Browse Prior Art Database

Single Exposure Bubble Device Fabrication

IP.com Disclosure Number: IPCOM000085752D
Original Publication Date: 1976-May-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Ahn, KY: AUTHOR

Abstract

In bubble memory devices that employ consecutive layers of SiO(2), NiFe and Au between a bubble-supporting film and electrical circuitry on top of the Au layer, the devices work more reliably if the Au layer is removed from beneath the sensor of the device, without removing such Au layer beneath the I and T-bars of the device. A process is described that accomplishes such removal using only a single lithographic exposure.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 62% of the total text.

Page 1 of 2

Single Exposure Bubble Device Fabrication

In bubble memory devices that employ consecutive layers of SiO(2), NiFe and Au between a bubble-supporting film and electrical circuitry on top of the Au layer, the devices work more reliably if the Au layer is removed from beneath the sensor of the device, without removing such Au layer beneath the I and T-bars of the device. A process is described that accomplishes such removal using only a single lithographic exposure.

The figure is a cross-sectional view of a typical two micron thick bubble device. On a substrate, not shown, is deposited a 10,000 Angstrom film 2 of GdCoMo or other amorphous material that serves as a metallic element that supports bubbles of magnetism. Atop of this magnetic film is a 3000 Angstrom layer 4 of SiO(2), over which is lain a NiFe layer 6 having a thickness of about 3000 Angstroms. A 3000 Angstrom thick layer 8 of Au is deposited on the NiFe film 6 so that a T-bar 10, an I-bar 12 and a sensor 14, all made of permalloy, can be made adherent to the NiFe without allowing electromigration between the different layers of NiFe.

The elements 10, 12, and 14 are made of a resist that is sensitive to X-rays or E-beans. Such a resist is polymethyl methacrylate (PMMA). Although, at first, equal thicknesses (such as 9000 Angstroms) of PMMA are located on the Au in the desired design pattern, such resist is differentially exposed to radiation. For example, the PMMA of sensor region 14 is exposed to greate...