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

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.