JP2002203871A - Adhesive composite, method for connecting circuit terminal using the same and structure of connecting circuit terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric and electronic adhesive composite having an electric connection with a low resistivity to COG mountings and COF mountings and no short circuit, a method for connecting a circuit terminal and a connection structure of the circuit terminal. SOLUTION: The adhesive is inserted between circuit electrodes opposing to one another to apply pressure to the circuit electrodes and electrically connect electrodes in the pressurizing direction. The adhesive composite consists of (1) an epoxy resin, (2) a latent curing agent, (3) a film forming material and (4) conduction particles as essential components, and has a fluidity expressed as (B)/(A) is 1.3-2.0, where (A) represents an area before heating pressurization and (B) an area after heating pressurization. In the method for connecting circuit terminals, a first circuit member having a first connection terminal and a second circuit member having a second connection terminal are arranged so that the first connecting terminal is opposing to the second circuit terminal, said adhesive composite is inserted between the first connection terminal and the second connection terminal opposing to one another, and the first connection terminal and the second connection terminal are electrically connected by heat and pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive composition, and a circuit terminal in a CHIP-ON-GLASS mounting (hereinafter referred to as COG mounting) or a CHIP-ON-FLEX (hereinafter referred to as COF mounting) using the same. The present invention relates to a connection method and a connection structure of circuit terminals.

[0002]

2. Description of the Related Art A liquid crystal driving IC is mounted on a liquid crystal display glass panel by a COG mounting method in which the liquid crystal driving IC is directly joined to the glass panel by a circuit connecting member, or the liquid crystal driving IC has metal wiring. A COF mounting method of bonding to a flexible tape and bonding to a glass panel and a circuit connecting member is used. As the definition of liquid crystal displays has become higher,
The gold bump, which is the electrode of C, has a narrow pitch and a narrow area. For this reason, there is a problem that the conductive particles in the bonding material flow out between the adjacent electrodes, causing a short circuit, and a problem that the number of conductive particles in the bonding material captured on the bumps is reduced, resulting in poor connection. . In order to solve these problems, a method has been developed in which an insulating adhesive layer is formed on at least one surface of a bonding material to prevent a decrease in bonding quality in COG mounting and COF mounting (for example, Japanese Patent Application Laid-Open No. H08-208,1992). -279371).

[0003]

However, when the bump area of the connection member is less than 3000 μm ² , the number of conductive particles in the bonding material captured on the bump is reduced, and a stable connection resistance value is obtained. However, there is a problem that when the filling amount of the particles is increased to increase the short-circuiting rate and the insulation failure occurs, the connection resistance value is lowered. The present invention provides an electric / electronic adhesive composition that provides low-resistance electrical connection to COG mounting and COF mounting and does not cause short circuit, a method for connecting circuit terminals using the same, and a method for connecting circuit terminals. Provides structure.

[0004]

According to the present invention, there is provided [1] an adhesive which is interposed between opposing circuit electrodes, presses the opposing circuit electrodes, and electrically connects the electrodes in the pressing direction. And the adhesive composition is (1) an epoxy resin, (2)
A fluid containing a latent curing agent, (3) a film forming material, and (4) conductive particles as essential components, and is expressed using an area (A) before heating and pressing and an area (B) after heating and pressing. Sex (B) /
The adhesive composition has a value of (A) of 1.3 to 2.0. If the fluidity of the adhesive composition is less than 1.3, the fluidity is poor and good connection may not be obtained. If the fluidity of the adhesive composition is more than 2.0, the number of conductive particles captured on the bumps is small. The electrical resistance of the connection part increases. The flowability was measured by using a glass having a thickness of 0.7 mm and a size of 15 mm × 15 mm, and sandwiching an adhesive composition having a thickness of 35 μm and a size of 5 mm × 5 mm between the two glasses.
Heating and pressurization was performed in 10 seconds, and the value of (B) / (A) was determined from the initial area (A) and the area (B) after the heat and pressure. This area can also be measured using an image processing device or the like. When the thickness of each adhesive layer was different, the thickness of the bonding material was 35 μm in proportion to the thickness. [2] The adhesive composition according to the above [1], wherein the surface of the conductive particles is covered with an organic polymer compound. Further, the present invention provides [3] a first circuit member having a first connection terminal, and a second circuit member having a second connection terminal, by combining the first connection terminal and the second connection terminal. The adhesive composition according to the above [1] or [2] is interposed between the first connection terminal and the second connection terminal which are arranged to face each other, and heated and pressed to form the counter This is a method of connecting circuit terminals for electrically connecting the first connection terminals and the second connection terminals arranged. [4] The circuit member having at least one connection terminal is I
The method for connecting circuit terminals according to the above [3], which is a C chip. [5] The surface of at least one of the connection terminals is gold, silver, tin,
The circuit terminal connection method according to the above [3] or [4], comprising at least one selected from a platinum group metal and indium-tin oxide (ITO). [6] at least one circuit member surface is silicon nitride,
The method of connecting a circuit terminal according to any one of the above [3] to [5], wherein the circuit terminal is coated or adhered with at least one selected from a silicone compound and a polyimide resin. Furthermore, the present invention relates to [7] the above [3]
To a circuit terminal connection structure obtained by the circuit terminal connection method according to any one of the above [6].

