MAGNETIC SENSOR PRODUCTION METHOD

摘要

Disclosed is a magnetic sensor production method that is capable of fixing the magnetization of a plurality of magnetic detection elements in differing directions upon the same substrate with a high degree of accuracy, by using a weak magnetic field. In process (a), a second magnetic layer (13c) is formed with a larger Mst than a first magnetic layer (13a). In process (b), a laminated film (20) is heat treated in a magnetic field. At this time, the current directions running to an electrically conductive section (6) differ, and an exterior magnetic field of a differing direction is applied to each area (A-D) of the laminated film (20). By making the exterior magnetic field a weak magnetic field, the magnetization of the second magnetic layer (13c) with the larger Mst orients in the applied magnetic field direction, and the magnetization of the first magnetic layer (13a) is fixed anti-parallel to the second magnetic layer (13c) by means of an RKKY coupling magnetic field. In process (c), a portion of the second magnetic layer (13c) is removed, and the Mst in the first magnetic layer (13a) and the second magnetic layer (13c) are made equal. In process (d), a nonmagnetic material layer, a free magnetic layer, and a protective layer are formed, and the magnetic detection elements are formed in patterns in each area.