JPH09310057A - Anisotropic electroconductive paste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an anisotropic electroconductive paste by a production process and a use process carried out by simple operations in a short time without requiring a protecting film such as an anisotropic electroconductive film. SOLUTION: This anisotropic electroconductive paste comprises an epoxy resin, a curing agent which is a microcapsulated modified substance of imidazole blended in the ratio of 4,400/(a)-40,000/(a) pts.wt. based on 100 pts.wt. of the epoxy resin when the epoxy equivalent value of the epoxy resin is (a), electroconductive particles which have 0.1-10μm particle diameter blended in the ratio of 1-8 pts.wt. based on 100 pts.wt. of the total of the epoxy resin and the curing agent and non-electroconductive particles blended in the ratio of <=10 pts.wt. based on 100 pts.wt. of the total of the epoxy resin and the curing agent.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a paste-like thermosetting adhesive used for anisotropic conductive connection,
In particular, the anisotropic conductive connection suitable for use in, for example, bonding an IC chip and a circuit board can be performed.

[0002]

2. Description of the Related Art Conventionally, for example, as an adhesive for bonding an electronic component to a predetermined portion of an electronic substrate such as between a transparent electrode in a liquid crystal display element and a wiring pattern of a driving external circuit,
It has been proposed to use a film-like anisotropic conductive adhesive coated and supported on a polymer protective sheet.

This type of film-shaped anisotropic conductive adhesive (anisotropic conductive film) is used during work steps such as peeling from a protective sheet, temporary pressure bonding to an electronic substrate, and final pressure bonding of electronic components. It was essential.

[0004]

The above-mentioned conventional anisotropic conductive film is formed into a film in the manufacturing process thereof, when the thermosetting adhesive is applied to the protective sheet, the adhesive repels or flows. It had the drawback of being difficult. Further, in the use process as well, there is a drawback that the work time is long because several steps such as peeling from the protective sheet, temporary pressure bonding, and final pressure bonding are required.

In view of the problems in the prior art, an object of the present invention is that the manufacturing process and the use process can be performed in a short time and in a simple operation without requiring a protective sheet such as an anisotropic conductive film. An anisotropic conductive paste is provided.

[0006]

To achieve the above object, the present invention provides a paste-like anisotropic conductive adhesive,
The present invention has been completed by discovering that this can be achieved by including a curing agent in which an imidazole-modified product is microencapsulated and specific conductive particles and non-conductive particles, and completed the present invention.

That is, the anisotropic conductive paste according to the present invention is a paste-like paste containing an epoxy resin, a curing agent for an epoxy resin which is inactive at room temperature and active by heating, conductive particles and non-conductive particles. The anisotropic conductive adhesive of claim 1, wherein the curing agent is a microcapsule of an imidazole-modified product, and when the epoxy equivalent value of the epoxy resin is a, relative to 100 parts by weight of the epoxy resin. It is mixed in a ratio of 4,400 / a to 40,000 / a parts by weight, and the conductive particles have a particle size of 0.1 to 10 μm, and the total amount of the epoxy resin and the curing agent is 100 parts by weight.
1 to 8 parts by weight, and the non-conductive particles are added to 100 parts by weight of the total amount of epoxy resin and curing agent.
It is characterized by being mixed in a ratio of 10 parts by weight or less.

The present invention will be described in detail below.

The epoxy resin used in the present invention includes:
Generally used epoxy resins can be used as long as they are polyvalent epoxy resins having two or more epoxy groups in the molecule. As specific examples, bisphenol type epoxy resin, cresol novolac type epoxy resin, aliphatic polyepoxy resin, etc., and dimer acid or trimer acid modified product, other epoxy modified product, etc. can be used, and these are used alone or Two or more kinds can be mixed and used.

The curing agent used in the present invention is an epoxy resin curing agent which is inactive as a powder at room temperature and which is activated and reacts after the powder is melted by heating. Specifically, a microcapsule obtained by coating a modified imidazole (heterocycle-containing amine derivative) with a coating substance such as an acid anhydride can be used. These curing agents are
By raising the temperature, the coating substance is broken, the imidazole-modified product inside is melted, and the reaction with the epoxy resin is started. Even imidazole-modified products that are active at room temperature,
If it is covered with an inert coating material, it will not come into direct contact with the epoxy resin, which will extend the pot life.

In the present invention, the imidazole-modified product of the curing agent is added in a proportion of 4,400 / a to 40,000 / a parts by weight with respect to 100 parts by weight of the epoxy resin (epoxy equivalent a). If the imidazole-modified product is less than 4400 / a part by weight, the curing speed will be slower and 40,000 / a
If it is blended in excess of parts by weight, unreacted curing agent may remain after curing, resulting in poor reliability.

