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Browse Prior Art Database

Disk Coating Thickness Control by Means of Plasma Ashing

IP.com Disclosure Number: IPCOM000045303D
Original Publication Date: 1983-Mar-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

DePalma, V: AUTHOR [+2]

Abstract

In the development of magnetic disk files, one approach to increasing bit density requires a decrease in magnetic media thickness and/or a decrease in the read/write head-medium spacing. The inside diameter thickness of currently available disks is roughly 0.5 - 0.6 Mu. This final thickness is obtained by coating a substrate with dispersion to an initial thickness of approximately 1.0 - 1.5 Mu and buffing the cured coating to the desired thickness. Thus, buffing is needed to remove about half the stock. This is achieved by abrading the coating with a composite material (silica or aluminum oxide) imbedded onto a constantly changing roll of paper that is held in contact with the coated surface.

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Disk Coating Thickness Control by Means of Plasma Ashing

In the development of magnetic disk files, one approach to increasing bit density requires a decrease in magnetic media thickness and/or a decrease in the read/write head-medium spacing. The inside diameter thickness of currently available disks is roughly 0.5 - 0.6 Mu. This final thickness is obtained by coating a substrate with dispersion to an initial thickness of approximately 1.0 - 1.5 Mu and buffing the cured coating to the desired thickness. Thus, buffing is needed to remove about half the stock. This is achieved by abrading the coating with a composite material (silica or aluminum oxide) imbedded onto a constantly changing roll of paper that is held in contact with the coated surface. The buffing process is difficult to control because of the many mechanical variables involved, such as the pressure holding the abrasive paper down on the disk surface. As a result, buffing to achieve current disk thickness is poorly reproducible. The problems of buffing future product disks are expected to be even more significant.

The present proposal offers a novel alternative to reduce the particulate coating thickness and to improve its control. Plasma ashing is a method commonly used to remove organics from metal or ceramic surfaces prior to welding, glazing, sputtering or applying adhesives. The process involves the production of a reactive plasma consisting of ionized gas molecules which rapidly oxidize organic...