Method of copper plating small diameter hole

Abstract

A method of copper plating a small diameter hole which uses a copper sulfate plating solution containing copper sulfate, sulfuric acid, chlorine ions, a sulfur compound, and a surfactant to copper plate the inside of a small diameter hole of an object being plated having a small diameter hole by the PPR method, comprising performing reverse electrolysis by a range of current density of 0.1 to 1 A/dm 2 to peel off a sulfur compound near the opening of the small diameter hole in the sulfur compound adsorbed to the object being plated so as to keep the polarization resistance in the small diameter hole at the time of regular electrolysis lower than that near the opening of the small diameter hole and form a copper plating film of a uniform thickness inside the small diameter hole. Since a high precision, large capacity pulse power supply is not required, the capital costs can be reduced and the inside of the small diameter hole can be plated well.

4 . (AS ONCE AMENDED HEREIN) A method of copper plating a small diameter hole as set forth in  claim 1 , characterized by performing the regular electrolysis in a range of current density of 1 to 2 A/dm 2 .  
     
     
         5 . (AS ONCE AMENDED HEREIN) A method of copper plating a small diameter hole as set forth in  claim 1 , characterized by using a low electrical resistance, high copper concentration copper sulfate plating solution set to a sulfuric acid concentration of 150 to 250 g/l and a concentration of copper sulfate of 130 to 200 g/l.  
     
     
         6 . (AS ONCE AMENDED HEREIN) A method of copper plating a small diameter hole as set forth in  claim 1 , characterized by burying the inside of the small diameter hole by copper plating.  
     
     
         7 . (AS NEW HEREIN) A method of copper plating a small diameter hole as set forth in  claim 2 , characterized by performing the regular electrolysis in several tens to several hundreds of seconds and performing the reverse electrolysis in several seconds to several tens of seconds.  
     
     
         8 . (AS NEW HEREIN) A method of copper plating a small diameter hole as set forth in  claim 2 , characterized by performing the regular electrolysis in a range of current density of 1 to 2 A/dm 2 .  
     
     
         9 . (AS NEW HEREIN) A method of copper plating a small diameter hole as set forth in  claim 3 , characterized by performing the regular electrolysis in a range of current density of 1 to 2 A/dm 2 .  
     
     
         10 . (AS NEW HEREIN) A method of copper plating a small diameter hole as set forth in  claim 2 , characterized by using a low electrical resistance, high copper concentration copper sulfate plating solution set to a sulfuric acid concentration of 150 to 250 g/l and a concentration of copper sulfate of 130 to 200 g/l.  
     
     
         11 . (AS NEW HEREIN) A method of copper plating a small diameter hole as set forth in  claim 3 , characterized by using a low electrical resistance, high copper concentration copper sulfate plating solution set to a sulfuric acid concentration of 150 to 250 g/l and a concentration of copper sulfate of 130 to 200 g/l.  
     
     
         12 . (AS NEW HEREIN) A method of copper plating a small diameter hole as set forth in  claim 4 , characterized by using a low electrical resistance, high copper concentration copper sulfate plating solution set to a sulfuric acid concentration of 150 to 250 g/l and a concentration of copper sulfate of 130 to 200 g/l.  
     
     
         13 . (AS NEW HEREIN) A method of copper plating a small diameter hole as set forth in  claim 2 , characterized by burying the inside of the small diameter hole by copper plating.  
     
     
         14 . (AS NEW HEREIN) A method of copper plating a small diameter hole as set forth in  claim 3 , characterized by burying the inside of the small diameter hole by copper plating.  
     
     
         15 . (AS NEW HEREIN) A method of copper plating a small diameter hole as set forth in  claim 4 , characterized by burying the inside of the small diameter hole by copper plating.  
     
     
         16 . (AS NEW HEREIN) A method of copper plating a small diameter hole as set forth in  claim 5 , characterized by burying the inside of the small diameter hole by copper plating. REMARKS 
 The foregoing amendment to the specification is submitted to correct a typographical error.    The claim amendments are set forth to delete the multiple dependencies of the original claims. No new matter is presented.    
     
     
         1 . A method of copper plating a small diameter hole which uses a copper sulfate plating solution containing copper sulfate, sulfuric acid, chlorine ions, a sulfur compound, and a surfactant to copper plate the inside of a small diameter hole of an object being plated having a small diameter hole by the PPR method, said method of copper plating a small diameter hole characterized by performing reverse electrolysis by a range of current density of 0.1 1 A/dm 2  to peel off a sulfur compound near the opening of the small diameter hole in the sulfur compound adsorbed to the object being plated so as to keep the polarization resistance in the small diameter hole at the time of regular electrolysis lower than that near the opening of the small diameter hole and form a copper plating film of a uniform thickness inside the small diameter hole.  
     
     
         2 . A method of copper plating a small diameter hole as set forth in  claim 1 , characterized by, at the time of said reverse electrolysis, performing two-stage reverse electrolysis consisting of performing the first half reverse electrolysis by a high current density and the second half reverse electrolysis by a current density lower than the first half.  
     
     
         3 . A method of copper plating a small diameter hole as set forth in  claim 1  or  2 , characterized by performing the regular electrolysis in several tens to several hundreds of seconds and performing the reverse electrolysis in several seconds to several tens of seconds.  
     
     
         4 . A method of copper plating a small diameter hole as set forth in  claim 1 ,  2 , or  3 , characterized by performing the regular electrolysis in a range of current density of 1 to 2 A/dm 2 .  
     
     
         5 . A method of copper plating a small diameter hole as set forth in  claim 1 ,  2 ,  3 , or  4 , characterized by using a low electrical resistance, high copper concentration copper sulfate plating solution set to a sulfuric acid concentration of 150 to 250 g/l and a concentration of copper sulfate of 130 to 200 g/l.  
     
     
         6 . A method of copper plating a small diameter hole as set forth in any one of  claims 1  to  5 , characterized by burying the inside of the small diameter hole by copper plating.