conductivity because it electrically connects the glass substrate of the LCD to the FPC and IC. However, since it is formed on the above-mentioned polymer film by electroforming as described below, it is preferable that it is made of a metal that can be electrodeposited. Since the one side conductive film becomes expensive, it is preferable to make it with an inexpensive metal such as copper or nickel. This size is a portion spread like a rivet,
That is, the diameter may be 150 μm or less at both ends and the height may protrude from the surface of the polymer film by 2 to 100 μm.

Next, the method for producing the anisotropic conductive film of the present invention will be described. This production method is carried out for the above-mentioned electrically insulating polymer film supported and formed on a metal support.

FIG. 1 and FIG. 2 illustrate this manufacturing method. First, as shown in FIG. 1 a) and FIG. 2 a), a thermoplastic polymer material is deposited on a metal support. Supported and formed. Since this metal support has a polymer film formed thereon by the following film-forming method, it has sufficient strength and heat resistance necessary for the film-forming process, and is then subjected to etching and electroforming. Therefore, it is preferable to use a metal, but since it is necessary to finally peel off the polymer film, it is preferable to use a metal that does not adhere to the polymer film very strongly, Therefore, this may be a composite support of stainless steel, nickel, iron, copper, iron with its surface nickel-plated, copper, etc., but this also has a release layer on its surface to facilitate release of the polymer film. It may be provided. If the thickness of the metal support is too thin, the strength may be insufficient and the film forming process of the polymer film may be hindered, which is sufficiently thicker than the depth corroded during the etching process described later. However, if it is too thick, it will be difficult to form a roll and continuous processing will be difficult, so 30 to 1,000 μm, preferably 50 to 3 μm.
The range may be 00 μm.

As a method for forming a polymer film on this metal support, a generally known film forming method may be used,
Therefore, when this polymer film has thermoplasticity, the melt extrusion method (extrusion method) is used.
The resin melted by means of a T-die may be extruded on the metal support to form a film having a predetermined thickness. When the polymer film is soluble in a solvent, the polymer may be formed by a solution casting method (casting method). After coating the solvent solution of the film on the metal support by a known coating method using a lip coater, a knife coater, a reverse coater, a gravure coater, an air knife coater, etc., the solvent is scattered by heating, and this polymer film is When it is thermosetting, it may be cured by heating, and heated and cured as necessary. If it is already formed as a film or if the adhesion of this polymer film to the metal support is too low, this polymer film should be supported on the metal using an adhesive that has suitable adhesion and releasability. It may adhere to the body and this adhesive may be selected experimentally.

The polymer film thus formed is then punched through a hole penetrating in the thickness direction of the polymer film, and a conductor is formed there. If it is difficult to process, it is preferable to process it optically, so that this can be done, for example, as shown in FIG.
Irradiation with a laser or an excimer laser may be performed. The holes can be drilled by these lasers by converging the output laser to a target hole diameter using an appropriate lens or the like, and using a mask in which a desired hole diameter is arranged in a polymer film at a desired pitch. It can be placed and irradiated with a laser that has a processable energy density (J / cm ³ ), which also adjusts the magnification of the focusing lens to the desired hole diameter and pitch before focusing the output. A magnifying mask having the same magnification may be used, and the laser output may be patterned by the magnifying mask and then the lens may be used for focusing and processing. Since it is preferable that the target anisotropic conductive film is formed into a continuous ribbon, this processing is preferably performed continuously by sequentially moving the hole processing position on the ribbon. Regarding the laser output, if the energy density when condensing this is too large, one pulse irradiation will pierce the film as well as dig into the metal support, which will affect the etching accuracy after that. Needs to be changed appropriately depending on the thickness of the polymer film to be processed, and this is preferably done by irradiating the polymer film with a few pulses rather than by irradiating it once. The reduction of the laser output is made by branching this output using a mirror, etc., reducing the energy density when converging the branched light and performing multiple drilling processes at the same time. It may be set to Hodokosuru so.

