Laser bending of ceramics and application to manufacture magnetic head sliders in disk drives

We have developed and implemented into high-volume manufacturing recently a new micro-laser-bending process, called Laser Curvature Adjust Technique ( LCAT), for fine adjustment of the curvature of the Air Bearing Surface (ABS ) of ceramic magnetic sliders. This process utilizes a compact diode-pumped Q-switched laser to produce photothermal scribe patterns on the back side (i.e. opposite side to the ABS) of the slider. The laser-scribed patterns c ause a permanent decrease in the compressive stress on the back side, and h ence cause the ABS side to bulge out (i.e., increase in crown). Extremely f ine control of the crown change is possible by performing the laser scribin g in "installments", as controlled by an in-situ optical curvature monitor at the ABS side. This "close-loop" Laser-bending process can produce desire d crown values to accuracies of a few nanometers.