JP2009249634A - Anisotropic conductive film with optimized thermal characteristic and curing characteristic, and circuit connection structure using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a parameter of affecting connection reliability of an anisotropic conductive film, and an optimum value of the parameter. <P>SOLUTION: This anisotropic conductive film connects mechanically and electrically fellow members to be connected, by bonding the members, contains a thermoplastic resin for forming a film, a thermosetting resin as a binder, a curing agent, a conductive particle and a mold release film, and has a value larger than 0.05 and smaller than 0.4 of flow parameter λ=[(Tc-Tg)/Tc] (Tc: curing starting temperature of the anisotropic conductive film). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an anisotropic conductive film used for connecting circuit boards to each other or an electronic component such as an IC chip and a circuit board, and a circuit connection structure using the same, and more particularly, thermal characteristics and curing characteristics. The present invention relates to an anisotropic conductive film that is optimized and has good connection reliability.

  An anisotropic conductive film in which conductive particles are dispersed in an adhesive is used in order to electrically connect circuit boards to each other or an electronic component such as an IC chip and the circuit board. This anisotropic conductive film is disposed between opposing electrodes, and heats and presses to bond the electrodes together, and at the same time, provides electrical connection by imparting conductivity in the pressing direction. Such an anisotropic conductive film is used for, for example, packaging of LCD panels of LCD modules, printed circuit boards (PCBs), and driver ICs.

  In recent years, LCDs have been applied in a variety of applications, from large panels for notebook computers, monitors, and televisions to medium and small panels for mobile devices such as mobile phones, PDAs (Personal Digital Assistants), and game consoles. A driver IC is mounted on the LCD using an anisotropic conductive film. For mounting the driver IC in the LCD, the driver IC is converted into a tape carrier package (TCP) or a COF (Chip On Film) and bonded to the LCD panel, or an OLB (Outer Lead Bonding) method, or A PCB system that adheres to a printed circuit board (PCB) is employed. Further, in medium and small-sized LCDs such as mobile phones, a COG (Chip On Glass) system in which a driver IC is directly mounted on an LCD panel using an anisotropic conductive film is employed.

  Thus, when connecting electronic components such as circuit boards or IC chips and a circuit board using an anisotropic conductive film, connection reliability is most problematic. That is, the anisotropic conductive film is required to have high connection properties and good connection reliability.

  Therefore, various efforts have been made to improve the connection reliability of anisotropic conductive films. For example, structural changes such as forming an anisotropic conductive film in multiple layers, and adjustment of the composition of the adhesive, the type and composition ratio of the conductive particles, etc. are made as disclosed in Patent Document 1. It was.

JP 2007-297636 A

  As described above, the connection reliability of the anisotropic conductive film is mainly made by adjusting the composition of the adhesive, the type and composition ratio of the conductive particles, etc., but the connection is made with the characteristics of the anisotropic conductive film itself. Reliability could not be evaluated. Then, this invention makes it a subject to provide the parameter which influences the connection reliability of an anisotropic conductive film, and the optimal value of this parameter.

  Below, the outline | summary of this invention is demonstrated, embodiment is shown and the effect etc. are clarified. Further, it is apparent that the objects and advantages of the present invention can be realized by the means shown in the claims and combinations thereof.

  As a result of intensive studies, the inventors of the present invention have found a parameter (flow parameter) that can affect the connection reliability of the anisotropic conductive film and its optimum value, and have completed the present invention.

  An anisotropic conductive film includes a thermoplastic resin for film formation, a thermosetting resin used as a binder, conductive particles and a release film, and is disposed between opposing circuit members. The circuit members (namely, connected members) facing each other by heating and pressurizing (thermocompression bonding) are bonded to each other mechanically and electrically.

  That is, the anisotropic conductive film applies heat to fluidize the resin components (thermoplastic resin and thermosetting resin) and simultaneously apply pressure to connect the connected members mechanically and electrically. It is an adhesive film to be connected to. An anisotropic conductive film fluidizes and decreases in viscosity as the temperature increases, and exhibits a flow characteristic that can exhibit sufficient connection characteristics when the temperature is equal to or higher than the glass transition temperature (Tg). Moreover, if an anisotropic conductive film becomes more than hardening start temperature (Tc), a viscosity will rise by thermosetting resin hardening | curing.

