New single-mask approach to bubble device fabrication

Permalloy devices with two separate levels of fine permalloy and conductor patterns have been fabricated by the use of a single-mask process. This process makes possible the production of devices having an essentially conventional design in addition to a completely planar structure. The features of this new process include 1) preparation of a reticle on which patterns for both permalloy and conductor layers are superimposed, 2) use of SiO2, Mo/Au/Mo, SiO2, permalloy, and TiO2thin films deposited sequentially on the bubble materials, and 3) simultaneous delineation of both photoresist patterns with two different thicknesses and of the desired patterns by CF4plasma etching and ion-milling.