Method and apparatus for manufacturing a magnetic field sensor device and diesbezüglicheMagnetfeldsensorvorrichtung

The invention relates to a method and apparatus for permanent magnetization of at least a ferromagnetic layer applied in a on a chip substrate (12) magnetic field sensor device (10). The method comprises the steps of: - producing at least one resistance element (14) on a chip substrate (12) which comprises at least one ferromagnetic layer and at least one antiferromagnetic layer, acting between ferromagnetic and antiferromagnetic layer exchange coupling, which disappears when reaching the blocking temperature; adjacent applying at least one soft magnetic structuring element (18) on the chip substrate (12) or partially overlapping with the resistor element (14) -; - heating of the resistance element (14) via the blocking temperature of the material of the antiferromagnetic layer and injecting a pretreatment magnetic field (38); - cooling of the resistance element (14) below the blocking temperature; - removing the pretreatment magnetic field (38). The magnetic pre-treatment device (50) comprises a heating furnace (52) and a magnetic field generating means (66) having a pole and Gegenpoloberflache (56, 58) in the interior of the heating furnace (52), said at least one chip substrate (12) having a soft magnetic structuring element (18) between the pole and Gegenpoloberflache (56, 58) can be inserted