JP2005116183A - Forming method of anisotropic conductive film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simpler and more convenient forming method of an anisotropic conductive film. <P>SOLUTION: As for this forming method of the anisotropic conductive film, a process is simplified by arranging conductive wire materials so as not to be contacted with one another by applying a woven fabric technique. That is, a plurality of woven fabrics in which either the warp or the weft is composed of a conductive fiber, in which the other is a fiber composed of insulating resin, and which are woven so that the conductive fibers are not contacted with one another, and are arranged and laminated in the longitudinal direction of the conductive fiber, so that the conductive fibers are not contacted with one another, the insulating resin is fused and integrated, and fused and integrated laminates are approximately perpendicularly cut with respect to the longitudinal direction of the conductive fiber and made into sheets. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing an anisotropic conductive film, and more particularly to a method for manufacturing an anisotropic conductive film that is preferably used for connection between a semiconductor device and a substrate.

In recent years, with the increase in functionality and reduction in size and weight of electronic devices, wiring circuit patterns have been highly integrated in the semiconductor field, and fine patterns with multiple pins and narrow pitches have been adopted. In order to cope with such fine patterns of circuits, anisotropic conductive films have begun to be used for connection between a plurality of conductor patterns formed on a substrate and conductor patterns or ICs or LSIs connected to the conductor patterns. An anisotropic conductive film is a film that has electrical conductivity only in a certain direction but is electrically insulated in other directions.

  Regarding the manufacturing method of the anisotropic conductive film that is insulated in the planar direction and conductive only in the thickness direction, a method of making conductive fine particles dispersed in the adhesive film, or providing a through hole in the adhesive film, A method of filling a metal with a metal by plating is used.

  However, although the anisotropic conductive film made by the former method can be manufactured at low cost, since conductive fine particles are blended in the adhesive film by dispersion, the electrical connection with a narrow pitch is performed. Has the disadvantage of being unreliable.

  On the other hand, in the latter method, by providing the through-holes with high accuracy, high reliability can be obtained with respect to the electrical connection with a narrow pitch, but the cost is high because it takes time for drilling and metal filling. There is a problem.

In order to solve such an object, Patent Document 1 discloses a method for producing an anisotropic conductive film characterized by having at least the following steps 1) to 3).
1) A step of winding an insulated conductive wire in which two or more coating layers made of an insulating material are provided on a wire made of a conductive material around a core material in a roll shape.
2) While winding in the step 1) or after the step 1), heating and / or pressurizing the roll-shaped winding coil so as to fuse and / or coat the coated layers of the wound insulated conductors. Alternatively, a process of forming a coiled coil block by being crimped and integrated.
3) A step of cutting the wound coil block obtained in the step 2) to a predetermined film thickness with a plane intersecting the wound wire rod at an angle.

However, this method is complicated in process because it is necessary to provide two or more coating layers on the conductive wire. In addition, since it is made by cutting from a coil-shaped block using a core material, a necessary size must be obtained from the portion excluding the core material, which is a wasteful process that is not suitable for large area.
Patent No. 3179503 (Claim 11 etc.)

  This invention is made | formed in view of the above prior arts, Comprising: It aims at providing the simpler manufacturing method of an anisotropically conductive film.

In the method for producing an anisotropic conductive film according to the present invention, by applying a woven fabric technique, conductive wires are arranged so as not to contact each other, thereby simplifying the process.

That is, the method for producing an anisotropic conductive film according to the present invention is as follows.
One of the warp and the weft is made of a conductive fiber, the other is a fiber made of an insulating resin, and a plurality of woven fabrics woven so that the conductive fibers are not in contact with each other. Laminate with the longitudinal direction of the conductive fibers so as not to contact each other,
Insulating resin is fused and integrated,
The fused and integrated laminate is characterized by being cut into a sheet by cutting substantially perpendicularly to the longitudinal direction of the conductive fibers.

  In the present invention, the woven fabric may be impregnated with a heat-welding insulating resin, and then fusion integration may be performed.

  Further, a heat-welding insulating film may be interposed between the woven fabrics and laminated, and then fusion integration may be performed.

  According to such a method for producing an anisotropic conductive film according to the present invention, by applying the woven fabric technology, the conductive fibers can be arranged without contacting each other, so that it is not necessary to use a covered wire. For this reason, the process can be simplified. Further, since a necessary size is cut out from the block in which the woven fabric is laminated, the waste is less than that in the conventional manufacturing method, and the area can be increased.