  At this time, if the glass transition temperature (Tg) is too higher than the curing start temperature (Tc) or the curing start temperature (Tc) is too lower than the glass transition temperature (Tg), the conductive particles are cured before being sufficiently pressed. The reaction may be completed and connection reliability may not be obtained. If the glass transition temperature (Tg) is too lower than the curing start temperature (Tc) or the curing start temperature (Tc) is too higher than the glass transition temperature (Tg), the time during which the resin is in a fluid state is excessive. It becomes longer, causing problems in adhesion such as bubbles.

As described above, the glass transition temperature (Tg) and the curing start temperature (Tc) of the anisotropic conductive film are parameters that must be regarded as important in order for the anisotropic conductive film to exhibit good connection reliability. It is. That is, the glass transition temperature (Tg) and the curing start temperature (Tc) of the anisotropic conductive film having good connection reliability are in a fluid state showing a specific viscosity (n _{1 to} n ₂ ). It is necessary to provide an appropriate temperature difference.

  Therefore, the present inventors have focused on the relationship between the glass transition temperature (Tg) and the curing start temperature (Tc) of the anisotropic conductive film, and have come up with a new parameter for adjusting the above-described temperature difference. That is, the anisotropic conductive film having good connection reliability is expressed by the formula [λ = (Tc−Tg) / Tc] (λ: flow parameter, Tc: curing start temperature of the anisotropic conductive film, Tg: anisotropic The value of the flow parameter λ calculated from the glass transition temperature of the conductive conductive film has a predetermined value.

  The anisotropic conductive film according to the present invention exhibits high adhesiveness and good connection reliability when electrically connecting circuit boards or electronic components such as IC chips and the circuit board.

It is a schematic diagram which shows the state which has arrange | positioned the anisotropic conductive film between the circuit members which oppose. It is a graph which shows the change of the viscosity accompanying the temperature rise of an anisotropic conductive film. It is a graph which shows the change of the viscosity accompanying the temperature rise of 4 types of anisotropic conductive films from which a glass transition temperature (Tg) differs. It is a graph which shows the change of the viscosity accompanying the temperature rise of 4 types of anisotropic conductive films from which hardening start temperature (Tc) differs. It is a schematic diagram which shows the connection process which heat-presses COF or TCP to a glass substrate or PCB via an anisotropic conductive film, and is set as a circuit connection structure.

  The above-mentioned drawings attached to the present specification illustrate preferred embodiments of the present invention, and together with the detailed description of the invention, serve to further understand the technical idea of the present invention. It should be noted that the present invention should not be construed as being limited to the matters described in the drawings.

  Hereinafter, the present invention will be described in detail with reference to the drawings. In the drawings, the same reference numerals indicate the same or equivalent components.

  FIG. 1 shows a state in which an anisotropic conductive film 10 according to the present invention is disposed between opposing circuit boards 20 and 30.

  The anisotropic conductive film 10 preferably includes a thermoplastic resin for film formation, a thermosetting resin as a binder, a curing agent, conductive particles, a release film, and other additives.

  Examples of the thermoplastic resin include polyvinyl butyral, polyvinyl formal, polyvinyl acetal, polyamide, phenoxy resin, polysulfone, styrene-butadiene-styrene block copolymer, carboxylated styrene-ethylene-butylene-styrene block copolymer, and polyacrylate resin. Etc., and preferably 30 to 60% by weight.

  As the thermosetting resin, it is preferable to use an epoxy resin or an acrylate resin.

  As the epoxy resin, a polyvalent epoxy resin having two or more glycidyl groups in one molecule is preferably used. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, A biphenyl type epoxy resin, a dicyclopentadiene type epoxy resin, a naphthalene type epoxy resin, or the like is preferably used alone or in combination, and is preferably blended in an amount of 5 to 45% by weight.

  At this time, it is preferable to use a curing agent for epoxy resin as the curing agent, and in particular, an imidazole compound, an amine compound, an acid anhydride compound, as a latent curing agent having excellent storage stability and a fast curing rate, It is preferable to use one or more selected from polyamide-based compounds and isocyanate-based compounds. Specifically, dicumyl peroxide, t-butyl-cumyl peroxide, bis (α-tert-butylperoxyisopropyl) benzene, 2,5-di (tert-butylperoxy) -2 5-dimethylhexyne-3, diterbutyl peroxide, 1,1-di (terbutylperoxy) -3,3,5-trimethylcyclohexane, n-butyl-4,4-di- ( Terbutylperoxy) valerate, 1,1-di-terbutylperoxycyclohexane, isopropylcumylterbutylperoxide, bis (α-teramylperoxyisopropyl) benzene, imidazole, 2-ethylimidazole, 2-phenyl-4 -Methylimidazole, 2-dodecylimi Sol, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 4-methylimidazole, boron trifluoride-amine complex, sulfonium salt, amine imide, polyamine salt, dicyandiamide, etc. It is preferable to add 0.1 to 20% by weight.

