Polishing slurry, method of producing same, and method of polishing substrate
Disclosed is a polishing slurry, particularly, a slurry for chemical mechanical polishing, which is used in a chemical mechanical polishing process for flattening a semiconductor laminate. More particularly, the present invention provides a method of producing a slurry which has high removal selectivity to a nitride layer used as a barrier film in a shallow trench isolation CMP process needed to fabricate ultra highly integrated semiconductors of 256 mega D-RAM or more (Design rule of 0.13 μm or less) and which decreases the occurrence of scratches on a flattened surface, and a method of polishing a substrate using the same.
1. A polishing slurry having a conductivity of 300-900 μs/cm and a pH of 7-11, which comprises polishing particles having a surface area per mass of 1-100 m 2 /g, deionized water, and a dispersing agent in the amount of 0.0001-10.0 weight % based on the polishing particles, in which agglomeration of the polishing particles is minimized and the difference between the median diameter of the polishing particles before and after forcible dispersion treatment is 30 nanometers or less, by controlling an amount of the dispersing agent added or a stage at which the dispersing agent is added.
2. The polishing slurry as set forth in claim 1 , wherein the difference between the median diameter of the polishing particles before and after forcible dispersion treatment is 10 nanometers or less.
3. The polishing slurry as set forth in claim 1 , wherein conductivity of the polishing slurry is 500-600 μs/cm.
4. The polishing slurry as set forth in claim 1 , wherein the dispersing agent is made of an anionic polymer compound, and the anionic polymer compound is at least one selected from a group consisting of polymethacrylic acid, polyacrylic acid, ammonium polymethacrylate, ammonium polycarboxylate, and carboxyl-acryl polymer.
5. The polishing slurry as set forth in claim 1 , wherein the polishing particles are ceria.