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Material Deposition for Curvature Adjustment of Recording Heads

IP.com Disclosure Number: IPCOM000013628D
Original Publication Date: 2001-Mar-01
Included in the Prior Art Database: 2003-Jun-18
Document File: 4 page(s) / 119K

Publishing Venue

IBM

Abstract

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.

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Material Deposition for Curvature Adjustment of Recording Heads

  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.

Several techniques for producing positive or negative curvature changes on a slider

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surface are known. These provide the basis of a variety of curvature adjust techniques practiced by various slider manufacturers. Since an increase in the level of compressive stress (generated, for example, by surface grinding or ion implantation) causes a surface to bulge outward, and since higher crown or higher camber is usually desired by manufacturers, a process which produces compressive stress would be applied to the ABS side of the slider. The generation of a tensile stress would be appropriate for the opposite (or flex) side of the slider to cause an increase in crown or camber. A fairly popular adjust technique being practiced by other manufacturers is diamond scribing. Here, a diamond tip is used to scribe lines across the slider (side to side) on the ABS surface to increase cro...