Material Deposition for Curvature Adjustment of Recording Heads
Original Publication Date: 2001-Mar-01
Included in the Prior Art Database: 2003-Jun-18
Disclosed here is a technique to use material deposition to adjust the shape of a body upon which it is deposited. The conditions of deposition can control the stress in the deposited material and thereby control the amount and sign of the shape change in the body being coated. Specifically, this technique is applied to the changing of the shape of a recording head body. As magnetic spacing continues to decrease, the shape or curvature characteristics of magnetic recording sliders become increasingly important. Variations in slider shape typically dominate other contributors to flying height variations, as well as have dramatic affect on the tribological performance of the slider on a rotating disk, or during contact start stop (CSS) or slider load/unload (L/UL) operations. It is becoming increasingly difficult to control slider shapes in manufacturing volumes to the required shape tolerances of only a few nanometers. Currently, all sliders are “lapped” to control dimensions of the magnetic read element, and this lapping process introduces variations in surface stress, which in turn result in variations of slider shape. Most lapping processes are carried out at the slider row level; i.e., before they are cut into individual sliders, so most of the variation in shapes are from row to row. Fig. 1. Slider distortions, crown, camber and twist. Figure 1 schematically illustrates a magnetic head slider with an Air Bearing Surface (ABS) pattern, and the definition of various slider curvature parameters that are considered important for FH control and tribology. These parameters are shown in Fig. 1 and described as follows. Crown is defined as the maximum degree of protrusion of the slider ABS surface relative to a plane drawn from the front to rear slider edge. Camber has a similar definition and is the deviation from a plane drawn between the two side edges of the slider. Twist is the difference of the “diagonal” cylindrical curvatures.