Anisotropic conductive adhesive sheet and connecting structure

Abstract

An anisotropic conductive adhesive sheet comprising at least a curing agent, a curable insulating resin and conductive particles, wherein in a region extending from a one-side surface of the anisotropic conductive adhesive sheet along the thickness direction to a position of not greater than 2.0 times the average diameter of the conductive particles, 90% or more of the sum of conductive particles are present, the 90% or more of the sum of conductive particles being present without contact with other conductive particles, and wherein the average diameter of conductive particles is in the range of 1 to 8 μm, the average particle distance between adjacent conductive particles being in the range of 1 to 5 times the average particle diameter and not greater than 20 μm, and wherein the thickness of the anisotropic conductive adhesive sheet is at least 1.5 times the average particle distance but not greater than 40 μm.

Description

TECHNICAL FIELD [0001] The present invention relates to an anisotropic conductive adhesive sheet that has excellent microcircuit connecting properties, and a connecting structure BACKGROUND ART [0002] Heretofore, concerning an anisotropic conductive adhesive sheet for connecting microcircuits, various conductive particles and anisotropic conductive adhesive compositions have been examined in order to improve connecting properties and prevent short-circuiting. For example, heretofore known methods include a method wherein insulating particles having a coefficient of thermal expansion equivalent are compounded to conductive particles (see Patent Document 1); a method wherein insulating particles are deposited on the surfaces of conductive particles in order to prevent short-circuiting (see Patent Document 2); a method wherein the surfaces of conductive particles are coated with an electrically insulating resin (see Patent Document 3); a method wherein layers containing and not contain...

AI Technical Summary

Benefits of technology

[0017] The anisotropic conductive adhesive and connecting structure of the present invention have favorable insulating characteristics between adjacent circuits, and have favorable electrical connecting properties between coupled circuits. The present invention also exerts the above-described effect particularly in the connecting of microcircuits

Problems solved by technology

However, in the conventional art wherein insulating properties are imparted to conductive particles or the like, there was limitation to micronize the particle diameter of conductive particles for insulating coating or insulating coating deposition, and both the security of insulating properties and the security of number of connecting particles could not be satisfied in the case of microcircuit connecting Also in the conventional art for preventing short-circuiting by adhesive compositions, the security of insulation properties and electrical connecting properties were not simultaneously satisfied in the case of microcircuit connecting Furthermore, in Patent Document 6, although an example wherein a peeling liner having a depression is previously formed and a single or plurality of conductive particle is disposed in the depression is disclosed, no examples wherein this is deposited on the adhesive layer to form an anisotropic conductive adhesive sheet are disclosed It was actually difficult to dispose a single conductive particle in each depression shallower than the particle diameter of the conductive particle.

To the contrary, although a single conductive particle could be disposed in each depression deeper than the particle diameter of the conductive particle, it was difficult to deposit on the adhesive layer As a result, the obtained anisotropic conductive adhesive could not satisfy both the security of insulating properties and the security of number of connecting particles.

Therefore, the gaps in the lateral direction of a terminal to be coupled were not filled with the insulating resin, and insulation properties were not be satisfied.

Connecting properties of terminals themselves were also not satisfactory due to a small amount of resin.

In view of the security of electrical conductivity, the distance between adjacent conductive particles cannot exceed the particle diameter of the conductive particles, and particularly in the case of microcircuit connecting, it is difficult to satisfy both the security of insulating properties and the security of electrical connecting properties at the same time.