Browse Prior Art Database

Batch-Fabricated Magnetic Microactuators

IP.com Disclosure Number: IPCOM000113586D
Original Publication Date: 1994-Sep-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 61K

Publishing Venue

IBM

Related People

Fan, LS: AUTHOR [+3]

Abstract

Disclosed is a batch-fabricatable magnetic pole-finger actuator that can achieve the magnetic saturation limit on the pole faces and have high linearity for fine lateral movements, and the process to make it. The direct conversion of a spring-constrained flexure (*) into magnetic dual is not usable because the magnetic flux saturates the constraining springs, which typically have a cross section a hundredth of that of pole faces, and limits the magnetic field on the pole faces. Fig. 1 shows the schematic top view of such devices. The edge of the movable plate is divided into two sections to form a re-entrant path to the driving electrode so that the cross sections will not be restricted by the constraining springs. High susceptibility, low hysteresis, isotropic materials should be used for this purpose.

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Batch-Fabricated Magnetic Microactuators

      Disclosed is a batch-fabricatable magnetic pole-finger actuator
that can achieve the magnetic saturation limit on the pole faces and
have high linearity for fine lateral movements, and the process to
make it.  The direct conversion of a spring-constrained flexure (*)
into magnetic dual is not usable because the magnetic flux saturates
the constraining springs, which typically have a cross section a
hundredth of that of pole faces, and limits the magnetic field on the
pole faces.  Fig. 1 shows the schematic top view of such devices.
The edge of the movable plate is divided into two sections to form a
re-entrant path to the driving electrode so that the cross sections
will not be restricted by the constraining springs.  High
susceptibility, low hysteresis, isotropic materials should be used
for this purpose.  The electrodes are interdigitated electrodes so
that the driving force is a function of the mmf, and independent of
the plate position.  Fig. 2 shows the cross section and indicates the
fabrication process of such devices.  First, a sacrificial spacer
layer (such as phosphosilicate glass) is deposited and patterned.
Then, a copper-wire layer is plated and a spacer layer is deposited
and patterned.  An isotropic, low-hysteresis film (such as sputtering
of the super susceptor film) is deposited and patterned.  Another
spacer layer is deposited and contact holes opened for copper studs.
Another copper-wire layer is...