Electrolyte for forming anodic oxide film, method of forming anodic oxide film, and anodic oxide film and member for semiconductor device manufactured thereby

Abstract

Proposed are an electrolyte for forming an anodic oxide film, the electrolyte including citric acid and an additive, wherein the citric acid accounts for 3.0 wt % or more and 6.0 wt % or less based on 100 wt % of the electrolyte, the additive includes one or more selected from among tartaric acid, sulfuric acid, and sodium acetate, and the additive accounts for 0.5 wt % or more and 4.0 wt % or less based on 100 wt % of the electrolyte, a method of forming an anodic oxide film using the electrolyte, and an anodic oxide film and a member for a semiconductor device manufactured thereby.

What is claimed is: 
     
         1 . An electrolyte for forming an anodic oxide film, the electrolyte comprising:
 citric acid; and   an additive,   wherein the citric acid accounts for 3.0 wt % or more and 6.0 wt % or less based on 100 wt % of the electrolyte,   the additive comprises one or more selected from among tartaric acid, sulfuric acid, and sodium acetate, and   the additive accounts for 0.5 wt % or more and 4.0 wt % or less based on 100 wt % of the electrolyte.   
     
     
         2 . The electrolyte of  claim 1 , wherein the electrolyte comprises 1.5 wt % or more and 2.5 wt % or less of one or more selected from among the tartaric acid, the sulfuric acid, and the sodium acetate. 
     
     
         3 . The electrolyte of  claim 1 , wherein the electrolyte comprises:
 6.0 wt % of the citric acid;   1.0 wt % of the tartaric acid;   0 wt % or more and 0.5 wt % or less of the sulfuric acid; and   0 wt % or more and 0.5 wt % or less of the sodium acetate.   
     
     
         4 . The electrolyte of  claim 1 , wherein the electrolyte comprises:
 6.0 wt % of the citric acid;   0.5 wt % of the sulfuric acid; and   0 wt % or more and 0.5 wt % or less of the sodium acetate.   
     
     
         5 . A method of forming an anodic oxide film, the method comprising:
 preparing an electrolyte comprising 3.0 wt % or more and 6.0 wt % or less of citric acid and 0.5 wt % or more and 4.0 wt % or less of an additive, based on 100 wt % of the electrolyte; and   forming an anodic oxide film on a metal member by immersing the metal member in the electrolyte,   wherein the additive comprises one or more selected from among tartaric acid, sulfuric acid, and sodium acetate.   
     
     
         6 . The method of  claim 5 , wherein the electrolyte comprises 1.5 wt % or more and 2.5 wt % or less of one or more selected from among the tartaric acid, the sulfuric acid, and the sodium acetate. 
     
     
         7 . The method of  claim 5 , wherein the electrolyte comprises:
 6.0 wt % of the citric acid;   1.0 wt % of the tartaric acid;   0 wt % or more and 0.5 wt % or less of the sulfuric acid; and   0 wt % or more and 0.5 wt % or less of the sodium acetate.   
     
     
         8 . The method of  claim 5 , wherein when forming the anodic oxide film, a current to be supplied to the electrolyte is 0.1 A/dm 2  or more and 1.0 A/dm 2  or less. 
     
     
         9 . The method of  claim 5 , wherein when forming the anodic oxide film, the electrolyte has a temperature of 20° C. or higher and 30° C. or lower. 
     
     
         10 . The method of  claim 5 , wherein a time required for forming the anodic oxide film is 100 minutes or more and 150 minutes or less. 
     
     
         11 . The method of  claim 5 , wherein the anodic oxide film is formed to have a thickness of 500 nm or greater and 900 nm or smaller. 
     
     
         12 . The method of  claim 5 , wherein the metal member is formed of aluminum or an aluminum alloy. 
     
     
         13 . The method of  claim 12 , wherein the metal member is a showerhead. 
     
     
         14 . An anodic oxide film manufactured by the method of  claim 5 . 
     
     
         15 . The anodic oxide film of  claim 14 , wherein the anodic oxide film comprises a barrier layer without a porous layer, and
 the anodic oxide film has a thickness of 500 nm or greater and 900 nm or smaller.   
     
     
         16 . The anodic oxide film of  claim 14 , wherein the electrolyte comprises 1.5 wt % or more and 2.5 wt % or less of one or more selected from among the tartaric acid, the sulfuric acid, and the sodium acetate. 
     
     
         17 . The anodic oxide film of  claim 14 , wherein the electrolyte comprises:
 6.0 wt % of the citric acid;   1.0 wt % of the tartaric acid;   0 wt % or more and 0.5 wt % or less of the sulfuric acid; and   0 wt % or more and 0.5 wt % or less of the sodium acetate.   
     
     
         18 . A member for a semiconductor device, the member being manufactured by the method of  claim 5 . 
     
     
         19 . The member of  claim 18 , wherein the electrolyte comprises 1.5 wt % or more and 2.5 wt % or less of one or more selected from among the tartaric acid, the sulfuric acid, and the sodium acetate. 
     
     
         20 . The member of  claim 18 , wherein the electrolyte comprises:
 6.0 wt % of the citric acid;   1.0 wt % of the tartaric acid;   0 wt % or more and 0.5 wt % or less of the sulfuric acid; and   0 wt % or more and 0.5 wt % or less of the sodium acetate.   
     
     
         21 . The member of  claim 18 , wherein the metal member is a showerhead. 
     
     
         22 . The electrolyte of  claim 1 , wherein the anodic oxide film comprises no porous layer, and
 the anodic oxide film has a thickness of 500 nm or greater and 900 nm or smaller.   
     
     
         23 . The method of  claim 5 , wherein the anodic oxide film comprises no a porous layer, and
 the anodic oxide film has a thickness of 500 nm or greater and 900 nm or smaller.