Plating substrate, electroless plating method, and circuit forming method using the same

Abstract

An electroless copper plating method is provided having a first catalyst step of forming a first catalyst layer on a ceramic base material containing a glass component using a tin chloride solution and a palladium chloride solution; a pre-copper-plating heat treatment step of heating the ceramic base material in an atmosphere containing oxygen; a laminate catalyst treatment step of forming a laminate catalyst layer on the ceramic base material using a tin chloride solution and a palladium chloride solution; a plating treatment step of forming a copper plating film on the ceramic base material using a copper plating solution containing a small amount of nickel ions; and a post-copper-plating heat treatment step of heating the ceramic base material at a heat treatment temperature not more than the glass transition temperature thereof.

1 . An electroless copper plating method comprising: 
 a catalyst treatment step of forming a catalyst layer on an insulating base material;    a plating treatment step of forming a plating film using a copper plating solution containing at least one of nickel ions, cobalt ions, and iron ions at a low concentration after the catalyst treatment step; and    a post-copper-plating heat treatment step of heating the base material in an atmosphere substantially containing no oxygen and hydrogen after the plating treatment step.    
     
     
         2 . The electroless copper plating method according to  claim 1 , 
 wherein the catalyst treatment step is a step of forming the catalyst layer on the base material using a tin chloride solution and a palladium chloride solution or using a tin-palladium colloidal solution.    
     
     
         3 . The electroless copper plating method according to  claim 1 , 
 wherein the base material is a glass base material.    
     
     
         4 . The electroless copper plating method according to  claim 1 , 
 wherein the base material is a glass base material or a ceramic base material, having at least an oxide on a surface thereof,    further comprising a pre-copper-plating heat treatment step of heating the base material in an atmosphere containing oxygen after the catalyst treatment step and before the plating treatment step.    
     
     
         5 . The electroless copper plating method according to  claim 4 , 
 wherein the catalyst treatment step is a first catalyst treatment step of forming a first catalyst layer,    further comprising a laminate catalyst treatment step of forming a laminate catalyst layer on the base material using a tin chloride solution and a palladium chloride solution or using a tin-palladium colloidal solution after the pre-copper-plating heat treatment step and before the plating treatment step.    
     
     
         6 . The electroless copper plating method according to  claim 4 , 
 wherein the base material is a base material having a Ag-based via, and    a heat treatment temperature in the pre-copper-plating heat treatment step is not less than the decomposition temperature of a silver oxide,    further comprising an oxide film removing step of removing an oxide film formed on a surface of the via after the pre-copper-plating heat treatment step and before the plating treatment step.    
     
     
         7 . The electroless copper plating method according to  claim 6 , 
 wherein, in the oxide film removing step, one of purified water, an aqueous H 2 O 2  solution, hot purified water, ammonia water, and diluted nitric acid is used.    
     
     
         8 . The electroless copper plating method according to  claim 6 , 
 wherein the catalyst treatment step is a first catalyst treatment step of forming a first catalyst layer,    further comprising a laminate catalyst treatment step of forming a laminate catalyst layer on the base material using a tin chloride solution and a palladium chloride solution or using a tin-palladium colloidal solution after the oxide film removing step and before the plating treatment step.    
     
     
         9 . The electroless copper plating method according to  claim 1 , 
 wherein the amount of the nickel ions is 1 to 25 moles relative to 100 moles of copper ions contained in the copper plating solution.    
     
     
         10 . The electroless copper plating method according to  claim 1 , 
 wherein a heat treatment temperature in the post-copper-plating heat treatment step is 250 to 450° C.    
     
     
         11 . The electroless copper plating method according to  claim 4 , 
 wherein a heat treatment temperature in the pre-copper-plating heat treatment step is 250 to 450° C.    
     
     
         12 . The electroless copper plating method according to  claim 1 , 
 wherein, in the post-copper-plating heat treatment step, heat treatment is performed while a predetermined pressure is being applied to the base material.    
     
     
         13 . The electroless copper plating method according to  claim 12 , 
 wherein a heat treatment temperature in the post-copper-plating heat treatment step in which the predetermined pressure is being applied to the base material is 150 to 400° C.    
     
     
         14 . The electroless copper plating method according to  claim 1 , 
 wherein the plating treatment step is a first plating treatment step of forming a copper plating film;    further comprising: a second plating treatment step of forming a nickel plating film using a plating solution containing a nickel compound after the post-copper-plating heat treatment step, and    a post-nickel-plating heat treatment step of heating the base material after the second plating step in an atmosphere substantially containing no oxygen and hydrogen at a heating temperature at which the hardness of the nickel compound is not changed.    
     
     
         15 . The electroless copper plating method according to  claim 14 , further comprising: 
 a third plating treatment step of forming a gold plating film using a gold plating solution after the second plating treatment step and before the post-nickel-plating heat treatment step.    
     
     
         16 . The electroless copper plating method according to  claim 14 , 
 wherein a heat treatment temperature in the post-nickel-plating heat treatment step is 150 to 350° C.    
     
     
         17 . A circuit forming method using the electroless plating method according to  claim 1 , comprising: 
 a patterning treatment step of patterning the catalyst layer or the plating film.