  Hereinafter, the present invention will be described more specifically with reference to the drawings.

  In the method for producing an anisotropic conductive film according to the present invention, as shown in FIG. 1, first, either warp or weft is made of conductive fiber 10, and the other is fiber 11 made of insulating resin. And the woven fabric 1 woven so that the conductive fibers 10 do not contact each other is prepared. Although FIG. 1 shows an example in which the conductive fiber 10 is a warp, the conductive fiber may be a weft. Further, if there is a sufficient distance so that the conductive fibers 10 do not contact each other, the warp may be formed only from the conductive fibers 10, but in order to ensure insulation between the conductive fibers, FIG. As shown in FIG. 2, the insulating fibers 11 may be interposed as warps between the conductive fibers 10. The number of the insulating fibers 11 interposed between the conductive fibers 10 may be one, or two or more.

  In addition, although the case of plain weave is taken as an example in FIG. 1, plain weave, twill weave, satin weave, or other weaving methods may be used as long as the conductive fibers are reliably insulated from each other.

  As the conductive fiber 10, for example, a gold wire, silver wire, copper wire, stainless steel wire, nickel wire, solder wire or the like is used. The outer surface of the conductive fiber may be coated with an insulating resin. The diameter of the conductive fiber 10 is not particularly limited as long as the woven fabric can be produced, but preferably 1 to 50 μm, more preferably, considering that the cross section of the conductive fiber 10 is a contact portion with the device. Is about 2 to 30 μm, particularly preferably about 5 to 20 μm.

  The insulating fiber 11 is preferably a thermoplastic resin for fusion in a later step, and for example, a thermoplastic polyimide or the like is used. The diameter of the insulating fiber 11 is not particularly limited as long as a woven fabric can be produced. In order to prevent the occurrence, it is preferable to have the same degree as that of the conductive fiber 10.

The distance between the conductive fibers 10 is the shortest distance for reliable insulation, preferably 1 to 1.
The thickness is 200 μm, more preferably 2 to 100 μm, particularly preferably about 5 to 50 μm. Further, the distance between the insulating fibers 11 is not particularly limited as long as the insulation between the conductive fibers 10 is ensured, but in order to form a dense fusion product, the adjacent insulating fibers 11 are adjacent to each other. It is desirable to be as close as possible.

The woven fabric 1 as described above may be used as it is in a subsequent process, but is preferably used after being immersed in an insulating resin in order to ensure insulation between the conductive fibers 10. Thereby, since insulating resin fills the space | gap between fibers, insulation of the conductive fibers 10 can be performed reliably. In addition, since a dense fusion product is obtained, generation of voids in the finally obtained film can be prevented. Here, as the insulating resin, a resin having the same material as that of the insulating fiber 11 is preferably used.
Next, a plurality of the woven fabrics 1 are laminated with the longitudinal direction of the conductive fibers 10 aligned. Since the thickness to laminate | stack becomes one side of an anisotropic conductive film, it matches with the dimension of the member to apply. For example, when the anisotropic conductive film according to the present invention is applied to a silicon wafer at the wafer level, the wafer is laminated so that the diameter of the wafer becomes the thickness of the laminate. When applied to the chip size, the length of one side of the chip is the thickness of the laminate.

  In addition, when the woven fabric 1 is immersed in an insulating resin, the conductive fibers 10 are surely insulated from each other. In the case of laminating as it is, it is preferable to interpose an insulating film between the woven fabrics 1. As the insulating film, a resin film made of the same material as the insulating fiber 11 is preferably used. The film thickness of such an insulating film is not particularly limited, but a film having a film thickness approximately equal to the interval between the conductive fibers 10 in the woven fabric 1 is preferable so that the pitch of the conductive fibers 10 is equal. Used.

  Further, after the woven fabric 1 is laminated, an insulating resin may be further immersed in the laminate. Here, as the insulating resin, a resin having the same material as that of the insulating fiber 11 is preferably used. Thus, by immersing the resin in the laminate, the resin is filled between the layers of the woven fabric 1 or between the woven fabric 1 and the insulating film, and a denser fused product is finally obtained. Generation of voids in the produced film can be prevented.

