Anisotropically conductive member and method of manufacture

Abstract

An anisotropically conductive member has an insulating base material, and conductive paths composed of a conductive material which pass in a mutually insulated state through the insulating base material in a thickness direction thereof and which are provided in such a way that a first end of each conductive path is exposed on a first side of the insulating base material and a second end of each conductive path is exposed on a second side of the insulating base material. The conductive paths have a density of at least 2 million paths/mm 2 and the insulating base material is a structure composed of an anodized aluminum film having micropores therein.

1 . An anisotropically conductive member comprising:
 an insulating base material; and   conductive paths composed of a conductive material which pass in a mutually insulated state through the insulating base material in a thickness direction thereof and which are provided in such a way that a first end of each conductive path is exposed on a first side of the insulating base material and a second end of each conductive path is exposed on a second side of the insulating base material;   
     wherein the conductive paths have a density of at least 2 million paths/mm 2  and the insulating base material is a structure composed of an anodized aluminum film having micropores therein. 
   
   
       2 . The anisotropically conductive member of  claim 1 , wherein the micropores have a degree of ordering, as defined by formula (i):
   Degree of ordering (%)= B/A× 100   (i)   
     (wherein A represents a total number of micropores in a region of measurement and B represents a number of specific micropores in the region of measurement for which, when a circle is drawn so as to be centered on a center of gravity of a specific micropore and so as to be of a smallest radius that is internally tangent to an edge of another micropore, the circle includes centers of gravity of six micropores other than the specific micropore) of at least 50%. 
   
   
       3 . The anisotropically conductive member of  claim 1 , wherein the conductive paths are provided in such a way that the first end of each conductive path protrudes from the first side of the insulating base material and the second end of each conductive path protrudes from the second side of the insulating base material. 
   
   
       4 . The anisotropically conductive member of  claim 1 , wherein the insulating base material has a thickness of from 1 to 1,000 μm and the conductive paths have a diameter of from 5 to 500 nm. 
   
   
       5 . A method of manufacturing the anisotropically conductive member of  claim 1 , comprising, in order:
 an anodizing step of anodizing an aluminum substrate so as to form said anodized film having micropores therein;   a perforating step of passing holes determined by the micropores through the anodized film so as to obtain said insulating base material; and   a metal filling step of filling a metal as the conductive material into the holes which pass through the insulating base material so as to obtain said anisotropically conductive member.   
   
   
       6 . The method of  claim 5 , further comprising, after the metal filling step, a surface planarizing step of planarizing a front side and a back side of the anisotropically conductive member by chemical mechanical polishing. 
   
   
       7 . The method of  claim 5 , further comprising, after the metal filling step, a step of trimming the insulating base material on the surface of the anisotropically conductive member.