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Control of Magnetostriction of Plated Permalloy Films, Measured on Circular Test Sites

IP.com Disclosure Number: IPCOM000114097D
Original Publication Date: 1994-Nov-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 59K

Publishing Venue

IBM

Related People

Baratte, H: AUTHOR [+8]

Abstract

This article describes the determination of magnetostriction of plated permalloy films on small test sites of circular shape by means of the currently used Kerr BH Imager (KerrBHI) without the necessity to initiate additional process steps.

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This is the abbreviated version, containing approximately 53% of the total text.

Control of Magnetostriction of Plated Permalloy Films, Measured on
Circular Test Sites

      This article describes the determination of magnetostriction of
plated permalloy films on small test sites of circular shape by means
of the currently used Kerr BH Imager (KerrBHI) without the necessity
to initiate additional process steps.

      The performance, especially the instability, of inductive thin
film heads depends on the magnetostriction.  The magnetostriction, in
turn, is influenced by the microstructure.  In controlling the
plating bath it is important to establish also a control loop for
magnetostriction.

      By applying the described method, the magnetostriction can be
measured on product wafers and directly correlated to performance
data.

      The films were plated in circles surrounded by photo resist
frames on wafers with an 80 nm thick NiFe seed.  The circles were 0.9
mm, 2.9 mm and 4.9 mm in diameter, each with a frame width of 1.1 mm,
3.1 mm and 4.9 mm.  Magnetostriction was measured on a high and low
Ni wafer before and after sputter etching (S/E).  Additionally, after
S/E the composition of the circles were determined by means of the
micro probe.

      The measurement of magnetostriction requires to determine the
change of the magnetic anisotriopy field  Hk and the corresponding
change of stress.  The change of stress is given by a well defined
deflection of the wafer.  The anisotropy fields are measured in a
rotating magne...