  Next, the laminate is heated and pressurized to fuse and integrate the insulating resin components in the laminate. The heating and pressing conditions are appropriately set depending on the type of insulating fiber, insulating resin and / or insulating film used, the size of the laminate, and the like. By such heating and pressing, the resin component in the laminate, that is, the insulating fiber 11, and the insulating resin and insulating film used as necessary are fused and integrated. As a result, as shown in FIG. 2, the conductive fiber / insulating resin composite 2 in which the conductive fibers 10 are embedded in the insulating resin 12 at substantially regular intervals and aligned in the longitudinal direction. can get.

  Finally, the anisotropically conductive film 3 is obtained by slicing the fusion-integrated laminate (composite 2) almost perpendicularly to the longitudinal direction of the conductive fibers 10. For example, when the conductive fiber 10 is cut at 90 ° with respect to the longitudinal direction, the anisotropic conductive material in which the conductive fiber 10 is embedded perpendicularly to the plane of the film as shown in FIGS. Film 3 is obtained.

The thickness of the anisotropically conductive film 3 finally obtained varies depending on the target device, but is preferably 20 to 1000 μm, more preferably 30 to 500 μm, and particularly preferably about 50 to 200 μm. Further, the thickness of the anisotropic conductive film 3 can be set as appropriate when the composite 2 is cut.
If it is not possible to obtain an appropriate thickness by cutting alone or the thickness accuracy is inferior, the cut surface may be polished and then polished to finish the set thickness and accuracy.

  FIG. 5 is a schematic diagram of an anisotropic conductive film when cut thickly. In the figure, the insulating fiber, the insulating film, and the insulating resin are indicated by solid lines, but they are actually integrated by heat fusion. Since the conductive fibers are woven like a woven cloth, they communicate in the thickness direction while wavy. Even if the anisotropic conductive film is applied to the object at a considerably high pressure, the conductive fiber acts like a spring with such a structure, so that it is difficult to damage the object.

  The anisotropic conductive film according to the present invention thus obtained is applied to, for example, conductive bonding between a semiconductor chip and a chip mounting substrate. In particular, since the area can be increased, it can be applied to a wafer before dicing.

  Specifically, the anisotropic conductive film according to the present invention is attached to a circuit surface of a wafer having a circuit formed on the surface by heating and pressing. Subsequently, the wafer is divided into pieces together with the anisotropic conductive film by dicing, and then flip chip bonding is performed on a predetermined position of the chip mounting substrate. Since the semiconductor device can be manufactured in this way, the work performed for each chip is only chip bonding, and the manufacturing of the semiconductor device can be greatly simplified.

According to the method for manufacturing an anisotropic conductive film according to the present invention, by applying the woven fabric technology, the conductive fibers can be arranged without contacting each other, so that it is not necessary to use a covered wire. For this reason, the process can be simplified. Moreover, since the laminated | stacked block only makes a rectangular parallelepiped, what is necessary is just to make it the cross section become the size of an anisotropic conductive film. Therefore, there is less waste than a conventionally proposed method for manufacturing an anisotropic conductive film, and an area such as a wafer size can be increased.

The top view of the woven fabric used for manufacture of the anisotropic conductive film which concerns on this invention is shown. 1 process of the manufacturing method of the anisotropically conductive film which concerns on this invention is shown. The perspective view of the anisotropically conductive film obtained by this invention is shown. Sectional drawing of the one aspect | mode of the anisotropically conductive film obtained by this invention is shown. Sectional drawing of the other aspect of the anisotropically conductive film obtained by this invention is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Woven cloth 2 ... Conductive fiber / insulating resin composite 3 ... Anisotropic conductive film 10 ... Conductive fiber 11 ... Insulating fiber

Claims (3)

Either a warp or a weft is made of a conductive fiber, the other is a fiber made of an insulating resin, and a plurality of woven fabrics woven so that the conductive fibers do not contact each other, Laminate so that they do not touch and align the longitudinal direction of the conductive fibers,
Insulating resin is fused and integrated,
A method for producing an anisotropic conductive film, characterized in that the fused and integrated laminate is cut into a sheet by cutting substantially perpendicularly to the longitudinal direction of the conductive fibers.   The method for producing an anisotropic conductive film according to claim 1, wherein the woven fabric is impregnated with a heat-fusible insulating resin.   The method for producing an anisotropic conductive film according to claim 1, wherein a heat-sealable insulating film is laminated between the woven fabrics.

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