JPH11126964A - Flexible circuit board with anisotropic conductive adhesive and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide flexible circuit board with anisotropic conductive adhesive from which release paper stuck to anisotropic conductive adhesive layers formed in a connecting terminal section can be peeled off easily and a method for manufacturing the circuit board. SOLUTION: A flexible circuit board constituted by forming a circuit pattern having a connecting terminal section 5 on the surface of a substrate 3 composed of a flexible insulating film is formed in a work sheet 2 in such a state that the board 1 is divided from the sheet 2 by means of notched sections 13, 14, 15, 16, and 17 through micro-joint sections 18 and 19 and anisotropic conductive adhesive layers 7 and 7a are formed on the terminal section 5 of the board 1 and on the work sheet 2 in the extended part of the section 5. Then two pieces of released paper 8 and 8a are respectively stuck to the layers 7 and 7a in such a state that the paper 8 and 8a can be cut by means of the notched section 14 at a position on the work sheet 2 extended from the terminal section 5 beyond the notched section 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible circuit board having an anisotropic conductive adhesive in which a connecting terminal portion has an anisotropic conductive adhesive layer, and a method of manufacturing the same.

[0002]

2. Description of the Related Art A flexible circuit board having a conductive circuit pattern on at least one surface of a substrate made of a flexible insulating film has a connection terminal portion to be connected to a liquid crystal display by an anisotropic conductive adhesive. It is used by connecting to connection terminals of electric and electronic devices such as a circuit board for driving the device, a printed circuit board, and an IC chip. In this case, the connection terminal pattern of the flexible circuit board and the connection terminal of the electric / electronic device formed at a position corresponding to the connection terminal pattern are opposed to each other, and a thermocompression bonding is performed with an anisotropic conductive adhesive interposed therebetween. Make a connection.

[0003] The anisotropic conductive adhesive is obtained by dispersing conductive particles in an adhesive resin. The conductive particles are connected between connection terminals by thermocompression bonding to exhibit conductivity, and a space region where no terminals are present is provided. In this case, the conductive particles are dispersed in the resin and do not exhibit conductivity, and the adhesive strength is obtained by the adhesive force of the cured resin.

[0004] Generally, the anisotropic conductive adhesive is obtained in the form of an anisotropic conductive adhesive film integrated with a release paper, and the release paper is peeled off before or after attaching to the connection terminal portion of the flexible circuit board. It is necessary, but the peeling is difficult. In particular, a flexible circuit board with an anisotropic conductive adhesive is attached to a connection terminal portion in a state where release paper and an anisotropic conductive adhesive film are integrated with the same dimensions, so that the release paper may be peeled. Difficult and difficult to automate. There is also a peeling method in which the release paper side of the flexible circuit board is placed on a carrier sheet (tape) to peel the flexible circuit board and leave the release paper on the carrier sheet, but in this case, it is difficult to adjust the sticking force. And the release paper may not remain on the carrier sheet.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to propose a flexible circuit board with an anisotropic conductive adhesive, which can easily release a release paper, and a method for manufacturing the same.

[0006]

[Means for Solving the Problems]

(1) A flexible circuit board having a conductive circuit pattern formed to have a connection terminal portion on at least one surface of a base made of a flexible insulating film, wherein the flexible circuit board is a worksheet The flexible circuit board and the worksheet are separated by a notch, leaving a micro-joint portion between the flexible circuit board and the worksheet. An adhesive layer is formed, a release sheet is adhered to the anisotropic conductive adhesive layer, and the release sheet extends from the connection terminal of the flexible circuit board to the worksheet extending beyond the adhesive layer cutout. A flexible circuit board with an anisotropic conductive adhesive, which is cut at an extended position. (2) A flexible circuit board with an anisotropic conductive adhesive separated from the worksheet according to the above (1), wherein an anisotropic conductive adhesive is applied in a state where a release paper protrudes from a connection terminal portion. Flexible circuit board with agent. (3) On a work sheet on which a flexible circuit board having a conductor circuit pattern formed to have a connection terminal portion is formed on at least one surface of a substrate made of a flexible insulating film, Forming an adhesive layer cut notch at the boundary with the extension, forming an adhesive layer cut notch on the connection terminal of the unit circuit board formed on the worksheet and the worksheet of the extension thereof; Step of forming an anisotropic conductive adhesive layer with a release sheet beyond, and a release sheet at a position extending from the connection terminal portion of the flexible circuit board beyond the cutout for the adhesive layer cut onto the work sheet. A method for producing a flexible circuit board with an anisotropic conductive adhesive, comprising a step of cutting and forming a notch for separating a substrate around a unit circuit board so as to leave a micro joint portion. (4) The method according to the above (3), further comprising a step of performing an electrical check of a circuit pattern after forming a cut portion for plating lead cutting connected to the connection terminal portion. (5) The method according to the above (3) or (4), further comprising a step of separating the flexible circuit board with release paper from the worksheet after the formation of the cutout for separating the substrate.

