Patent ID: 8859428

Claim:
A method of forming Chemical mechanical polishing (CMP) composition for Shallow Trench Isolation (STI) comprising: (a) reducing trace metal contaminants and smaller sized cerium oxide particles in a cerium oxide slurry; (b) adding polymeric electrolyte to cerium oxide slurry obtained from (a); and (c) adding biocide to cerium oxide slurry obtained from (a); wherein reducing step (a) comprising (i) adding a chemical chelator to the cerium oxide slurry; wherein the chemical chelator reacts with trace metal ions in trace metal contaminants to form metal ion-chelator complexes; (ii) centrifuging cerium oxide slurry obtained from step (i) to remove metal ion-chelator complexes; wherein the chemical chelator has a chemical structure selected from the group consisting of: and combinations thereof; wherein R is selected from the group consisting of alkyl, alkoxy, organic group with one or more hydroxyl groups, substituted organic sulfonic acid, substituted organic sulfonic acid salt, substituted organic carboxylic acid, substituted organic carboxylic acid salt, organic carboxylic ester, organic amine groups, and combinations thereof; one of R′ and R″ is selected from the group consisting of hydrogen, alkyl, alkoxy, organic group with one or more hydroxyl groups, substituted organic sulfonic acid, substituted organic sulfonic acid salt, substituted organic carboxylic acid, substituted organic carboxylic acid salt, organic carboxylic ester, organic amine, and combinations thereof; and the other of R′ and R″ is selected from the group consisting of alkyl, alkoxy, organic group with one or more hydroxyl groups, substituted organic sulfonic acid, substituted organic sulfonic acid salt, substituted organic carboxylic acid, substituted organic carboxylic acid salt, organic carboxylic ester, organic amine, and combinations thereof.