Patent ID: 8427929
Filing Date: 2013-04-23
Classification: G01R,G11B

Abstract:
1. A method of determining a quality parameter of a write pole of a write head using an optical metrology device having an optical resolution limit expressed by a point spread function, the method comprising: producing a polarized light beam with a polarization state; causing the polarized light beam to be incident on and reflected by the write pole, the write pole being smaller than the optical resolution limit of the optical metrology device so that a light intensity from the write pole that is detected by the optical metrology device is determined by the point spread function; producing a magnetization of the write pole, reflected light from the write pole having an altered polarization state that is different than the polarization state of the polarized light beam, the write pole being smaller than the optical resolution limit of the optical metrology device; analyzing the reflected light to transform the altered polarization state into an intensity; detecting the intensity of the analyzed light; generating an intensity value based on the intensity distributed over the point spread function; determining the quality parameter of the write pole based on the intensity value; and storing in memory the quality parameter.