JPH05205531A - Anisotropic conductive film and method for manufacturing the same - Google Patents

Abstract

(57) [Abstract] [Purpose] Anisotropic conductivity, which has excellent conductivity in the conductive part and insulation in the insulating part, as well as excellent reliability in developing or maintaining the conductive part and the insulating part, and excellent thinness and mass productivity. To obtain a membrane and a manufacturing method thereof. [Structure] An anisotropic conductive film obtained by filling a hole (11) provided in a predetermined portion of an insulating adhesive sheet or insulating sheet (1) with a metal film (2), and transfer onto an easily peelable sheet. The method for producing an anisotropic conductive film as described above, comprising filling and transferring a possible provided metal film into a hole provided in a predetermined portion of the insulating adhesive sheet or the insulating sheet. [Effect] It is possible to form an insulating part containing no conductive material and a conductive part made of a metal film containing no insulating material, and it is possible to achieve a joining process involving necessary circuit connection of a printed wiring board or the like. Further, the anisotropic conductive film can be mass-produced efficiently by a simple operation of filling and transferring the metal film, and the filled metal film is excellent in purity, thinness, uniformity of thickness, and the like, and has excellent conductivity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anisotropic conductive film having excellent conductivity in the conductive part and excellent insulation in the insulating part, and a method for producing the same.

[0002]

2. Description of the Related Art Heretofore, there has been known an anisotropic conductive film having an adhesive force, which is made of a mixture of a polymer and a conductive powder into a sheet, which is insulating in a normal state but exhibits conductivity in a pressing portion. It was being done. This is for the purpose of interposing between the printed wiring boards or the like and pressing the boards so as to electrically connect the circuits on the boards and to join the boards while maintaining the insulating property in other parts. Used for.

However, since the insulating material and the conductive material are mixed, the insulating portion is poor in insulating property, the conductive portion is poor in conductive property, and the insulating portion is changed to the conductive portion by pressing. There were problems such as poor reliability in maintenance and development of conductive parts.

[0004]

DISCLOSURE OF THE INVENTION The present invention is excellent not only in the conductivity of the conductive portion and the insulation of the insulating portion, but also in the reliability of the development and maintenance of the conductive portion and the insulating portion, and the thinness and mass productivity. It is an object to develop an anisotropic conductive film and a manufacturing method thereof.

[0005]

DISCLOSURE OF THE INVENTION The present invention is an anisotropic conductive film characterized in that a hole formed in a predetermined portion of an insulating adhesive sheet or an insulating sheet is filled with a metal film, and an easy peeling. Provided is a method for producing an anisotropic conductive film, wherein a transferable metal film provided on a conductive sheet is filled and transferred into a hole provided in a predetermined portion of the insulating adhesive sheet or the insulating sheet. It is a thing.

[0006]

With the anisotropic conductive film having the above structure, the insulating adhesive sheet or the insulating sheet is used to form an insulating portion in which the conductive material is not mixed, and the conductive portion is formed of a metal film in which the insulating material is not mixed. It is possible to achieve bonding treatment or pressure contact with the formed circuit, which has excellent insulation properties in the insulating part and excellent conductivity in the conductive part, and which involves necessary circuit connection of a printed wiring board or the like. In addition, an insulating adhesive sheet or insulating sheet can be formed by a simple process of transferring the metal film to a predetermined position by the above method using a transfer sheet in which a metal film is transferably provided on an easily peelable sheet. Can be filled in the holes provided in, and the anisotropic conductive film can be mass-produced efficiently. Further, the metal film is excellent in purity, thinness, uniformity of thickness and the like, and is excellent in conductivity.

[0007]

EXAMPLE An anisotropic conductive film of the present invention is illustrated in FIG. 1
Is an insulating adhesive sheet or insulating sheet, and a metal film filled with 2. For manufacturing such an anisotropic conductive film, for example, as shown in FIG. 2, a transfer sheet 5 which is provided with a metal film 4 transferably provided on an easily peelable sheet 3 is used, and the metal film 4 is applied to an insulating adhesive sheet or an insulating adhesive sheet. This can be performed by filling and transferring into a hole 11 provided in a predetermined portion of the insulating sheet 1.

