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An Integrated Process Control to Reduce Flying Height Distribution

IP.com Disclosure Number: IPCOM000011385D
Original Publication Date: 2003-Feb-14
Included in the Prior Art Database: 2003-Feb-14
Document File: 2 page(s) / 88K

Publishing Venue

IBM

Abstract

Disclosed is a process for reducing flying height distribution by adjusting air bearing surface curvature to compensate under- or over-milled air bearing step heights of recording heads within a batch or in batch-to- batch.

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An Integrated Process Control to Reduce Flying Height Distribution

Monte Carlo simulation on flying height with given air bearing step height distribution and surface curvature distribution of recording heads establishes a process recipe, how to minimize process control error for achieving minimum flying height variation. First, influences of air bearing surface curvature and step heights on flying height are formulated separately. Then, combine the results as error sources in flying height variation and finally find the condition for the minimum. Numerical equations to explain sensitivity of air bearing surface curvature and step heights on flying height follow. Take derivative of equations for air bearing surface curvature (crown) and step heights (IM depth and RIE depth)

Crown ID dfh = 0.1726 *dcrn

          OD dfh = 0.2094 *dcrn AVG dfhc = 0.1910 *dcrn IM ID dfh = 106.1 *dim

          OD dfh = 127.9 *dim AVG dfhi = 117.0 *dim RIE ID dfh = 2*12.394*rie*drie -34.763*drie

          OD dfh = 2*13.002*rie*drie -46.219*drie AVG dfhr = 25.396 *rie*drie -40.491*drie 0 = dfhi + dfhr + dfhc < === equation to solve Solving for Crown as a function of IM and RIE to get an equation; dCrn = A*dRIE + B*RIE*dRIE + C*dIM

          A B C ID dCrn = 201.408*dRIE -143.615*RIE*dRIE -614.716*dIM OD dCrn = 220.721*dRIE -124.183*RIE*dRIE -610.793*dIM AVG dCrn = 211.995*dRIE -132.963*RIE*dRIE -612.565*dIM Experimental result shows this method reduces overall flying height distribution by avg 21% and also reduces flying heigh...