Abstract: A method for measuring recession in a wafer undergoing an asymmetrical ion mill process. The method includes the formation of first and second reference features and possibly a dummy feature. The reference features are constructed such that the location of the midpoint between them is unaffected by the asymmetrical ion mill. By measuring the distance between a portion of the dummy feature and the midpoint between the reference features, the amount of recession of the dummy feature can be measured. The measurement can be used to calculate the relative location of the flare to the read sensor rear edge through overlay information. By keeping the angles of the sides of the features steep (ie. nearly parallel with the direction in which the ion mill is asymmetrical) the amount of material consumed on each of the reference features is substantially equal and the midpoint between the reference features is substantially stationary.

Abstract: A method of making and using thin film calibration features is described. To fabricate a calibration standard according to the invention raised features are first formed from an electrically conductive material with a selected atomic number. A conformal thin film layer is deposited over the exposed sidewalls of the raised features. The sidewall material is selected to have a different atomic number and is preferably an nonconductive such as silicon dioxide or alumina. After the nonconductive material deposition, a controlled directional RIE process is used to remove the insulator layer deposited on the top and bottom surface of the lines and trenches. The remaining voids between the sidewalls of the raised features are filled with a conductive material. The wafer is then planarized with chemical mechanical planarization (CMP) to expose the nonconductive sidewall material on the surface. The nonconductive sidewall material will be fine lines embedded in conductive material.

Abstract: A method is provided of smoothing the perturbations on a surface, in particular the surface of a magnetic head slider, the method comprising several steps. At least one air-bearing surface to be smoothed is exposed to an ion species generated from a defined source to form a beam of incident radiation. The beam has a linear axis emanating from the source and thus forms an angle of incident radiation with respect to the surface to be smoothed. The at least one surface is smoothed by exposing the surface(s) to be smoothed to the beam of incident radiation, where the angle of incident radiation is less than 90° relative to a vertical axis drawn perpendicular to the surface to be smoothed. To make a corrosion resistant magnetic head slider, the method further comprises coating the smoothed surface with a layer of amorphous carbon.