John J Hagen

US Patent:

6882956, Apr 19, 2005

Filed:

Oct 30, 2002

Appl. No.:

10/283884

Inventors:

Carl Francis Sermon - Los Gatos CA, US
Terry Fredrick Banitt - Altura MN, US
John Patrick Hagen - Rochester MN, US
Roger Willard Johnson - Harmony MN, US
Thomas Donald Weller - Rochester MN, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G01B021/00

US Classification:

702168, 702167, 702157, 702166

Abstract:

A lapping plate topography system includes a measuring apparatus for measuring the surface of a lapping plate, and an analysis apparatus for analyzing and presenting the data resulting from such measurements. The measurement apparatus has a non-contacting capacitive probe for measuring a height of the surface of the lapping plate, a rotary arm assembly for moving the probe in an arc over the surface of the lapping plate, and a spindle assembly for rotating the lapping plate about its center. The computer-based analysis apparatus is operable to input from the measurement apparatus the measured height at a plurality of data points on the surface of the lapping plate, calculate Fourier transform harmonic coefficients based on the plurality of measured heights, calculate surface ripple coefficients based on the calculated Fourier transform harmonic coefficients, and output the calculated surface ripple coefficients to an appropriate display device.