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Element Height Determination for Thin Film Transducers

IP.com Disclosure Number: IPCOM000085539D
Original Publication Date: 1976-Apr-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 3 page(s) / 32K

Publishing Venue

IBM

Related People

Albrecht, DW: AUTHOR

Abstract

In order to provide a comparison factor for determining the final element height of a head by the use of lapping guide elements, a test element, photoetched having the nominal stripe height of a finished transducer, permits determination of the functional element's stripe height with accuracy and without concern for the resistivity, thickness of the films, or the effective path length of the lapping guide element.

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Element Height Determination for Thin Film Transducers

In order to provide a comparison factor for determining the final element height of a head by the use of lapping guide elements, a test element, photoetched having the nominal stripe height of a finished transducer, permits determination of the functional element's stripe height with accuracy and without concern for the resistivity, thickness of the films, or the effective path length of the lapping guide element.

Previously, the final stripe height of the transducer has been determined by either one of the following two equations: h(f) = R(0) over R(f) L(f) over L(0) h(0) and;

h(f) = Rho over t L(f) x 1 over R(f)

where;

R(0) = Initial stripe resistance.

h(0) = Deposited stripe height.

L(0) = Initial path length.

R(f) = Final stripe resistance.

L(f) = Final path length.

Rho over t = Composite resistivity Divide thickness.

In the first equation, the initial stripe resistance cannot be measured directly as the lead resistance to the stripe is included. The error in estimating the lead resistance affects the accuracy of the initial stripe resistance R(0), which can cause a significant error in the final throat height calculation. Furthermore, the effective path length in the lapping guide element can change significantly through the process, so that the ratio of the final path length to the initial path length has to be determined by means other than direct measurement.

In the second equation, the composite resistivity and the thickness must be known. These parameters are process dependent, especially the film thickness for the conductors and element material. In addition, the final path length is not easily measured and must be determined by indirect means.

In the means for controlling the lapping of transducers as shown in the figure, test elements are provided together with the lapping guide element. As is understood, the lapping guide elements are connected to a resistance measuring d...