Chemical-mechanical polishing (CMP) slurry and method of planarizing computer memory disk surfaces
Compositions and methods for planarizing or polishing a surface, particularly a semiconductor wafer surface. The polishing compositions described herein comprise (a) a liquid carrier; (b) purified clay; and optional additives, such as (c) a chemical accelerator; and (d) a complexing or coupling agent capable of chemically or ionically complexing with, or coupling to, the metal and/or insulating material removed during the polishing process. The complexing or coupling agent carries away the removed metal and/or silicon dioxide insulator particles, during polishing, to prevent the separated particles from returning to the surface from which they were removed. Also disclosed are methods of planarizing or polishing a surface comprising contacting the surface with the compositions.
1. A composition for planarizing or polishing a surface comprising (a) a liquid carrier, and (b) solids comprising about 10-100 wt. % clay abrasive particles comprising a sodium-containing clay that has been ion-exchanged to make the clay essentially sodium-free, based on the total weight of solids in the composition, said clay abrasive particles having a particle size such that at least 90% of the particles (by number), when slurried in water, have a particle size in the range of about 0.002 μm to about 10 μm.
2. The composition of claim 1 wherein the clay abrasive particles comprising a smectite clay.
3. The composition of claim 2 , wherein the clay abrasive particles are selected from calcium smectite clay, ammonium smectite clay or a combination thereof.
4. The composition of claim 1 , wherein the solids are present in the composition in an amount of about 0.1 to about 40 wt. % of the composition.
5. The composition of claim 3 , wherein the carrier is water.
6. The composition of claim 2 , further including a chemical accelerator selected from a peroxide, a sulfate, a persulfate, or a nitrate.
7. The composition of claim 6 , wherein the a chemical accelerator is selected from the group consisting of hydrogen peroxide, ammonium persulfate, iron (III) nitrate, and hydroxylamine nitrate.
8. The composition of claim 1 , wherein the clay is selected from the group consisting of a smectite clay; a kaolinite clay; a serpentine clay; a Pyrophyllite clay; talc, and mica.
9. The composition of claim 8 , wherein the clay is selected from the group consisting of Beidellite; Nontronite; Volkonskoite; Saponite; Hectorite; Halloysite; Kaolin; Serpentine clays, such as Lizardite; Amesite; Chrysotile; Pyrophyllite; Talc; Illite; Vermiculite; and a combination thereof.
10. The composition of claim 1 , wherein the clay is any clay except for kaolin and diatomite.
11. The composition of claim 1 , wherein the clay has a particle size in the range of 0.5 μm to 10 μm.
12. The composition of claim 11 , wherein the clay has a particle size in the range of 0.5 μm to 5 μm.
13. The composition of claim 12 , wherein the clay has a particle size in the range of 0.81 μm to 4 μm.