  As the acrylate monomer constituting the acrylate resin, an acrylic monomer, a methacrylic monomer, a maleimide compound, an unsaturated polyester, acrylic acid, vinyl acetate, and a radical polymerizable resin having a functional group that is polymerized by radicals such as acrylonitrile. Specifically, methyl acrylate, ethyl acrylate, bisphenol A-ethylene glycol modified diacrylate, isocyanuric acid ethylene glycol modified diacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, trimethylolpropane propylene Glycol-modified triacrylate, isocyanuric acid ethylene glycol-modified triacrylate, dipentaerythritol pentaacrylate , Dipentaerythritol hexaacrylate, pentaerythritol tetraacrylate, dicyclopentenyl acrylate, tricyclodecanyl acrylate, ethylene isoamyl acrylate, lauryl acrylate, stearyl acrylate, butoxyethyl acrylate, ethoxydiethylene glycol acrylate, methoxytriethylene glycol acrylate, methoxy Polyethylene glycol acrylate, methoxydipropylene glycol acrylate, phenoxyethyl acrylate, phenoxy polyethylene glycol acrylate, isobornyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, methyl methacrylate, isobutyl methacrylate, tridecyl meta Relate, methoxydiethylene glycol methacrylate, methoxypolyethylene glycol methacrylate, furfuryl methacrylate (furfuryl methacrylate), furfuryl acrylate, isobutyl acrylate, isobornyl methacrylate, methoxytriethylene glycol methacrylate, etc. are used alone or in combination of two or more of the above acrylates When using a monomer, it is preferable to mix 30 to 70% by weight.

  Further, as the curing initiator in the case of using the acrylate-based resin, it is preferable to use an azo-based compound or an organic peroxide. Specifically, decanoyl peroxide, benzoyl peroxide, dicumyl peroxide is used. Oxide, dibutyl peroxide, cumene hydroperoxide, t-butyl-cumyl peroxide, bis (α-t-butylperoxyisopropyl) benzene, 2,5-di ( t-butylperoxy) -2,5-dimethylhexane, 2,5-di (t-butylperoxy) -2,5-dimethylhexyne-3, diterbutyl peroxide, 1,1-di-ter Butyl peroxycyclohexa , Isopropyl cumyl ether butyl peroxide, it is preferable to use bis (alpha-Tel amyl peroxy-isopropyl) benzene, etc. composition selected from the singly or in admixture, it is preferable to blend 0.1 to 30 wt%.

  The conductive particles are for electrically connecting a body to be connected such as a fine circuit electrode, and are preferably selected from a wide range of particles having high melting point and hardness and excellent conductivity. Examples of such conductive particles include gold (Au), silver (Ag), iron (Fe), copper (Cu), nickel (Ni), cadmium (Cd), bismuth (Bi), indium (In), aluminum ( Examples thereof include polystyrene coated with Al), palladium (Pd), platinum (Pt), chromium (Cr), and the like, polymethacrylate, polymethyl methacrylate, polyvinyl acetate, divinylbenzene, and benzoguanamine. Moreover, as the conductive particles according to the present invention, silver powder or nickel powder can be used as it is. At this time, the conductive particles preferably contain 1 to 10% by weight of conductive particles having a diameter of 3 to 20 μm and a uniform particle size distribution with a particle size deviation within ± 0.1 μm.

  In addition, it is also preferable to additionally use a coupling agent, an adhesion imparting agent, or the like as an additive.

  The anisotropic conductive film having the above-described configuration is the type and content of thermoplastic resin, the type and content of thermosetting resin, the type and content of curing agent and curing initiator, and the type of additive. As will be described later, the value of the flow parameter λ can be freely adjusted.

  Hereinafter, the flow parameter λ that is an index representing the connection reliability (adhesiveness, conductivity) of the anisotropic conductive film will be described in detail.

