JP2002265916A - Adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition excellent in heat resistance, humidity resistance, and workability and desirable as, especially, an electrical and electronic adhesive which needs to meet requirements severe in reliability. SOLUTION: This composition essentially consists of components: (1) a phenoxy resin, (2) a polyfunctional glycidyl ether type epoxy resin, and (3) a catalyst-type latent curing agent having temperature activity and gives a cured product which gives an extract of an Na<+> ion concentration of at most 300 ppm and a Cl<-> ion concentration of at most 300 ppm when extracted with water at 100 deg.C for 10 hr.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an adhesive composition.

[0002]

2. Description of the Related Art Epoxy resin adhesives are widely used in various applications such as electric, electronic, construction, automobile, and aircraft because of their high adhesive strength and excellent water resistance and heat resistance. Among them, one-pack type epoxy resin-based adhesives are used in the form of a film, a paste, a powder, or the like because it is not necessary to mix a main agent and a curing agent and is easy to use. In this case, it is general to obtain a specific performance by various combinations of an epoxy resin, a curing agent and a modifying agent, and for example, an attempt disclosed in Japanese Patent Application Laid-Open No. Sho 62-141083 is known.

[0003]

However, the film adhesive disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 62-141083 has the disadvantage that, although it is excellent in workability, heat resistance and moisture resistance are insufficient. Was.

[0004] The reason for this is that in order to obtain good workability by satisfying both short-time curability (rapid curability) and storage stability (preservability), a catalytic curing agent which is inactive at room temperature is used. In addition, a sufficient reaction cannot be obtained during curing. That is, the glass transition point (Tg), which is a measure of heat resistance, is around 100 ° C. at the maximum, and for example, a pressure cooker test (PCT, 121 ° C.,
2 atm), the resistance to high temperature and high humidity evaluation was insufficient. In addition, in the case of a polyaddition type such as an acid anhydride or an aromatic amine or a polyphenol which is a curing agent frequently used for heat resistance applications, curing requires a long time of several hours or more, and workability is insufficient. .

An object of the present invention is to provide an adhesive composition which is excellent in heat resistance, moisture resistance and workability, and is particularly suitable as an adhesive for electric and electronic applications requiring strict reliability.

[0006]

Means for Solving the Problems The present invention provides the following (1) to
(3) The concentration of Na ⁺ and Cl ⁻ ions in the extraction water after 10 hours at 100 ° C. of the cured product essentially containing the component is 300 pp.
m or less, and may contain a bisphenol-type epoxy resin if necessary. (1) Phenoxy resin (2) Polyfunctional glycidyl ether type epoxy resin (3) Catalytic latent curing agent having temperature activity

Further, the cured product of the above adhesive composition has a Tg of 1
The adhesive composition has a temperature of 20 ° C. or higher.

The phenoxy resin used in the present invention will be described.

The phenoxy resin has a molecular weight of 10,000.
It corresponds to the above-mentioned high molecular weight epoxy resin, and has characteristics of good compatibility and good adhesiveness since the structure is similar to the epoxy resin. The larger the molecular weight, the more easily the film-forming property can be obtained, and the melt viscosity which affects the fluidity at the time of connection can be set in a wide range. A molecular weight of 15,000 or more is more preferable. When these resins contain polar groups such as hydroxyl groups and carboxyl groups, the compatibility with the epoxy resin is improved, and a film having a uniform appearance and properties can be obtained. It is also preferable from the viewpoint of obtaining.

The polyfunctional epoxy resin has three or more oxirane groups in one molecule, and examples thereof include a polyfunctional glycidyl ether type epoxy resin and a polyfunctional glycidylamine type epoxy resin.

The polyfunctional glycidyl ether type epoxy resin used in the present invention includes triphenyl glycidyl ether and tetraphenyl glycidyl ether ethane, and a hydrophobic group such as a t-butyl group can be introduced into the molecule.