As the insulating adhesive sheet, a suitable insulating sheet having an adhesive force may be used. For example,
Examples include adhesive sheets and heat-sensitive adhesive sheets. In addition, as the insulating sheet used when adhesiveness is not required such as contacting with pressure, sheets made of various insulating substances such as insulating polymers may be used. In addition, in the case of the above-mentioned pressure-sensitive adhesive sheet, it is used in a state where both surfaces thereof are covered with a separator, and the separator is peeled and removed when it is put to practical use. The thickness of the insulating adhesive sheet or the insulating sheet can be appropriately determined according to the insulating performance and the like. Generally, the thickness is about 10 μm to 2 mm.

As the pressure-sensitive adhesive sheet, an appropriate one using a rubber-based or acrylic-based pressure-sensitive adhesive can be used.
An appropriate heat-sensitive adhesive sheet may be used, but a heat-sensitive adhesive sheet is preferably made of a thermoplastic resin having a good film-forming property, a large adhesive force and an excellent insulating property. Examples of the thermoplastic resin include polyethylene, polyalkylenes such as polypropylene, ethylene / vinyl acetate copolymer,
Examples thereof include ethylene / ethyl acrylate copolymer, ethylene / acrylic acid copolymer, polyvinyl acetate, acrylic polymer, polyamide, polyurethane, polyester, polyvinyl ether, polyvinyl alcohol, and mixtures thereof.

The metal film filling holes provided in the insulating adhesive sheet or the insulating sheet can be appropriately determined according to the connection target such as the circuit position to be connected between the printed wiring boards. The holes may be formed by an arbitrary method such as a punching method using a press or the like, a hole forming method using a laser or the like. The size of the holes to be formed may be appropriately determined as needed. Even a hole having a diameter of about 100 μm can be filled by the method of the present invention.

As described above, in the method of the present invention, the transfer sheet is used to fill and transfer the metal film into the holes provided in a predetermined portion of the insulating adhesive sheet or the insulating sheet. The transfer sheet is such that the metal film 4 is transferably provided on the easily peelable sheet 3 as illustrated in FIG.

As the easily peelable sheet, for example, an appropriate one known as a separator in an adhesive sheet or the like can be used. Generally, from a fluororesin such as polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, tetrafluoroethylene / hexafluoropropylene copolymer, chlorotrifluoroethylene / vinylidene fluoride copolymer. Sheet, a sheet made of a polyolefin resin such as polyethylene or polypropylene, or a sheet made of a usual plastic such as polyester, polyamide, polyvinyl chloride or polystyrene, or a thin foil such as a metal foil, for example, a silicone release agent or a fluorine-based release agent. A release agent, a long-chain acrylic release agent, or a material surface-treated with a release property imparting agent such as molybdenum sulfide is used.
The thickness of the easily peelable sheet may be appropriately determined, but is generally 1 to 600 μm in view of the transferability of the metal film. The easily peelable sheet may have a deformability such as elongation controlled by a stretching treatment or the like.

The transferably provided metal film on the easily peelable sheet is formed of an electrically conductive metal suitable for the purpose of use. Examples thereof include gold, silver, indium, tin, bismuth, lead, thallium, zinc, aluminum, copper, nickel, chromium and alloys thereof. Generally, a low melting point alloy such as indium, tin, or solder, particularly indium, indium type alloy, tin type alloy, bismuth type alloy, lead type alloy, thallium type alloy or the like having a melting point of 200 ° C. or less is used.

The metal film can be formed by a thin film forming method such as a vacuum deposition method, a sputtering method, an ion plating method, and a wet plating method such as electrolytic or electroless. The thickness of the metal film to be formed is usually 10Å to 300 μm, especially 1 to 100 μm in view of transferability and the like. The metal film may be formed as a superposed film of different metals for the purpose of improving connectivity between circuits.