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (1) Epoxy resins used in the present invention include epichlorohydrin and bisphenol A
, F, bisphenol type epoxy resin derived from AD, epichlorohydrin and epoxy novolak resin derived from phenol novolak or cresol novolak or naphthalene-based epoxy resin having a skeleton containing a naphthalene ring, glycidylamine, glycidyl ether, biphenyl, Various epoxy compounds having two or more glycidyl groups in one molecule such as alicyclic compounds can be used alone or in combination of two or more. These epoxy resins have impurity ions (Na ⁺ , Cl ^- etc.)
It is preferable to use a high-purity product in which hydrolyzable chlorine or the like is reduced to 300 ppm or less in order to prevent electron migration.

Examples of the latent curing agent (2) used in the present invention include imidazoles, hydrazides, boron trifluoride-amine complexes, sulfonium salts, amine imides, salts of polyamines and dicyandiamide. These may be used alone or as a mixture, and may be used in combination with a decomposition accelerator, an inhibitor and the like. A microcapsule obtained by coating these curing agents with a polyurethane-based or polyester-based polymer substance or the like is preferable because the pot life is extended.

The (3) film-forming material used in the present invention includes phenoxy resin, polyvinyl formal resin,
Polystyrene resin, polyvinyl butyral resin, polyester resin, polyamide resin, xylene resin, polyurethane resin and the like can be mentioned. Film forming material, when the liquid material is solidified and the constituent composition is in the form of a film,
The film is easy to handle and imparts mechanical properties and the like that are not easily torn, cracked or sticky, and can be handled as a film in a normal state. Phenoxy resins are preferred among the film-forming materials because of their excellent adhesiveness, compatibility, heat resistance, and mechanical strength. The phenoxy resin is a resin obtained by reacting a bifunctional phenol and epihalohydrin to a high molecular weight or by polyaddition of a bifunctional epoxy resin and a bifunctional phenol. Specifically, it is obtained by reacting 1 mol of bifunctional phenols with epihalohydrin 0.985 to 1.015 in a non-reactive solvent at a temperature of 40 to 120 ° C. in the presence of an alkali metal hydroxide. Can be. In addition, from the viewpoint of the mechanical and thermal properties of the resin, in particular, the blending equivalent ratio of the bifunctional epoxy resin and the bifunctional phenol is set such that epoxy group / phenol hydroxyl group = 1.
/0.9 to 1 / 1.1, amides, ethers, ketones having a boiling point of 120 ° C. or more in the presence of a catalyst such as an alkali metal compound, an organic phosphorus compound, or a cyclic amine compound;
Those obtained by heating at 50 to 200 ° C. in a lactone-based or alcohol-based organic solvent at a reaction solid content of 50 parts by weight or less and performing a polyaddition reaction are preferred. Examples of the bifunctional epoxy resin include a bisphenol A epoxy resin, a bisphenol F epoxy resin, a bisphenol AD epoxy resin, and a bisphenol S epoxy resin. Bifunctional phenols have two phenolic hydroxyl groups and include, for example, hydroquinones, bisphenols such as bisphenol A, bisphenol F, bisphenol AD, and bisphenol S. The phenoxy resin may be modified with a radically polymerizable functional group. The phenoxy resins may be used alone or as a mixture of two or more.

