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EMPIRICAL REPLACEMENT OF RLG IN MAGNETIC RECORDING HEADS EMPLOYING MULTIPLE LAPPING GUIDES

IP.com Disclosure Number: IPCOM000013193D
Original Publication Date: 1999-Oct-01
Included in the Prior Art Database: 2003-Jun-17
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

T CHEN: AUTHOR

Abstract

Disclosed is a method that improves the 4 tiered resistive lapping system employed in the lapping of thin film heads during slider machining. In this system, all 4 resistive lapping guides, 2 pairs of Rough Lapping Guides (RLG) and Fine Lapping Guides (FLG) on each side of the chip, must be manufactured defect free with nominal resistances in order for accurate lapping to occur.

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  EMPIRICAL REPLACEMENT OF RLG IN MAGNETIC RECORDING HEADS EMPLOYING MULTIPLE LAPPING GUIDES

  Disclosed is a method that improves the 4 tiered resistive lapping system employed in the lapping of thin film heads during slider machining. In this system, all 4 resistive lapping guides, 2 pairs of Rough Lapping Guides (RLG) and Fine Lapping Guides (FLG) on each side of the chip, must be manufactured defect free with nominal resistances in order for accurate lapping to occur.

     The equation Rs (W / h) = R describes the relationship between an element's geometry and its electrical resistance, where Rs is the sheet resistance of the element, h is the stripe height of the element, W is the width of the element and R is the electrical resistance of the element. For an element with uniform Rs and fixed W, the R increase as the h decreases. In the 4 tiered system, the pair of RLGs on each side is monitored, allowing dynamic balance adjustment if the rate of change in resistance on one side becomes too high. The function of the FLG is also critical; its resistance is used to zero out the small, localized variations in Rs, W and h that are inherent to all thin film manufacturing. For each pair of RLG and FLG, the equation above is adopted and solved differentially for both RLG and FLG to obtain a target resistance for a desired stripe height. Typically, the FLG is recessed and not lapped and used only in the calculation. When the FLG is damaged, process variations can not be zeroed out and when the RLG is damaged, lapping can not be monitored. Therefore, if any one of the RLGs or FLGs is damaged, the slider cannot be lapped accurately to the desired stripe height. The method disclosed copes with certain damages to this RLG/FLG system and allows for accurate lapping to occur in an otherwise lost slider.

     The most common damage to the lapping system is a defect to the FLG. Because of the differential nature of the solution to the resistance equation, the stripe of the FLG is made a lot smaller the stripe of...