Effect of etching on the electrical and magnetic properties of writer shield material

Magnetron sputtered permalloy films are treated by wet chemical etchings with acid etchant as well as fluorine based reactive ion etch (RIE). Upon these treatments, the resistivity and coercivity of the permalloy film increase is within 10 %. No significant increase observed with prolonged etching time. The effective magnetization change of the permalloy films are within 5 % post the treatments. Atomic force microscope (AFM) and transmission electron microscope (TEM) are used to study the surface and interface evolution of permalloy film upon etching. The small impact on the electrical and magnetic properties of permalloy films can be correlated with the surface oxide protecting layer formation during the etch. Consequently, sputtered NiFe is a safe material to expose to these etching processes for write pole shield application.