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HDD File Family Design to Maximize Use of Head Wafers and Thus Reduce Costs

IP.com Disclosure Number: IPCOM000014436D
Original Publication Date: 2000-Dec-01
Included in the Prior Art Database: 2003-Jun-19
Document File: 1 page(s) / 41K

Publishing Venue

IBM

Abstract

HDD file designs traditionally offer multiple capacity models. These are generally made by keeping the same TPI, BPI, and capacity per disk but reducing the number of heads and/or disks. However, one problem in head wafer manufacturing is that tolerances are not scaling with TPI increases. This puts a cost penalty on products which need to have tolerances scaled, or a yield or performance (squeeze margin degradation, or TMR reduction) to work with current process capability. An alternative is to sort the sliders into two bins: wide and narrow. Then the narrow sliders can be routed into the fully populated HDDs and the wide ones into the de-populated, but the de-populated would add an extra head and decrease the track pitch accordingly. This would make maximum use of the wafer production and significantly reduce the tolerances. Sorting could be done on either read or write width. Sorting could be done into more than two bins, and could be used on different depopulated models, for example 9, 18 36 could support 3 bins, 9, 18, 36 and 72 would support 4 and so forth. 1

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HDD File Family Design to Maximize Use of Head Wafers and Thus Reduce Costs

   HDD file designs traditionally offer multiple capacity models. These are generally made by keeping the same TPI, BPI, and capacity per disk but reducing the number of heads and/or disks. However, one problem in head wafer manufacturing is that tolerances are not scaling with TPI increases. This puts a cost penalty on products which need to have tolerances scaled, or a yield or performance (squeeze margin degradation, or TMR reduction) to work with current process capability. An alternative is to sort the sliders into two bins: wide and narrow. Then the narrow sliders can be routed into the fully populated HDDs and the wide ones into the de-populated, but the de-populated would add an extra head and decrease the track pitch accordingly. This would make maximum use of the wafer production and significantly reduce the tolerances.

   Sorting could be done on either read or write width. Sorting could be done into more than two bins, and could be used on different depopulated models, for example 9, 18 & 36 could support 3 bins, 9, 18, 36 and 72 would support 4 and so forth.

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