From the viewpoint of transferability and the like, the transfer sheet is preferably one in which the interfacial adhesive force of the metal film to the easily peelable sheet is larger than the tensile strength of the metal film, especially 10 g or more, particularly 50 g or more. Thereby, the force required for peeling the metal film from the easily peelable sheet becomes larger than the film strength of the metal film, and the metal film can be cut by the pressing force at the time of the transfer. The transfer sheet may be in a form such that a long roll or the like can be continuously supplied, which is advantageous for continuous production of the anisotropic conductive film.

The filling transfer of the metal film through the transfer sheet to the insulating adhesive sheet or the holes provided in the insulating sheet is performed, for example, by stacking the insulating adhesive sheet and the metal film of the transfer sheet and pressing the metal film. Can be pushed into a hole of an insulating adhesive sheet or the like to separate the easily peelable sheet. In the present invention, since the metal film is excellent in cutting property at the interface between the transferred portion and the non-transferred portion, the filling transfer can be performed only by pushing in the metal film and separating the easily peelable sheet.

The pressing process can be carried out by an appropriate system such as a roll system or a press system. Pressing force required for filling transcription, but are not limited to commonly 30kg / cm ² or less, especially 0.5 to 10 / cm ² approximately. For the pressing process, an appropriate method such as a heating pressing method, a vibration pressing method using ultrasonic waves, or a combination thereof can be adopted. As described above, according to the present invention, holes having a diameter of about 100 μm can be filled, but in that case, the metal film can be sufficiently pushed into the holes by simple pressing with a roll or the like because the holes have a narrow pitch. When it is not possible, it may be pushed in with a pen or the like.

As described above, in the method of the present invention, the anisotropic conductive film is manufactured by the filling transfer method of the metal film, but in that case, it may be formed in advance as a size body according to the purpose of use. Since it can be cut easily with a cutter or a sandwich, it can be cut into a large size and cut into a size suitable for the purpose of use.

The anisotropic conductive film of the present invention can be used for the same purpose as in the prior art, for example, for insulating and joining opposing printed wiring boards while achieving necessary electrical connection between circuits. In that case, the metal film portion of the anisotropic conductive film of the present invention is arranged so as to correspond to the circuit position to be connected, and is heat-treated as necessary. The heat treatment is intended to activate the insulating adhesive sheet, or to connect the circuits by melting the metal film. In the case of an insulating sheet that replaces the insulating adhesive sheet, it is preferably used for a method such as a pressure contact method in which no adhesion treatment is performed through a sheet, or a method for achieving an adhesion purpose by melting a metal film filled in a hole. sell.

[0020]

According to the anisotropic conductive film of the present invention, it is possible to form a conductive part made of a metal film containing no insulating material and an insulating part containing no conductive material, and to improve the insulating property of the insulating part. It is possible to achieve a joining process involving necessary circuit connection of a printed wiring board or the like having excellent conductivity in the conductive portion. Further, according to the method of the present invention, the anisotropic conductive film can be mass-produced with high production efficiency by a simple operation of filling and transferring the metal film, and the purity, thinness, thickness uniformity, etc. of the filled metal film can be improved. Excellent in conductivity.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of an anisotropic conductive film.

FIG. 2 is a cross-sectional view illustrating a method for manufacturing an anisotropic conductive film.

[Explanation of symbols]

 1: Insulating adhesive sheet or insulating sheet 11: Holes provided in the sheet 2: Filled metal film 5: Transfer sheet 3: Easy peeling sheet 4: Metal film

Claims (2)

[Claims] 1. An anisotropic conductive film, characterized in that a hole is formed in a predetermined portion of the insulating adhesive sheet or the insulating sheet and is filled with a metal film. 2. A transferable metal film provided on an easily peelable sheet is filled and transferred in a hole provided in a predetermined portion of the insulating adhesive sheet or the insulating sheet.
The method for producing an anisotropic conductive film as described in.