Electrodeposited copper foil with a uniform matte surface

Abstract

The present invention discloses an electrodeposited copper foil with a uniform matte surface. The electrodeposited copper foil of the present invention has an average thickness (TAve) of about 30 μm to about 400 μm; and the matte surface of the present electrodeposited copper foil has a uniformity factor (UF) of 5.5 μm or less.Also disclosed are methods for manufacturing the present electrodeposited copper foils and articles made therefrom.

What is claimed is: 
     
         1 . An electrodeposited copper foil, characterized in that:
 the electrodeposited copper foil has an average thickness (T Ave ) of about 30 μm to about 400 μm;   the electrodeposited copper foil has a matte surface and a shiny surface;   the matte surface of the electrodeposited copper foil comprises a plurality of protrusions; and   a number (PA 50+ ) of the protrusions on the matte surface having flattened peaks after polishing with a surface area of 50 μm 2  or more per 1 mm 2  of the matte surface is 8.0 or less;   
       wherein
 the average thickness is measured by a scanning electron microscope (SEM); 
 peaks of some protrusions on the matte surface are flattened by: a) placing the electrodeposited copper foil on a glass substrate with the matte surface in contact with the glass substrate, and b) polishing off about 1 μm of the shiny surface of the electrodeposited copper foil by using a silicon carbide sandpaper with a grit size of 1200; 
 the number and the surface area of the protrusions on the matte surface having flattened peaks after polishing is counted and measured by using an optical microscope having a magnifying power of 50 times or more and a resolution of at least 0.1 μm. 
 
     
     
         2 . The electrodeposited copper foil of  claim 1 , wherein the matte surface of the electrodeposited copper foil has a PA 50+  per 1 mm 2  of the matte surface is 6.0 or less. 
     
     
         3 . The electrodeposited copper foil of  claim 1 , wherein the matte surface of the electrodeposited copper foil has a uniformity factor (UF) of 5.5 μm or less, and the UF is calculated according to the equation 1 below: 
       
         
           
             
               
                 
                   
                     UF 
                     = 
                     
                       
                         A 
                         max 
                       
                       / 
                       
                         T 
                         Ave 
                       
                     
                   
                 
                 
                   
                     ( 
                     
                       eq 
                       . 
                          
                       1 
                     
                     ) 
                   
                 
               
             
           
         
         wherein A max  is a maximum surface area (A max ) of the protrusions on the matte surface having flattened peaks after polishing; and
 T Ave  is the average thickness of the electrodeposited copper foil. 
 
       
     
     
         4 . The electrodeposited copper foil of  claim 1 , wherein the matte surface of the electrodeposited copper foil has a UF of 4.0 μm or less. 
     
     
         5 . A method for manufacturing the electrodeposited copper foil of  claim 1 , comprising:
 i) providing an electrolytic solution in an electrolytic cell;   ii) applying an electric current at a current density to an anode plate and a rotating cathode drum that are spaced apart from each other in the electrolytic solution;   iii) electrodepositing a copper foil on the rotating cathode drum; and   iv) separating the copper foil formed in step iii) to obtain an electrodeposited copper foil;   
       wherein
 the electrodeposited copper foil has an average thickness of about 30 μm to about 400 μm; 
 the electrodeposition of step iii) is performed at a current density of about 30 A/dm 2  to about 100 A/dm 2 ; 
 the electrolytic solution comprises:
 about 120 g/L to about 450 g/L of copper sulfate; 
 about 30 g/L to about 140 g/L of sulfuric acid; 
 about 0.1 ppm to about 60 ppm of chloride ion; and 
 about 0.1 ppm to about 50 ppm of an additive. 
 
 
     
     
         6 . The method of  claim 5 , wherein the electrodeposition of step iii) is performed at a temperature of the electrolytic solution being about 20° C. to about 80° C. 
     
     
         7 . The method of  claim 5 , wherein the additive in the electrolytic solution comprises gelatin, animal glue, cellulose, an organosulfonic acid or salts thereof, a nitrogen-containing cationic polymer, or mixtures thereof. 
     
     
         8 . The method of  claim 7 , wherein the additive comprises a nitrogen-containing cationic polymer, and the nitrogen-containing cationic polymer has a weight-average molecular weight of from about 1,000 to about 10,000 g/mole. 
     
     
         9 . The method of  claim 8 , wherein the nitrogen-containing cationic polymer is a reaction product of a diamine of Formula (I) or an imidazole of Formula (II) with an epoxide of Formula (III) or a diepoxide of Formula (IV): 
       
         
           
           
               
               
           
         
       
       wherein
 R 1 , R 2 , R 3 , and R 4  are independently H or C 1 -C 3  alkyl; 
 R 5  is H or C 1 -C 6  alkyl; 
 each of R 6 , R 7 , R 8  is independently H or C 1 -C 6  alkyl, and R 7  and R 8  are optionally linked to each other to form a saturated ring; 
 R 9  and R 10  are independently H or C 1 -C 4  alkyl; 
 R 11  is a divalent linking group selected from C 2 -C 8  alkylene and C 5 -C 10  cycloalkylene, where R 11  is optionally substituted with C 1 -C 4  alkyl or OH; 
 A is a divalent linking group selected from C 2 -C 8  alkylene, C 5 -C 10  cycloalkylene, phenylene, and C 6 -C 20  arylene, where A is optionally substituted with C 1 -C 4  alkyl or OH; 
 Y is H or C 1 -C 4  alkyl; 
 X is halogen; 
 p, q, and r are each independently an integer of 0 to 10; and 
 n is an integer from 1 to 20. 
 
     
     
         10 . A surface-treated electrodeposited copper foil, comprising the electrodeposited copper foil of  claim 1  that has at one surface of the electrodeposited copper foil has been applied with at least one surface treatment step. 
     
     
         11 . The surface-treated electrodeposited copper foil of  claim 10 , wherein the surface treatment step includes a pickling step, a roughening step, a heat-resistant layer forming step, an antioxidant layer forming step, or an adhesion promotion layer forming step. 
     
     
         12 . An article, wherein the article comprises the electrodeposited copper foil of  claim 1  or the surface-treated electrodeposited copper foil of  claim 10 . 
     
     
         13 . The article of  claim 12 , wherein the article is a negative electrode collector of a lithium-ion battery, a copper clad laminate, a flexible copper clad laminate, a heat dissipation plate, or a printed circuit board.