The particle size of the conductive particles is preferably 0.1 to 10 μm. If the particle size is 0.1 μm or less, it is difficult to manufacture, and if it exceeds 10 μm, it cannot be applied to the connection of fine pitch circuits. Such conductive particles are made of epoxy resin.
It is desirable to add 1 to 8 parts by weight to 100 parts by weight. If the amount is less than 1 part by weight, electrical connection may be insufficient even if pressed at the time of bonding, and if the amount exceeds 8 parts by weight, horizontal insulation may be poor. Further, the non-conductive particles are 10
It is desirable that the amount is less than or equal to parts by weight, and if the amount is more than that, the adhesive force is reduced.

[0013]

According to the paste-like anisotropic conductive adhesive of the present invention, a curing agent which is microcapsulated with an imidazole-modified product which is inactive at room temperature and which is activated by heating and reacts with an epoxy resin is used. Thus, it is possible to satisfy two contradictory requirements that the curing time upon heating is fast and the storage stability at room temperature is excellent. Further, by using conductive particles and non-conductive particles in a predetermined ratio together, the particles can be dispersed well.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in detail with reference to Examples. In the following Examples and Comparative Examples, "part" means "part by weight" and "%" means "% by weight".

Example 1 Epoxy Coat 1009 (made by Yuka Shell Co., Ltd.,
(Commercial name) is mixed in a ratio of 10:90 with Epicoat 828 (manufactured by Yuka Shell Co., Ltd.) to obtain an average epoxy equivalent.
400 liquid epoxy resin. To 100 parts of this resin, 15 parts of microcapsule type imidazole modified hardener was mixed and mixed, and 2 parts of conductive particles and 1 part of non-conductive particles were added to 100 parts of the total amount of epoxy resin and hardener. By mixing, a paste-like anisotropic conductive adhesive was obtained.

Examples 2 to 3 By using the formulations shown in Table 1, paste type anisotropic conductive adhesives of Examples 2 and 3 were obtained in the same manner as in Example 1.

Table 1 shows the results of evaluation of the curing time, the continuity test, the adhesive strength, and the high temperature and high humidity test after curing of the adhesives of Examples 1 to 3. The curing time is obtained by heating the adhesive on a hot plate and measuring the time until curing. In the continuity test, apply an adhesive on the ITO glass electrode, overlay TAB, heat and pressure bond under the conditions of 150 ° C x 60 seconds, 40 kg / cm, and then connect resistance between opposing wiring patterns and between adjacent wiring patterns. The insulation resistance is measured at a pitch of 60 to 200 μm. Adhesive strength is as follows: sandwich the adhesive between ITO glass and TAB, 150 ℃ for 60 seconds, 40k
The peel strength was measured after thermocompression bonding under the condition of g / cm. In the high temperature and high humidity test, the sample after the continuity test was stored in a constant temperature bath at 85 ° C and 85%, and the continuity of the connection resistance value was examined.

[0018]

[Table 1]

Example 4 and Comparative Examples 1 to 5 Several kinds of paste-like adhesives having different blending ratios of the epoxy resin and the curing agent, the conductive particles, and the non-conductive particles were mixed according to the formulations shown in Table 2, Table 2 also shows the results of the same test as above, prepared in the same manner as in Example 1.

[0020]

[Table 2] * 1: Parts by weight based on 100 parts by weight of resin component.

As is clear from Tables 1 and 2, in the above-mentioned examples, good results were obtained in the examples with respect to curing time, connection resistance, insulation resistance and adhesive strength, but good results were obtained in the comparative examples. I couldn't get it.

[0022]

According to the present invention, by mixing an epoxy resin, a curing agent for an epoxy resin in which an imidazole-modified product is microencapsulated, conductive particles and non-conductive particles in a predetermined ratio, a paste-like anisotropy is obtained. A conductive adhesive could be obtained.

Further, by selecting an epoxy resin, it is possible to adjust the melt viscosity and to prepare a resin having less bleeding and bleeding.

Claims (1)

[Claims] 1. A paste-like anisotropic conductive adhesive containing an epoxy resin, a curing agent of an epoxy resin which is inactive at room temperature and active by heating, conductive particles, and non-conductive particles, The curing agent is a microcapsule of an imidazole-modified product, and when the epoxy equivalent value of the epoxy resin is a, the epoxy resin is an epoxy resin.
It is mixed in a ratio of 4,400 / a to 40,000 / a parts by weight with respect to 100 parts by weight. The conductive particles have a particle size of 0.1 to 10 μm, and the total amount of the epoxy resin and the curing agent is 100 parts by weight. 1 to 8 parts by weight, and the non-conductive particles are mixed in an amount of 10 parts by weight or less based on 100 parts by weight of the total amount of the epoxy resin and the curing agent. paste.