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.

Description

[0001] This application is a continuation-in-part of application Ser. No. 10 / 677,433 filed Oct. 2, 2003.TECHNICAL FIELD [0002] The present invention is directed to a clay-containing abrasive composition and method of planarizing or polishing computer memory disk surfaces. The composition is used as a purified clay-containing aqueous slurry, particularly useful in the manufacture of all types of computer memory disks, e.g., magnetic disks, hard disks, and / or rigid disks for retaining information in electromagnetic form. [0003] Desk-top computers include one or more memory or rigid disks formed from a substrate that typically is nickel-phosphorus (NiP). A lap-top computer memory disk is formed from a substrate that typically comprises glass, ceramic, or glass-ceramic materials. After planarization, these substrate surfaces are coated with a magnetic material. The memory disk planarization process (polishing) usually consists of two steps: a first polishing step for removing most of th...

AI Technical Summary

Benefits of technology

[0012] Still another aspect of the compositions and methods described herein is to provide clay abrasive particles, in a water/clay particle slurry having clay abrasive particles dispersed throughout the water and having a particle size such that at least 90% of the clay particles (by number) have a mean particle size in the range of about 0.002 μm to about 10 μm, preferably about 0.02 μm to about 5 μm, more preferably such that at least 90% of the particles have a mean particle size of about 0.1 μm to about 4 μm, to provide a slurry capable of planarizing metal and/or insulator surfaces.

[0013

Problems solved by technology

Conventional polishing compositions typically are not entirely satisfactory for planarizing computer memory disk substrates comprising NiP, glass, ceramic or glass-ceramic materials.

In particular, polishing slurries can have less than desirable polishing rates, and their use in chemically-mechanically polishing computer memory disk substrate surfaces can result in poor surface quality.