Examples of the polyfunctional glycidylamine type epoxy resin include triglycidylaminophenol, triglycidyl isocyanurate, tetraglycidyl metaxylenediamine, tetraglycidylaminodiphenylmethane and the like.

Among these, the polyfunctional glycidylamine type epoxy resin is advantageous in quick curing, but has a problem in storage stability, and the polyfunctional glycidyl ether type epoxy resin is preferable because it can obtain balanced properties.

These are trifunctional, tetrafunctional, etc., and can increase the crosslinking density by increasing the amount of epoxy groups in the composition. These epoxy resins contain impurity ions (Na
^+, CI ^-, etc.) and, 300pp and hydrolyzable chlorine
It is preferable to use a high-purity product reduced to m or less in order to prevent electron migration.

Known materials can be used as the catalytically active latent curing agent having temperature activity. For example, there are imidazole type, hydrazide type, boron trifluoride-amine complex, amine imide, polyamine salt, dicyandiamide and the like, and modified products thereof, and these can be used alone or as a mixture of two or more. These are so-called ionic polymerizable catalyst-type curing agents such as anionic or cationic polymerizable types, and are preferable because they can easily obtain rapid curability and require little consideration of chemical equivalents.

In a preferred embodiment of the present invention, which requires compatibility between the contradictory characteristics of long-term storage property and rapid curability, these curing agents are used as cores, and high molecular substances such as polyurethane and polyester, Ni, It is preferably a microcapsule type coated with a metal thin film such as Cu and an inorganic substance such as calcium silicate. When using the capsule-type curing agent, it should be noted that the particle size of the capsule is made smaller than, for example, the thickness of the film adhesive to prevent capsule destruction during storage, and that the material of the capsule coating layer is made of a composition. That is, it should be resistant to solvents and solvents.

The activation temperature of the catalytically active curing agent of the present invention is preferably from 50 to 200 ° C., more preferably from 70 to 150 ° C.
Is more preferred. The activation temperature indicates an exothermic peak temperature when the temperature of the mixture of the epoxy resin and the curing agent is raised from room temperature at a rate of 10 ° C./min using a DSC (differential scanning calorimeter) as a sample.

In the present invention, the epoxy resin optionally used is, for example, a bisphenol-type epoxy resin derived from epichlorohydrin and bisphenol A, F, D, S, etc., or an epoxy novolak derived from epichlorohydrin and phenol novolak or cresol novolak. Resin is typical, other glycidylamine,
Glycidyl ester, glycidyl ether, biphenyl, naphthalene, alicyclic, chlorinated, etc.
Various epoxy compounds having two or more oxirash groups can be applied. These can be used alone or in combination of two or more. These epoxy resins are capable of removing impurity ions (such as Na ⁺ and Cl ⁻ ) and hydrolyzable chlorine.
It is preferable to use a high-purity product reduced to 00 ppm or less in order to prevent electron migration.

Among the above-mentioned epoxy resins, bisphenol-type epoxy resins are preferred because grades having different molecular weights are widely available and adhesiveness and reactivity can be arbitrarily set. Among them, bisphenol F type epoxy resin is particularly preferable because its viscosity is particularly low so that the fluidity can be set in a wide range in combination with a high molecular weight phenoxy resin, and it is liquid and easy to obtain adhesiveness.

In the adhesive composition obtained as described above, for example, fillers, softeners, accelerators, antioxidants, coloring agents, flame retardants, thixotropic agents, couplings, etc. Agents and curing agents such as melamine resins and isocyanates. Among these, fillers such as conductive particles and silica, and coupling agents of various systems such as silane, titanium, chromium, zirconium, and aluminum are particularly useful.

As the conductive particles, Au, Ag, Ni, C
u, metal particles such as solder, carbon, and the like, and those obtained by forming the above-described conductive layer on these, non-conductive glass, ceramic, plastic, or the like by coating or the like. These are used properly in a wide range of 0.01 to 30% by volume depending on the application. For example, 15% by volume or more is used for a conductive paint or the like which requires conductivity in all directions, and 15% by volume or less for an anisotropic conductive adhesive or the like useful for circuit connection.

