Polishing composition and method of polishing a substrate having enhanced defect reduction
View Patent ↗An aqueous alkaline chemical mechanical polishing composition includes a quaternary ammonium compound having a phenyl group which enables enhanced reduction of defects on silicon oxide substrates and enables good silicon oxide removal rates during chemical mechanical polishing.
1. A method for chemical mechanical polishing of a substrate, comprising: providing a substrate, wherein the substrate comprises silicon oxide; providing a chemical mechanical polishing composition consisting of water; a colloidal silica abrasive; optionally a pH adjusting agent chosen from one or more of sodium hydroxide, potassium hydroxide and an ammonium salt; optionally a biocide; a pH greater than 7; a quaternary ammonium compound having (I):
wherein R 1 , R 2 and R 3 are independently selected from the group consisting of phenyl, benzyl, and linear or branched C 1 -C 5 alkyl; and X − is an anion selected from the group consisting of Br − , Cl − , I − , F − and OH − ;
providing a chemical mechanical polishing pad with a polishing surface; creating dynamic contact at an interface between the polishing surface of the chemical mechanical polishing pad and the substrate with a down force of 3 to 35 kPa; and dispensing the chemical mechanical polishing composition onto the chemical mechanical polishing pad at or near the interface between the chemical mechanical polishing pad and the substrate; and wherein some of the silicon oxide is removed from the substrate, and wherein the following expression is satisfied:
A>A 0
wherein A is silicon oxide removal rate in Å/min for the chemical mechanical polishing composition and A 0 is silicon oxide removal rate in Å/min for a chemical mechanical polishing composition consisting of water and colloidal silica abrasives.
2. The method of chemical mechanical polishing a substrate of claim 1 , wherein the quaternary ammonium compound has the following formula (I):
wherein R 1 , R 2 and R 3 are independently selected from the group consisting of C 1 -C 2 alkyl and X − is selected from the group consisting of Br − , Cl − and OH − .
3. The method of chemical mechanical polishing a substrate of claim 1 , wherein the following expression is satisfied:
X<X 0 ,
wherein X is defectivity for the chemical mechanical polishing composition and X 0 is the defectivity of a chemical mechanical polishing composition consisting of water and colloidal silica abrasives.
4. The method of claim 1 , wherein the following expression is satisfied:
( X 0 −X )/ X 0 *100>50,
wherein X is polishing defectivity of the chemical mechanical polishing composition and X 0 is the defectivity of a chemical mechanical polishing composition consisting of water and colloidal silica abrasives.
5. The method of claim 1 , wherein the quaternary ammonium compound is selected from the group consisting of phenyltrimethylammonium chloride, phenyltrimethylammonium bromide, phenyltrimethylammonium hydroxide and mixtures thereof.