CN107431280B

CN107431280B - Anisotropic conductive connection method and anisotropic conductive connection structure

Info

Publication number: CN107431280B
Application number: CN201680014131.2A
Authority: CN
Inventors: 青木和久; 田中雄介
Original assignee: Dexerials Corp
Current assignee: Dexerials Corp
Priority date: 2015-03-20
Filing date: 2016-03-16
Publication date: 2020-03-03
Anticipated expiration: 2036-03-16
Also published as: JP6508677B2; KR20170081664A; CN107431280A; JP2016178015A; TW201705616A; WO2016152673A1; TWI692913B; KR101992549B1; HK1245510A1

Abstract

There is provided an anisotropic conductive connection method for anisotropically conductive connecting a 1 st terminal row (11) provided in a 1 st electronic part and a 2 nd terminal row (41) provided in a 2 nd electronic part, comprising: a step of temporarily pressing the anisotropic conductive film (20) against the 1 st terminal row (11); and a step of main-pressing the 2 nd terminal row (41) onto the anisotropic conductive film (20), wherein the anisotropic conductive film (20) is colored, the colored state of the anisotropic conductive film (20) is not changed during the temporary pressing, and the transmittance of the anisotropic conductive film (20) is increased during the main pressing.

Description

Anisotropic conductive connection method and anisotropic conductive connection structure

Technical Field

The present invention relates to an anisotropic conductive connection method and an anisotropic conductive connection structure.

Background

For example, as disclosed in patent documents 1 to 3, there is known a technique for anisotropically electrically connecting (bonding) a plurality of electronic components (the 1 st electronic component and the 2 nd electronic component). These electronic components are, for example, substrates. Here, each electronic component is provided with a terminal row, and the terminal rows of the electronic components are anisotropically conductively connected to each other. In this technique, a plurality of electronic components are anisotropically and electrically connected by the following steps.

First, an Anisotropic Conductive Film (ACF) is temporarily attached to the 1 st terminal row provided on the 1 st electronic component. Here, a base material film such as a PET (polyethylene terephthalate) film is bonded to one surface of the anisotropic conductive film. Therefore, the other anisotropic conductive film is pasted on the 1 st terminal column while facing. Here, the 1 st electronic component is provided with an alignment mark, and the 1 st terminal row is disposed inside the alignment mark. Thus, the anisotropic conductive film is temporarily stuck on the inner side of the alignment mark. In this way, the alignment mark indicates a reference of the temporary bonding position of the anisotropic conductive film (and the mounting position of the 2 nd electronic component).

Next, a heating and pressing member such as a heating tool is brought into contact with the base material film, whereby the anisotropic conductive film is temporarily pressure-bonded to the 1 st terminal row. The temperature of the heating tool at the time of temporary pressure bonding is lower than the temperature of the heating tool at the time of final pressure bonding. Subsequently, the base material film is peeled off from the anisotropic conductive film. Next, the 2 nd electronic component is mounted on the anisotropic conductive film. Here, the 2 nd electronic component is positioned so that the 2 nd terminal row provided in the 2 nd electronic component is opposed to the 1 st terminal row, and mounted on the anisotropic conductive film. Specifically, the 2 nd electronic component is mounted inside the alignment mark. Then, the 2 nd terminal row is formally pressed against the anisotropic conductive film by abutting the heating and pressing member to the 2 nd electronic component. Through the above steps, the 1 st electronic component and the 2 nd electronic component are anisotropically conductively connected.

In the above-described technique, it is very important to anisotropically electrically connect the 1 st electronic component and the 2 nd electronic component. Therefore, in patent document 2, in order to confirm that the 1 st electronic component and the 2 nd electronic component are anisotropically electrically connected, a resin material that develops color under the conditions of main pressure bonding is included in the anisotropic conductive film. According to this technique, if the main pressure bonding is performed under a predetermined condition, the anisotropic conductive film develops color. Therefore, in patent document 2, it is confirmed whether or not the anisotropic conductive film develops color after the main pressure bonding, and whether or not the 1 st electronic component and the 2 nd electronic component are anisotropically conductively connected.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2006-127956

Patent document 2: japanese laid-open patent publication No. 11-307154

Patent document 3: japanese laid-open patent publication No. 2007-91798

Patent document 4: japanese patent laid-open No. 4-145180.

Disclosure of Invention

Problems to be solved by the invention

However, the state of the anisotropic conductive film after the final pressure bonding can be performed by visually recognizing a portion of the anisotropic conductive film extruded from the 2 nd electronic component by the final pressure bonding. In the technique disclosed in patent document 2, since the extruded portion of the anisotropic conductive film is colored, the above confirmation is performed based on the colored state of the extruded portion. However, what can be confirmed in patent document 2 is always only the temperature condition at the time of thermocompression bonding.

On the other hand, in order to anisotropically and electrically connect the 1 st terminal and the 2 nd terminal, it is necessary to maintain the mounting position of the 2 nd electronic component at an appropriate position even after the final pressure bonding. Therefore, although this need to be confirmed, it is not easy to confirm in patent document 2. Specifically, in patent document 2, since the extruded portion is colored, it is difficult to visually recognize the alignment mark present on the back surface side of the extruded portion. Therefore, it is difficult to confirm whether or not the mounting position of the 2 nd electronic component is properly maintained even after the final pressure bonding. Therefore, in the technique disclosed in patent document 2, it is not possible to accurately confirm whether or not the 1 st electronic component and the 2 nd electronic component are anisotropically electrically connected.

Further, in the technique of anisotropically connecting (bonding) a plurality of electronic components, it is also very important to temporarily press-bond an anisotropic conductive film at a correct position (position within the alignment mark). Therefore, although a technique capable of confirming the temporary pressure bonding of the anisotropic conductive film at the correct position is desired by earnest, such a technique has not been proposed at all.