The adhesive composition of the present invention comprises acrylic acid,
A copolymer or a copolymer containing at least one of acrylic acid ester, methacrylic acid ester and acrylonitrile as a monomer component can be used, and a copolymer acrylic rubber containing glycidyl acrylate or glycidyl methacrylate containing a glycidyl ether group can be used. The use of a combination of these is preferred because of excellent stress relaxation. The molecular weight (weight average) of these acrylic rubbers is preferably 200,000 or more from the viewpoint of increasing the cohesive strength of the adhesive. The adhesive composition of the present invention further includes a filler, a softener, an accelerator, an antioxidant, a flame retardant, a dye, a thixotropic agent, a coupling agent, a phenol resin, a melamine resin, and isocyanates. It can also be contained. When a filler is contained, it is preferable because an improvement in connection reliability and the like can be obtained. It can be used if the maximum diameter of the filler is smaller than the particle diameter of the conductive particles.
６０60 parts by volume (per 100 parts by volume of adhesive resin component)
Is preferable. If it exceeds 60 parts by volume, the effect of improving reliability may be saturated, and if it is less than 5 parts by volume, the effect of addition is small.

As the coupling agent, ketimine, a vinyl group, an acryl group, an amino group, an epoxy group and an isocyanate group-containing material are preferred from the viewpoint of improving the adhesiveness. Specifically, as a silane coupling agent having an amino group, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-aminopropyltrimethoxysilane Ethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane and the like can be mentioned. Examples of the silane coupling agent having a ketimine include those obtained by reacting a silane coupling agent having an amino group with a ketone compound such as acetone, methyl ethyl ketone, and methyl isobutyl ketone.

The adhesive composition of the present invention can be connected by direct contact of opposing circuit electrodes at the time of connection even without conductive particles, but more stable connection can be obtained when the adhesive composition contains conductive particles. Au, Ag, N as conductive particles
There are metal particles such as i, Cu, solder, and carbon, and the like. In order to obtain a sufficient pot life, the surface layer is preferably made of noble metals such as Au, Ag, and white metal instead of transition metals such as Ni and Cu. More preferred. Further, the surface of a transition metal such as Ni may be coated with a noble metal such as Au.
Further, the conductive layer described above may be formed on a nonconductive glass, ceramic, plastic, or the like by coating or the like, and the outermost layer may be made of a noble metal. When a conductive layer is formed on a plastic by coating, etc., or when it is deformed by fusing and heating and pressing of hot-melt metal particles, the contact area with the electrode increases during connection, and the thickness variation of the circuit terminal of the circuit member is absorbed. This is preferable because the reliability is improved. The thickness of the noble metal coating layer is preferably 100 Å or more in order to obtain good resistance. However, when a layer of a noble metal is formed on a transition metal such as Ni, free radicals are generated due to oxidation-reduction action caused by a defect of the noble metal layer or a defect of the noble metal layer generated during mixing and dispersion of conductive particles, and the storage is performed. The thickness is preferably 300 Å or more in order to cause deterioration in the property. When the thickness increases, their effects become saturated. Therefore, it is preferable to set the thickness to 1 μm at the maximum, but there is no limitation. The conductive particles are properly used in a range of 0.1 to 30 parts by volume based on 100 parts by volume of the adhesive resin component. In order to prevent a short circuit or the like in an adjacent circuit due to excessive conductive particles, the content is more preferably 0.1 to 10 parts by volume. The conductive particles preferably have the surface of the conductive particles covered with an organic polymer compound, and the coating of the organic polymer compound may be performed by a method usually used in a microcapsule technique. For example, spraying, immersion drying, and the like of a polymer compound on conductive particles are used. The coating thickness may be an insulating property, and may be an extremely thin thickness.