In addition, as shown in FIG. 2 b), this hole forming process is carried out by first applying a photoresist to the polymer film and patterning it and then curing it so that the polymer film in this portion is dissolved and removed. May be. Since these photoresists are generally liquid or film-like, they may be formed by a known resist forming method, specifically, a spin coater, a lip coater, a knife coater, a reverse coater, a gravure coater, an air knife coater, A method such as a spray coater may be used, but a spin coater is a single-wafer treatment, and a continuous roll-like coating cannot be performed. Therefore, a coating method other than the spin coater is preferable. When the resist is a film-shaped dry film, after peeling off the protective film, the above-mentioned electrically insulating polymer film is brought into contact with this surface, and appropriate pressure and heat are applied to the resist. A layer may be formed. When this photoresist is irradiated with ultraviolet (UV) or electron beam (EB), the exposed part hardens and is not dissolved in an alkaline solution or an organic solvent. 2 of positive type resist which dissolves in organic solvent
There are various types, and any of these resists can be used in the present invention, but if the area dissolved by development is large, it becomes difficult to control the composition of the developer, and defects are more likely to occur. Since it is excellent, it is preferable to use a positive type resist, and this positive type resist is composed of a cresol-based novolak resin, a photosensitizer mainly containing a naphthoquinone diamide ester compound, an organic solvent, and a small amount of a decomposition accelerator and a stabilizer. You can use one.

The reaction mechanism of this positive type resist is as a sensitizer. And as a base resist Causes Wanger-Meeywein rearrangement due to light energy, becomes an alkali-soluble indenecarboxylic acid through ketene, and dissolves the irradiated part. An example is poly (O-nitrobenzyl methyl acrylate) utilizing the photoreaction of O-nitrobenzene group as shown in.

Further, if the thickness of this photoresist is too thin, problems such as pinholes are likely to occur, the resistance to the developing solution becomes weak, and if it is too thick, the resolution in exposure decreases, and this resist is expensive. Therefore, when the resist is a liquid, it is 0.5 to 30 μm, and when the resist is a dry film, it is 0.5 to 100 μm.

When the resist is a positive-type resist, the polymer film on which the photoresist is formed in this way scatters the solvent and performs pre-baking to densify the resist film. After exposing the surface to UV or BE that has been patterned in a predetermined manner using a mask, etc., and then using a developing solution to dissolve the dissolved portion, a resist is a positive type of this developing solution. Occasionally, an alkaline solution such as an organic amine aqueous solution is used, and specific examples thereof include tetramethylammonium hydroxide.

The perforation of this polymer film is performed using the pattern developed by this developing solution. This is because when the polymer film dissolves in an alkaline solution like the resist, the resist developing process is performed. Subsequently, the polymer film may be immersed in an alkaline solution for dissolving it for a predetermined time. Examples of the polymer film that dissolves in this alkaline solution include a polyimide film, a polyamide-imide film, and a polyparabanic acid film, but if this polymer film is one that dissolves in a predetermined organic solvent instead of an alkaline solution, it is developed. After the resist coating film is after-baked at 100 ° C. or higher to improve its solvent resistance after completion, it may be perforated by dipping it in a predetermined organic solvent that dissolves this film. Aromatic hydrocarbons such as toluene and xylene for polycarbonate films for organic solvents, dimethylformamide for polyparabanic acid films,
Tetrahydrofuran and propylene carbonate may be used alone or as a mixed solvent. After this hole is drilled, the remaining resist film may be peeled off using a peeling agent, but if it is thin and it adheres to the polymer film sufficiently firmly, it must be peeled off strongly. There is no.

The diameter and pitch of the holes provided on the polymer film in this way are required to be 0.2 mm or less, which is the connection pitch between the target anisotropic conductive film and the LCD, FPC, and IC chip. Therefore, this pitch is 0.2 mm or less, but when the electrode width on the LCD side and the width between the electrodes are set to 1: 1, the diameter of the conductor that does not leak between adjacent electrodes is 100 mm.
Since the diameter is smaller than 100 μm and the diameter of the conductor involved in this connection is almost the same as the hole diameter, this hole diameter may be smaller than 100 μm. When the polymer film is a ribbon-shaped film, a plurality of staggered arrangements are provided in the longitudinal direction of the ribbon-shaped film as shown in FIG. When it is located almost at the center of this, if it is a ribbon-shaped anisotropic conductive film, it has a width of 2 to 3 mm, so the apparent connectable pitch is the pitch of holes. Since it can be halved, the array pitch of this hole is 0.4 m
It can be less than or equal to m.

