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Free Standing Magnetic Films on Thin Flexible Insulating Layers

IP.com Disclosure Number: IPCOM000075604D
Original Publication Date: 1971-Oct-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Albert, PA: AUTHOR [+3]

Abstract

This method provides free-standing magnetic films on thin, flexible insulating layers useful in fabricating magnetic heads.

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Free Standing Magnetic Films on Thin Flexible Insulating Layers

This method provides free-standing magnetic films on thin, flexible insulating layers useful in fabricating magnetic heads.

In the fabrication of these magnetic film assemblies, a rigid substrate, such as highly polished copper, is used. If free-standing films are desired, the copper is protected by a nonreactive layer, such as plated silver. The substrate is covered with two layers of polyimide resin applied normally to each other, in such a manner as to leave approximately a one-eighth border of exposed copper around the perimeter of the substrate. The total film thickness is about two microns. Each polyimide layer is applied at ambient temperature, allowed to dry for fifteen minutes at 50 degrees C and is then baked one hour at 120 degrees C in a forced draft oven. The metallization layer is applied to the entire surface of the substrate by vacuum evaporation at a substrate temperature of 100 degrees
C. This layer may be built as follows: chromium 40-50 angstrom units and copper 250 angstrom units. A magnetic layer having sufficient thickness may be applied using standard electroplating techniques. Thereafter, the plated films are annealed for eight hours at 200 degrees C in a 40 oersted easy-axis field. The results of this anneal are two-fold: one, it "fixes" the magnetic properties of the films; and, two, a long exposure to high temperature causes delamination over the polyimide. The films delam...