Fluorescent conductive fill material for plated through hole structures and methods of defect inspection utilizing the same

Abstract

A microelectronic substrate having a substrate core with at least one plated through hole extending therethrough, wherein the plated through hole includes a fluorescent conductive fill material. In one embodiment, the plated through hole may comprise a hole defined to extend from a first surface to an opposing second surface of the substrate core, wherein a conductive material layer is formed on a sidewall(s) of the substrate core hole and a conductive fill material, having a fluorescent component, is disposed to fill the remaining substrate core hole after forming the conductive material layer. In another embodiment of the present description, the fluorescent conductive fill material is used for the detection of defects.

What is claimed is: 
     
         1 . A microelectronic substrate, comprising:
 a substrate core having at least one plated through hole extending from a first surface of the substrate core to a second surface of the substrate core, wherein the plated through hole comprises:
 a hole defined to extend from the substrate core first surface to the substrate core second surface forming at least one sidewall; 
 a conductive material liner formed on the at least one substrate core hole sidewall; and 
 a fluorescent conductive fill material disposed to abut the conductive material liner and substantially fill the substrate core hole. 
   
     
     
         2 . The microelectronic substrate of  claim 1 , wherein the fluorescent conductive fill material comprises an epoxy resin having a fluorescent component dispersed therein. 
     
     
         3 . The microelectronic substrate of  claim 1 , wherein the fluorescent conductive fill material includes a fluorescent component selected from the group consisting of rhodamine, fluorescein, cyanine, and inorganic quantum dots. 
     
     
         4 . The microelectronic substrate of  claim 1 , wherein the fluorescent conductive fill material includes a fluorescent component comprising between about 0.5% and 50% by weight of the fluorescent conductive fill material. 
     
     
         5 . A method of fabricating a microelectronic substrate, comprising:
 forming a substrate core having a first surface and an opposing second surface;   forming a hole to extend from the substrate core first surface to the substrate core second surface defining at least one sidewall;   forming a conductive material layer on the at least one substrate core hole sidewall; and   disposing a fluorescent conductive fill material to abut the conductive material layer and substantially fill the substrate core hole.   
     
     
         6 . The method of  claim 5 , wherein disposing the fluorescent conductive fill material comprises disposing a fluorescent conductive fill material comprising an epoxy resin having a fluorescent component dispersed therein. 
     
     
         7 . The method of  claim 5 , wherein disposing the fluorescent conductive fill material comprises disposing a fluorescent conductive fill material including a fluorescent component selected from the group consisting of rhodamine, fluorescein, cyanine, and inorganic quantum dots. 
     
     
         8 . The method of  claim 5 , wherein disposing the fluorescent conductive fill material includes disposing a fluorescent conductive fill material having a fluorescent component comprising between about 0.5% and 50% by weight of the fluorescent conductive fill material. 
     
     
         9 . The method of  claim 5 , wherein forming a conductive material layer on the at least one substrate core hole sidewall comprising depositing a conductive material layer on the substrate core first surface, the substrate core second surface, and the at least one substrate core hole sidewall. 
     
     
         10 . The method of  claim 9 , wherein depositing the conductive material layer comprises depositing a substantially uniform layer of conductive material layer on the substrate core first surface, the substrate core second surface, and the at least one substrate core hole sidewall. 
     
     
         11 . The method of  claim 9 , wherein depositing the conductive material layer comprises plating a metal material. 
     
     
         12 . The method of  claim 9 , wherein disposing the fluorescent conductive fill material comprising disposing the fluorescent conductive fill material into the substrate core hole and over the conductive material layer proximate the substrate core first surface; and further including removing a portion of the fluorescent conductive fill material over the conductive material layer proximate the substrate core first surface. 
     
     
         13 . The method of  claim 9 , further including forming a first capping conductive material layer on the fluorescent conductive fill material and the conductive material layer proximate the substrate core first surface, forming a second capping conductive material layer on the fluorescent conductive fill material and the conductive material layer proximate the substrate core second surface, removing a portion of the first capping conductive material layer and the conductive material layer proximate on the substrate core first surface, and removing a portion of the second capping conductive material layer and the conductive material layer proximate to substrate core second surface to separate the conductive material layer into individual conductive material liners within each of substrate core holes and form first capping layers on the fluorescent conductive fill material proximate the substrate core first surface and second capping layers on the fluorescent conductive fill material proximate the substrate core second surface. 
     
     
         14 . A method of detecting a defect in a plated through hole, comprising:
 forming a substrate core having a hole defined to extend from the substrate core first surface to the substrate core second surface forming at least one sidewall, a conductive material layer formed on the at least one substrate core hole sidewall; and a fluorescent conductive fill material disposed abutting the conductive material layer and substantially filling the substrate core hole;   illuminating an exposed portion of the fluorescent conductive fill material; and   detecting anomalies in the light fluoresced by the exposed portion of the fluorescent conductive fill material.   
     
     
         15 . The method of  claim 14 , wherein forming the substrate core comprises forming the substrate core having the fluorescent conductive fill material comprising an epoxy resin having a fluorescent component dispersed therein. 
     
     
         16 . The method of  claim 14 , wherein forming the substrate core comprises forming the substrate core having the fluorescent conductive fill material comprising a fluorescent component selected from the group consisting of rhodamine, fluorescein, cyanine, and inorganic quantum dots. 
     
     
         17 . The method of  claim 14 , wherein forming the substrate core comprises forming the substrate core having the fluorescent conductive fill material comprising a fluorescent component comprising between about 0.5% and 50% by weight of the fluorescent conductive fill material. 
     
     
         18 . A computing device, comprising:
 a board; and   a microelectronic package attached to the board, wherein the microelectronic package comprises:
 a microelectronic substrate, comprising:
 a substrate core having at least one plated through hole extending from a first surface of the substrate core to a second surface of the substrate core, wherein the plated through hole comprises: 
 a hole defined to extend from the substrate core first surface to the substrate core second surface forming at least one sidewall; 
 a conductive material liner is formed on the at least one substrate core hole sidewall; and 
 a fluorescent conductive fill material disposed to abut the conductive material liner and substantially fill the substrate core hole. 
 
   
     
     
         19 . The computing device of  claim 18 , wherein the fluorescent conductive fill material includes a fluorescent component selected from the group consisting of rhodamine, fluorescein, cyanine, and inorganic quantum dots. 
     
     
         20 . The computing device of  claim 18 , wherein the fluorescent conductive fill material includes a fluorescent component comprising between about 0.5% and 50% by weight of the fluorescent conductive fill material.