As the coupling agent, an amino group- or epoxy group-containing material is particularly preferred in terms of improving adhesiveness and dispersibility of a filler and the like.

The adhesive composition of the present invention can be applied as a one-pack type adhesive to paints, laminate materials, impregnating materials, molding materials, etc., and is used for bonding IC chips to substrates and bonding electric circuits. It is particularly useful as a film adhesive.

In this case, for example, the adhesive composition obtained above is liquefied as a solvent or a dispersion in the case of an emulsion and formed on a peelable substrate such as release paper, or a substrate such as a nonwoven fabric. Is formed on a peelable substrate by impregnating the above-mentioned compounding solution, and dried at a temperature lower than the activation temperature of the curing agent to remove the solvent or the dispersion.

At this time, a mixed solvent of an aromatic hydrocarbon type and an oxygen-containing type is preferably used as the solvent to improve the solubility of the material. Here, the SP value of the oxygen-containing solvent is 8.1 to 1
The range of 0.7 is preferable for protection of the catalytic latent curing agent having a temperature activity, and acetates are more preferable. Further, the boiling point of the solvent can be 150 ° C. or less. If the boiling point exceeds 150 ° C., a high temperature is required for drying, and the temperature is close to the activation temperature of the latent curing agent, resulting in a decrease in the potential. At a low temperature, the workability during drying decreases. Therefore, the boiling point is 60 to 1
50 ° C is preferable, and 70 to 130 ° C is more preferable.

The connection of the electrodes using the adhesive composition obtained in the present invention will be described.

According to this method, an adhesive composition having a cured product Tg of 120 ° C. or higher is formed between electrodes facing each other on a substrate, and the contact between the two electrodes is caused by heating and pressing. This is a method of connecting electrodes to obtain adhesion. Here, the Tg of the cured product is the peak temperature of Tan δ due to dynamic viscoelasticity (tensile mode, 10 Hz). The reason why the Tg is 120 ° C. or higher is to make the temperature substantially equal to the higher-order target temperature of the reliability evaluation. At temperatures below Tg, changes in physical properties such as elastic modulus are relatively small.

As the substrate for forming the space between the electrodes, a semiconductor,
Inorganic substances such as glass and ceramic, organic substances such as polyimide and polycarbonate, and combinations of these composites such as glass / epoxy can be applied.

The metal foil with an adhesive using the adhesive composition obtained in the present invention will be described. BACKGROUND ART A metal foil with an adhesive is used for bonding a metal foil such as copper or aluminum to the above-described substrate, and is often used as, for example, a printed circuit board.

According to the metal foil with an adhesive using the adhesive composition obtained in the present invention, a rapid laminating property and a preserving property can be compatible, so that a continuous laminating method can be applied to the adhesion to a substrate. Workability is improved. In addition, it is possible to improve Tg and obtain high temperature and high humidity resistance, so that characteristics are improved. The method for forming the adhesive composition on the metal foil may be a coating or a film adhesive, and the formation surface may be one side or both sides.

In the present invention, by containing a phenoxy resin, a polyfunctional glycidyl ether type epoxy resin, and a latent curing agent having a temperature activity, it is possible to improve Tg while achieving both fast curing and preservability. High temperature and high humidity resistance can be obtained. The reason for this is that the presence of hydroxyl groups in the phenoxy resin accelerates the curing reaction of the polyfunctional epoxy resin and enables rapid curing, and the phenoxy resin has a high molecular weight and high viscosity. It can be presumed that good preservability is obtained due to the low contact with the agent.

The phenoxy resin has a long molecular chain and a similar structure to an epoxy resin, and acts as a flexible material in a composition having a high cross-linking density, and imparts high toughness. can get.

The polyfunctional glycidyl ether type epoxy resin cures to increase the crosslink density in the composition, thereby improving Tg. Regarding the mechanism for improving high temperature and high humidity, in addition to maintaining high elastic modulus at high temperatures by improving the crosslink density, it is considered that the introduction of the ether structure of the polyfunctional glycidyl ether type epoxy resin reduces water absorption and improves interfacial adhesion. Can be These effects are more effectively obtained as a synergistic effect when used in combination with a phenoxy resin.

