MICROPLAQUETTE DE DOMAINES A BULLES ET PROCEDES DE FABRICATION

MICROPLAQUETTE DE DOMAINES EN FORME DE BULLES COMPRENANT UN SOCLE DE MATERIAU ISOLANT DANS LES REGIONS OU UN DETECTEUR OU GENERATEUR DE DOMAINES EST FORME.ELLE COMPREND UN FILM SUPPORT DE DOMAINES 10, UNE COUCHE DE MATERIAU CONDUCTEUR 46 DANS LAQUELLE EST FORME UN SOCLE DE MATERIAU ISOLANT 42 ET UNE COUCHE DE MATERIAU MAGNETIQUE 56 DISPOSEE AU-DESSUS DE LA COUCHE CONDUCTRICE ET DE L'ISOLANT. LA STRUCTURE PEUT ETRE OBTENUE PAR UN PROCEDE SOUSTRACTIF OU ADDITIF.APPLICATION AUX MEMOIRES A DOMAINES EN FORME DE BULLES. An improved magnetic bubble domain chip and processes for making the chip are described. The chip is comprised of a magnetic bubble domain film in which small bubble domains can be moved, and overlying layers of metallurgy. The layer of metallurgy closest to the bubble film is an electrically conductive layer having apertures (or recesses) therein. This layer is patterned to provide current carrying conductors. The next overlayer is a layer of magnetic material having in-plane magnetization which is patterned to provide the propagation elements used to move the bubble domains. In a particular embodiment, the magnetic layer is comprised of a magnetically soft material, such as permalloy. The chip is characterized by the provision of insulating pedestals located in the apertures of the conductive layer. These insulating pedestals are located in the regions of the chip used for sensing (and/or bubble generation). That is, they take the place of the thick conductive material in those areas of the chip. The sensor and bubble generators are usually portions of the in-plane magnetic layer. If the height of the insulating pedestals is the same as the height of the conductive layer, planarization is achieved and each overlayer lies in a single plane, where the planes are parallel to one another. However, the pedestal can be of any desired height. This chip is particularly advantageous for use with bubble domains having diameters of about 1 micron and less, since the pedestal magnetic chip can be provided by single level masking techniques in which only a single critical masking step is required. The insulating pedestal can be formed prior to deposition of the current carrying conductive layer, or subsequent to deposition of this layer.