Magnetic field sensor and method of manufacturing same using a self-organizing polymer mask

Abstract

A giant magnetoresistance (GMR) sensor is formed using a self organizing diblock copolymer as an etching mask. The diblock copolymer is deposited over a magnetic layer and is self organized into regions of two discrete thicknesses; higher thickness island regions separated by lower thickness valley regions. After the diblock layer is self organized, an etching of process is performed to remove the polymer material from the valley regions as well as the underlying magnetic material. After etching, a patterned magnetic thin film of submicron islands of magnetic material, preferably having a diameter in the single domain range, remain under the mesa region. The islands are interconnected by a non-magnetic, conductive layer with electrical contacts coupled thereto to complete the GMR sensor. When the sensor is not subjected to a magnetic field, the magnetic alignment of the islands is random, and electron scattering results in a high resistance state. When the sensor is magnetically saturated, the magnetic islands have a common magnetic alignment, resulting in reduced sensor resistance.