The perforated polymer film forms a conductor in this hole, but the conductor of the anisotropic conductive film obtained in the perforated state does not protrude from the polymer film surface. Since both ends are not enlarged, it is necessary to etch the metal support as shown in FIGS. 1 (c) and 2 (c) before attaching the conductor. The metal support may be etched by, for example, a method using a conventionally known metal chloride-based etching solution such as ferric chloride, or electrolytic etching in which the metal support is immersed in an electrolytic solution as an anode and etched by anodic oxidation. However, since the target anisotropic conductive film is preferably in the form of a continuous ribbon, it is preferable to use a metal chloride-based etching solution that is easily compatible with this.
However, even in this etching, if the processed hole diameter is small, the etching will be incomplete because the air inside the hole will not escape when immersed in the etching solution. It is preferable to use a spray method of spraying the etching liquid thus obtained from a nozzle or a method of applying ultrasonic waves to the etching liquid. In addition, Fig. 1c) and Fig. 2c) made in this way.
If the depth of the etching part shown in Fig. 2 is too shallow, the protruding height of the enlarged conductors at both ends finally becomes smaller than the polymer film, and good connection with the electrode cannot be obtained. However, if the depth is too deep, the diameter of the obtained conductor becomes too large because the etching proceeds not only in the thickness direction of the metal support but also in the surface direction thereof, so this depth is 2 to 100 μm. It should be a range.

Then, after the above-described drilling and etching are completed, a conductor is formed in the hole of the polymer film by electroforming as shown in FIGS. 1d) and 2d). However, the conductor formed by this electroforming method may be made of a metal that can be electrodeposited. This is because the anisotropic conductive film obtained with a noble metal such as gold or silver becomes expensive. It is preferable to use copper or nickel for which many plating baths are known. In addition, the plating bath used for this electroforming is not preferable because it is an extremely acidic or alkaline bath or a bath with high stress such as heat because of problems such as the influence on the polymer film and peeling of the film. When is copper is a pyrophosphate bath, a sulfamate copper bath, when it is nickel, it is preferable to be a Watts bath, a nickel sulfamate bath, and the like. It can be easily formed.
The thickness of the thus obtained rivet-shaped conductor with enlarged both ends is preferably such that the conductor protrudes from 2 to 100 μm from the surface of the polymer film.

In addition, the conductor with enlarged both ends produced in this way is conductive, and nickel has problems such as reduction of conductivity due to oxide film and corrosion, so corrosion resistant metal plating should be applied to this. This metal plating is often done by applying a layer of corrosion-resistant metal plating to the hole that has been etched before forming the conductor by electroforming, and then using electroforming to expand the conductor with both ends enlarged. Formed, and then at least one layer of metal plating is applied to the surface of this conductor, or at least one layer of electroless plating is performed after peeling the anisotropic conductive film provided with this conductor on the polymer film from the metal support. However, in the case of the former plating method, there is the significance that different metals can be used in accordance with the material of the electrodes for connecting the plating material on the upper surface and the lower surface of this conductor. Further, the corrosion-resistant metal used here is a noble metal having excellent corrosion resistance, or an oxide thereof having conductivity, and is further heated by an anisotropic conductive film such as solder. Examples of the metal having a low melting point that melts to form a connection include units such as gold, silver, palladium, platinum, tin, solder, indium, molybdenum, and chromium, or alloys of two or more of these. However, if the thickness is too thin, the effect of corrosion resistance cannot be obtained, and if it is too thick, the anisotropic conductive film obtained is expensive, so the thickness may be set in the range of 0.01 to 10 μm. However, if the conductor material is copper and gold plating is applied to it, problems such as gold diffusion into the copper during long-term use and deterioration of corrosion resistance occur. It is preferable that the copper is plated with nickel, and then this is plated with gold to obtain multi-layer plating.

In addition, since the conductor with both ends enlarged thus formed needs to be finally peeled from the metal support together with the polymer film, after performing the above-mentioned punching and etching treatment, electrolysis is performed. Anodizing treatment may be performed for a short time in a degreasing solution or a caustic soda solution, or it may be immersed in a sodium chromate or sodium sulfide solution for a short time to form an oxide thin film or a chromate thin film as a peeling film.