For example, the resin material disclosed in patent document 2 does not develop color under the condition of temporary pressure bonding. Therefore, the anisotropic conductive film disclosed in patent document 2 maintains transparency during temporary pressure bonding. Therefore, in the technique disclosed in patent document 2, it is difficult to confirm that the anisotropic conductive film is temporarily pressed in a correct position.

On the other hand, patent document 3 discloses a color former that develops color by irradiation with UV light. However, the color former does not develop color when temporarily pressed. That is, the anisotropic conductive film disclosed in patent document 3 maintains transparency even when temporarily pressure-bonded. Therefore, the technique disclosed in patent document 3 fails to solve the above problem at all.

Patent document 4 discloses an anisotropic conductive adhesive that changes color under the conditions of main pressure bonding. The anisotropic conductive adhesive is colored at the time of temporary pressure bonding. Therefore, in the technique disclosed in patent document 4, it can be confirmed that the anisotropic conductive film is temporarily pressed in the correct position. However, in this technique, since the anisotropic conductive film is colored even after the main pressure bonding, there is a problem that it is difficult to visually recognize the back surface side of the extruded portion after the main pressure bonding.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a novel and improved anisotropic conductive connection method and an anisotropic conductive connection structure, which can more accurately confirm whether an anisotropic conductive film is temporarily pressed at a correct position or whether a 1 st electronic component and a 2 nd electronic component are anisotropically and conductively connected.

Means for solving the problems

In order to solve the above problems, according to an aspect of the present invention, there is provided an anisotropic conductive connection method for anisotropically and electrically connecting a 1 st terminal row provided in a 1 st electronic component and a 2 nd terminal row provided in a 2 nd electronic component, the method comprising: a step of temporarily pressing an anisotropic conductive film onto the 1 st terminal column; and a step of positively pressure-bonding the 2 nd terminal row to the anisotropic conductive film, wherein the anisotropic conductive film is colored, the colored state of the anisotropic conductive film is not changed at the time of temporary pressure bonding, and the transmittance of the anisotropic conductive film is increased at the time of positive pressure bonding.

Here, the anisotropic conductive film may be colored in the same color as any one of the alignment marks drawn on the 1 st electronic component, the 1 st terminal row, and the 1 st electronic component.

The 1 st electronic component may be colored in a transparent or achromatic color, and the anisotropic conductive film may be colored in the same color as that of the 1 st terminal row and the alignment mark.

The 1 st electronic component may be a ceramic substrate.

According to another aspect of the present invention, there is provided an anisotropic conductive connection structure produced by the anisotropic conductive connection method.

According to the above aspect of the present invention, since the colored state of the anisotropic conductive film does not change when temporarily pressure-bonding, it is possible to more accurately confirm that the anisotropic conductive film is temporarily pressure-bonded at the correct position. Further, since the transmittance of the anisotropic conductive film increases during the main pressure bonding, it is possible to more accurately confirm that the main pressure bonding is performed under the predetermined conditions. Further, since the rear surface side of the extruded portion of the anisotropic conductive film can be easily visually recognized, it can be confirmed that the mounting position of the 2 nd electronic component is maintained at an appropriate position more accurately. Therefore, the anisotropic conductive connection between the 1 st electronic component and the 2 nd electronic component can be confirmed more accurately.

Effects of the invention

As described above, according to the present invention, it is possible to more accurately confirm the case where the anisotropic conductive film is temporarily pressed at the correct position and the case where the 1 st electronic component and the 2 nd electronic component are anisotropically and electrically connected.

Drawings

Fig. 1 is a side sectional view for explaining an anisotropic conductive connection method according to an embodiment of the present invention.

Fig. 2 is a side sectional view for explaining an anisotropic conductive connection method according to an embodiment of the present invention.

Fig. 3 is a plan view for explaining an anisotropic conductive connection method according to an embodiment of the present invention.

Fig. 4 is a side sectional view for explaining an anisotropic conductive connection method according to an embodiment of the present invention.

Fig. 5 is a side sectional view for explaining an anisotropic conductive connection method according to an embodiment of the present invention.

Fig. 6 is a plan view for explaining an anisotropic conductive connection method according to an embodiment of the present invention.

Fig. 7 is a side sectional view for explaining an anisotropic conductive connection method according to an embodiment of the present invention.

Fig. 8 is a plan view for explaining an anisotropic conductive connection method according to an embodiment of the present invention.

Fig. 9 is a side sectional view for explaining an anisotropic conductive connection method according to an embodiment of the present invention.

Fig. 10 is a side sectional view for explaining an anisotropic conductive connection method according to an embodiment of the present invention.

Fig. 11 is a plan view for explaining an anisotropic conductive connection method according to an embodiment of the present invention.

Detailed Description

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and the drawings, the same reference numerals are given to the constituent elements having substantially the same functional configuration, and redundant description thereof is omitted.

< 1. Structure of Anisotropic conductive film >

In the present embodiment, the 1 st terminal 11 provided on the base substrate 10 (1 st electronic component) and the 2 nd terminal 41 provided on the flexible substrate 40 (2 nd electronic component) are anisotropically electrically connected by the anisotropic conductive film 20 shown in fig. 7. Therefore, first, the structure of the anisotropic conductive film 20 according to the present embodiment will be described. The anisotropic conductive film 20 contains at least a film-forming resin, an acrylic polymerizable compound, a heat curing initiator, a colorant, and conductive particles.

