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MR Sensor Shaping by a Combination of RIE and Ion Milling

IP.com Disclosure Number: IPCOM000123807D
Original Publication Date: 1999-May-01
Included in the Prior Art Database: 2005-Apr-05
Document File: 1 page(s) / 41K

Publishing Venue

IBM

Related People

Fontana Jr, RE: AUTHOR [+2]

Abstract

MR sensor is usually fabricated by first defining islands of bias and lead material into a field of MR material. The island separation sets the sensor trackwidth. Next a resist pattern covering both MR track and lead/bias materials are formed followed by ion milling to remove the sensor material in the field to define the final sensor shape. Since the MR shaping photo mask cannot be aligned perfectly to the previous trackwidth definition step, in the perimeter region near the MR track edge, the lead/bias materials are not masked by the resist. Preferably, this lead/bias materials should also be removed to assure the optimum MR sensor performance.

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MR Sensor Shaping by a Combination of RIE and Ion Milling

   MR sensor is usually fabricated by first defining islands
of bias and lead material into a field of MR material.  The island
separation sets the sensor trackwidth.  Next a resist pattern
covering both MR track and lead/bias materials are formed followed
by ion milling to remove the sensor material in the field to define
the final sensor shape.  Since the MR shaping photo mask cannot be
aligned perfectly to the previous trackwidth definition step, in the
perimeter region near the MR track edge, the lead/bias materials are
not masked by the resist.  Preferably, this lead/bias materials
should also be removed to assure the optimum MR sensor performance.
Since the lead/bias bias materials are typically thicker than the
sensor material, when milling for lead/bias materials is complete,
the field originally covered by the sensor material is overmilled.
This results in a thinned first gap and a MR structure with undesired
topograghy.

   Disclosed is a method of shaping MR sensor by a combination
of RIE and ion milling.  With a resist mask for MR shaping in place,
the lead material (e.g. tantalum) is first removed from the top of
the bias material with a F-containing RIE process.  Since the RIE
chemistry does not etch NiFe, the thickness of the sensor material in
the field will not change.  After this RIE step, the thickness of the
remaining material (bias) in the unmasked region is comparable to the
sensor mate...