Cleaning method, cleaning system, and method for manufacturing microstructure

Abstract

According to one embodiment, a cleaning method is disclosed. The method can produce an oxidizing solution including an oxidizing substance by electrolyzing a dilute sulfuric acid solution. In addition, the method can supply a highly concentrated inorganic acid solution individually, sequentially, or substantially simultaneously with the oxidizing solution to a surface of an object to be cleaned.

1 . A cleaning method, comprising
 producing an oxidizing solution including an oxidizing substance by electrolyzing a dilute sulfuric acid solution, and   supplying a highly concentrated inorganic acid solution individually, sequentially, or substantially simultaneously with the oxidizing solution to a surface of an object to be cleaned.   
     
     
         2 . The method according to  claim 1 , wherein the supplying of the highly concentrated inorganic acid solution to the surface of the object to be cleaned and the supplying of the oxidizing solution to the surface of the object to be cleaned are performed repeatedly. 
     
     
         3 . The method according to  claim 1 , wherein a sulfuric acid concentration of the dilute sulfuric acid solution is not less than 30 weight percent and not more than 70 weight percent. 
     
     
         4 . The method according to  claim 1 , wherein the highly concentrated inorganic acid solution is a concentrated sulfuric acid solution having a sulfuric acid concentration not less than 90 weight percent. 
     
     
         5 . The method according to  claim 1 , wherein the oxidizing substance includes at least one selected from peroxomonosulfuric acid and peroxodisulfuric acid. 
     
     
         6 . The method according to  claim 1 , wherein at least one selected from a temperature of the oxidizing solution and a temperature of the highly concentrated inorganic acid solution is not less than 100° C. and not more than 110° C. 
     
     
         7 . The method according to  claim 1 , wherein a heat of reaction when the highly concentrated inorganic acid solution and the oxidizing solution are mixed on the surface of the object to be cleaned is utilized to perform a temperature adjustment of a solution. 
     
     
         8 . The method according to  claim 1 , wherein a supplying of a rinsing fluid to the surface of the object to be cleaned is not performed between the supplying of the highly concentrated inorganic acid solution and the supplying of the oxidizing solution. 
     
     
         9 . The method according to  claim 1 , wherein a resist is formed on the surface of the object to be cleaned, a surface of the resist having an altered layer. 
     
     
         10 . 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 anode and the partitioning membrane, the sulfuric acid electrolysis unit producing an oxidizing substance in the anode chamber by electrolyzing a dilute sulfuric acid solution;   a dilute sulfuric acid supply unit supplying a dilute 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;   an inorganic acid supply unit supplying a highly concentrated inorganic acid solution to the cleaning processing unit; and   an oxidizing solution supply unit supplying an oxidizing solution including the oxidizing substance to the cleaning processing unit,   the highly concentrated inorganic acid solution being supplied to the cleaning processing unit by the inorganic acid supply unit individually, sequentially, or substantially simultaneously with the oxidizing solution supplied by the oxidizing solution supply unit.   
     
     
         11 . The system according to  claim 10 , further comprising a solution circulation unit that recovers at least one selected from the highly concentrated inorganic acid solution and the oxidizing solution discharged from the cleaning processing unit and resupplies the at least one to the cleaning processing unit. 
     
     
         12 . The system according to  claim 11 , wherein the solution circulation unit recovers at least one selected from the highly concentrated inorganic acid solution and the oxidizing solution discharged from the cleaning processing unit and resupplies the at least one to the cleaning processing unit via the sulfuric acid electrolysis unit. 
     
     
         13 . The system according to  claim 12 , wherein the sulfuric acid electrolysis unit produces an oxidizing substance in the anode chamber by electrolyzing a dilute sulfuric acid solution and at least one selected from the highly concentrated inorganic acid solution and the oxidizing solution, the dilute sulfuric acid solution being supplied by the dilute sulfuric acid supply unit, the at least one being supplied by the solution circulation unit. 
     
     
         14 . The system according to  claim 10 , wherein a sulfuric acid concentration of the dilute sulfuric acid solution is not less than 30 weight percent and not more than 70 weight percent. 
     
     
         15 . The system according to  claim 10 , wherein the highly concentrated inorganic acid solution is a concentrated sulfuric acid solution having a sulfuric acid concentration not less than 90 weight percent. 
     
     
         16 . The system according to  claim 10 , wherein the inorganic acid supply unit includes a heater performing a temperature control of the inorganic acid solution. 
     
     
         17 . The system according to  claim 11 , wherein the solution circulation unit includes a heater performing a temperature control of the oxidizing solution. 
     
     
         18 . The system according to  claim 11 , wherein a heater is provided in at least one selected from piping supplying the oxidizing solution to the cleaning processing unit and piping supplying the highly concentrated inorganic acid solution to the cleaning processing unit. 
     
     
         19 . 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. 
     
     
         20 . A method for manufacturing a microstructure comprising cleaning an object to be cleaned by the cleaning method according to  claim 1  and forming a microstructure.