The film-forming resin is a resin for holding the anisotropic conductive film 20 in a film shape. The film-forming resin is not particularly limited as long as the film-forming resin that is the conventional anisotropic conductive film 20 can be used. As the film-forming resin, various resins such as epoxy resin, phenoxy resin, polyester urethane resin, polyester resin, polyurethane (polyurethane) resin, acrylic resin, polyimide resin, butyral resin, and the like can be used. In the present embodiment, any one of these film-forming resins may be used alone, or two or more of them may be used in combination. In addition, the film-forming resin is preferably a phenoxy resin from the viewpoint of satisfactory film formability and adhesion reliability.

The propylene polymerizable compound is a resin that is cured by heat together with a thermal curing initiator. The cured propylene polymerizable compound bonds the 1 st terminal row and the 2 nd terminal row in the adhesive layer 20a described later, and holds the conductive particles in the adhesive layer 20 a.

The propylene polymerizable compound is a monomer, oligomer, or prepolymer having 1 or 2 or more propylene groups in the molecule. Examples of the propylene polymerizable compound include methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, epoxy acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylolpropane triacrylate, dimethylol tricyclodecanyl diacrylate, 1, 4-butanediol tetraacrylate, 2-hydroxy-1, 3-diacryloyloxypropane, 2-bis [ 4- (acryloyloxymethyl) phenyl ] propane, 2-bis [ 4- (acryloyloxyethoxy) phenyl ] propane, dicyclopentenyl acrylate, tricyclodecanyl acrylate, tris (acryloyloxyethyl) isocyanurate, and amino acrylate.

In the present embodiment, any one of the above-listed propylene polymerizable compounds may be used, or any two or more thereof may be used in combination.

The thermal curing initiator is a material that is cured by heat together with the above-mentioned propylene polymerizable compound. The present inventors have found that in the case where a specific thermal curing initiator is used as the thermal curing initiator, the coloring agent does not fade during temporary pressure bonding, and the color of the coloring agent disappears (i.e., the transmittance of the anisotropic conductive film increases) during formal pressure bonding. Specifically, the thermal curing initiator of the present embodiment contains di-t-butyl hexahydro-terephthalate peroxide (ジ -t- ブチルパ - オキシヘキサヒドロテレフタレート). The thermal curing initiator of the present embodiment may further contain a known thermal curing initiator other than di-t-butyl hexahydro-terephthalate. The content of the thermosetting initiator is not particularly limited as long as it is a content suitable for the known anisotropic conductive film 20.

The colorant is a material for coloring the anisotropic conductive film 20. The kind of the colorant is not particularly limited, and the colorant of the present embodiment can be used if it is a colorant that can be applied to the conventional anisotropic conductive film 20. For example, various pigments, dyes, pigments, and the like can be used as the colorant of the present embodiment.

Here, as will be described later, any one of the base substrate 10 (1 st electronic component), the 1 st terminal 11, the 1 st wiring pattern 12, and the alignment mark 10a may be colored in color. Hereinafter, these members are also referred to as "base members". In this case, the color of the colorant is preferably the same color as that of the base member colored in color. Here, the "same-kind color" of the color of the base member means a color close to (but not the same as) the color of the base member on the hue circle. More specifically, the color wheel was divided evenly into 4 parts. Here, the color wheel is divided into 4 parts so that the color of the base member is arranged at the center of any of the divided regions (hereinafter, also referred to as "divided regions"). Further, the divided regions to which the color of the base member belongs and the colors in the same region become "same-kind colors" of the color of the base member. When the color of the colorant, that is, the color of the anisotropic conductive film 20 and the color of the base member are the same, the visibility of the anisotropic conductive film 20 at the time of temporary pressure bonding is improved. This makes it easy to confirm whether or not the anisotropic conductive film 20 is temporarily pressed at the correct position. The term "different colors" means that when the hue circle is divided into 24 or more parts, the hue circle exists in different divided regions.

In addition, the area of the base substrate 10 is the largest among the base members. Therefore, among the colors of the base member, the color of the base substrate 10 is most conspicuous. Therefore, the color of the anisotropic conductive film 20 is most preferably the same as the color of the base substrate 10. However, the base substrate 10 may be colored in a transparent or achromatic color, or other base members may be colored in a chromatic color. In this case, the color of the anisotropic conductive film 20 may be clear as described later, or may be the same color as that of any one of the 1 st terminal 11 and the alignment mark 10 a.

Examples of the color (chromatic color) of the base substrate 10 include brown (dull brown), dark brown, light brown, orange, green, and the like. Examples of the same color of brown, dark brown, and light brown include orange, red, and the like. Examples of the similar orange color include yellow and red. Examples of the similar color to green include yellow green.

The color (color) of the 1 st terminal 11, the 1 st wiring pattern 12, and the alignment mark 10a may be gold, for example. Examples of the similar color of gold include red, orange, and yellowish green.

In addition, the base member may be colored in an achromatic color (e.g., milky white, silver). The base substrate 10 and the 1 st terminal 11 may be formed of a transparent member (e.g., glass or ITO). When all the base members are colorless or transparent, the color of the anisotropic conductive film 20 is preferably colored in a clear color that is easily visible to the naked eye. Here, a clear color is a color in which, when a color is detected by a detector such as a CCD, a difference between peaks is more easily detected than in other colors (that is, a peak (such as a peak of a voltage value) detected with respect to a clear color is more easily distinguished than a peak detected with respect to other colors). The clear color may be, for example, a color within the divided region centered on orange.

