Patent ID: 7646570

Claim:
A method of making a current-perpendicular-to-plane (CPP) read sensor having a constrained current path, comprising: forming at least part of a sensor stack structure of the read sensor; depositing a metal sublayer over and adjacent an electrically conductive layer of the sensor stack structure, the electrically conductive layer forming at least part of a spacer layer of the sensor stack structure; performing, on the metal sublayer, one of an oxidation process, a nitridation process, and an oxynitridation process, to produce an insulator from the metal sublayer; repeating the steps of depositing and performing; forming a resist structure over the insulator which exposes materials of the insulator; etching, with the resist structure in place, to remove the exposed materials of the insulator to thereby form one or more apertures through the insulator down to the electrically conductive layer; and forming electrically conductive materials within the one or more apertures to form one or more lithographically-defined conductive vias of a current-constraining structure of the read sensor.