Method of reducing main pole corrosion during aluminum oxide etch

摘要

A method of removing an alumina layer around a main pole layer during perpendicular magnetic recording head fabrication is disclosed. The alumina etch sequence includes immersing a substrate in a series of aqueous solutions purged with an inert gas to remove oxygen thereby avoiding corrosion of the main pole. Initially, the substrate is soaked and heated in deionized (DI) water. Once heated, the substrate is immersed in an etching bath at about 80� C. and pH 10.5. Bath chemistry is preferably based on Na2CO3 and NaHCO3, and N2 purging improves etch uniformity and reduces residue. Thereafter, the substrate is rinsed in a second DI water bath between room temperature and 80� C., and finally subjected to a quick dump rinse before drying. Inert gas, preferably N2, may be introduced into the aqueous solutions through a purge board having a plurality of openings and positioned proximate to the bottom of a bath container.