The conductive particles are a material for connecting the 1 st terminal row and the 2 nd terminal row in the adhesive layer 20a in an anisotropic conductive manner. Specifically, the conductive particles held between the 1 st terminal row and the 2 nd terminal row in the adhesive layer 20a conduct the 1 st terminal row and the 2 nd terminal row. On the other hand, since other conductive particles (for example, conductive particles that enter the gap between the 1 st terminals 11 and conductive particles that enter the gap between the 2 nd terminals 41) are dispersed in the adhesive layer 20a, conduction between the conductive particles is not caused. Therefore, the conductive particles can maintain the insulation between the 1 st terminals 11 and the 2 nd terminals 41 in the adhesive layer 20a, and can conduct the 1 st terminal row and the 2 nd terminal row. That is, the conductive particles anisotropically conductively connect the 1 st terminal row and the 2 nd terminal row in the adhesive layer 20 a.

The kind of the conductive particles is not particularly limited. Examples of the conductive particles include metal particles and metal-coated resin particles. Examples of the metal particles include metal particles of nickel, cobalt, copper, silver, gold, palladium, or the like. Examples of the metal-coated resin particles include particles in which the surface of a core resin particle such as a styrene-divinylbenzene copolymer, a benzoguanamine resin, a crosslinked polystyrene resin, an acrylic resin, or a styrene-silica composite resin is coated with a metal such as nickel, copper, gold, or palladium. A gold or palladium thin film, an insulating resin thin film that is thin enough to be broken at the time of pressure bonding, or the like may be formed on the surface of the conductive particles.

The anisotropic conductive film 20 of the present embodiment may contain a photo-curing initiator for curing the acrylic polymerizable compound. The kind of the photo-curing initiator is not particularly limited. Examples of the photo-curing initiator include a photo radical polymerization type curing agent.

In addition, the anisotropic conductive film 20 may contain various additives in addition to the above components. Examples of additives that can be added to the anisotropic conductive film 20 include silane coupling agents, inorganic fillers, antioxidants, and rust inhibitors. The kind of the silane coupling agent is not particularly limited. Examples of the silane coupling agent include epoxy, amine, mercapto/sulfide, and ureide silane coupling agents. When these silane coupling agents are added to the anisotropic conductive film 20, the adhesiveness to an inorganic substrate such as a glass substrate can be improved.

The inorganic filler is an additive for adjusting the fluidity and film strength of the anisotropic conductive film 20. The kind of the inorganic filler is also not particularly limited. Examples of the inorganic filler include silica, talc, titanium oxide, calcium carbonate, and magnesium oxide.

< 2. Anisotropic conductive connection method >

Next, an anisotropic conductive connection method according to the present embodiment will be described with reference to fig. 1 to 10. In the following description, an anisotropic conductive connection method will be described with reference to a case where the 1 st terminal 11 on the base substrate 10 and the 2 nd terminal 41 on the flexible substrate 40 are connected to each other by anisotropic conductive connection as an example. The base substrate 10 is an example of a 1 st electronic component, and the flexible substrate 40 is an example of a 2 nd electronic component. Of course, these electronic components are not limited to the substrate. For example, the 2 nd electronic component may be an IC chip or the like in which a plurality of bumps are formed as the 2 nd terminal row.

First, as shown in fig. 1, a base substrate 10 is mounted on a sample stage 100. Here, the kind of the base substrate 10 is not particularly limited. Examples of the base substrate 10 include a glass substrate, a rigid substrate, and a ceramic substrate. The glass substrate is a transparent substrate. Further, some films (oxide films) or the like may be formed on the surface of the glass substrate, and the films may develop color. In this case, the color of the film may be regarded as the color of the glass substrate. The rigid substrate and the ceramic substrate may be colored in various colors or achromatic colors depending on the material thereof. For example, the rigid substrate may be colored in a milky color. The ceramic substrate may be colored in a brown color (dull brown color).

Here, when the base substrate 10 is a ceramic substrate, a relatively expensive electronic component is often mounted on the base substrate 10. For example, a ceramic substrate can be used as a substrate of a camera module, but electronic components constituting the camera module are often expensive. Therefore, when the base substrate 10 is a ceramic substrate, it is necessary to reduce the frequency of occurrence of defects as much as possible. That is, the temporary pressure bonding of the anisotropic conductive film 20 and the final pressure bonding of the 2 nd terminal 41 to the anisotropic conductive film 20 need to be performed more accurately and reliably. In this regard, in the present embodiment, it can be more accurately confirmed that the anisotropic conductive film 20 is temporarily pressed in the correct position. Further, it is possible to more accurately confirm that the base substrate 10 and the flexible substrate 40 are anisotropically conductively connected. Therefore, when the base substrate 10 is a ceramic substrate, the effects of the present embodiment are more remarkably exhibited.

Further, the base substrate 10 is provided with a 1 st terminal 11 and a 1 st wiring pattern 12. A plurality of 1 st terminals 11 are provided on the base substrate 10. The 1 st terminals 11 are parallel to each other, and a 1 st terminal row is formed by a plurality of the 1 st terminals 11.

The material constituting the 1 st terminal 11 is not particularly limited as long as it has conductivity. Examples of the material constituting the 1 st terminal 11 include metals such as aluminum, silver, nickel, copper, and gold; conductive metal oxides such as Indium Tin Oxide (ITO), Indium Zinc Oxide (IZO), indium oxide, conductive tin oxide, Antimony Tin Oxide (ATO), and conductive zinc oxide; and conductive polymers such as polyaniline, polypyrrole, and polythiophene. The metal constituting the 1 st terminal 11 may be plated with various metals. For example, in the embodiment described later, the 1 st terminal 11 is formed of gold-plated and nickel-plated copper. In this case, the 1 st terminal 11 is colored in gold.

