Aqueous anionic functional silica slurry and amine carboxylic acid compositions for selective nitride removal in polishing and methods of using them
The present invention provides aqueous chemical mechanical planarization polishing (CMP polishing) compositions comprising one or more dispersions of a plurality of elongated, bent or nodular anionic functional colloidal silica particles or their mixture with one or more dispersions of anionic functional spherical colloidal silica particles, one or more amine carboxylic acids having an isoelectric point (pI) below 5, preferably, an acidic amino acid or pyridine acid, and, preferably, one or more ethoxylated anionic surfactants having a C 6 to C 16 alkyl, aryl or alkylaryl hydrophobic group, wherein the compositions have a pH of from 3 to 5. The compositions enable good silicon nitride removal and selectivity of nitride to oxide removal in polishing.
1. An aqueous chemical mechanical planarization polishing composition comprising an abrasive of one or more dispersions of elongated, bent or nodular anionic functional colloidal silica particles or their mixture with one or more dispersions of anionic functional spherical colloidal silica particles, and one or more amine carboxylic acids chosen from glutamic acid, aspartic acid, nicotinic acid and picolinic acid having an isoelectric point (pI) from 2.0 to 4.0, wherein the compositions have a pH of from 3 to 5 and further wherein, the amount of the abrasive particles as solids, ranges from 0.01 to 30 wt. %, based on the total weight of the composition.
2. The aqueous chemical mechanical polishing composition as claimed in claim 1 , wherein the total solids amount of the one or more amine carboxylic acids ranges from 0.005 to 5 wt. %, based on the total weight of the composition.
3. The aqueous chemical mechanical polishing composition as claimed in claim 2 , wherein the total solids amount of the one or more amine carboxylic acids ranges from 0.01 to 1 wt. %, based on the total weight of the composition.
4. The aqueous chemical mechanical polishing composition as claimed in claim 1 , further comprising one or more ethoxylated anionic surfactants having a C 6 to C 16 alkyl, aryl or alkylaryl hydrophobic group.
5. The aqueous chemical mechanical polishing composition as claimed in claim 4 , wherein the ethoxylated anionic surfactant is chosen from ethoxylated sulfates, ethoxylated sulfonic acid, ethoxylated sulfonate salts, ethoxylated phosphates, ethoxylated phosphonates, or ethoxylated carboxylates.
6. The aqueous chemical mechanical polishing composition as claimed in claim 4 , wherein the amount of the ethoxylated anionic surfactant ranges from 0.0001 to 1 wt. %, based on the total weight of the composition.
7. The aqueous chemical mechanical polishing composition as claimed in claim 1 having a pH of from 3.5 to 4.5.