The polymer film on which the rivet-shaped conductors with enlarged ends are formed is then peeled off from the metal support to obtain the purpose as shown in FIGS. 1e) and 2e). Although it becomes an anisotropic conductive film, the polymer film and the metal support are peeled off by immersing the polymer film in a melt having an appropriate composition or ejecting a solvent pressurized by ultrasonic waves or a pump from a nozzle. The spray method may be used.
The polymer film is strongly bonded to the metal support, and the polymer film has low solvent resistance and does not have an appropriate solvent. For example, the metal support is a copper foil and the rivet shape is used. When the conductor of nickel is nickel, it is made alkaline by adding ammonia to an aqueous solution of chlorite (sodium salt, ammonium salt), and when immersed in an alkaline etching solution having a pH of about 10, only the copper foil is removed. Since it is selectively etched, it can be easily peeled off. In this case, when the polymer film is an alkali-soluble film, the opposite surface of the metal support may be masked, but when the anisotropic conductive film is finally made adhesive, The adhesive layer may be formed first and used as a substitute for masking. Further, in the peeling method by the selective etching described above, the metal material used for this conductor may be nickel-plated in advance by the above-mentioned method, and therefore the metal material is not limited to nickel and copper or Other metals may be used.

The anisotropic conductive film thus obtained is subjected to treatment such as plating as described above, if necessary.
After that, it is slit into a predetermined width and used as a ribbon, which is used for LCD and FPC or IC.
Since this is to electrically connect the LCD and the FPC or IC by interposing between them and press-contacting each other, it is preferable that this one has an adhesive function. Immersion in a hot-melt adhesive solution, or coating of this adhesive solution on an anisotropic conductive film, then drying this to form an adhesive layer on both sides of the anisotropic conductive film, or peeling The adhesive layer is preferably formed by laminating an adhesive layer formed on a substrate such as a film on both surfaces of the anisotropic conductive film. The coating method used to form the molecular film by casting may be used. However, if the thickness of this hot-melt adhesive is smaller than the height of the rivet-shaped conductor with both ends enlarged that protrudes from the polymer film surface, the adhesive and the electrode cannot contact and cannot be bonded, and if this is too thick The amount of adhesive that flows due to heat and pressure during bonding becomes too large, it takes time for the resin to flow, the time required for connection becomes long, and because the FPC is deformed due to the pool of flowing adhesive, Since stress may occur and connection reliability may be reduced, this may be about 5 to 50 μm thicker than the height of the conductor protruding from the polymer film surface. The advantage is given that the connection can be made easier. In addition,
The adhesive used here may be one that is heat-meltable, and includes styrene-butadiene-styrene block copolymer, styrene-isobutylene-styrene block copolymer, saturated copolymer polyester resin, ethylene-acetic acid. Vinyl copolymers, ethylene-ethyl acrylate copolymers, ethylene-isobutyl acrylate copolymers, nylon 11, nylon 12, ionomer resins and other thermoplastic elastomers and thermoplastic resins as required for rosin and rosin derivatives, terpenes Resins and modified terpene resins, petroleum resins, coumarone-indene resins, phenol resins, alkyd resins and other tackifiers, epoxy resins, isocyanate-based latent curing agents, photocurable resins, antioxidants, stabilizers, etc. Add toluene, methyl ethyl ketone, and acetic acid as needed. It may be dissolved in a solvent such as chill or cellosolve, but the heat-melting adhesive formed on the upper and lower surfaces of this anisotropic conductive film is exemplified by a glass substrate or FPC whose upper and lower surfaces are bonded. As described above, the upper and lower surfaces may have different compositions according to the bonding partner.

When the anisotropic conductive film obtained by the present invention is used,
Leakage due to secondary agglomerates, which has been a problem with conventional dispersion type anisotropic conductive films, does not occur, and the conductor does not move with the flow of the adhesive, so adhesion around the heat seal part There is no leak due to the chain of conductive particles in the agent accumulation part, and the conductor is not arbitrarily dispersed like the conductive particles of the dispersion type anisotropic conductive film, and it is arranged at a predetermined position. Since it was done,
There is no problem as in the conventional dispersed type anisotropic conductive film that the conductive particles are not present between the electrodes to be connected, which causes non-conduction. Since the thickness and shape are excellent in uniformity, it has the advantage that there will be no problems such as the connection resistance becoming extremely high due to the dispersion of conductive particles in the conventional dispersion type anisotropic conductive film, or the occurrence of non-conduction. This is also the connection pitch of 0.2mm in color LCD panels.
It has an advantage that the following electrodes can be connected.

[Examples] Next, examples of the present invention will be described.

Example 1 100 μm thick rolled copper foil C having a width of 225 mm as a metal support
-1020 [trade name of Takeuchi Metal Foil & Powder Co., Ltd.]
Polyparabanic acid varnish Sollac XT-101 is on this surface.
[Nitto Chemical Industry Co., Ltd. product name] was coated using a knife coater, and this was applied at a temperature of 100 ° C from the metal support side for 30
After heating for 2 seconds, introduce it into a continuous drying oven and
After heating and drying for 2 seconds, a polyparabanic acid film having a thickness of 30 μm was formed on the metal support.

