Laser Bumps Controlling The Head/Disk Interface Tribology

Increasing storage densities of magnetic hard disk drives require ultra-low head fly heights over ultra smooth surfaces. These requirements are incompatible with the tribology of the head/disk interface if the slider is to be landed and parked on the disk. Hence, it becomes necessary to decouple the tribology from magnetics in high-end hard disk drives. An attractive solution first implemented in an IBM product in 1994, and now widely accepted in the HDD industry is the use of a dedicated laser textured landing zone on the disk /1-3/. The process involves the formation of an array of distinct microscopic bumps on the disk substrate which provide the necessary reduction of contact area to lower stiction. This approach offers several advantages over traditional abrasive roughening of the disk substrate. The manufacturing process is cleaner, faster, and more precise in the texturing and zone location. It avoids slurries and solvents, and is, overall more economical. Moreover, it offers a new level of control of the slider/disk interface: the amount of contact area and the shape of contacting asperities. Last but not least, it lends itself to experimental testing and quantitative theoretical modeling of tribological phenomena at the slider/disk interface i4i.