The 1 st wiring pattern 12 is a wiring pattern extending from the 1 st terminal 11, and is provided on the base substrate 10. The material constituting the 1 st wiring pattern 12 may be the same as the 1 st terminal 11. The 1 st terminal 11 and the 1 st wiring pattern 12 are colored in various colors or achromatic colors depending on the material thereof. For example, the 1 st terminal 11 and the 1 st wiring pattern 12 may be colored in gold.

As shown in fig. 3, an alignment mark 10a is formed on the base substrate 10. The alignment mark 10a is a mark indicating a reference of the temporary bonding position of the anisotropic conductive film 20 and the installation position of the flexible substrate 40. Therefore, although not shown in fig. 3, the 1 st terminal row is arranged in the alignment mark 10 a. In the present embodiment, the front end portion of the flexible substrate 40 is provided inside the alignment mark 10 a. Thus, the anisotropic conductive film 20 is also temporarily pressed at this position. The alignment mark 10a is colored in various colors, achromatic colors. For example, when the base substrate 10 is a rigid substrate or a ceramic substrate, the alignment mark 10a may be colored in gold. In addition, when the base substrate 10 is a glass substrate, the alignment mark 10a may be colored in silver.

Next, as shown in fig. 2 and 3, the anisotropic conductive film 20 according to the present embodiment is temporarily attached to the alignment mark 10 a. Here, since the 1 st terminal row is arranged in the alignment mark 10a, the anisotropic conductive film 20 is temporarily attached to the 1 st terminal row. Further, a base material film 30 is attached to the anisotropic conductive film 20. Therefore, here, a base material film 30 such as a PET (polyethylene terephthalate) film is attached to one surface of the anisotropic conductive film 20. Therefore, the other surface of the anisotropic conductive film 20 is temporarily stuck in the alignment mark 10 a. Here, the base material film 30 supports the anisotropic conductive film 20, and for example, a release agent such as silicone is coated on PET (polyethylene Terephthalate: Poly Ethylene Terephthalate), OPP (Oriented Polypropylene), PMP (Poly 4-methylpentene-1: Poly-4-methylpentene-1), PTFE (Polytetrafluoroethylene), or the like. The base material film 30 prevents drying of the anisotropic conductive film 20 and maintains the shape of the anisotropic conductive film 20.

Next, as shown in fig. 4, the buffer material 200 is provided on the base material film 30. Next, the anisotropic conductive film 20 is temporarily pressure-bonded to the 1 st terminal row by bringing a heating and pressing member 300 such as a heating tool into contact with the buffer material 200. The pressure temperature and pressure at the time of temporary pressure bonding are, for example, 60 to 80 ℃ and 1 to 2 MPa. The pressing time is appropriately adjusted depending on the material of the anisotropic conductive film 20, but is set to at least a value at which the anisotropic conductive film 20 can be fixed to the base substrate 10. The pressing temperature, i.e., the temperature of the heating and pressing member is lower than the pressing temperature at the time of final pressure bonding described later. Under such conditions at the time of temporary pressure bonding, the coloring state (hue, shade of color, transmittance, etc.) of the anisotropic conductive film 20 does not change.

Next, as shown in fig. 5 and 6, the base material film 30 is peeled off from the anisotropic conductive film 20. Here, the colored state of the anisotropic conductive film 20 is not changed by the temporary pressure bonding. Therefore, the anisotropic conductive film 20 is sufficiently colored (without discoloration or the like) even after temporary pressure bonding. Therefore, it is possible to more accurately confirm that the anisotropic conductive film 20 is temporarily pressed in the correct position, that is, in the alignment mark 10 a.

Here, in the case where the base member (for example, the base substrate 10) is colored in color, the anisotropic conductive film 20 is preferably colored in the same color as the color of the base member. In addition, when the base member is colored in a completely transparent or achromatic color, the color of the anisotropic conductive film 20 is preferably colored in a clear color. The detailed relationship between the color of the anisotropic conductive film 20 and the color of the base member is as described above. When the color of the anisotropic conductive film 20 is selected in this way, visibility of the anisotropic conductive film 20 is improved. As shown in the embodiment described later, the visibility of the anisotropic conductive film 20 is improved in both the case where the anisotropic conductive film 20 is directly viewed and the case where the anisotropic conductive film is viewed through a CCD camera (that is, the photographed image obtained by the CCD camera is viewed). In addition, in the case where the color of the anisotropic conductive film 20 is the same as the color of the base member, it is also expected to reduce the fatigue of the observer.

In recent years, a technique for automatically recognizing that the anisotropic conductive film 20 is temporarily pressed at a correct position has also been studied. In this technique, the anisotropic conductive film 20 and its periphery are photographed by a CCD camera or the like, and the photographed image is recognized by an automatic recognition device. Then, the automatic recognition device determines whether or not the anisotropic conductive film 20 is temporarily pressed at a correct position based on the captured image. When the color of the anisotropic conductive film 20 is the same as the color of the base member, it is expected that the accuracy of automatic recognition is improved.

Next, as shown in fig. 7 and 8, the distal end portion of the flexible substrate 40 is mounted on the anisotropic conductive film 20. More specifically, the front end portion of the flexible substrate 40 is mounted in the alignment mark 10 a. The 1 st terminal row and the anisotropic conductive film 20 are disposed in the alignment mark 10 a. Therefore, the flexible substrate 40 is positioned so that the 2 nd terminal row and the 1 st terminal row face each other, and then mounted on the anisotropic conductive film 20.

Here, the flexible substrate 40 is a substrate made of a material having high flexibility and high flexibility. The material constituting the flexible substrate 40 is not particularly limited, and a material suitable for a known flexible substrate can be applied to the present embodiment. Examples of the material constituting the flexible substrate 40 include resins such as polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyethylene, polycarbonate, polyimide, and acrylic resin, and in addition, a metal or glass formed into a thin film.