In FIG. 2, the change of the viscosity accompanying the temperature rise of an anisotropic conductive film is shown. As shown in FIG. 2, when heat is applied to the anisotropic conductive film, the viscosity decreases until reaching a specific temperature, and the viscosity increases when curing starts. At this time, the viscosity at the time of curing of the anisotropic conductive film if it exceeds the upper limit viscosity n _2, the conductive particles showed no only liquidity is fully pressed. Further, falls below the lower limit viscosity n _1, the bubble is liable to occur becomes excessive fluidity, adhesive properties become poor. That is, the anisotropic conductive film exhibits sufficient fluidity to press the conductive particles by thermocompression bonding in the region B shown in FIG. However, in the region C, the fluidity is deteriorated and the conductive particles are not sufficiently pressed, and in the region A, the fluidity is excessive and bubbles are easily generated, and the adhesive property is deteriorated.

  Therefore, the anisotropic conductive film must maintain the characteristics of region B in FIG. 2 until the conductive particles are sufficiently pressed. For this purpose, the glass transition temperature (Tg) and the curing start temperature (Tc) of the anisotropic conductive film must be set to desired values, and the temperature difference (ΔT = Tc−Tg) must also be appropriate. . In the present invention, the absolute temperature [° K] is adopted as a display unit of the glass transition temperature (Tg) and the curing start temperature (Tc).

  In FIG. 3, the change of the viscosity accompanying the temperature rise of four types of anisotropic conductive film a, b, c, d from which glass transition temperature (Tg) differs is shown with a graph. According to the graph shown in FIG. 3, a, b, c, and d are glass transition temperatures (Tg) of Tg (a), Tg (b), Tg (c), Tg (d) [Tg (d) < An anisotropic conductive film having Tg (a) <Tg (b) <Tg (c)], wherein a and b are in the region B when cured, and c is in the region C when cured. Yes, d is the viscosity in the region A when cured.

  Therefore, in order for the anisotropic conductive film to have good connection reliability, it must have an appropriate glass transition temperature (Tg) as shown in FIGS. If the anisotropic conductive film has a glass transition temperature (Tg) that is too low, such as d, or too high, such as c, it has flow characteristics that can provide sufficient pressure contact characteristics and adhesion performance of conductive particles. I can't.

  In FIG. 4, the change of the viscosity accompanying the temperature rise of four types of anisotropic conductive films e, f, g, and h from which hardening start temperature (Tc) differs is shown with a graph. As shown in FIG. 4, e, f, g, and h are curing start temperatures (Tc) of Tc (e), Tc (f), Tc (g), Tc (h) [Tc (g) <Tc ( f) An anisotropic conductive film with <Tc (e) <Tc (h)], wherein e and f have a viscosity at the time of curing in region B, and g has a viscosity at the time of curing in region C, h is the viscosity in the region A when cured.

  Therefore, in order for the anisotropic conductive film to have good connection reliability, it is necessary to have an appropriate curing start temperature (Tc) as shown by e and f in FIG. If the curing start temperature (Tc) of the anisotropic conductive film is too low as in g or too high as in h, it has flow characteristics that can provide sufficient pressure contact characteristics and adhesion performance of conductive particles. I can't.

  In addition, it is not preferable that the anisotropic conductive film starts curing immediately after reaching the glass transition temperature (Tg), and it takes a long time from the time when the glass transition temperature (Tg) is reached until the curing starts. It is also not preferable to require. If the anisotropic conductive film reaches the glass transition temperature (Tg) and immediately begins to cure, the conductive particles are not sufficiently pressed. Therefore, it is preferable that the curing start temperature (Tc) of the anisotropic conductive film is 20 ° K or higher than the glass transition temperature (Tg).

  As described above, the glass transition temperature (Tg) and the curing start temperature (Tc) of the anisotropic conductive film are the viscosity range in which the resin at the time of curing starts (region B in FIGS. 2 to 4). Further, the curing start temperature (Tc) and the glass transition temperature (Tg) are controlled so as to have a certain temperature difference (ΔT = Tc−Tg ≧ 20 ° K).

  The flow characteristics of such an anisotropic conductive film can be expressed by the flow parameter λ shown in the following formula 2.

  Thus, if the value of the flow parameter λ of the anisotropic conductive film is appropriately adjusted, it is possible to produce an anisotropic conductive film having good connection reliability.

