Patent ID: 7713755

Claim:
A process to manufacture a magnetic angle sensor, comprising: providing a substrate and depositing thereon a seed layer; depositing on said seed layer, in unbroken succession, an antiferromagnetic layer, a synthetic magnetic pinned trilayer, a copper spacer layer, a magnetic free layer, and a capping layer, thereby forming a GMR stack; depositing on said capping layer, to a thickness whose value ranges from 120 to 200 Angstroms with a precision of ±5 Angstroms, a layer of tantalum nitride; then annealing said GMR stack at a temperature of at least 250° C. in the presence of a magnetic field of at least 1000 Oe, thereby establishing good magnetic pinning; forming a photoresist mask on said tantalum nitride layer and then selectively patterning only said tantalum nitride layer, through etching in CF 4 gas, to become a hard mask having a serpentine shape; stripping said photoresist mask in an oxygen plasma whereby between 30 and 60% of said tantalum nitride layer is converted to tantalum oxynitride; and then, through use of reactive ion etching, removing all layers of said GMR stack that are not protected by said partially oxidized tantalum nitride hard mask, whereby said magnetic angle sensor is formed.