Abrading – Abrading process – Glass or stone abrading
Reexamination Certificate
2000-09-07
2002-10-22
Nguyen, George (Department: 3723)
Abrading
Abrading process
Glass or stone abrading
C451S060000, C438S692000, C216S088000
Reexamination Certificate
active
06468137
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method of planarizing or polishing a substrate, particularly a memory or rigid disk.
BACKGROUND OF THE INVENTION
The demand for increased storage capacity in memory or rigid disks and the trend towards miniaturization of memory or rigid disks (due to the requests of computer manufacturers for smaller hard drives) continues to emphasize the importance of the memory or rigid disk manufacturing process, including the planarization or polishing of such disks for ensuring maximal performance. While there exist several chemical-mechanical polishing (CMP) compositions and methods for use in conjunction with semiconductor device manufacture, few conventional CMP methods or commercially available CMP compositions are well-suited for the planarization or polishing of memory or rigid disks.
In particular, such polishing compositions and/or methods can result in less than desirable polishing rates and high surface defectivity when applied to memory or rigid disks. The performance of a rigid or memory disk is directly associated with its surface quality. Thus, it is crucial that the polishing compositions and methods maximize the polishing or removal rate yet minimize surface defectivity of the memory or rigid disk following planarization or polishing.
There have been many attempts to improve the removal rate of memory or rigid disks during polishing, while minimizing defectivity of the polished surface during planarization or polishing. For example, U.S. Pat. No. 4,769,046 discloses a method for polishing a nickel-plated layer on a rigid disk using a composition comprising aluminum oxide and a polishing accelerator such as nickel nitrate, aluminum nitrate, or mixtures thereof.
There remains a need, however, for improved methods of planarizing or polishing memory or rigid disks at a high removal rate, while minimizing surface defectivity. The present invention seeks to provide such a method. These and other advantages of the present inventive method will be apparent from the description of the invention provided herein.
BRIEF SUMMARY OF THE INVENTION
The invention provides a method for planarizing or polishing a surface of a memory or rigid disk comprising abrading at least a portion of the surface with a polishing system comprising (i) a polishing composition comprising a liquid carrier, at least one oxidized halide, and at least one amino acid, and (ii) a polishing pad and/or an abrasive.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides a method for planarizing or polishing a surface of a memory or rigid disk comprising abrading at least a portion of the surface with a polishing system comprising (i) a polishing composition comprising a liquid carrier, at least one oxidized halide, and at least one amino acid, and (ii) a polishing pad and/or an abrasive. The abrasive forms part of the polishing composition when present and suspended in the liquid carrier of the polishing composition.
The term “memory or rigid disk” refers to any magnetic disk, hard disk, rigid disk, or memory disk for retaining information in electromagnetic form. The memory or rigid disk typically has a surface that comprises nickel-phosphorus, but the memory or rigid disk surface can comprise any other suitable material.
The liquid carrier can be any suitable carrier (e.g., solvent). Suitable liquid carriers include, for example, aqueous carriers (e.g., water) and non-aqueous carriers. Preferably, the liquid carrier is water.
A surface of the memory or rigid disk can be planarized or polished with the polishing system with any suitable polishing pad (e.g., polishing surface) and/or abrasive. It is suitable, for example, for the polishing system to comprise a polishing pad (e.g., an abrasive pad or a non-abrasive pad) and/or an abrasive that is suspended in the liquid carrier of the polishing composition. Moreover, it is suitable for the polishing system to comprise a polishing pad (e.g., an abrasive pad or a non-abrasive pad) when no abrasive is suspended in the liquid carrier of the polishing composition.
Suitable polishing pads include, for example, woven and non-woven polishing pads. Moreover, suitable polishing pads can comprise any suitable polymer of varying density, hardness, thickness, compressibility, ability to rebound upon compression, and compression modulus. Suitable polymers include, for example, polyvinylchloride, polyvinylfluoride, nylon, fluorocarbon, polycarbonate, polyester, polyacrylate, polyether, polyethylene, polyamide, polyurethane, polystyrene, polypropylene, and coformed products thereof, and mixtures thereof. As discussed above, the abrasive of the polishing system can be fixed (e.g., embedded) in whole or in part, in or on the polishing pad such fixation on the polishing pad can be accomplished, for example, by blending the abrasive material, e.g., abrasive particles, into the aforementioned polymers during the formation of the polishing pad.
The abrasive of the polishing system can be any suitable abrasive. The abrasive desirably is in the form of particles and desirably is a metal oxide, e.g., metal oxide particles. Metal oxide abrasives include, for example, alumina, silica, titania, ceria, zirconia, germania, magnesia, coformed products thereof, and mixtures thereof. Preferably, the abrasive of the polishing system is a condensation-polymerized metal oxide, e.g., condensation-polymerized silica particles. Condensation-polymerized silica particles typically are prepared by condensing Si(OH)
4
to form colloidal particles. Such abrasive particles can be prepared in accordance with U.S. Pat. No. 5,230,833 or can be obtained as any of various commercially available products, such as the Akzo-Nobel Bindzil 50/80 product and the Nalco 1050, 2327, and 2329 products, as well as other similar products available from DuPont, Bayer, Applied Research, Nissan Chemical, and Clariant.
It should be understood that the polishing or planarization of a memory or rigid disk can involve two or more distinct polishing steps, utilizing different polishing systems, or alternatively utilizing substantially similar, or even the same, polishing systems. It is suitable, for example, to utilize in a first polishing step a “coarse” polishing system comprising abrasive particles with a particle size greater than 100 nm, and to utilize in a second polishing step a “fine” polishing system comprising abrasive particles with a particle size less than 100 nm. The abrasive particles of the polishing system of the present invention desirably are such that about 90% or more of the abrasive particles (by number) have a particle size no greater than 100 nm. Preferably, the abrasive particles are such that at least about 95%, 98%, or even substantially all (or actually all) of the abrasive particles (by number) have a particle size no greater than 100 nm. These particle size preferences for the abrasive particles (i.e., whereby at least about 90%, 95%, 98%, substantially all, and all of the abrasive particles (by number) are no greater than a specific size of abrasive particle) also can pertain to other particle sizes, such as 95 nm, 90 nm, 85 nm, 80 nm, 75 nm, 70 nm, and 65 nm.
Similarly, the abrasive can be such that at least about 90%, 95%, 98%, or even substantially all (or actually all) of the abrasive particles (by number) have a particle size no less than 5 nm. These particle size preferences for the abrasive particles (i.e., whereby at least about 90%, 95%, 98%, substantially all, and all of the abrasive particles (by number) are no less than a specific size of abrasive particle) also can pertain to other particle sizes, such as 7 nm, 10 nm, 15 nm, 25 nm, and 30 nm.
The percentage values used herein to describe the nature of the abrasive in terms of particle size are percentages “by number,” rather than being weight percentages, unless otherwise noted. The particle size of the abrasive refers to the particle diameter. The particle size can be measured by any suitable technique. The particle size values set forth herein are based on a
Fang Mingming
Wang Shumin
Cabot Microelectronics Corporation
Nguyen George
LandOfFree
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