Carbon-Based Direct Plating Process

Abstract

A method of preparing a non-conductive substrate to allow metal plating thereon. The method includes the steps of a) contacting the non-conductive substrate with a conditioner comprising a conditioning agent; b) applying a carbon-based dispersion to the conditioned substrate, wherein the carbon-based dispersion comprises carbon or graphite particles dispersed in a liquid solution; and c) etching the non-conductive substrate. The etching step is performed before the liquid carbon-based dispersion dries on the non-conductive substrate.

What is claimed is: 
     
         1 . A method of preparing a non-conductive substrate to allow metal plating thereon, the method comprising the steps of:
 a) conditioning the non-conductive substrate with a conditioning agent, wherein the conditioning agent comprises a conditioner having a molecular weight of at least 1,000,000 g/mol;   b) applying a liquid carbon-based dispersion to the conditioned non-conductive substrate to form a carbon coating on the conditioned non-conductive substrate, wherein the carbon-based dispersion comprises carbon or graphite particles dispersed in a liquid solution, wherein the carbon particles coagulate onto the conditioned non-conductive substrate to form a carbon/conditioner gel coating; and   c) etching the substrate.   
     
     
         2 . The method according to  claim 1 , further comprising the step of drying the substrate and carbon-based dispersion after step c) to form a conductive carbon coating on the substrate 
     
     
         3 . The method according to  claim 1 , further comprising the step of electroplating a conductive metal on the substrate after step c). 
     
     
         4 . (canceled) 
     
     
         5 . (canceled) 
     
     
         6 . (canceled) 
     
     
         7 . The method according to  claim 1 , wherein the substrate comprises a printed circuit board or a printed wiring board. 
     
     
         8 . The method according to  claim 1 , wherein the substrate is contacted with the conditioner by immersing the substrate in the conditioner for at least about 20 seconds. 
     
     
         9 . (canceled) 
     
     
         10 . (canceled) 
     
     
         11 . (canceled) 
     
     
         12 . The method according to  claim 1 , wherein the carbon-based dispersion comprises one or more surfactants capable of dispersing the carbon or graphite particles. 
     
     
         13 . The method according to  claim 1 , wherein the average particle diameter of the carbon or graphite particles is between about 0.05 and about 3.0 microns. 
     
     
         14 . The method according to  claim 1 , wherein concentration of the carbon or graphite particles in the carbon-based dispersion is less than about 15% by weight. 
     
     
         15 . The method according to  claim 3 , wherein the substrate is dried for about 20 to about 90 seconds after one or more of the etching step and the electroplating step. 
     
     
         16 . The method according to  claim 15 , wherein the substrate is dried for about 30 to about 60 seconds. 
     
     
         17 . (canceled) 
     
     
         18 . The method according to  claim 1 , wherein the step of etching the substrate comprises etching metal portions of the substrate with an etchant, the etchant being selected from the group consisting of sodium persulfate-based etchants, peroxide sulfuric-acid based etchants, copper chloride-based etchants, and ferric-based etchants. 
     
     
         19 . A method of conditioning a substrate to accept a carbon coating thereon, wherein the substrate comprises a printed wiring board having one or more non-conductive layers, the method comprising the step of contacting the substrate with a conditioner, wherein the conditioner comprises a conditioning having a molecular weight of at least 1,000,000 g/mol. 
     
     
         20 . The method according to  claim 19 , wherein the step of contacting the substrate with the conditioner comprises immersing the substrate in the conditioner. 
     
     
         21 . The method according to  claim 19 , wherein the conditioner has a pH in the range of about 7 to about 14. 
     
     
         22 . The method according to  claim 19 , wherein the conditioner is maintained at a temperature of between about 80 and about 130° F. 
     
     
         23 . The method according to  claim 19 , wherein the carbon coating is formed by applying a liquid carbon dispersion to the conditioned substrate, wherein the carbon-based dispersion comprises carbon or graphite particles dispersed in a liquid solution.