Aqueous Acidic Bath for Electrolytic Deposition of Copper

Abstract

The invention relates to an aqueous acidic bath for electrolytic deposition of copper, comprising, at least one source of copper ions, at least one acid, at least one brightener compound, and at least one leveler for copper-deposition, wherein at least one leveler is a ruthenium compound, and to a process for the electrolytic deposition of copper, in particular for filling a blind micro Vertical Interconnect Access (VIA), through hole VIA, trench and similar structures on printed circuit boards, chip carriers and semiconductor wafers.

1 . An aqueous acidic bath for electrolytic deposition of copper, comprising
 at least one source of copper ions,   at least one acid,   at least one brightener compound,   at least one source of halide ions, and   at least one substance that serves as a leveler for copper-deposition, comprising dissolved ruthenium.   
     
     
         2 . The aqueous acidic bath according to  claim 1 , wherein the dissolved ruthenium has a concentration of 0.01 mg/l-100 mg/l. 
     
     
         3 . The aqueous acidic bath according to  claim 1 , wherein the dissolved ruthenium has an average oxidation state in the range of II to III. 
     
     
         4 . The aqueous acidic bath according to  claim 1 , further comprising at least one source of iron ions as leveler and/or inhibitor for copper-deposition. 
     
     
         5 . The aqueous acidic bath according to  claim 4 , wherein the iron ions are present in molar excess in relation to ruthenium. 
     
     
         6 . The aqueous acidic bath according to  claim 5 , wherein the iron ions are present in a molar ratio of at least 1.5 Mol(Fe)/1 Mol(Ru). 
     
     
         7 . The aqueous acidic bath according to  claim 4 , wherein the iron ions are present at a concentration of 0.1 mg/l-20 g/l. 
     
     
         8 . A method for filling a blind micro Vertical Interconnect Accesses (VIA), trench, or through hole VIA of a work piece comprising a) contacting the work piece and at least one anode with the aqueous acidic bath of  claim 1 , and b) providing an electric current flow between the work piece and the at least one anode, so that copper is deposited on the work piece. 
     
     
         9 . A method for the deposition of copper within a through hole VIA, comprising a) contacting the work piece and at least one anode with the aqueous acidic bath of  claim 1 , and b) providing an electric current flow between the work piece and the at least one anode, c) depositing copper on the work piece, and d) forming a copper deposition within the through hole that extends transverse to the wall or the walls of the though hole VIA, so that the through hole VIA is divided by the copper deposition and two blind holes are formed. 
     
     
         10 . A method for pulse plating a workpiece comprising a) contacting the work piece and at least one anode with the aqueous acidic bath of  claim 1 , and b) providing a current between the work piece and the anode that is potentiostatically set to modulate over time. 
     
     
         11 . A method for electrolytic deposition of copper on a work piece, comprising a) contacting the work piece and at least one anode with the aqueous acidic bath of  claim 1 , and b) providing an electric current flow between the work piece and the at least one anode, so that copper is deposited on the work piece. 
     
     
         12 . The method according to  claim 8 , comprising treating the work piece with a pretreatment-solution comprising copper ions, an acid, a brightener compound, a leveler compound, halide ions, or ruthenium. 
     
     
         13 . The method according to  claim 9 , comprising treating the work piece with a pretreatment-solution comprising copper ions, an acid, a brightener compound, a leveler compound, halide ions, or ruthenium. 
     
     
         14 . The method according to  claim 10 , comprising treating the work piece with a pretreatment-solution comprising copper ions, an acid, a brightener compound, a leveler compound, halide ions, or ruthenium. 
     
     
         15 . The method according to  claim 11 , comprising treating the work piece with a pretreatment-solution comprising copper ions, an acid, a brightener compound, a leveler compound, halide ions, or ruthenium.