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Method for Lapping Silicon Slider with Alumina Overcoat to Eliminate Silicon Dioxide Protrusion

IP.com Disclosure Number: IPCOM000118927D
Original Publication Date: 1997-Sep-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Carr, JW: AUTHOR [+4]

Abstract

Silicon dioxide, the overcoat of choice for magnetic recording heads processed on a silicon substrate, has a hardness to elasticity ratio of 0.14 to 0.16, which is approximately two times that of silicon. This difference produces a significant protrusion of the silicon dioxide at row lapping. Sputtered alumina, on the other hand, has a hardness to elasticity ratio of approximately 0.7 and, therefore, a better match to silicon. Its lapping rate is very comparable to that of silicon, resulting in negligible recession or protrusion at row lapping. However, it is virtually impossible to find a set of suitable gases for Reactive Ion Etching (RIE) that can etch silicon and alumina at the same rate for the formation of the air bearing. Ion milling also removes silicon faster than alumina.

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Method for Lapping Silicon Slider with Alumina Overcoat to Eliminate
Silicon Dioxide Protrusion

      Silicon dioxide, the overcoat of choice for magnetic recording
heads processed on a silicon substrate, has a hardness to elasticity
ratio of 0.14 to 0.16, which is approximately two times that of
silicon.  This difference produces a significant protrusion of the
silicon dioxide at row lapping.  Sputtered alumina, on the other
hand, has a hardness to elasticity ratio of approximately 0.7 and,
therefore, a better match to silicon.  Its lapping rate is very
comparable to that  of silicon, resulting in negligible recession or
protrusion at row lapping.  However, it is virtually impossible to
find a set of suitable  gases for Reactive Ion Etching (RIE) that can
etch silicon and alumina  at the same rate for the formation of the
air bearing.  Ion milling also removes silicon faster than alumina.

      Removing all silicon dioxide at the air bearing surface
location with wafer level processing, e.g., chemical etch or RIE,
before covering with alumina, will prevent any significant recession
or protrusion at row lapping due to silicon dioxide.  After the
alumina overcoat is deposited and/or overcoat surface lapped, the
pockets of alumina overcoat material near the air bearing surface
location can be etched off, e.g., chemical etch.  As a result, no
alumina or silicon dioxide will be exposed during the patterning of
air bearing rails.