Method for roughening copper surfaces for bonding to substrates

Abstract

The invention is directed to a method and composition for providing roughened copper surfaces suitable for subsequent multilayer lamination. A smooth copper surface is contacted with an adhesion promoting composition under conditions effective to provide a roughened copper surface, the adhesion promoting composition consisting essentially of an oxidizer, a pH adjuster, a topography modifier, and a uniformity enhancer. A coating promoter may be used in place of the uniformity enhancer or in addition to the uniformity enhancer. The adhesion promoting composition does not require a surfactant. The process may further comprise the step of contacting the uniform roughened copper surface with a post-dip, wherein the post-dip comprises an azole or silane compound or a combination of said azole and said silane. The post-dip may further comprise, alone or in combination, a titanate, zirconate, and an aluminate. The pH adjuster is preferably sulfuric acid and the oxidizer is preferably hydrogen peroxide. A hydrogen peroxide stabilizer may be used in the adhesion promoting composition.

The claimed inventions are:  
     
         1 . A process for preparing roughened copper surfaces suitable for subsequent multilayer lamination, said process comprising the steps of: (a) applying a highly built alkaline cleaning solution to a copper surface to provide a substantially clean copper surface; and (b) dipping the clean copper surface into an adhesion promoting composition to provide a uniform roughened copper surface suitable for subsequent multilayer lamination, said adhesion promoting composition consisting essentially of an oxidizer, a pH adjuster, a topography modifier, and at least one of a uniformity enhancer and a coating promoter.  
     
     
         2 . The process according to  claim 1 , said adhesion promoting composition including a coating promoter.  
     
     
         3 . A process for increasing the adhesion of a dielectric material to a metal surface, wherein the metal surface comprises copper or copper alloys, said process comprising: 
 (a) contacting the metal surface with an adhesion promoting composition comprising an adhesion-promoting effective amount of: 
 (1) an oxidizer;  
 (2) an acid;  
 (3) a topography modifier; and  
 (4) a coating promoter;  
   (b) bonding the dielectric material to the metal surface.    
     
     
         4 . A process according to  claim 3  wherein the adhesion promoting composition further comprises a uniformity enhancer.  
     
     
         5 . A process according to  claim 3  wherein the topography modifier is a 5-membered aromatic fused N heterocyclic compound, wherein the N heterocyclic ring has a nitrogen atom at position  1  bonded to a hydrogen atom.  
     
     
         6 . A process according to  claim 3  wherein the coating promoter is a 5-membered aromatic fused N-heterocyclic compound with 1 to 3 nitrogen atoms in the fused ring, wherein none of said nitrogen atoms are bonded to a hydrogen atom.  
     
     
         7 . A process according to  claim 3  wherein the coating promoter has the following structure:  
       
         
           
           
               
               
           
         
       
       wherein R1 is selected from the group consisting of hydroxyl groups, amino groups, alkyl groups, hydroxyalkyl groups, aminoalkyl groups, nitroalkyl groups, mercaptoalkyl groups, and alkoxy groups.  
     
     
         8 . A process according to  claim 3  wherein the coating promoter is 1-hydroxybeznotriazole.