A flexible circuit board is a board having a conductive circuit pattern formed on at least one surface of a base made of a flexible insulating film so as to have connection terminals. The circuit pattern may be formed on one side, may be formed on both sides, and may be formed on an intermediate layer.

The flexible insulating film serving as the base material is a film having flexibility and insulating properties, and is preferably a film of polyimide, polyester, aramid, polycarbonate or the like, but may be a film made of another plastic or other material. . The substrate is 10 to 100 μm, preferably 15
Thicknesses of ~ 75 [mu] m are preferred.

The connection terminal portion is a portion in which terminal patterns connected to the conductor circuit pattern are gathered and generally formed so as to be arranged in a line. An anisotropic conductive adhesive layer is formed on the connection terminal portion. It is formed. The conductor circuit pattern and the connection terminal pattern can be subjected to electrolytic solder plating, electrolytic tin plating, or nickel plating, and then further subjected to gold plating, etc. to form a metal film, thereby improving the durability of the pattern. Better.

The anisotropic conductive adhesive is an adhesive in which conductive particles are dispersed in an adhesive resin, preferably a thermosetting resin,
Generally, it is used in the form of an anisotropic conductive adhesive film formed in a film shape. Such an anisotropic conductive adhesive does not have conductivity before thermocompression bonding, but thermosetting in a state where conductive particles are crimped between connection terminals by thermocompression bonding and conductive particles are dispersed in other parts A resin that cures and provides conductivity and adhesion is used.

The adhesive resin is preferably a thermosetting resin such as an epoxy resin, a phenol resin, a hydroxyl group-containing polyester resin, or a hydroxyl group-containing acrylic resin, but may be a thermoplastic resin. When a thermosetting resin is used, production and storage at room temperature and relatively low temperature (40 to 100 ° C)
The curing is preferably carried out with a heat-active latent curing agent which does not cause a curing reaction at the time of drying and causes a curing reaction by heating and pressurizing (thermocompression bonding) at a curing temperature.

The conductive particles include graphite powder, copper, silver,
Any conductive powder such as a metal powder such as nickel, tin, palladium, and solder, a resin plated with nickel, gold, and the like, a metal, and other powders can be used. The conductive particles having a particle size of 1 to 50 μm, preferably 3 to 20 μm can be used.

The adhesive resin and the conductive particles are dispersed or dissolved in an appropriate solvent to form an anisotropic conductive adhesive. Such anisotropic conductive adhesive is generally formed into a film to form an anisotropic conductive adhesive film,
Used in a state integrated with release paper.

In general, a flexible circuit board is formed by forming a plurality of circuit patterns by exposure, etching, etc. on a worksheet in which a conductive layer such as copper is formed by metallizing a substrate made of a flexible insulating film. Are separated by a notch and separated to obtain a flexible circuit board.

In this case, each circuit pattern is obtained in a state in which a pattern serving as a plating lead is connected to a connection terminal pattern for plating, and nickel plating, gold plating, solder plating, or the like is performed using the plating lead. After the plating lead is cut, an electrical check of the circuit pattern is performed. Thereafter, a notch is formed in the outer portion of each circuit pattern, and the flexible circuit board is partitioned.

The flexible circuit board formed as described above may be made into a product in a state where it is connected to a worksheet or in a state where it is separated from the worksheet. The flexible circuit board with the adhesive has an anisotropic conductive adhesive layer with release paper on the connection terminal portion.

According to the present invention, a notch for cutting the adhesive layer is formed between the connection terminal portion and its extension in accordance with the plating lead cut. Then, an anisotropic conductive adhesive layer with a release sheet is formed on the connection terminal portion and the worksheet of the extension thereof beyond the cutout for the adhesive layer in accordance with the electrical check. After that, when forming the notch for separating the substrate while leaving the micro joint on the outer peripheral portion of the flexible circuit board, the peeling sheet is moved from the connection terminal portion of the flexible circuit board to the worksheet beyond the notch for cutting the adhesive. By cutting at the extended position, a flexible circuit board is formed in which the release paper is attached so as to protrude from the connection terminal portion.

