Ruthenium removal composition and method of producing magnetoresistive random access memory

Abstract

An object is to provide a ruthenium removal composition capable of dissolving Ru while suppressing dissolution of CoFeB, and a method of producing a magnetoresistive random access memory (MRAM) using the same. A ruthenium removal composition of the present invention contains orthoperiodic acid and water, and the pH is 11 or more. It is preferable that the content of orthoperiodic acid in the ruthenium removal composition is 0.01% to 5% by mass with respect to the total mass of the composition.

What is claimed is: 
     
         1 . A ruthenium removal composition comprising orthoperiodic acid and water, wherein the ruthenium removal composition has a pH of 11 or more. 
     
     
         2 . The ruthenium removal composition according to  claim 1 , wherein a content of orthoperiodic acid in the ruthenium removal composition is 0.01% to 5% by mass with respect to a total mass of the ruthenium removal composition. 
     
     
         3 . The ruthenium removal composition according to  claim 1 , wherein a content of water in the ruthenium removal composition is 30% by mass or more with respect to a total mass of the ruthenium removal composition. 
     
     
         4 . The ruthenium removal composition according to  claim 1 , further comprising at least one selected from the group consisting of tetramethylammonium hydroxide, tetraethylammonium hydroxide, and monoethanolamine, as a pH adjusting agent. 
     
     
         5 . The ruthenium removal composition according to  claim 4 , wherein a content of the pH adjusting agent in the ruthenium removal composition is 0.01% to 5% by mass with respect to a total mass of the ruthenium removal composition. 
     
     
         6 . The ruthenium removal composition according to  claim 1 , which is used for removing MRAM dry etching residues. 
     
     
         7 . The ruthenium removal composition according to  claim 2 , further comprising at least one selected from the group consisting of tetramethylammonium hydroxide, tetraethylammonium hydroxide, and monoethanolamine, as a pH adjusting agent. 
     
     
         8 . The ruthenium removal composition according to  claim 7 , wherein a content of the pH adjusting agent in the ruthenium removal composition is 0.01% to 5% by mass with respect to a total mass of the ruthenium removal composition. 
     
     
         9 . The ruthenium removal composition according to  claim 8 , which is used for removing MRAM dry etching residues. 
     
     
         10 . A method of producing a magnetoresistive random access memory, the method comprising:
 dry etching a semiconductor substrate, the semiconductor substrate including a ferromagnetic layer and a Ru-containing layer, the ferromagnetic layer including at least one of CoFeB or CoFe, and the Ru-containing layer including Ru; and   removing dry etching residues, using the ruthenium removal composition of  claim 1 .   
     
     
         11 . The method according to  claim 10 , wherein the semiconductor substrate further includes an insulator layer that includes MgO. 
     
     
         12 . The method according to  claim 10 , wherein a MgO dissolution rate of the ruthenium removal composition is 2 nm/min or less. 
     
     
         13 . The method according to  claim 10 , wherein a content of orthoperiodic acid in the ruthenium removal composition is 0.01% to 5% by mass with respect to a total mass of the ruthenium removal composition. 
     
     
         14 . The method according to  claim 10 , wherein a content of water in the ruthenium removal composition is 30% by mass or more with respect to a total mass of the ruthenium removal composition. 
     
     
         15 . The method according to  claim 10 , wherein the ruthenium removal composition further comprises at least one selected from the group consisting of tetramethylammonium hydroxide, tetraethylammonium hydroxide, and monoethanolamine, as a pH adjusting agent. 
     
     
         16 . The method according to  claim 10 , wherein a content of the pH adjusting agent in the ruthenium removal composition is 0.01% to 5% by mass with respect to a total mass of the ruthenium removal composition.