  An anisotropic conductive film with good connection reliability must have a flow parameter λ value greater than 0.05 and less than 0.4 (ie, 0.05 <λ <0.4). At this time, the curing start temperature (Tc) of the anisotropic conductive film is preferably 323 ° K to 393 ° K, and the temperature difference between the curing start temperature and the glass transition temperature (Tg) is 20 ° K or more. Is preferred.

  When the value of the flow parameter λ of the anisotropic conductive film is smaller than 0.05, the curing proceeds rapidly, so that the curing is completed before the conductive particles are sufficiently pressed together, resulting in poor pressure welding. On the other hand, when the value of the flow parameter λ is 0.4 or more, the fluidity becomes excessive and bubbles are likely to be generated, resulting in poor adhesive properties.

  The value of the flow parameter λ changes the type and amount of thermoplastic resin, thermosetting resin (epoxy resin or acrylate resin), curing agent (or curing initiator), additive, etc. that make up the anisotropic conductive film. You can adjust it.

  The curing start temperature (Tc) of the anisotropic conductive film can be adjusted by changing the type of curing agent or curing initiator used.

  Table 1 below shows typical curing agent half-life temperatures (Half-life temperature: a measure of the temperature at which the curing agent decreases in half over a period of time, proportional to the cure start temperature (Tc)). Show.

  As shown in Table 1, the curing agents have different half-life temperatures. Therefore, the curing start temperature (Tc) of the anisotropic conductive film containing a curing agent having different half-life temperatures is also different. That is, in the anisotropic conductive film using a curing agent having a low half-life temperature and a fast curing rate, the value of the flow parameter λ decreases as the curing start temperature (Tc) decreases. On the other hand, an anisotropic conductive film using a curing agent having a high half-life temperature and a slow curing rate increases the value of the flow parameter λ as the curing start temperature (Tc) increases.

  Therefore, if a curing agent (or a curing initiator) having a different half-life temperature is selected and used, the value of the flow parameter λ of the anisotropic conductive film is more than 0.05, even if the other conditions are the same. It can be adjusted to be smaller than 4.

  Further, even when a curing agent having the same half-life temperature is used, if the amount is increased, the value of the flow parameter λ decreases, and if the amount is decreased, the value of the flow parameter λ increases. Therefore, if the content of the curing agent is adjusted, the value of the flow parameter λ of the anisotropic conductive film can be adjusted to be larger than 0.05 and smaller than 0.4 even if other conditions are the same.

  Further, the glass transition temperature (Tg) of the anisotropic conductive film that affects the value of the flow parameter λ can be adjusted by the type of thermosetting resin, the type of thermoplastic resin, or the ratio of these components. That is, the glass transition temperature (Tg) can be adjusted while maintaining the excellent characteristics of the anisotropic conductive film by the kind and amount of the curing agent and the kind and blending of the resin. In particular, the glass transition temperature (Tg) of the anisotropic conductive film largely depends on the glass transition temperature (Tg) of the thermoplastic resin. Table 2 below shows the glass transition temperature (Tg) of typical thermoplastic resins.

  As shown in Table 2, the glass transition temperatures (Tg) of the thermoplastic resins are different, and the glass transition temperatures (Tg) of anisotropic conductive films using these thermoplastic resins are also different. In general, an anisotropic conductive film using a thermoplastic resin having a high glass transition temperature (Tg) has a high glass transition temperature (Tg) and an anisotropic conductive film using a thermoplastic resin having a low glass transition temperature (Tg). The glass transition temperature (Tg) of the film is lowered.

  Therefore, if thermoplastic resins having different glass transition temperatures (Tg) are used, the flow parameter λ of the anisotropic conductive film is adjusted to be larger than 0.05 and smaller than 0.4 even if the other conditions are the same. I can do it.

  Moreover, if a thermoplastic resin having a radical curing delay effect (for example, an acrylic polyfunctional monomer such as methacrylate, maleimide compound, unsaturated polyester, acrylic acid, vinyl acetate, acrylonitrile, etc.) is used, the curing rate can be adjusted. Can be adjusted and flow parameters can be adjusted.

  The flow parameter can also be adjusted by the type of thermosetting monomer used (ie, acrylate monomer). That is, by adjusting the number of functional groups and molecular weight of the thermosetting monomer, the reaction rate and the curing density can be adjusted, and as a result, the flow parameter can be adjusted. That is, in general, the more functional groups, the faster the reaction rate, the higher the crosslink density, and the smaller the flow parameter. Conversely, if there are few functional groups, the reaction rate will be slow, the crosslinking density will be low, and the flow parameter will be large.