The bisphenol type epoxy resin is
It is effective for arbitrarily adjusting fluidity, tackiness, adhesiveness, reactivity and the like.

The adhesive film used in the present invention comprises a phenoxy resin, a polyfunctional glycidyl ether type epoxy resin and a latent curing agent having a temperature activity, and the activation temperature of the latent curing agent having a temperature activity. Since drying is performed below, stable storage stability is obtained without deterioration of the curing agent.

The electrode connection body of the present invention is characterized in that the adhesive used contains a phenoxy resin, a polyfunctional glycidyl ether type epoxy resin and a latent curing agent having a temperature activity, so that the cured product has a Tg of 120 ° C. or more. Therefore, the connection portion has excellent heat resistance, high temperature and high humidity resistance, and extremely good connection reliability can be obtained.

According to the metal foil with an adhesive using the adhesive composition obtained in the present invention, it is possible to obtain both fast-curing property and preservability,
Workability during manufacturing is improved. In addition, it is possible to improve Tg and obtain high temperature and high humidity resistance, so that characteristics are improved.

[0038]

(Example 1) PKHA (phenoxy resin, molecular weight 25,000, hydroxyl group 6%, trade name, manufactured by Union Carbide Co.) and EPPN501H (triphenyl glycidyl ether type epoxy resin, epoxy equivalent 176, Nippon Kayaku Co., Ltd.) 50 g of product name (abbreviated as EPPN)
Weighed 50 g with respect to each, and all of them were reagent grade toluene (boiling point 1
10.6 ° C, SP value 8.90) / ethyl acetate (boiling point 7
7.1, SP value 9.10) = 50/50 (wt%) to obtain a 40% solution. 250 g of this solution
A latent curing agent A having a temperature activity (average particle size 10 μm)
of 1-cyanoethyl-2-undecyl trimellitate imidazolium (abbreviation: C11Z-CNS), 20 g of a microcapsule type having a copper plating layer having a thickness of about 0.2 .mu.m on the surface of the powder; . After applying the mixed solution obtained above on a roughened surface of copper foil 105 μm, 100
℃ 10 minutes hot air drying, adhesive layer thickness 15μ
m of copper foil with an adhesive was obtained.

Using the copper foil with adhesive and the copper foil with adhesive stored at 50 ° C. for 240 hours, a roughened surface of copper foil 105 μm and an ITO surface-treated glass 1.
Connection with 1 mm is made at 160 ° C.-20 kg / mm ² -30 seconds, and high temperature and high humidity treatment (PCT-121 ° C., 2 atm)
Before and after tensile shear bond strength (JIS, K-6850,
However, an adhesion area of 3 × 1 mm ² , an average of five pieces was obtained. The evaluation results are shown in Table 1, and showed good short-term connectivity, storage stability, and high temperature and high humidity.

(Examples 2 to 7) The same as Example 1, except that the materials and amounts of other components except PKHA were changed, and 0.5 part of γ-glycidic acid was added to 100 parts of the adhesive composition. Xypropyl trimethoxysilane was added. The ratio of the phenoxy resin to the polyfunctional glycidyl ether type epoxy resin and the latent curing agent having a temperature activity (including the epoxy resin for convenience) is 40/30/30 in terms of solid content ratio, and toluene / ethyl acetate (both are used). It was dissolved in a mixed solvent of (reagent special grade) = 70/30 to obtain a 40% solution.

The material newly used here was a polyfunctional epoxy resin which was Epicoat 1032 (triphenylglycidyl ether type epoxy resin, epoxy equivalent 176, hydrolyzable chlorine 270 ppm, trade name of Yuka Shell Epoxy Co., Ltd., 1032). ESX-220 (glycidyl ether type epoxy resin having a t-butyl group introduced into a trifunctional structure, epoxy equivalent 220, trade name, manufactured by Sumitomo Chemical Co., Ltd., abbreviated as ESX), and Epicoat 1031
(Tetraphenyl glycidyl ether ethane type epoxy resin, epoxy equivalent: 176, trade name, manufactured by Yuka Shell Epoxy Co., Ltd., abbreviated as 1031).

