Method for fabricating lead overlay (LOL) on the bottom spin valve GMR read sensor

A method for fabricating a longitudinally biased bottom spin valve GMR read sensor having a lead overlay configuration and narrow trackwidth comprising:

• providing a substrate;
• forming on the substrate a bottom spin valve stack, said stack having a barrier layer capped by a bilayer formed of an upper layer and a lower layer and said stack being bounded laterally by edges;
• annealing said stack with a first anneal;
• forming a longitudinal bias layer of permanent magnetic material contiguous to said stack edges;
• forming a second capping layer on said bias layer;
• forming a blanket conducting lead overlay layer (LOL) over said stack and capped bias layer;
• annealing said LOL blanketed stack and bias layer with a second anneal;
• forming an opening within a central portion of said lead overlay layer (LOL), the lateral dimension of said opening defining a physical trackwidth and the opening extending vertically through the LOL and the upper layer of the capping bilayer and reaching at least to the upper surface of the lower layer of said capping bilayer but not reaching the lower surface of said lower layer and the remaining thickness of said lower layer being oxidized thereby to form a specularly reflecting layer.