  The flow parameters can also be adjusted by using radical curing accelerators, chain transfer aids, molecular weight modifiers, etc., and thermoplastic resins and thermosetting resins (epoxy resins or acrylates) that constitute anisotropic conductive films. The value of the flow parameter λ can be adjusted to be larger than 0.05 and smaller than 0.4 by adjusting the composition ratio of the system monomer) and the curing agent (or curing initiator).

  In Examples, as Experimental Examples 1 to 4, anisotropic conductive films having different values of the flow parameter λ were prepared, and film forming tests and connection reliability tests were performed on the anisotropic conductive films. Carried out.

[Creation of anisotropic conductive film]
An adhesive composition containing a thermoplastic resin for forming a film, an epoxy thermosetting resin (or acrylate monomer) as a binder, and a curing agent (or a curing initiator) is dissolved in an organic solvent, and conductive particles are obtained. Furthermore, it disperse | distributed and the varnish for film coating was created. The organic solvent used at this time was a mixed solvent of an aromatic hydrocarbon type and an oxygen-containing type in order to improve the solubility of the material. Next, this solution was applied to a transparent PET film having a surface treated on one side using a coating apparatus, dried with hot air at 70 ° C. for 10 minutes, and experimental examples 1 to 1 having different flow parameters shown in Table 3 below. The anisotropic conductive film of Example 4 was obtained.

[Film formability test]
In the step of applying the film coating varnish to a transparent PET film having one surface treated by using a coating apparatus and drying with hot air at 70 ° C. for 10 minutes, the film was finally obtained. The film was visually observed. At this time, phase separation and non-uniform mixing are not observed, and when the transparent PET film is removed without difficulty, it is judged as ◯, and the film itself is not formed or phase separation and non-uniform mixing is observed. When the transparent PET film was difficult to remove due to the adhesiveness of the mixed solution, it was determined as x.

[Creating a circuit connection structure]
FIG. 5 schematically shows a connection process for bonding COF or TCP to a glass substrate or PCB through an anisotropic conductive film, which was performed to manufacture a circuit connection structure.

  As shown in FIG. 5, the anisotropic conductive film 10 according to the present invention was temporarily pressure-bonded onto a glass substrate or PCB substrate 31, and COF or TCP 22 was disposed opposite to the anisotropic conductive film. Thereafter, a fluororesin sheet having a thickness of 0.15 mm is interposed on the COF or TCP 22 as a buffer material 42, and heated and pressurized for 7 seconds under the conditions of 180 ° C. and 3 MPa using the heating bar 41 to form a circuit connection structure. Created.

[Connection reliability test]
The circuit connection structure obtained in the above was measured using a multimeter the resistance Omega _a after 500 hours aging at a temperature 85 ° C. and 85% relative humidity. In this case, it labeled "OPEN" when the resistance value Ω _a after aging is impossible to measure.

  The anisotropic conductive film of the Example used for the said circuit connection structure was created so that the following glass transition temperature (Tg) and hardening start temperature (Tc) might be provided.

[Experiment 1]
An anisotropic conductive film (λ = 0.29) having a glass transition temperature (Tg) of 236 ° K and a curing start temperature (Tc) of 373 ° K was prepared, and a film forming test was performed. And the circuit connection structure was created using this anisotropic conductive film, and the connection reliability test was implemented. The evaluation results are shown in Table 3 below.

[Experimental example 2]
An anisotropic conductive film (λ = 0.24) having a glass transition temperature (Tg) of 283 ° K and a curing start temperature (Tc) of 373 ° K was prepared. A connection reliability test was conducted. The results are shown in Table 3 below.

[Experiment 3]
An anisotropic conductive film (λ = 0.31) having a glass transition temperature (Tg) of 273 ° K and a curing start temperature (Tc) of 393 ° K was prepared. A connection reliability test was conducted. The results are shown in Table 3 below.

[Experimental Example 4]
An anisotropic conductive film (λ = 0.21) having a glass transition temperature (Tg) of 278 ° K and a curing start temperature (Tc) of 353 ° K was prepared. A connection reliability test was conducted. The results are shown in Table 3 below.

