Fabrication of micro- and submicron-bubble memory devices by a mask transfer technique with subsequent getter-ion etching

Abstract

In order to fabricate magnetic bubble memory circuits of high bit density using x-ray lithography, it is necessary to form accurate gold absorber patterns for x-ray masks and accurate permalloy patterns for the bubble memory circuits. The combined processes of mask transfer technique and getter-ion etching instead of conventional ion etching in pure argon gas were used to make patterns in these metal films. Pattern width accuracies within ±0.1 μm and the angles of edge slope up to 70° were obtained by using these processes. Our new method was applied to the microfabrication of gold x-ray mask patterns and permalloy patterns of the circuits for magnetic bubbles of diameters 0.95 and 1.5 μm.