Disk Lubrication

Hard disk media is basically composed of a layered magnetic alloy stack for information storage, a protective layer that guards against impact and corrosion of the magnetic media, and a top lubricant layer that reduces friction and wear. After the various sputtered layer depositions, a microscopic (approx. 2nm thick) layer of lubricant is applied by dipping the disk into a solution containing a lubricant in solvent, spin coating or vacuum vapor deposition. The lubricant is typically composed of a PFPE perfluoropolyether (like Teflon) polymer. This layer is then partially cured to stabilize the amount of bonded and unbounded material on the disk surface via thermal or UV curing. As new types of HDDs are commercialized, the chemistry and deposition technology for the lubricating layer is undergoing rapid evolution.

HDD industry leaders are working closely with Intevac in the development of new lubrication chemistries, to ensure their timely and cost-effective production. Intevac’s lubrication deposition systems, the DLS-100 and AccuLuber, employ different techniques for lubricant deposition. The DLS-100 dips disks into a lubricant/solvent mixture; the solvent is evaporated, leaving the lubricant on the disk surface. It is critical that the process temperature be carefully controlled, and the process conducted in a contamination free environment with minimal solvent loss. The system design prevents evaporative loss of expensive solvent, limiting solvent loss to less than 3 liters per day in a full production environment.

Intevac’s new AccuLuber vacuum vapor lubrication system deposits a thin vapor film of lubricant on the disk under vacuum, eliminating the need for solvents. The AccuLuber system’s superior vapor process capability creates a uniform lube coating that meets the requirements of the most advanced PMR and other technologies. Its twin process chambers provide both high throughput and redundancy with a throughput of over 1200 dph.