Method for manufacturing a magnetoresistive sensor having a flat shield

A method for manufacturing a magnetoresistive sensor, comprising:

• providing a substrate;
• depositing a plurality of sensor layers over the substrate;
• depositing a first thin high density carbon CMP stop layer over the plurality of sensor layers;
• forming a mask structure over the thin high density carbon CMP stop layer;
• transferring an image of the mask structure onto the thin high density carbon CMP stop layer;
• performing an ion milling to remove a portion of the plurality of sensor layers that are not protected by the mask and the thin high density carbon CMP stop layer;
• depositing a layer of hard magnetic bias material;
• depositing a capping layer over the hard bias material, the capping layer comprising a layer of Ta and at least one layer of Cr or Rh;
• depositing second high density carbon CMP stop layer;
• performing a chemical mechanical polishing to remove the mask structure, the chemical mechanical polishing including a first CMP step followed by a second CMP step, the first CMP step being more aggressive than the second CMP step;
• and
• performing a reactive ion etching to remove the first and second thin high density carbon CMP stop layer.