The adhesive composition of the present invention is formed into a film, the adhesive composition is divided into two or more layers, and the composition is divided into a layer containing an epoxy resin and a layer containing conductive particles. An improvement is obtained. The adhesive composition of the present invention can also be used as a film adhesive for bonding a flexible tape or a glass substrate to an IC chip in COG mounting or COF mounting. That is, a first circuit member having a first connection terminal and a second circuit member having a second connection terminal are arranged such that the first connection terminal and the second connection terminal are opposed to each other. The adhesive composition (film-like adhesive) of the present invention is interposed between the arranged first connection terminal and the second connection terminal, and heated and pressurized, and the first connection terminal and the second connection terminal arranged opposite to each other are heated and pressed. The connection terminals can be electrically connected. These circuit members are usually provided with a large number of connection terminals (in some cases, a single terminal may be provided), and at least one set of the circuit members may be provided with at least a part of the connection terminals provided on the circuit members facing each other. And
The adhesive of the present invention is interposed between the connection terminals arranged to face each other,
By applying heat and pressure, the connection terminals arranged opposite to each other are electrically connected to each other to form a circuit board. By heating and pressurizing at least one set of circuit members, the connection terminals arranged opposite to each other can be electrically connected to each other by direct contact or via conductive particles in the adhesive composition.

In the method for connecting a circuit terminal of the present invention, the adhesive composition of the present invention is used, and the surface of the connection terminal is selected from gold, silver, tin, platinum group metals, and indium-tin oxide (ITO). After forming at least one type of connection terminal (electrode circuit), the other connection terminal (circuit electrode) can be aligned, heated and pressed, and connected. At this time, light may be emitted from one of the circuit members. In the present invention, the flexible tape is an organic insulating material such as a polyimide resin, the surface of a glass substrate is particularly good for a circuit member coated or adhered with at least one selected from silicon nitride, a silicone compound, a polyimide resin, and a silicone resin. It is possible to provide an electric / electronic adhesive composition capable of obtaining an adhesive strength, a circuit terminal connection method using the same, and a circuit terminal connection structure.

[0013]

EXAMPLES (Example 1) A phenoxy resin having a glass transition temperature of 80 ° C was synthesized from bisphenol A type epoxy resin and bisphenol A. 50 g of this resin was mixed with toluene (boiling point 110.6 ° C.) / Ethyl acetate (boiling point 77.
1 ° C.) = 50/50 mixed solvent to give a solid content of 40
% Solution. Phenoxy resin 4 by solid weight ratio
0 g and 60 g of a liquid epoxy containing a microcapsule-type latent curing agent (HX3941HP; trade name, epoxy equivalent: 185, manufactured by Asahi Kasei Kogyo Co., Ltd.). 0.2 μm nickel layer, thickness 0.04 μm outside
5 μ% by volume of PVA solution to 5 μm particles having an average particle diameter of 5 μm provided with a gold layer).
An 80 μm-thick surface-treated PET (polyethylene terephthalate) film is applied using a coating apparatus, and dried with hot air at 70 ° C. for 10 minutes to obtain a film-like adhesive composition having an adhesive layer thickness of 20 μm. Was.

Example 2 A film was prepared in the same manner as in Example 1 except that 35 g of a phenoxy resin and 65 g of a liquid epoxy containing a microcapsule-type latent curing agent (epoxy equivalent: 185) were mixed in a solid weight ratio of 35 g. An adhesive composition was obtained.

Comparative Example 1 A film-like adhesive composition was prepared in the same manner as in Example 1 except that the solid weight ratio was changed to 30 g of a phenoxy resin and 70 g of a liquid epoxy containing a microcapsule type latent curing agent (epoxy equivalent: 185). I got something.

(Circuit connection) Bump area 50 μm × 50
An IC chip on which gold bumps having a pitch of 100 μm and a height of 20 μm are arranged, and an indium tin oxide (ITO) formed on a 1.1 mm thick glass by vapor deposition.
An O substrate (surface resistance, <20Ω / □) was sandwiched between quartz glass and a pressure head using the above-mentioned adhesive composition.
The connection was made by heating and pressing at 100 ° C. and 100 MPa (bump area conversion) for 10 seconds. At this time, the adhesive surface of the adhesive composition was previously coated on the ITO substrate by 7 minutes.
At 0 ° C, 0.5MPa (converted to bump area), heat and pressure for 5 seconds to adhere, then peel off the PET film and
Connected to C chip. (Measurement of fluidity) Thickness 0.7 mm, 15 mm x 15 mm
A circuit connecting material made of a resin composition for circuit connecting having a thickness of 35 μm and 5 mm × 5 mm was sandwiched between the glasses, and heated and pressed at 200 ° C., 2 MPa, and 10 seconds to obtain an initial area (A ) And the area (B) after heating and pressing, the value of (B) / (A) was determined. (Measurement of Number of Trapped Particles on Bump) After connection of the circuit, the bumps were observed from the glass side with a metallographic microscope (magnification: 200 times), and the number of conductive particles on the bumps was counted to obtain an average value. (Measurement of connection resistance) After the circuit was connected, the electric resistance value of the connection portion was initially kept at 500 cycles in a temperature cycle bath of −40 ° C./30 minutes and 100 ° C./30 minutes, and then a two-terminal measurement method was used. It was measured with a multimeter. Table 1 shows the measurement results.

