Abstract: Apparatus for inspecting the surface of a sample includes a wide scanning interferometer, which is used to locate defects, or anomalies in the surface, and a narrow scanning interferometer, which is used to develop profiles of individual defects found by the narrow scanning interferometer. The sample may be driven in rotation about an axis, while the interferometers are independently moved radially to the axis.

Abstract: A disk texturing process uses a single pulsed laser to texture disks within a first group, which are carried through the texturing process on a first spindle assembly, and from a second group, which are carried through the texturing process on a second spindle assembly. Preferably, disks from the first group are textured alternately with disks in the second group. A first level of least one texturing parameter is stored for use only as the process is applied to disks from the first group, while a second level of the same texturing parameter is stored for use only as the process is applied to disks from the second group. These levels may be derived from measurements of textured spots made with interferometric devices forming portions of a texturing station.

Abstract: An interferometer forms a pair of projected sub-beams by decomposing a single coherent, linearly-polarized beam. These sub-beams are focussed by an objective lens onto a pair of test spots on a test surface. The reflections of these sub-beams are recombined to form an elliptically polarized return beam, which is broken into return sub-beams of opposing polarities in a polarizing beam splitter. The intensities of these return sub-beams are used to calculate a difference in height between the two test spots. When these test spots are aligned along a path of relative motion with the test surface, the resulting differences in height are added to form an accumulative profile of the test surface.

Abstract: An interferometer is used to locate and examine defects in a test surface of a test specimen. Defects are first located as the test surface is driven past the objective of the interferometer at a constant speed, with a darkfield interferogram being examined as it flows across a row of CCD elements. During this process, the location of each defect is stored. Next, the test specimen is sequentially moved into the locations at which static measurements are made using an area array of CCD elements. During these measurements, the phase angle relationship of the interferometer is varied so that heights of surface segments may be calculated. If some to these segments are located more than a quarter wave length of the interferometer light source from the surface at which the darkfield is established, a process is used to perform height corrections for segments within transition boundaries.

Abstract: A glide height tester for inspecting a surface of a spinning magnetic disk includes a glide plate, which is mounted to pivot above the disk surface. A reflective surface fastened to the glide plate is imaged by interferometric apparatus which produces a calculated output indicating a first angle of the glide plate. The interferometric apparatus includes a Wollaston prism, which can be rotated 90-degrees to provide an output indicating a second angle of the glide plate, perpendicular to the first angle.

Abstract: Inspection apparatus for determining the profile of textured spots extending in a pattern along a surface of a magnetic disk includes an interferometer which illuminates first and second, adjacently disposed test spots on the surface. The disk and the interferometer are moved, relative to one another, so that one of the test spots traverses the textured spots in the pattern while the other test spot is moved along a flat portion of the disk surface. In one embodiment, the inspection apparatus is built into the device forming the textured spots, providing feedback controlling the texturing process.