The latent curing agent having a temperature activity is Novacure 3748 (a microcapsule-type curing agent having an imidazole-modified nucleus as a nucleus and its surface coated with polyurethane, and a liquid bisphenol A type epoxy resin having an average particle size of 5 μm). Masterbatch-type curing agent dispersed in the above, active temperature 132 ° C., trade name of Asahi Kasei Corporation, abbreviation 3748), and Novacure 3941 (similar to 3748 but dispersed in liquid bisphenol F type epoxy resin, active temperature 125) ℃, the product name of Asahi Kasei Industry Co., Ltd., 3941
Abbreviated).

The results of evaluation in the same manner as in Example 1 are shown in Table 1. As a result of the inclusion of the silane coupling agent, good short-term connectivity, storage stability, and high-temperature and high-humidity properties were exhibited.

Example 8 The solution of Example 5 was applied on a biaxially stretched polypropylene film (abbreviated as OPP) using a roll coater, and then dried at 100 ° C. for 10 minutes with hot air to form an adhesive layer. Was obtained as a film adhesive having a particle size of 25 μm.

This film had sufficient flexibility at room temperature and could be continuously wound. Using this film and a film obtained by preserving this film at 50 ° C. for 240 hours, a connection between the roughened surface of copper foil 105 μm and the ITO surface-treated glass 1.1 mm was 160 ° C.-20 kg.
/ Mm ² -30 seconds, high temperature and high humidity treatment (PCT-12
Tensile shear bond strength around 1 ° C., 2 atm) was determined. The evaluation results are shown in Table 1, and showed good short-term connectivity, storage stability, and high temperature and high humidity.

The adhesive was heated at 200 ° C. for 10 minutes in the air, and was subjected to a tensile mode, 1
The peak temperature of Tan δ at 0 Hz and 5 ° C./min was found to be 180 ° C. or higher.

The cured product is immersed in pure water,
The extracted water after 0 ° C. for 10 hours was analyzed by ion chromatography to find that Na ⁺ 5.2 ppm, C 1 ⁻
3.5 ppm.

(Examples 9 to 11 and Comparative Examples 1 and 2) The same as Example 8, except that PKHA, which is a flexible product of PKHA, is used.
Using HM-30, the above-mentioned Novacur 3941 was used as a latent curing agent having a temperature activity of 40%. The amount ratio of the phenoxy resin to the polyfunctional epoxy resin is PKHM-30.
/ Epicoat 1032 = 0/60 (Comparative Example 1), 5/5
5 (Example 9), 30/30 (Example 10), 55/5
(Example 11) and 60/0 (Comparative Example 2). The peak temperature of Tan δ determined in the same manner as in Example 8 was obtained in Example 9,
In Example 10, all were 180 ° C. or higher. Similarly, Example 10 is 154 ° C., Example 11 is 123 ° C., and Comparative Example 2
Was 85 ° C. Comparative Example 1 did not contain a phenoxy resin, and thus was inferior in film formability and could not be tested.

Table 1 shows the evaluation results of the tensile shear bond strength. In Examples 9 to 11, the amount ratio of the phenoxy resin to the polyfunctional epoxy resin was varied, but all had good tensile shear adhesive strength. On the other hand, Comparative Example 1 could not be tested. Comparative Example 2 did not contain a polyfunctional epoxy resin, and thus did not have heat resistance and was peeled off after high-temperature and high-humidity treatment.

(Comparative Example 3) The same as Example 6, except that 30 parts of Epicoat 1032 was replaced with 12 parts of aromatic amine diaminodiphenyl sulfone as a curing agent. In this case, curing was impossible under the curing conditions of 160 ° C. for 30 seconds in the above example, and no peeling strength was exhibited.

