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Planarizing Coating Using PMR Polyimides

IP.com Disclosure Number: IPCOM000050366D
Original Publication Date: 1982-Oct-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 1 page(s) / 13K

Publishing Venue

IBM

Related People

Mock, GA: AUTHOR [+3]

Abstract

Disk substrates (AlMg) currently used in the manufacturing of magnetic recording disks have defects and topography which can be partially removed during polishing. The unfilled defects, if large enough, can often result in missing bits, whereas the remaining topography can transform into more surface roughness for the finished disks. Therefore, any coating material that can smooth out the substrates will be most beneficial to the technology. Furthermore, there is an increasing demand for better resolution and higher sensitivity, which can only be achieved with smoother substrates and thinner coatings.

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Planarizing Coating Using PMR Polyimides

Disk substrates (AlMg) currently used in the manufacturing of magnetic recording disks have defects and topography which can be partially removed during polishing. The unfilled defects, if large enough, can often result in missing bits, whereas the remaining topography can transform into more surface roughness for the finished disks. Therefore, any coating material that can smooth out the substrates will be most beneficial to the technology. Furthermore, there is an increasing demand for better resolution and higher sensitivity, which can only be achieved with smoother substrates and thinner coatings.

Of the many polymers that have been evaluated for this ability to planarize (smooth out) substrates, together with other considerations such as processability, coatability, mechanical properties, and thermal and chemical stability, PMR (Polymerization of Monomeric Reactants) polyimides appear to be some of the most suitable candidates.

PMR polyimides can be easily prepared by mixing a diester of a dianhydride and a diamine in high boiling aprotic solvents at room temperature. One of such PMR polyimides can be purchased from Monsanto Chemical Company under the tradename of SKYBOND 703, which is basically composed of the dimethyl ester of benzophenone tetracarboxylic dianhydride and methylene dianiline. The PMR polyimides can be prepared in very high solids content solutions (70-85 percent). They can be stored in a refrigerator over a prolonged period of time without a...