Narrow top poles for inductive magnetic heads, masks and processes for making the same

A mask forms a top magnetic pole piece of an inductive magnetic head having a layer of insulating material over a hill region and a gap region on a wafer. The mask comprises a layer of photolithographic material on the insulating material and a waste region of the wafer and includes a first aperture exposing the insulating material to define a paddle region of the pole piece over the hill region and a trench over the gap region. A second aperture is connected to the first aperture to define a feeder region over the waste region that funnels solvent to and through the trench and establishes laminar flow of solvent through the trench. Solvent is admitted into the feeder region for laminar flow through the trench region to form the mask and expose a surface of the layer of insulating material in the paddle and trench regions of the mask. The top pole piece defines a gap at an air bearing surface of the head having an average gap width not greater than 1.0 microns with a standard deviation of the average gap widths no more than 0.07 for heads formed on a single wafer and no more than 0.12 for heads formed on different wafers.