Cleaning liquid, cleaning method, cleaning system, and method for manufacturing microstructure

Abstract

According to embodiments, a cleaning liquid includes an oxidizing substance and hydrofluoric acid and exhibiting acidity. A cleaning method is disclosed. The method includes producing an oxidizing solution including an oxidizing substance by one selected from electrolyzing a sulfuric acid solution, electrolyzing hydrofluoric acid added to a sulfuric acid solution, and mixing a sulfuric acid solution with aqueous hydrogen peroxide. The method includes supplying the oxidizing solution and hydrofluoric acid to a surface of an object to be cleaned.

1 . A cleaning liquid, comprising an oxidizing substance and hydrofluoric acid and exhibiting acidity. 
     
     
         2 . The cleaning liquid according to  claim 1 , wherein the oxidizing substance includes at least one selected from peroxomonosulfuric acid and peroxodisulfuric acid. 
     
     
         3 . The cleaning liquid according to  claim 1 , wherein the oxidizing substance is produced by one selected from electrolyzing a sulfuric acid solution, electrolyzing hydrofluoric acid added to a sulfuric acid solution, and mixing a sulfuric acid solution with aqueous hydrogen peroxide. 
     
     
         4 . A cleaning method, comprising
 producing an oxidizing solution including an oxidizing substance by one selected from electrolyzing a sulfuric acid solution, electrolyzing hydrofluoric acid added to a sulfuric acid solution, and mixing a sulfuric acid solution with aqueous hydrogen peroxide, and   supplying the oxidizing solution and hydrofluoric acid to a surface of an object to be cleaned.   
     
     
         5 . The method according to  claim 4 , wherein a sulfuric acid concentration of the sulfuric acid solution is not less than 30 weight percent and not more than 70 weight percent. 
     
     
         6 . The method according to  claim 4 , wherein the oxidizing substance includes at least one selected from peroxomonosulfuric acid and peroxodisulfuric acid. 
     
     
         7 . The method according to  claim 4 , wherein at least one selected from a temperature of the oxidizing solution and a temperature of the hydrofluoric acid is not less than 100° C. and not more than 110° C. 
     
     
         8 . The method according to  claim 4 , wherein the oxidizing solution is supplied to the surface of the object to be cleaned sequentially or substantially simultaneously with the hydrofluoric acid. 
     
     
         9 . The method according to  claim 4 , wherein
 the oxidizing solution and the hydrofluoric acid are mixed, and   the mixed solution is supplied to the surface of the object to be cleaned.   
     
     
         10 . The method according to  claim 9 , wherein a temperature of the mixed solution is not less than 100° C. and not more than 110° C. 
     
     
         11 . A cleaning system, comprising:
 a sulfuric acid electrolysis unit including an anode, a cathode, a partitioning membrane provided between the anode and the cathode, an anode chamber provided between the anode and the partitioning membrane, and a cathode chamber provided between the cathode and the partitioning membrane, the sulfuric acid electrolysis unit electrolyzing a sulfuric acid solution to produce an oxidizing substance in the anode chamber;   a sulfuric acid supply unit supplying a sulfuric acid solution to the anode chamber and the cathode chamber;   a cleaning processing unit performing a cleaning processing of an object to be cleaned;   a first hydrofluoric acid supply unit supplying hydrofluoric acid to the cleaning processing unit; and   an oxidizing solution supply unit supplying an oxidizing solution including the oxidizing substance to the cleaning processing unit.   
     
     
         12 . The system according to  claim 11 , wherein the first hydrofluoric acid supply unit supplies the hydrofluoric acid to the cleaning processing unit sequentially or substantially simultaneously with the oxidizing solution supplied by the oxidizing solution supply unit. 
     
     
         13 . The system according to  claim 11 , further comprising a mixing unit to mix the hydrofluoric acid supplied by the first hydrofluoric acid supply unit with the oxidizing solution supplied by the oxidizing solution supply unit. 
     
     
         14 . The system according to  claim 11 , further comprising a solution circulation unit recovering at least one selected from the oxidizing solution and the hydrofluoric acid discharged from the cleaning processing unit and resupplying the at least one to the cleaning processing unit. 
     
     
         15 . The system according to  claim 14 , wherein the solution circulation unit includes a heater to perform a temperature control of the oxidizing solution. 
     
     
         16 . The system according to  claim 11 , wherein at least one selected from the anode and the cathode includes a conductive diamond film formed on a surface of a conductive base member. 
     
     
         17 . A cleaning system, comprising:
 a sulfuric acid electrolysis unit including an anode, a cathode, a partitioning membrane provided between the anode and the cathode, an anode chamber provided between the anode and the partitioning membrane, and a cathode chamber provided between the cathode and the partitioning membrane, the sulfuric acid electrolysis unit electrolyzing a sulfuric acid solution to produce an oxidizing substance in the anode chamber;   a sulfuric acid supply unit supplying a sulfuric acid solution to the anode chamber and the cathode chamber;   a cleaning processing unit performing a cleaning processing of an object to be cleaned;   a second hydrofluoric acid supply unit supplying hydrofluoric acid to the anode chamber; and   an oxidizing solution supply unit supplying an oxidizing solution including the oxidizing substance to the cleaning processing unit.   
     
     
         18 . The system according to  claim 17 , further comprising a solution circulation unit recovering at least one selected from the oxidizing solution and the hydrofluoric acid discharged from the cleaning processing unit and resupplying the at least one to the cleaning processing unit. 
     
     
         19 . The system according to  claim 17 , wherein at least one selected from the anode and the cathode includes a conductive diamond film formed on a surface of a conductive base member. 
     
     
         20 . A method for manufacturing a microstructure, comprising cleaning an object to be cleaned by a cleaning method and forming a microstructure,
 the cleaning method including
 producing an oxidizing solution including an oxidizing substance by one selected from electrolyzing a sulfuric acid solution, electrolyzing hydrofluoric acid added to a sulfuric acid solution, and mixing a sulfuric acid solution with aqueous hydrogen peroxide, and 
 supplying the oxidizing solution and hydrofluoric acid to a surface of an object to be cleaned.