Structure and method of making interconnect element having metal traces embedded in surface of dielectric

Abstract

An interconnect element is provided which includes a dielectric element having a major surface. Metal interconnect patterns are embedded in recesses which extend inwardly from the major surface, the outer surfaces of the interconnect patterns being substantially co-planar with the major surface and extending in one or more directions of the major surface. A projecting conductive film extends over the major surface in at least one direction parallel to a plane defined by the major surface such that it contacts the dielectric element along at least a portion of the major surface and conductively contacts an outer surface of at least one of the metal interconnect patterns.

1 . An interconnect element, comprising:
 a dielectric element having a major surface and a plurality of recesses extending inwardly from said major surface;   a plurality of metal interconnect patterns embedded in said plurality of recesses, said plurality of metal interconnect patterns having outer surfaces substantially co-planar with said major surface and extending in one or more directions of said major surface; and   a projecting conductive film extending over said major surface in at least one direction parallel to a plane defined by said major surface to contact said dielectric element along at least a portion of said major surface and conductively contact an outer surface of at least one of said metal interconnect patterns.   
     
     
         2 . The interconnect element as claimed in  claim 1 , further comprising an insulating cover film overlying only a portion of said major surface and at least one of said metal interconnect patterns such that said projecting conductive film is exposed by said insulating cover film. 
     
     
         3 . The interconnect element as claimed in  claim 1 , wherein at least a portion of said projecting conductive film conductively interconnects respective ones of said metal interconnect patterns. 
     
     
         4 . The interconnect element as claimed in  claim 1 , wherein said major surface is a first major surface, said dielectric element includes a second major surface remote from said first major surface and a plurality of second recesses extending inwardly from said second major surface, said metal interconnect patterns are first metal interconnect patterns embedded in said first recesses, and said interconnect element further comprises a plurality of second metal interconnect patterns embedded in said second recesses extending in one or more directions of said second major surface and having outer surfaces substantially co-planar with said second major surface, and at least some of said first metal interconnect patterns are conductively connected to at least some of said second metal interconnect patterns. 
     
     
         5 . The interconnect element as claimed in  claim 4 , wherein said at least some first metal interconnect patterns are conductively connected to said at least some second metal interconnect patterns by one or more conductors extending through said dielectric element in a direction transverse to said plane defined by said first major surface of said dielectric element. 
     
     
         6 . The interconnect element as claimed in  claim 5 , wherein said one or more conductors extending through said dielectric element includes a conductor lining a through hole extending through said dielectric element. 
     
     
         7 . An assembly including the interconnect element as claimed in  claim 6 , further comprising an external circuit element having an exposed lead inserted into said through hole in conductive contact with said conductor to provide conductive interconnection to said interconnect element. 
     
     
         8 . The interconnect element as claimed in  claim 5 , wherein said one or more conductors extending through said dielectric element includes a solid conductive post contacting inner surfaces of at least some of said first and second metal interconnect patterns recessed inwardly from said first and second major surfaces. 
     
     
         9 . The interconnect element as claimed in  claim 4 , further comprising a first insulating cover film overlying a first portion of said first major surface and at least one of said first metal interconnect patterns such that said projecting conductive film is exposed by said insulating cover film. 
     
     
         10 . An assembly including the interconnect element as claimed in  claim 1 , further comprising an external circuit element including an exposed contact, said contact being conductively connected to said projecting conductive film. 
     
     
         11 . The assembly as claimed in  claim 10 , wherein said projecting conductive film is conductively connected to said contact through an anisotropic conductive film. 
     
     
         12 . A method of fabricating an interconnect element, comprising:
 providing structure including a first metal layer overlying a second metal layer;   patterning a plurality of metal interconnect patterns from said first metal layer;   forming a dielectric element overlying said structure;   removing said second metal layer selectively to said plurality of metal interconnect patterns, such that said plurality of metal interconnect patterns are embedded in said dielectric element, said metal interconnect patterns having outer surfaces co-planar with a first major surface of said dielectric element; and   forming a projecting conductive film extending over said first major surface in at least one direction parallel to a plane defined by said major surface to contact said dielectric element along at least a portion of said first major surface and conductively contact an outer surface of at least one of said metal interconnect patterns.   
     
     
         13 . The method as claimed in  claim 12 , wherein said step of forming said dielectric element includes pressing a layer including an uncured resin over said plurality of metal interconnect patterns. 
     
     
         14 . The method as claimed in  claim 12 , wherein said metal interconnect patterns are first metal interconnect patterns embedded in first recesses extending inwardly from said first major surface, said method further comprising providing a second structure including a third metal layer overlying a fourth metal layer and patterning a plurality of second metal interconnect patterns from said third metal layer, said step of forming said dielectric element including pressing said second structure onto a second major surface of said dielectric element remote from said first major surface and removing said fourth metal layer selectively to said plurality of second metal interconnect patterns, such that said second metal interconnect patterns are embedded in said second major surface of said dielectric element and said second metal interconnect patterns have outer surfaces co-planar with said second major surface, said method further comprising:
 forming a through hole extending through said dielectric element between said first metal interconnect patterns and said second metal interconnect patterns; and   forming a conductor lining said through hole to connect said first metal interconnect patterns to said second metal interconnect patterns simultaneously when forming said projecting conductive film.