Then, the oscillation wavelength of this polyparabanic acid film was 1.06.
TEA ₀₀ oscillation mode continuously pumped YAG laser SL115L with μm and maximum oscillation output of 12 W [trade name of NEC Corporation]
Ultrasonic Q switch unit ・ SL231G [NEC]
[Product name] incorporated, repetition frequency 1kHz, peak output
Using a YAG laser scriber with a pulse width of about 80 nsec and a power of 20 kW or more, this YAG laser is focused to a spot diameter of 50 μm using a precision optical lens, and this is irradiated onto the polyparabanic acid film to produce a hole diameter. Make a hole of about 50 μm,
The irradiation position of this film is 100μ using NC tape.
After performing side drilling after shifting by m, 50 μm holes are drilled in the width direction of the film at a pitch of 100 μm by repeating this, and when one row in the width direction is completed, the next row is moved by 100 μm, and After arranging them in a staggered manner so that the punching position is in the center of the punching position in the front row, the surface of this film is rubbed with a cloth impregnated with methyl alcohol, washed with pure water and laser drilled. The dust that had come out was removed.

After completion of washing, this was dried and a copper foil on the back side was laminated with an adhesive film for masking, and this perforated polyparabanic acid film was dipped in an etching tank containing a 40 ° Baume ferric oxide solution. The etching solution is pressurized by a pressure pump and jetted from a nozzle, and ultrasonic waves are applied to the etching solution so that the etching solution is completely immersed in the hole to etch a copper foil as a metal support to a thickness of 20 μm. After repeating washing with pure water several times, it was immersed in an aqueous solution of 0.1 N sodium chromate for 1 second to form a peeling film, and washed with water.

Next, this is immersed in a Watt bath, nickel is deposited by an electroforming method, and the thickness of this nickel is projected by 20 μm from the surface of the polyparabanic acid film to form a rivet-like conductor with an enlarged terminal. After peeling off this masking film from the copper foil, it was immersed in an alkaline etching solution / alkali etch [product name of Yamatoya Shokai Co., Ltd.] to pH 10 by adding ammonia to an aqueous solution of ammonium chlorite to form a metal support. After completely removing the copper foil, washing with water and drying, an anisotropic conductive film based on a polyparabanic acid film in which rivet-like nickel conductors of about 50 μm were arranged in a zigzag pattern at a pitch of 100 μm was obtained. As a result, the nickel surface is electroless plated to a thickness of 0.
After forming a gold thin film with a thickness of 015 μm, a glass transition was performed on the upper and lower surfaces of this anisotropic conductive film, with a 50 μm thick silicone release agent coated polyester film, Therapy Q-1 [trade name of Toyo Metallizing Co., Ltd.]. 6 ℃, softening point of ring and ball method
Saturated copolyester Byron # 300 [trade name of Toyobo Co., Ltd.] at 123 ° C 100 parts by weight of 200 parts by weight of toluene dissolved in a hot-melt adhesive solution was applied using a knife coater and dried. Then, an adhesive film having a dry film thickness of 30 μm and having a hot-melt adhesive layer formed thereon was laminated by heating and pressing.

Next, the anisotropic conductive film obtained in this way was slit into a width of 3 mm to form a ribbon, and 1 ounce of copper foil (36 μm)
m), flexible printed circuit board (FPC) with tin-plated electrodes with an electrode width of 0.075 mm and an electrode pitch of 0.15 mm
And an ITO electrode glass substrate with the same electrode width and electrode pitch as above, insert it from the FPC side at 150 ° C, 40 kg
Heat sealing was performed under the condition of f / cm ² for 10 seconds, and the connection resistance and insulation resistance between adjacent electrodes were measured.
In the measurement at 000 points, the connection resistances were all 0.5 Ω / Pin or less, and the insulation resistance was 10 ¹⁰ Ω or more.

