MR head wafer fabrication technology: current and future perspectives

Areal storage densities and yield requirements continuously drive process optimizations in volume manufacturing of magnetoresistive (MR) heads. Several topics related to the manufacturability of MR heads are discussed. A dependable supply of MR sputter targets with low magnetostriction /spl lambda//sub s/ is critical. By using an internally developed technique, /spl lambda//sub s/ can be predicted to within /spl plusmn/1.0/spl times/10/sup -7/. MR film thickness uniformity can be improved by 60% by synchronizing the shutter activation with the substrate table. The profile of the photoresist for the read trackwidth definition is affected by initial exposure dose and post expose bake temperature. The use of mass-spectrometric and optical emission endpoint detection methods during ion beam etching of the MR layers allows a precise determination of the stopping point without overmilling into the layer underneath.