The 2 nd terminal 41 is provided in plurality at the distal end portion of the flexible substrate 40. The 2 nd terminals 41 are parallel to each other, and a 2 nd terminal row is formed by the plurality of 2 nd terminals 41. The 2 nd terminals 41 are each anisotropically conductively connected to the 1 st terminal 11. That is, the 1 st terminal column and the 2 nd terminal column are anisotropically conductively connected. The material constituting the 2 nd terminal 41 may be the same as the 1 st terminal 11.

The 2 nd wiring pattern 42 is a wiring pattern extending from the 2 nd terminal row, and is provided on the base substrate 10. The material constituting the 2 nd wiring pattern 42 may be the same as the 1 st terminal 11.

Next, as shown in fig. 9, the 2 nd terminal row is formally pressure-bonded to the anisotropic conductive film 20. Specifically, the buffer material 200 is disposed on the flexible substrate 40. Next, the 2 nd terminal row is pressed against the anisotropic conductive film 20 by contacting the heat and pressure member 300 to the cushion material 200. The pressure temperature and pressure during the final pressure bonding vary depending on the material of the anisotropic conductive film, etc., but are set at least within the range of 120 to 190 ℃ and 0.5 to 8 MPa. The pressing time can be appropriately adjusted depending on the material of the anisotropic conductive film 20, but is set to at least a value of a degree of flowing and curing the anisotropic conductive film 20.

Thus, a part of the anisotropic conductive film 20 remains between the 1 st terminal row and the 2 nd terminal row, and the rest flows between the 1 st terminals 11, between the 2 nd terminals 41, or outside the 1 st terminal row and the 2 nd terminal row. Then, the anisotropic conductive film 20 is cured to form an adhesive layer 20 a. In the adhesive layer 20a, the portion remaining between the 1 st terminal row and the 2 nd terminal row conducts the 1 st terminal row and the 2 nd terminal row, but the other portions maintain insulation. Therefore, for example, the 1 st terminals 11 and the 2 nd terminals 41 are insulated from each other. Thus, the adhesive layer 20a anisotropically conductively connects the 1 st terminal 11 and the 2 nd terminal 41. That is, the adhesive layer 20a connects the base substrate 10 and the flexible substrate 40 in an anisotropic conductive manner. In the adhesive layer 20a, a part flowing outside the 1 st and 2 nd terminal rows, a so-called extruded part, is an object to be observed by an observer. Fig. 11 shows a case where the extruded portion is formed.

The anisotropic conductive film 20 has increased transmittance due to the formal pressure bonding. That is, the color of the anisotropic conductive film 20 disappears. Therefore, by confirming that the color of the extruded portion disappears, it can be confirmed that the main press bonding is performed under a predetermined condition. Further, since the transmittance of the extruded portion is increased, the rear surface side of the extruded portion can be sufficiently visually recognized. In the example shown in fig. 11, the alignment mark 10a present on the back side of the extruded portion can be sufficiently visually recognized. Therefore, it can be easily confirmed that the mounting position of the flexible substrate 40 after the final pressure bonding is properly maintained even after the final pressure bonding.

Through the above steps, an anisotropic conductive connection structure in which the base substrate 10 and the flexible substrate 40 are anisotropically and electrically connected (more specifically, the 1 st terminal row and the 2 nd terminal row are anisotropically and electrically connected) can be produced. Hereinafter, the anisotropic conductive connection structure is also referred to as a "connection structure". As shown in fig. 10, the connection structure includes: a base substrate 10; a 1 st terminal row; the 1 st wiring pattern 12; a flexible substrate 40; a 2 nd terminal 41; the 2 nd wiring pattern 42; and an adhesive layer 20 a.

Examples

(production of Anisotropic conductive film)

(example 1)

An adhesive composition was prepared by mixing 40 parts by mass of a phenoxy resin (brand name: YP-50, made by Nippon Tekken Co., Ltd.), 15 parts by mass of an acrylic monomer (brand name: ARONIX M-315, made by Toyo Seiki Co., Ltd.), 25 parts by mass of an amino acrylate oligomer (brand name: ARONIXM1600, made by Toyo Seiki Co., Ltd.), 5 parts by mass of a rubber component (brand name: SG80H, made by NAGASE CHEMTEX Co., Ltd.), 1 part by mass of an acrylic acid monomer (brand name: Light Ester P-1M, made by Kyowa Kazao Co., Ltd.), 3 parts by mass of a thermosetting initiator (brand name: KAYA Ester HTP-65W, made by YAKAKU AKZO (Chemicals アクゾ) and 0.3 parts by mass of a coloring agent (brand name: KayaOranger A-N, made by Nippon Chemicals Co., Ltd.), and 5 parts by mass of conductive particles (Au and 10 μ M). Then, the adhesive composition was applied to a base material film having a thickness of 50 μm (made of PET, surface peeling treatment) by a bar coater and dried to obtain an anisotropic conductive film having a thickness of 25 μm. KAYA Ester HTP-65W is a thermal curing initiator comprising di-t-butyl peroxyhexahydroterephthalate. The anisotropic conductive film is colored orange with a colorant.

(example 2)

An anisotropic conductive film having the same thickness as in example 1 was obtained by performing the same treatment as in example 1 except that the colorant was changed to "Kayaset Blue a-2R" (manufactured by japan chemical industries, ltd.). The anisotropic conductive film is colored in blue by a colorant.

(example 3)

The same treatment as in example 1 was carried out except that the coloring agent was changed to "Kayaset Green a-B" (manufactured by japan chemical corporation), thereby obtaining an anisotropic conductive film having the same thickness as in example 1. The anisotropic conductive film is colored in green by a colorant.