The flexible circuit board thus formed may be made into a product while being connected to a worksheet, or may be made into a product when separated from the worksheet. At the time of separation, the microjoint is separated by separating it, but at this time, the substrate can be separated with the release paper attached by peeling the substrate from the side without the release paper toward the release paper side it can.

On the other hand, when the substrate is peeled off in the opposite direction, the release paper is left on the worksheet, and the release paper is peeled off to obtain a flexible circuit board with the adhesive layer exposed. Can be connected to certain electrical and electronic equipment.

Since the anisotropic conductive adhesive layer of the flexible circuit board with the release paper is covered with the release paper, the activity of the anisotropic conductive adhesive layer is maintained. Since the release paper protrudes from the connection terminal portion of the flexible circuit board from which the worksheet is separated with the release paper attached, the release paper can be easily formed by clipping the protruding portion and peeling. Peeled off. Accordingly, the release paper is easily peeled, and automation for the peeling is also facilitated.

[0021]

The flexible circuit board with anisotropically conductive adhesive according to the present invention is formed on a worksheet through a cutout portion, and is formed on a connection terminal portion and an extension portion. Since the release paper is pasted beyond the notch, you can easily separate it from the worksheet with the release paper attached or peeled off by selecting the separation direction. Also, it is easy to automate the separation operation.

Further, the flexible circuit board with anisotropic conductive adhesive, which is separated while the release paper is attached, is easily peeled off since the release paper is attached in a state of protruding from the connection terminal portion. And the peeling operation is easy.

According to the method of manufacturing a flexible circuit board with anisotropic conductive adhesive of the present invention, after forming a cutout for adhesive cut and forming an anisotropic conductive adhesive layer with release paper, Since the cutout for cutting off the release paper and the cutout for separation are formed, the above-described flexible circuit board with anisotropic conductive adhesive can be easily manufactured by a simple process.

When an electrical check is performed after the formation of the plating lead cut notch, the plating lead cut notch and the adhesive cut notch are simultaneously formed to perform the electrical check and the formation of the adhesive layer with release paper. It can be performed at the same time or in close proximity, and the process can be simplified.

When the flexible circuit board with the release paper is separated after the formation of the cutout for separating the substrate, the flexible circuit board with an anisotropic conductive adhesive, which facilitates peeling of the release paper as described above, is efficiently used. Can be manufactured well.

[0026]

Embodiments of the present invention will be described below with reference to the drawings. 1A and 1B show a flexible circuit board with an anisotropic conductive adhesive according to an embodiment, wherein FIG. 1A is a plan view showing a state formed on a worksheet, FIG. 1B is a plan view showing a state separated from the worksheet, and FIG. a), (b) and FIG. 3 (a) are plan views showing a manufacturing process, and FIG. 3 (b) is a plan view in a state where release paper is peeled off.

In FIG. 1, reference numeral 1 denotes a flexible circuit board provided with an anisotropic conductive adhesive, wherein (a) shows a state formed on a work sheet 2 and (b) shows a state separated from the work sheet 2. Is shown. The circuit board 1 has a conductive circuit pattern 4 formed on at least one surface of a base material 3 made of a flexible insulating film, and both end portions of these conductive circuit patterns 4 are gathered in a line shape to form connection terminal portions 5 and 6. Is formed. The conductor circuit patterns 4 are formed on both sides and are connected in a complicated manner through through holes, but are shown in a simplified manner.

One connecting terminal 5 is connected to a liquid crystal display (LC).
D) is formed in a wide area corresponding to the connection terminal portions so as to be connected to the drive circuit board and other printed wiring boards of D), and an anisotropic conductive adhesive layer 7 is formed thereon, A release paper 8 is stuck thereon. The release paper 8 has protrusions 9 protruding from both ends integrated with the anisotropic conductive adhesive layer 7 formed on the connection terminal portion 5.

The connection terminal portion 6 is formed in a narrow area so as to be connected to an anisotropic conductive connector (not shown), and a reinforcing plate 10 is attached to the back surface thereof. The connection terminal portion 6 is not formed with the anisotropic conductive adhesive layer 7 and the release paper 8, but may be formed.

In the worksheet 2, a conductor layer 12 made of copper or other metal is formed on one side, both sides, or an intermediate layer of a base material 11 made of a flexible insulating film, and this is etched and connected by through holes. Thus, the conductor circuit pattern 4 is formed. The circuit board 1 has a cutout 13 for cutting the adhesive layer and cutouts 14 and 15 for separating the board.
The worksheets 16 and 17 partition the worksheet 2. The substrate 1 and the worksheet 2 are connected by micro joints 18 and 19 formed between the substrate separation notches 14, 15, 16 and 17.