[0017]

[Table 1]

When the amount of the phenoxy resin used as the film forming material is small and the amount of the epoxy resin is large, the fluidity increases. As the fluidity increases, the number of conductive particles on the bump decreases. When the number of particles decreases, the connection resistance for evaluating the connection reliability after the temperature cycle test greatly increases, and reaches as high as 20Ω or more. When the fluidity of the bonding material of the present invention is in the range of 1.3 to 2.0, both the initial and the connection resistance after the reliability test are low, and good results are shown. On the other hand, when the fluidity of Comparative Example 1 is 2.5, the initial value of the connection resistance is low and good, but the connection resistance after the reliability test is remarkably large and is not suitable as a bonding material for circuit members. In addition, as a result of various experiments, when the fluidity was less than 1.3, the fluidity was poor and bubbles were involved, so that a good connection could not be obtained. When the conductive particles are covered with the organic polymer, there is no significant effect on the fluidity, but there is no short circuit between adjacent connection terminals and the insulation failure is eliminated. In addition, the filling amount of the conductive particles was increased, and a reliable connection could be secured.

[0019]

According to the present invention, there is provided an adhesive composition for electric / electronic use which can provide a low-resistance electric connection even in a driving IC having a small bump area in COG mounting or COF mounting. It is possible to provide the connection method of the used circuit terminals and the connection structure of the circuit terminals.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 23/31 (72) Inventor Yukihisa Hirosawa 1150 Gozamiya, Oaza, Shimodate-shi, Ibaraki Prefecture Gosho, Hitachi Chemical Co., Ltd. Within Miya Works (72) Inventor Masaru Fujii 1150 Goshomiya, Oaza, Shimodate City, Ibaraki Prefecture F-term within Goshomiya Works, Hitachi Chemical Co., Ltd.F-term (reference) EC122 ED001 ED002 EE061 EE062 EF031 EF032 EG001 EG002 HA026 HA066 HC01 HC15 HC16 HC18 HC23 HD18 JA09 JA12 JB02 JB10 KA14 KA32 KA42 LA09 MA02 MA04 MA10 NA20 4M109 AA01 BA05 BA07 CA22 EA04 EA02 EK04 EB02 EB04

Claims (7)

[Claims] An adhesive interposed between opposing circuit electrodes, pressurizing the opposing circuit electrodes, and electrically connecting the electrodes in the pressing direction, wherein the adhesive composition comprises (1) ) An epoxy resin, (2) a latent curing agent, (3) a film-forming material, and (4) conductive particles as essential components, and an area (A) before heating and pressing and an area (B) after heating and pressing. An adhesive composition having a fluidity (B) / (A) value of 1.3 to 2.0 expressed by using formula (1). 2. The adhesive composition according to claim 1, wherein the surface of the conductive particles is covered with an organic polymer compound. 3. A first circuit member having a first connection terminal and a second circuit member having a second connection terminal are arranged with the first connection terminal and the second connection terminal facing each other. And, the adhesive composition according to claim 1 or claim 2 is interposed between the first connection terminal and the second connection terminal arranged opposite to each other,
A method of connecting circuit terminals for electrically connecting the first connection terminal and the second connection terminal arranged opposite to each other by heating and pressing. 4. The method according to claim 3, wherein the circuit member having at least one connection terminal is an IC chip. 5. The surface of at least one of the connection terminals is gold,
Silver, tin, platinum group metals, indium-tin oxide (IT
4. A structure comprising at least one selected from O).
Alternatively, the circuit terminal connection method according to claim 4. 6. The method according to claim 3, wherein at least one surface of the circuit member is coated or adhered with at least one selected from silicon nitride, a silicone compound, and a polyimide resin. . 7. A circuit terminal connection structure obtained by the circuit terminal connection method according to any one of claims 3 to 6.