Chemical-mechanical polishing (CMP) slurry and method of planarizing computer memory disk surfaces

Abstract

Compositions and methods for planarizing or polishing a NiP, glass, ceramic or Glass-ceramic surface in the manufacture of a computer memory disk. The polishing compositions described herein comprise (a) a liquid carrier, preferably water; (b) an abrasive; (c) purified clay; and optional additives, such as (d) a chemical accelerator or oxidizing agent; and (e) a complexing or coupling agent capable of chemically or ionically complexing with, or coupling to, the NiP, glass, ceramic, and/or glass-ceramic material removed during the polishing process. The complexing or coupling agent carries away the metal, glass, ceramic and/or glass-ceramic particles removed 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 NiP, glass, ceramic and/or glass-ceramic 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 10-95 wt. % solid abrasive particles, and about 0.1 wt. % to about 90 wt. % of purified sodium-containing clay particles, based on the total weight of solids in the composition, said clay 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 20 μm.  
     
     
         2 . The composition of  claim 1 , wherein the clay particles comprise a smectite clay.  
     
     
         3 . The composition of  claim 2 , wherein the clay particles are selected from sodium montmorillonite, sodium bentonite or a combination thereof.  
     
     
         4 . The composition of  claim 1 , wherein the composition is a slurry including a liquid carrier, and solids are present in the slurry 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, mica, and a synthetic clay.  
     
     
         9 . The composition of  claim 8 , wherein the clay is selected from the group consisting of Beidellite; Nontsonite; Volkonskoite; Saponite; Hectorite; Halloysite; Kaolin; Serpentine clays, such as Lizardite; Amesite; Chrysotile; Pyrophyllite; Talc; Illite; Vermiculite; a synthetic smectite; Japonite; 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 about 0.02 μm to about 10 μm.  
     
     
         12 . The composition of  claim 11 , wherein the clay has a particle size in the range of about 0.05 μm to about 5 μm.  
     
     
         13 . The composition of  claim 12 , wherein the clay has a particle size in the range of about 0.1 μm to about 4 μm.  
     
     
         14 . A method of planarizing or polishing a surface comprising contacting a surface with a composition comprising (a) a liquid carrier, (b) abrasive solids; and (c) 0.1 wt. % to about 90 wt. % of sodium-containing smectite clay particles, based on the total weight of solids in the composition, wherein about 90% or more of the clay particles (by number) have a particle size in the range of about 0.02 μm to about 20 μm.  
     
     
         15 . The method of  claim 14 , wherein the surface is a memory disk, or a rigid disk surface comprising NiP, glass, ceramic, or a glass/ceramic material.  
     
     
         16 . The method of  claim 14 , wherein the composition further includes a chemical accelerator selected from a peroxide, a sulfate, a persulfate or a nitrate.  
     
     
         17 . The method of  claim 14 , wherein the chemical accelerator is selected from the group consisting of hydrogen peroxide, ammonium persulfate, iron (III) nitrate, and hydroxylamine nitrate.  
     
     
         18 . The method of  claim 14 , wherein the smectite clay has a particle size in the range of about 0.02 μm to about 10 μm, when slurried in water.  
     
     
         19 . The method of  claim 18 , wherein the smectite clay has a particle size in the range of about 0.05 μm to about 5 μm, when slurried in water.  
     
     
         20 . The method of  claim 19 , wherein the ion-exchanged smectite clay has a particle size in the range of about 0.1 μm to about 4 μm, when slurried in water.