Browse Prior Art Database

Recessed Overlay Structure

IP.com Disclosure Number: IPCOM000083099D
Original Publication Date: 1975-Mar-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Ahn, KY: AUTHOR [+2]

Abstract

In the processing of magnetic bubble domain chips having overlays thereon, poor adhesion can result when low-temperature techniques are used for deposition of the overlay films. For instance, when the bubble domain material is an amorphous material, the bubble chip processing temperatures should be below the crystallization temperature of the bubble domain material. As another example, low-temperature depositions generally are required when electron-beam resists are used.

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Recessed Overlay Structure

In the processing of magnetic bubble domain chips having overlays thereon, poor adhesion can result when low-temperature techniques are used for deposition of the overlay films. For instance, when the bubble domain material is an amorphous material, the bubble chip processing temperatures should be below the crystallization temperature of the bubble domain material. As another example, low-temperature depositions generally are required when electron- beam resists are used.

By providing a recess of the spacer layer located on the bubble domain film, the overlay deposition will be mechanically anchored, thereby providing increased adhesion. In the figure the magnetic bubble domain film has a dielectric spacer, such as SiO(2) thereon. The NiFe overlay is deposited into recessed portions of the dielectric spacer in order to mechanically anchor this layer. The Au conductor layer is deposited on the NiFe layer. All layers deposited on the resist layer are later removed by lift-off.

To provide the structures shown, the bubble domain film containing the dielectric spacer is exposed with an E-beam, followed by a chemical etching of the exposed pattern. For a SiO(2) spacer layer, typical etch rates at 25 degrees C in 10:1 buffered HF are about 800 angstroms/minute. The overlay film of NiFe is then evaporated to a thickness of about 3000 angstroms. This is followed by deposition of the Au conductor film, also to a thickness of about 3,000 angstrom...