Browse Prior Art Database

Protection of (80:20) Ni:Fe Patterns from Ion Bombardment

IP.com Disclosure Number: IPCOM000088973D
Original Publication Date: 1977-Aug-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 3 page(s) / 45K

Publishing Venue

IBM

Related People

Krongelb, S: AUTHOR [+2]

Abstract

One approach to fabricating bubble domain devices requires electroplating an alloy (80:20) Ni:Fe propagation pattern 10 (Fig. 1) through a photoresist mask 12 onto a gold plating base 14 on substrate 16, and then removing the resist with a solvent and the unwanted gold by sputter etching or ion milling. Because of the micron dimensions of the propagation elements, it is impractical to register a photoresist protective pattern over the alloy 10. Therefore, alloy 10 is used as its own mask during sputter etching or ion milling of the gold, and some alloy 10 is lost during etching. In principle, one can note that gold etches about six times faster than Ni:Fe alloy under argon ion bombardment. Enough excess alloy 10 can be electroplated to compensate for that lost during etching.

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Protection of (80:20) Ni:Fe Patterns from Ion Bombardment

One approach to fabricating bubble domain devices requires electroplating an alloy (80:20) Ni:Fe propagation pattern 10 (Fig. 1) through a photoresist mask 12 onto a gold plating base 14 on substrate 16, and then removing the resist with a solvent and the unwanted gold by sputter etching or ion milling. Because of the micron dimensions of the propagation elements, it is impractical to register a photoresist protective pattern over the alloy 10. Therefore, alloy 10 is used as its own mask during sputter etching or ion milling of the gold, and some alloy 10 is lost during etching. In principle, one can note that gold etches about six times faster than Ni:Fe alloy under argon ion bombardment. Enough excess alloy 10 can be electroplated to compensate for that lost during etching. When dealing with patterns, however, the corners and edges of the mask are eroded more rapidly than planar surfaces. Consequently, the initial rectangular cross-section of the plated patterns 10 (Fig. 1) becomes trapezoidal (Fig. 2), and may, for sufficiently narrow elements, degenerate into a triangle. These changes in cross- section of the alloy 10, which will eventually be used as a propagation pattern, affect the magnetic properties and lead to high coercivity alloy 10, which has an adverse effect on the performance of bubble devices

The nearly rectangular initial cross-section of alloy 10 (Fig. can be preserved during etching if oxygen is introduced into the system. Presence of about 40% oxygen in an Ar plasma when sputter etching with 1.3 KV DC developed on the cathode suppresses the etch rate of the Ni:Fe alloy to about 1/20 that of gold. The loss of alloy 10 from the top of the line, edges, corners and sides is significantly reduced by the presence of oxygen, and the cross-section of the propagation elements is much closer to that of the initially plated pattern. Similar benefits are expected from the use of oxygen in ion milling since th...