Comparative example

[Comparative Example 1]
In the same manner as in the example, an anisotropic conductive film (λ = 0.04) having a glass transition temperature (Tg) of 357 ° K and a curing start temperature (Tc) of 373 ° K was prepared. The film formation test and the connection reliability test were conducted. The results are shown in Table 3 below.

[Comparative Example 2]
In the same manner as in the example, an anisotropic conductive film (λ = 0.43) having a glass transition temperature (Tg) of 213 ° K and a curing start temperature (Tc) of 373 ° K was prepared. The film formation test and the connection reliability test were conducted. The results are shown in Table 3 below.

[Comparative Example 3]
In the same manner as in the example, an anisotropic conductive film (λ = 0.04) having a glass transition temperature (Tg) of 282 ° K and a curing start temperature (Tc) of 295 ° K was prepared. The film formation test and the connection reliability test were conducted. The results are shown in Table 3 below.

[Comparative Example 4]
In the same manner as in the example, an anisotropic conductive film (λ = 0.42) having a glass transition temperature (Tg) of 274 ° K and a curing start temperature (Tc) of 472 ° K was prepared. The film formation test and the connection reliability test were conducted. The results are shown in Table 3 below.

[Comparative Example 5]
In the same manner as in the example, an anisotropic conductive film (λ = 0.43) having a glass transition temperature (Tg) of 275 ° K and a curing start temperature (Tc) of 484 ° K was prepared. The film formation test and the connection reliability test were conducted. The results are shown in Table 3 below.

[Contrast between Example and Comparative Example]
As is apparent from Table 3, all of the anisotropic conductive films of Experimental Examples 1 to 4 show good connection reliability and film formability. However, the anisotropic conductive film of Comparative Example 1 to Comparative Example 5 is a defective connection reliability resistance Omega _a is all 2Ω or more after aging, and a film forming property is also inferior. Therefore, it can be confirmed that the adhesiveness and the connection reliability of the anisotropic conductive film having a value of the flow parameter λ larger than 0.05 and smaller than 0.4 as in Experimental Examples 1 to 4 are excellent. It was.

10 Anisotropic conductive film 21 Semiconductor chip 22 COF or TCP
31 Glass substrate or printed circuit board 41 Heating bar 42 Buffer materials A, B, C Region n ₁ Lower limit viscosity n ₂ Upper limit viscosity

  If the parameter of this invention is used, the connection reliability of an anisotropic conductive film can be judged using a flow parameter. Therefore, even if the anisotropic conductive film, which is conventionally managed mainly by the composition of the adhesive, the type and composition ratio of the conductive particles, is outside the control range, the characteristics of the anisotropic conductive film itself Can evaluate connection reliability. Therefore, it is possible to relieve products that had to be discarded in the conventional manufacturing process, which can contribute to resource saving and energy saving.

Claims (8)

An anisotropic conductive film that bonds mechanically and electrically connected members to be connected,
The anisotropic conductive film includes a thermoplastic resin for film formation, a thermosetting resin used as a binder, conductive particles and a release film,
Of the flow parameter λ calculated from the formula [λ = (Tc−Tg) / Tc] (λ: flow parameter, Tc: curing start temperature of anisotropic conductive film, Tg: glass transition temperature of anisotropic conductive film) An anisotropic conductive film having a value greater than 0.05 and less than 0.4. The anisotropic conductive film according to claim 1, wherein the curing start temperature (Tc) is 323 ° K to 393 ° K. The anisotropic conductive film according to claim 1 or 2, wherein a temperature difference between the curing start temperature (Tc) and the glass transition temperature (Tg) is 20 ° K or more. The anisotropic conductive film according to claim 1, wherein the thermosetting resin is an epoxy resin. The anisotropic conductive film according to claim 1, wherein the thermosetting resin is an acrylate resin. The connected member includes a first circuit member and a second circuit member;
The first circuit member is a tape carrier package (TCP) or a chip on film (COF), and the second circuit member is either a glass substrate or a printed circuit board (PCB). The anisotropic conductive film in any one of Claims 1-5. The anisotropic conductive film according to any one of claims 1 to 5 is interposed between the first circuit member and the second circuit member to heat and pressurize, whereby mechanical and electrical Connected circuit connection structure. 8. The circuit connection structure according to claim 7, wherein the first circuit member is either TCP or COF, and the second circuit member is either a glass substrate or PCB.

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