Example 2 On the rolled copper foil having a thickness of 100 μm used in Example 1, a thickness of 30
A positive type resist, ODUR-, using a roll coater on the film on which a polyparabanic acid film of μm is formed.
1010 [trade name of Tokyo Ohka Kogyo Co., Ltd.] is applied to a dry film thickness of 2 μm, prebaked at 120 ° C. for 20 minutes, and then an adhesive film for masking is laminated on the copper foil on the back side. did. Next, exposure machine PLA520F C
M-290 [trade name of Canon Inc.] was used to deposit chromium on a synthetic quartz plate on the resist surface.
After contacting a positive mask patterned to 50 μm and 100 μm pitch, irradiate with UV light for 10 seconds to expose,
The exposed product is immersed in a special developer, ODUR-1010 developer [trade name of Tokyo Ohka Kogyo Co., Ltd.] for 2 minutes while stirring, and then developed, and a special rinse solution, ODUR-1010.
The developer was neutralized by immersing it in a rinse solution (trade name of Tokyo Ohka Kogyo Co., Ltd.) with stirring for 1 minute, and then post-baked at 100 ° C. for 20 minutes. When immersed in an aqueous solution of caustic soda for about 5 minutes, the polyparabanic acid film was dissolved and a polyparabanic acid film perforated by a predetermined patterning was obtained.

Next, the polyparabanic acid film thus punched was etched in the same manner as in Example 1, and a nickel conductor was formed by electroforming so that both ends of the polyparabanic acid film protruded from the surface of the polyparabanic acid film by 20 μm. Then, after forming a gold thin film on this nickel surface, peeling this from the metal support, further providing an adhesive layer to make an anisotropic conductive film, and ribbon-like one slit into a width of 3 mm. When used to connect the same LCD and FPC as in 1, the connection resistance was 0.5Ω / Pin or less when measuring 1,000 electrodes.
The insulation resistance was 10 ¹⁰ Ω or more.

[Effect of the Invention] The present invention relates to a method for producing an anisotropic conductive film, which comprises forming an electrically insulating polymer film on a metal support,
A hole is formed on this film by a predetermined patterning, the metal support below the hole is etched to form a hole, a metal conductor is inserted therein, and then this is peeled from the metal support to make a difference. This is to manufacture a directional conductor.The resulting anisotropic conductor is used for the LCD glass substrate and FPC.
If installed between the two, the insulation between them is secured by the polymer film, and the glass substrate and the FPC are brought into contact with each other by this rivet-shaped conductor, in which case there is a problem with the conventionally known dispersed anisotropic conductive film. There is no leakage due to secondary agglomerate, which is said to occur, no leakage due to accumulation of adhesive in the heat seal part, and there is no particle between electrodes, so there is no disadvantage due to particle size variation. However, according to the above-mentioned manufacturing method, the target anisotropic conductive film can be easily and surely obtained, and in this case, the patterning for drilling can be performed in an arbitrary pattern. It is possible to sufficiently cope with an electrode pitch of 0.2 mm or less due to the increase, and it is possible to easily manufacture a connector such as an IC chip.

[Brief description of drawings]

1 a) to e) and 2 a) to e) are process diagrams of the anisotropic conductive film manufacturing method according to the present invention, and FIGS. 3 a) and c) are anisotropic conductive films according to the present invention. FIG. 3 is a perspective view, FIG. 3 b) is a longitudinal sectional view thereof, and FIGS. 4 a) to 4 c) are connection diagrams of an LCD glass substrate and an FPC using a conventionally known dispersion type anisotropic conductive film. is there.

Claims (3)

[Claims] 1. A rivet-shaped metal conductor having enlarged ends at both ends, which penetrates the electrically insulating polymer film in the thickness direction thereof and projects on the upper and lower surfaces thereof, is arranged in a dot shape independently of each other. A method for manufacturing an anisotropic conductive film, comprising the following 1) to
A method of manufacturing an anisotropic conductive film, characterized by comprising the order of 5). 1) An electrically insulating polymer film is formed on a flat metal support, 2) The polymer film is perforated by a predetermined patterning, and 3) From the perforated polymer film side. Etching the metal support, and 4) after the etching, forming a rivet-shaped metal conductor with enlarged ends at the holes of the polymer film by electroforming, and 5) filling the rivet-shaped metal conductor with the metal conductor. The polymer film is peeled off from the metal support. 2. The anisotropic conductivity according to claim 1, wherein the method of forming holes in the polymer film by predetermined patterning is performed by irradiating the surface of the polymer film formed on the metal support with laser light. Membrane manufacturing method. 3. A method of forming holes in a polymer film by a predetermined patterning method, the method comprising the steps of forming a photoresist layer on the surface of the polymer film formed on the metal support, exposing and developing the photoresist. The method for producing an anisotropic conductive film according to claim 1, which is performed by a step of patterning and a step of processing the polymer film by etching based on the pattern.