(Examples 12 to 14) The film adhesive of Example 8 (Example 12) and nickel having an average particle diameter of 3 μm as conductive particles of 1% by volume based on the adhesive (Example 13) A film adhesive containing plastic particles (Example 14) having a thin metal layer on the surface with an average particle diameter of 5 μm was prepared.

On the other hand, a semiconductor chip (3 × 1
Prepare a wiring board on which an ITO circuit having connection terminals corresponding to the bump arrangement of 0 mm, height 0.5 mm, and bumps of 50 μm square and 20 μm height called bumps is formed around four sides of the main surface. did. The film adhesive was placed between the bump surface of the semiconductor chip and the circuit of the wiring board. At this time, each of the films of the examples had tackiness at room temperature and could be temporarily temporarily adhered to the bump surface of the semiconductor chip. Thereafter, the OPP (separator) was peeled off, the glass circuit and the bump were aligned, and the glass circuit was connected to the semiconductor chip by heating and pressing at 170 ° C.-30 g / bump-20 seconds.

In the above-mentioned connection product, no air bubbles were mixed into the connection portion. When the continuity of the connected products was checked, all the connections were good. PCT-121 ° C, 2atm-
After 200 hours, good connection was obtained in each of the examples.

When the cross section of the connection portion was observed with a scanning electron microscope, in Example 12, some of the bumps were deformed to obtain flatness and to make good contact with the connection terminal. Example 1
In Example 3 so that nickel is attached to the bumps,
In No. 4, the plastic particles were deformed so as to be crushed in the pressing direction, and were in good contact with the connection terminals via the respective conductive particles. From these facts, it was found that in Example 13, the oxide layer on the electrode surface was broken through, and in Example 14, it was possible to cope with variations in bump height.

[0055]

[Table 1]

Example 15 and Comparative Example 4 The same evaluation as in Example 12 was performed using the film adhesives of Example 11 and Comparative Example 2. The connection product using the film of Example 11 (Example 15) was a good connection. In the connection product using the film of Comparative Example 2 (Comparative Example 4), many connection opens occurred after PCT. It is considered that the Tg of the cured product, which was 123 ° C. in Example 15 and 85 ° C. in Comparative Example 4, greatly affected the evaluation temperature of 121 ° C. By setting the Tg of the cured adhesive to be higher than the maximum temperature for evaluation, the connection reliability could be improved.

[0057]

As described above in detail, according to the present invention, it is excellent in electron migration prevention, heat resistance, moisture resistance and workability, and is particularly suitable as an adhesive for electric and electronic applications requiring strict reliability. An agent composition can be provided.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Naoyuki Shiozawa 1500 Oji Ogawa, Shimodate City, Ibaraki Pref.Hitachi Chemical Industry Co., Ltd. (72) Inventor Yutaka Yamaguchi 1500 Odai, Shimodate-shi, Ibaraki Pref.Hitachi Chemical Industry Co., Ltd. F term (reference) 4J040 EC051 EC121 EC131 EE061 HC12 HC15 HC24 HD41 KA16 LA02 LA07 LA08 MA02 MA04 MA05 MA10 NA19

Claims (4)

[Claims] 1. A cured product comprising the following components:
An adhesive composition in which the Na ⁺ and Cl ⁻ ion concentrations of extraction water after 10 hours at 300 ° C. are 300 ppm or less. (1) Phenoxy resin (2) Polyfunctional glycidyl ether type epoxy resin (3) Catalytic latent curing agent having temperature activity 2. The adhesive composition according to claim 1, wherein the polyfunctional glycidyl ether type epoxy resin is triphenyl glycidyl ether or tetraphenyl glycidyl ether ethane. 3. The polyfunctional glycidyl ether type epoxy resin has a hydrolyzable chlorine of 300 ppm or less.
Or the adhesive composition according to claim 2. 4. The cured product of the adhesive composition has a Tg (glass transition temperature) of 120 ° C. or higher.
The adhesive composition according to any one of the above.