Wyko, Inc.

Veeco Instruments Inc.

Veeco Corporation

Mark A Schmucker

Brian W Becker

Joanna Schmit

Colin T Farrell

An electronic template representing the topography of a magnetic head being tested and delineating distinct patterns corresponding to particular regions of interest, such as ABS surfaces, is provided in order to limit analysis of the sample's surface to such regions. The outline of the slider positioned within the field of view of an interferometric microscope is identified by measuring the modulation of incident light at each pixel inside and outside the contour of the sample using the loci of perceivable fringe contrast as the criterion for establishing the location of such edges. Once the outline of the slider within the plastic tray is so established, the slider is shifted within the field of view to match the position of the template, thereby automatically achieving a precise alignment of the template with the boundary of the slider. In turn, the template patterns will also be aligned with the regions of interest in the magnetic head and interferometric analysis can be limited to data corresponding to the pixels contained within those patterns. Curve-fitting schemes can be used to facilitate and expedite the process of identifying the contour of the slider sample. In the case of conventional magnetic-head sliders, which are substantially rectangular in plan view, straight-line fitting between a few data points along two adjacent edges is sufficient to find the location of the edges and the corner between them, which in turn can be used is straightforward manner to align the template with the slider.

Alignment of magnetic heads for automatic identification of regions of interest for interferometric measurement

A method of combining height profiles of adjacent sections of a test surface to produce a composite profile of the surface consists of taking successive measurements of adjacent sections of the surface of the test sample by sequentially placing them within the field of view of the instrument and profiling them by phase shifting or vertical scanning. The x-y translation of the microscope between successive measurements from one section to the next adjacent section of the surface being profiled is carried out by overlapping such sections, so that spatial continuity is maintained between measurements. The height data generated for each section are then combined to form a larger image corresponding to the entire surface tested and discontinuities and/or errors introduced by the x-y translation process are corrected by normalizing the overlapping portions to a common reference plane. A plane is fitted through each set of measured heights in the overlapping regions and the tip, tilt and offset of each fitted plane are corrected to produce matching overlapping height data in adjacent sections. The measured height data for the balance of each section are then also corrected by the same difference in tip, tilt and offset to obtain a continuous normalized image.

Method of combining multiple sets of overlapping surface-profile interferometric data to produce a continuous composite map

The process of combining various sets of measured data is carried out by first selecting a section of the test surface and its data set as the starting point and comparing the regions of overlap with adjacent sections of the test sample. All pixels containing an invalid data point in at least one of the data sets of each overlapping region are eliminated from consideration and the remaining valid pixels are counted. Then the adjacent section having an overlapping region with the largest number of valid pixels is selected for combination with the first section and their data sets are fitted according to a predetermined procedure, thereby producing an enlarged composite set of corrected data. The process is then repeated by comparing the overlapping regions of all sets adjacent to the composite section to determine the one having the largest number of pixels with valid data points. That set is then fitted to the existing composite profile to produce a new composite set of corrected data. These steps are repeated until the measured data corresponding to all sections are corrected and combined to produce a single uniform map of the sample surface.

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Tucson, AZ, United States of America

Mark A Schmucker