Comparative example 1

The same process as in example 1 was carried out except that the thermosetting initiator was changed to "NYPER BW" (manufactured by japan grease corporation), whereby an anisotropic conductive film having the same thickness as in example 1 was obtained. "NYPER BW" is a thermal cure initiator comprising benzoyl peroxide. The anisotropic conductive film is colored orange with a colorant.

(preparation of connection Structure for evaluation)

(example 4)

As a base substrate, ITO pattern glass was prepared. In the ITO pattern glass, 1 st terminals made of ITO were formed at a pitch of 200 μm. In addition, the height of the 1 st terminal is 2000

The thickness of the glass portion was 0.4 mm. In addition, silver alignment marks are drawn on the periphery of the 1 st terminal row. The shape of the alignment mark is the shape shown in fig. 3. Thus, the base substrate and the 1 st terminal column are transparent, and the alignment mark is silver (achromatic).

In addition, a flexible substrate made of polyimide was prepared as the flexible substrate. The thickness of the flexible substrate was 25 μm. Further, a 2 nd terminal made of copper plated with gold and nickel was formed on the flexible substrate at a pitch of 200 μm. The height of the 2 nd terminal was 12 μm. The flexible substrate is a long substrate, and the 2 nd terminal row is arranged at the tip end portion thereof. The anisotropic conductive connection is performed by using an ACF connector for CCM (camera module) manufactured by bridge manufacturing company. The connector incorporates a CCD camera, and the CCD camera can image each member. In addition, the observer can visually recognize the captured image of the CCD camera.

Next, a base substrate was set on the sample stage. Then, the anisotropic conductive film produced in example 1 was temporarily attached to the alignment mark. Here, since the base material film is attached to one surface of the anisotropic conductive film, the other surface is attached to the alignment mark.

Next, a silicone rubber film having a thickness of 200 μm was provided as a buffer material on the base material film. Next, a heating tool having a width of 2.0mm was brought into contact with the buffer material, and the anisotropic conductive film was temporarily pressure-bonded to the 1 st terminal row. The pressure temperature, pressure and pressure time at the time of temporary pressure bonding were 50 ℃ and 1MPa for 7 seconds. The pressing position of the heating tool is just above the 1 st terminal row. Subsequently, the base material film is peeled off from the anisotropic conductive film. Next, the visibility of the anisotropic conductive film at the time of temporary pressure bonding was evaluated. The specific evaluation method will be described later.

Next, the distal end portion of the flexible substrate is mounted on the anisotropic conductive film. More specifically, the front end portion of the flexible substrate is mounted in the alignment mark. Next, a silicone rubber film having a thickness of 200 μm was provided as a buffer material on the flexible substrate. Then, a heating tool having a width of 2.0mm was brought into contact with the buffer material, and the 2 nd terminal row was firmly pressed against the anisotropic conductive film. That is, an adhesive layer is formed between the 1 st terminal row and the 2 nd terminal row. The pressure temperature, pressure and pressure time during the final pressure bonding were 140 ℃ and 2MPa for 7 seconds. Then, the visibility of the adhesive layer after the main pressure bonding was evaluated. The specific evaluation method will be described later. Further, 100 trials of the above experiment were performed.

(example 5)

As a base substrate, a matte brown ceramic substrate was prepared. A1 st terminal made of copper plated with gold and nickel was formed on the ceramic substrate at a pitch of 200 μm. The height of the 1 st terminal was 10 μm, and the thickness of the ceramic substrate was 0.4 mm. In addition, a golden alignment mark is drawn on the periphery of the 1 st terminal row. The shape of the alignment mark is the shape shown in fig. 3. Therefore, the color of the ceramic substrate is a dull brown (color), and the color of the 1 st terminal row and the alignment mark is a gold (color). The same treatment as in example 4 was performed using this base substrate.

(example 6)

The same process as in example 5 was performed except that the anisotropic conductive film produced in example 2 was used.

(example 7)

The same process as in example 5 was performed except that the anisotropic conductive film produced in example 3 was used.

(example 8)

As a base substrate, a milky-white rigid substrate was prepared. A1 st terminal made of copper plated with gold and nickel was formed on the rigid substrate at a pitch of 200 μm. The height of the 1 st terminal was 35 μm, and the thickness of the rigid substrate was 0.95 mm. In addition, a golden alignment mark is drawn on the periphery of the 1 st terminal row. The shape of the alignment mark is the shape shown in fig. 3. Therefore, the color of the ceramic substrate is milk white (achromatic color), and the color of the 1 st terminal row and the alignment mark is gold (chromatic color). The same treatment as in example 4 was performed using this base substrate.

Comparative example 2

The same process as in example 4 was performed except that the anisotropic conductive film produced in comparative example 1 was used.

Comparative example 3

The same treatment as in comparative example 2 was performed except that the ceramic substrate of example 5 was used.

Comparative example 4

The same treatment as in comparative example 2 was performed except that the rigid substrate of example 8 was used.

(evaluation of visibility)

In the evaluation at the time of temporary pressure bonding, the anisotropic conductive film temporarily pressure bonded was directly visually recognized and visually recognized through a CCD, and it was judged whether or not the presence of the anisotropic conductive film in the alignment mark could be judged within 1 second. In addition, the case where the determination can be made in all of 100 trials is evaluated as "a", the case where the determination can be made in 90 or more out of 100 trials is evaluated as "B", and the case where the determination can be made in less than 90 trials out of 100 trials is evaluated as "C".

