Onboard multiphase electronic lapping guide design for MR heads

A method of lapping a magneto-resistive head having a magneto-resistive sensor element disposed for electrical communication with a pair of sensor electrical leads, comprising:

• forming an electronic lapping guide resistive element disposed for electrical communication with said electrical leads and spaced from said sensor element in a lapping direction;
• said resistive element having a predetermined height in a lapping direction;
• said resistive element being adapted to produce an electrical resistance in the presence of a lapping current that increases as said resistive element height is reduced during lapping;
• passing a lapping current through said resistive element;
• lapping said head while monitoring changes in said electrical resistance.

A method of forming a magnetoresistive sensor with an onboard electronic lapping guide, comprising;

• forming a plurality of sensor layers on a substrate;
• photolithographically etching said sensor layers using a track width defining mask to create a pair of etched pockets;
• forming a pair of sensor electrical leads in said etched pockets, said electrical leads being spaced from each other to define a sensor track width;
• photolithographically etching said sensor layers to define a sensor element using a stripe height defining mask to remove sensor material outside said mask;
• said stripe height defining mask further defining a lapping guide resistive element extending between said electrical leads and spaced from said sensor element in a lapping direction;
• said resistive element having a predetermined height in a lapping direction;
• and
• said resistive element being adapted to produce an electrical resistance in the presence of a lapping current that increases as said resistive element height is reduced during lapping.