2 (a), 2 (b) and 3 (a) show a manufacturing process of such a flexible circuit board 1 with an anisotropic conductive adhesive. First, a conductor layer 12 of copper or the like is formed on a base material 11 by metallizing, then the layers are connected by forming through holes, and the conductor layer 1 is etched.
The conductor circuit pattern 4 is formed by dissolving and removing a part of 2.

In this state, as shown in FIG. 2A, the conductor layer 12 and the conductor circuit pattern 4 are
, The necessary portions of the conductor circuit pattern 4, for example, the connection terminal portions 5, 6 are plated with nickel-gold plating or the like, and the connection terminal portions 5, 6 are removed as necessary. A protective layer is formed so as to cover conductive circuit pattern 4. 2 (a), 2 (b) and 3 (a)
In the figure, reference numeral 23 denotes a substrate area to be the circuit board 1.

The work sheet 2 on which the conductive circuit pattern 4 is formed is punched in a first punching step shown in FIG.
The substrate separation notch 16 and the plating lead cut notches 24 and 25 are formed. Notch 13 for cutting adhesive layer
Is formed along the outer shape of the substrate region 23 traversing the anisotropic conductive adhesive layer 7 so as to cut the anisotropic conductive adhesive layer 7 formed extending from the connection terminal portion 5 on an extension thereof. .

The notch 16 for separating the substrate is previously formed only partially in order to facilitate the formation of the micro joints 18 and 19. Further, the plating lead cutting notches 24 and 25 cut out the plating leads by punching out the plurality of plating leads 21 and 22 to cut off the connection between the conductor layer 12 and the conductor circuit pattern 4.

In the first punching step, the notches 13, 16, 2
After forming 4 and 25, processing such as electrical check of the conductive circuit pattern 4, formation of the anisotropic conductive adhesive layer 7 with the release paper 8, and attachment of the reinforcing plate 10 are performed as processing steps. The electrical check is to electrically check whether the conductor circuit pattern 4 functions normally, and whether there is a disconnection or a short circuit, and is possible by cutting each conductor circuit pattern 4 from the conductor layer 12 by plating lead cut. Becomes

In forming the anisotropic conductive adhesive layer 7, the anisotropic conductive adhesive layer 7 is formed on the connection sheet 5 and the extension of the worksheet 2 beyond the notch 13 for cutting the adhesive layer. In this case, the anisotropic conductive adhesive layer 7 on the connection terminal portion 5 and the adhesive layer 7a extending from the anisotropic conductive adhesive layer 7 are cut by the adhesive layer cutout notch 13. Release paper 8,
8a is stuck on the anisotropic conductive adhesive layers 7, 7a, and the anisotropic conductive adhesive layers 7, 7a and the release paper 8, 8a are formed in the same shape and size. Generally, these are preferably formed by sticking an anisotropic conductive adhesive film with release paper.

The reinforcing plate 10 is adhered to the base material 11 on the back side of the connecting terminal portion 6 by attaching a reinforcing plate 10 such as a rigid plastic film to the connecting terminal portion 6 to reinforce the connecting terminal portion 6. (Not shown).

After performing the above-described processing steps, punching is performed as a second punching step to form notches 14, 15, and 17 for separating the substrate in the outer peripheral portion of the substrate region 23, as shown in FIG. As shown, a flexible circuit board 1 with an anisotropic conductive adhesive is partitioned in a worksheet 2. The connection terminal portion 5 is formed at the end of the substrate 1 by forming the substrate separation notch portion 14, and peeled at a position extending from the connection terminal portion 5 beyond the adhesive layer cutout notch portion 13 and onto the work sheet 2. The paper 8 is cut to form the protrusion 9.

The notches 15 and 17 for separating the substrates are formed so as to leave the micro joints 18 and 19, whereby the outer peripheral portion of the circuit board 1 is separated from the work sheet 2. The micro joints 18 and 19 hold the circuit board 1 in the work sheet 2 and are formed to have such a small thickness that the circuit board 1 can be separated from the work sheet 2 by being easily cut by stress. The substrate separating notches 14 and 17 are formed so as to include the plating lead cut notches 24 and 25, but may be formed so as to be independent or partially overlap.

In order to separate the circuit board 1 from the worksheet 2 formed as described above and shown in FIG. 1A, the connection terminals 6 of the circuit board 1 are pulled toward the near side of the drawing to form the micro joints 18. 19, the adhesive layers 7 and 7a
Is cut at the notch 13, and the release papers 8 and 8a are cut by the notch 14 at positions extending from the notch 13, so that the release paper 8 is integrated with the adhesive layer 7 and the protrusion 9
Are separated in a protruding state, and a circuit board 1 with release paper shown in FIG. 1B is obtained.

