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.

1 . An isotropic conductive adhesive sheet comprising at least a curing agent, a curable insulating resin and conductive particles, wherein 90% or more of the conductive particles are present in a region of a thickness of not greater than 1.5 times the average particle size of the conductive particles extending from one surface of the anisotropic conductive adhesive sheet in the thickness direction, and 90% or more of the conductive particles are present without contact with other conductive particles, wherein the average particle size of the conductive particles is 1 to 8 μm, and the average particle distance between adjacent conductive particles is at least once but five times or less the average particle size 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.  
   
   
       2 . The anisotropic conductive adhesive sheet according to  claim 1 , wherein the conductive particles are at least those selected from the group consisting of noble metal-coated resin particles, noble metal-coated metal particles, metal particles, noble metal-coated alloy particles, and alloy particles.  
   
   
       3 . A method for manufacturing an anisotropic conductive adhesive sheet comprising providing an adhesive layer on a biaxially stretchable film to form a laminate, densely packing conductive particles having an average particle size of 1 to 8 μm on the laminate to form a conductive particle-attached film, biaxially stretching and holding the conductive particle-attached film so that the average particle distance between adjacent conductive particles is at least once but five times or less the average particle size of the conductive particles and not greater than 20 μm, and transferring the conductive particles to an adhesive sheet containing at least a curing agent and a curable insulating resin and having a thickness of at least 1.5 times the average particle distance between the conductive particles but not greater than 40 μm.  
   
   
       4 . The method according to  claim 3 , wherein the biaxially stretchable film is a long film and the adhesive sheet is a long adhesive sheet.  
   
   
       5 . A method for electrically connecting an electronic circuit component having fine connecting terminals to a circuit board having a circuit corresponding thereto using an anisotropic conductive adhesive sheet, comprising electrically connecting the electronic circuit component to the circuit board having a circuit corresponding thereto using the anisotropic conductive adhesive sheet according to  claim 1 , wherein said electronic circuit component has a height of the fine connecting terminals of 3 to 15 times the average particle distance between conductive particles and not greater than 40 μm, a distance between the fine connecting terminals of 1 to 10 times the average particle distance and not greater than 40 μm, and a pitch of the fine connecting terminals of 3 to 30 times the average particle distance and not greater than 80 μm.  
   
   
       6 . A fine connecting structure obtained by the method according to  claim 5 .  
   
   
       7 . An anisotropic conductive adhesive sheet comprising at least a curing agent, a curable insulating resin and conductive particles manufactured by the method according to  claim 3 , wherein 90% or more of the conductive particles are present in a region of a thickness of not greater than 1.5 times the average particle size of the conductive particles extending from one surface of the anisotropic conductive adhesive sheet in the thickness direction, and 90% or more of the conductive particles are present without contact with other conductive particles, wherein the average particle size of the conductive particles is 1 to 8 μm, and the average particle distance between adjacent conductive particles is at least once but five times or less the average particle size and not greater than 20 μm, and wherein the thickness of the anisotropic conductive adhesive sheet is at least twice the average particle distance but not greater than 40  
   
   
       8 . A method for electrically connecting an electronic circuit component having fine connecting terminals to a circuit board having a circuit corresponding thereto using an anisotropic conductive adhesive sheet, comprising electrically connecting the electronic circuit component to the circuit board having a circuit corresponding thereto using the anisotropic conductive adhesive sheet according to  claim 2 , wherein said electronic circuit component has a height of the fine connecting terminals of 3 to 15 times the average particle distance between conductive particles and not greater than 40 μm, a distance between the fine connecting terminals of 1 to 10 times the average particle distance and not greater than 40 μm and a pitch of the fine connecting terminals of 3 to 30 times the average particle distance and not greater than 80 μm.