Method for producing an electrodeposited copper foil and copper foil obtained therewith

Abstract

A method for producing an electrodeposited copper foil with a matte side having a Rz ISO of 0.8 μm or less, the electrodeposited copper foil being continuously formed in an electroforming cell including a rotating drum-shaped cathode, a stationary anode and an electrolyte. The electrolyte comprises: copper, preferably in the form of copper ions, at a concentration of at least 60 g/L; a halogen ion at a concentration composed of between 30 and 50 ppm; 3-mercapto-1-propane sulfonate at a concentration composed of between 5 and 15 ppm; a nitrogen-containing polymer leveler at a concentration composed of between 5 and 12 ppm, the nitrogen-containing polymer leveler having an average molecular weight Mw composed of between 1 000 and 30 000 g/mol; and a polyether suppressor at a concentration composed of between 15 and 30 ppm, the polyether suppressor having an average molecular weight Mw composed of between 500 and 12 000 g/mol.

1 . A method for producing an electrodeposited copper foil, comprising:
 continuously forming the electrodeposited copper foil in an electroforming cell having a rotating drum-shaped cathode, a stationary anode and an electrolyte, wherein the electrolyte comprises:
 copper, in the form of copper ions, at a concentration of at least 60 g/L; 
 a halogen ion at a concentration comprised between 30 and 50 ppm; 
 3-mercapto-1-propane sulfonate at a concentration comprised between 5 and 15 ppm; 
 a nitrogen-containing polymer leveler at a concentration comprised between 5 and 12 ppm, the nitrogen-containing polymer leveler having an average molecular weight Mw comprised between 1 000 and 30 000 g/mol; and 
 a polyether suppressor at a concentration comprised between 15 and 30 ppm, the polyether suppressor having an average molecular weight Mw comprised between 500 and 12 000 g/mol. 
   
     
     
         2 . The method according to  claim 1 , wherein the average molecular weight Mw of the nitrogen-containing polymer leveler is comprised between 1 500 and 15 000 g/mol. 
     
     
         3 . The method according to  claim 1 , wherein the nitrogen-containing polymer leveler is selected from polyvinylpyrrolidone, polyallylamine, polyethyleneimine, and mixtures thereof. 
     
     
         4 . The method according to  claim 1 , wherein the nitrogen-containing polymer leveler is present in the electrolyte at a concentration comprised between 6 and 11 ppm. 
     
     
         5 . The method according to  claim 1 , wherein the average molecular weight Mw of the polyether suppressor is comprised between 500 and 6 000 g/mol. 
     
     
         6 . The method according  claim 1 , wherein the polyether suppressor is selected from polyethylene glycol, polypropylene glycol, copolymers of polyethylene glycol and polypropylene glycol, and mixtures thereof. 
     
     
         7 . The method according to  claim 1 , wherein the polyether suppressor is present at a concentration comprised between 12 and 28 ppm. 
     
     
         8 . The method according to  claim 1 , wherein the copper is added to the electrolyte as copper sulfate. 
     
     
         9 . The method according to  claim 1 , wherein copper is present in the electrolyte at a concentration comprised between 60 and 100 g/L. 
     
     
         10 . The method according to  claim 1 , wherein the halogen ion is a chloride and/or bromide ion. 
     
     
         11 . The method according to  claim 1 , wherein the halogen ion is present in the electrolyte at a concentration comprised between 35 and 50 ppm. 
     
     
         12 . The method according to  claim 1 , wherein the electrodeposited copper foil is formed by applying a current density between the cathode and the anode, the current density being comprised between 40 and 80 A/dm 2 . 
     
     
         13 . The method according to  claim 1 , wherein the electrolyte has a temperature higher than 50° C. 
     
     
         14 . The method according to  claim 1 , wherein the method is a continuous process and wherein the electrolyte has a life time of more than three days. 
     
     
         15 . The method according to  claim 1 , wherein the electrolyte further comprises sulfuric acid at a concentration comprised between 65 and 85 g/L. 
     
     
         16 . An electrolyte for the production of an electrodeposited copper foil comprising:
 copper, in the form of copper ions, at a concentration of at least 60 g/L;   a halogen ion at a concentration comprised between 30 and 50 ppm;   3-mercapto-1-propane sulfonate at a concentration comprised between 5 and 15 ppm;   a nitrogen-containing polymer leveler at a concentration comprised between 5 and 12 ppm, the nitrogen-containing polymer leveler having an average molecular weight Mw comprised between 1000 and 30000 g/mol; and   a polyether suppressor at a concentration comprised between 15 and 30 ppm, the polyether suppressor having an average molecular weight Mw comprised between 500 and 12000 g/mol.   
     
     
         17 . The electrolyte according to  claim 16 , wherein the average molecular weight Mw of the nitrogen-containing polymer leveler is comprised between 1500 and 15000 g/mol. 
     
     
         18 . The electrolyte according to  claim 16 , wherein the nitrogen-containing polymer leveler is selected from a list comprising polyvinylpyrrolidone, polyallylamine, polyethyleneimine, and mixtures thereof. 
     
     
         19 . The electrolyte according to  claim 16 , wherein the nitrogen-containing polymer leveler is present in the electrolyte at a concentration comprised between 6 and 11 ppm. 
     
     
         20 . The electrolyte according to  claim 16 , wherein the average molecular weight Mw of the polyether suppressor is comprised between 500 and 6 000 g/mol. 
     
     
         21 . The electrolyte according to  claim 16 , wherein the polyether suppressor is selected from a list comprising polyethylene glycol, polypropylene glycol, copolymers of polyethylene glycol and polypropylene glycol, and mixtures thereof. 
     
     
         22 . The electrolyte according to  claim 16 , wherein the polyether suppressor is present in the electrolyte at a concentration comprised between 12 and 28 ppm. 
     
     
         23 . The electrolyte according to  claim 16 , wherein the copper is added to the electrolyte as copper sulfate, and/or wherein the copper is present in the electrolyte at a concentration comprised between 60 and 100 g/L. 
     
     
         24 . The electrolyte composition according to  claim 16 , wherein the halogen ion is a chloride and/or bromide ion, and/or wherein the halogen ion is present in the electrolyte at a concentration comprised between 35 and 50 ppm. 
     
     
         25 . The electrolyte composition according to  claim 16 , wherein the electrolyte further comprises sulfuric acid at a concentration comprised between 65 and 85 g/L. 
     
     
         26 . An electrodeposited copper foil, produced by a method according to  claim 1 , wherein the electrodeposited copper foil has a bright electrolyte side, a surface roughness Rz ISO of no more than 0.8 μm, a surface developed ratio of no more than 0.15%, and is free of surface and visual defects. 
     
     
         27 . The electrodeposited copper foil according to  claim 26 , wherein the electrodeposited copper foils has a thickness of 18 μm and an elongation of between 10 and 25% at 20° C. 
     
     
         28 . The electrodeposited copper foil according to  claim 26 , wherein the electrodeposited copper foil has a thickness of 35 μm, and an elongation between 15 and 35% at 20° C. 
     
     
         29 . The electrodeposited copper foil according to  claim 26 , wherein the electrodeposited copper foil has a tensile strength between 28 and 37 kgf/mm 2  at 20° C. regardless of the thickness.