In the circuit board 1 of FIG. 1B separated in this manner, since the release paper 8 is integrated with the adhesive layer 7 formed on the connection terminal portion 5, the adhesive layer 7 has an activity. maintain. Therefore, it can be transported and stored with the release paper 8 attached. When the circuit board 1 is used, the release paper 8 can be easily peeled off using the protrusion 9 as a trigger, and automation can be easily performed. FIG. 3B shows the circuit board 1 from which the release paper 8 has been peeled off.

The worksheet 2 shown in FIG. 1A can be transported and stored as it is, and when the connection terminals 6 of the substrate 1 are pushed toward the paper surface to cut the micro joints 18 and 19, the worksheet 2 is peeled off. The paper 8 remains in a state where the protruding portions 9 adhere to the worksheet 2, and the circuit board 1 of FIG. 3B from which the release paper is removed is obtained. Therefore, when the circuit board 1 is used immediately, such a separation method is preferable.

In any case, since the release paper 8 is provided with the protruding portion 9, the release paper can be easily separated and automation can be easily performed. For automation, the separated substrate 1 or the pre-separated worksheet 2 is placed on a carrier sheet (not shown) and transported, and the protrusion 9 is hooked by an appropriate jig to peel off the release paper 8. It is possible. In this case, transfer to the carrier sheet can be performed simultaneously with or close to the second punching step.

[Brief description of the drawings]

FIG. 1 shows a flexible circuit board with an anisotropic conductive adhesive according to an embodiment, (a) showing a state formed on a worksheet,
(B) is a plan view in a state separated from the worksheet.

FIGS. 2A and 2B are plan views showing manufacturing steps.

FIG. 3A is a plan view showing a manufacturing process, and FIG. 3B is a plan view showing a state where a release paper is peeled off.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flexible circuit board with anisotropic conductive adhesive 2 Worksheet 3, 11 Base material 4 Conductive circuit pattern 5, 6 Connection terminal part 7, 7a Anisotropic conductive adhesive layer 8, 8a Release paper 9 Projecting part 10 Reinforcement plate 12 Conductive layer 13 Notch for cutting adhesive layer 14, 15, 16, 17 Notch for separating board 18, 19 Micro joint 21, 22 Plating lead 23 Substrate area 24, 25 Notch for cutting lead

Claims (5)

[Claims] 1. A flexible circuit board having a conductive circuit pattern formed to have a connection terminal portion on at least one surface of a base made of a flexible insulating film, wherein the flexible circuit board is The flexible circuit board is formed in the worksheet, and the flexible circuit board and the worksheet are separated by notches except for the microjoint portion. The connection terminals of the flexible circuit board and the extension of the worksheet are anisotropically formed on the worksheet. A conductive adhesive layer is formed, and a release sheet is adhered to the anisotropic conductive adhesive layer. The release sheet extends from the connection terminal of the flexible circuit board to the adhesive layer cut-off portion. A flexible circuit board with an anisotropic conductive adhesive cut at a position extended on a worksheet. 2. A flexible circuit board with an anisotropically conductive adhesive separated from the worksheet according to claim 1, wherein a release paper is attached in a state of protruding from a connection terminal portion. Flexible circuit board with adhesive. 3. A worksheet in which a flexible circuit board having a conductor circuit pattern formed to have connection terminals is formed on at least one surface of a substrate made of a flexible insulating film. Forming a notch for cutting the adhesive layer at the boundary between the notch and the extension of the adhesive layer. The notch for cutting the adhesive layer is formed on the connection terminal of the unit circuit board formed on the worksheet and the worksheet of the extension. Forming an anisotropic conductive adhesive layer with a release sheet beyond the portion, and peeling at a position extending from the connection terminal portion of the flexible circuit board beyond the cutout portion for cutting the adhesive layer onto the worksheet A method of manufacturing a flexible circuit board with an anisotropic conductive adhesive, comprising a step of cutting a sheet and forming a notch for separating a substrate around a unit circuit board so as to leave a micro joint portion. 4. The method according to claim 3, further comprising the step of performing an electrical check of the circuit pattern after forming the cut-out portion for plating lead cutting connected to the connection terminal portion. 5. The method according to claim 3, further comprising the step of separating the flexible circuit board with release paper from the worksheet after forming the board separating notch.