In the evaluation after the main pressure bonding, the extruded part of the adhesive layer was visually recognized directly or via a CCD. Then, whether or not the color of the extruded part of the adhesive layer can be completely determined within 1 second, and whether or not the flexible substrate is mounted in the alignment mark is determined. If the color of the extruded portion disappears, the so-called full-scale pressure bonding is performed under a predetermined condition. Further, if the flexible substrate is mounted in the alignment mark, the mounting position of the flexible substrate is maintained at an appropriate position. Therefore, by confirming the above, the anisotropic conductive connection between the base substrate and the flexible substrate can be confirmed. The case where the determination can be made for all 95 out of 100 trials is evaluated as "a", the case where the determination can be made for 90 or more out of 100 trials is evaluated as "B", and the case where the determination can be made for less than 90 trials out of 100 trials is evaluated as "C". The evaluation results are shown in table 1.

[ Table 1]

(Table 1)

In examples 4 to 8, good results were obtained. That is, in examples 4 to 8, since the color of the anisotropic conductive film was sufficiently remained even after the temporary pressure bonding, the anisotropic conductive film could be easily visually recognized. In addition, the color of the adhesive layer after the main pressure bonding is sufficiently lost, and the transmittance of the adhesive layer is increased. Therefore, it is possible to easily confirm that the color of the adhesive layer disappears after the final pressure bonding. As a result, it can be easily confirmed that the main pressure bonding is performed under the predetermined condition. Further, the rear surface side of the extruded portion can be easily visually recognized. Therefore, it can be easily confirmed that the mounting position of the flexible substrate is maintained at an appropriate position. In addition, the same results were obtained in both direct viewing and viewing via a CCD. Therefore, it is expected that accurate automatic recognition can be performed even in an automatic recognition device using a CCD.

In example 4, the base member is transparent or achromatic, and the anisotropic conductive film is colored in a clear color (orange). In example 5, the anisotropic conductive film was colored in the same color as the base substrate. In example 8, the base substrate was milky white, but the anisotropic conductive film was colored in a clear color. In addition, the color of the anisotropic conductive film is the same as the color (gold) of the 1 st terminal. On the other hand, the color of the anisotropic conductive films of examples 6 and 7 is different from that of the base member. Therefore, in the evaluation of the temporary pressure bonding, examples 4, 5 and 8 gave better results than examples 6 and 7.

On the other hand, in all of comparative examples 2 to 4, evaluations of temporary pressure bonding were lower than those of examples 4 to 8. In comparative examples 2 to 4, the color of the anisotropic conductive film was almost disappeared at the time of temporary pressure bonding, and thus such evaluation was made. Further, since the extruded portion after the main pressure bonding was substantially transparent, the evaluation after the main pressure bonding was the same as that of examples 4 to 8. However, since the color of the anisotropic conductive film is almost disappeared before the final pressure bonding, it is not possible to accurately determine whether the final pressure bonding is in accordance with the predetermined condition in comparative examples 2 to 4.

(measurement of on-resistance)

The on-resistances of examples 4 to 8 were measured. Specifically, the on-resistance value when a current of 1mA was passed through the connection structure was measured by the 4-terminal method. A digital multimeter (manufactured by Yokogawa electric Co., Ltd.) was used for the measurement. As a result, the on-resistances of examples 4 to 8 were able to obtain values that were practically unproblematic in particular.

(measurement of adhesive Strength)

The adhesive strength of examples 4 to 8 was measured by a tensile tester (AND). That is, the base substrate of the connection structure is held on the sample stage, and the flexible substrate is pulled from above. The measurement speed (drawing speed) was set to 50 mm/sec. The tensile strength when the flexible substrate (more specifically, the 2 nd terminal) is completely peeled off from the 1 st terminal is defined as the adhesive strength. As a result, a value having no practical problem can be obtained.

Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited to the examples. It is obvious to those having ordinary knowledge in the art to which the present invention pertains that various modifications and alterations can be made within the scope of the technical idea described in the claims, and it is needless to say that these modifications and alterations also fall within the technical scope of the present invention.

Description of the reference symbols

1 a connection structure; 10a base substrate; 11 the 1 st terminal; 12 a 1 st wiring pattern; 20 an anisotropic conductive film; 30 a base material film; 40 a flexible substrate; 41 the 2 nd terminal; 42, 2 nd wiring pattern.

Claims

1. An anisotropic conductive connection method for anisotropically connecting a 1 st terminal row provided on a 1 st electronic part and a 2 nd terminal row provided on a 2 nd electronic part, comprising:

a step of temporarily pressing an anisotropic conductive film onto the 1 st terminal column; and

a step of positively pressure-bonding the 2 nd terminal row to the anisotropic conductive film,

the anisotropic conductive film is colored, the colored state of the anisotropic conductive film does not change when the temporary pressure bonding is performed, and the transmittance of the anisotropic conductive film increases when the permanent pressure bonding is performed.

2. The anisotropic conductive connection method according to claim 1, wherein the anisotropic conductive film is colored in the same color as any one of alignment marks drawn on the 1 st electronic component, the 1 st terminal row, and the 1 st electronic component.

3. The anisotropic conductive connection method according to claim 2,

the 1 st electronic component is colored in a transparent or colorless,

the anisotropic conductive film is colored in the same color as any one of the 1 st terminal row and the alignment mark.

4. The anisotropic conductive connection method according to any one of claims 1 to 3, wherein the 1 st electronic component is a ceramic substrate.

5. An anisotropic conductive connection structure produced by the anisotropic conductive connection method according to any one of claims 1 to 4, wherein the anisotropic conductive connection is provided between the 1 st terminal row of the 1 st electronic component and the 2 nd terminal row of the 2 nd electronic component.