Paper
29 March 1999 High-speed interferometric aluminum disk blank tester
Author Affiliations +
Abstract
Demand for faster disk drives with bigger storage capacity calls for higher quality of aluminum disks used in their production. Accordingly, decreasing tolerances on disk flatness and tighter specifications on defect presence (pockets) must be met by aluminum bland suppliers. At the same time volume of production is growing requiring automated quality control at high speed. Veeco Process Metrology has developed high performance automated 95 mm aluminum blank disk tester based on Twymann-Green interferometer working a wavelength of 10.6 micrometer. It is a fully automated tool for high volume production with throughput of one disk per second. Lateral resolution of 0.6 mm in the disk plane allows flatness and shape testing as well as pocket detection. The use of long wavelength makes interferometer insensitive to environmental vibrations and dust. Vertical accuracy of instrument is 300 nm (PV) and repeatability is 130 nm (RMS). In this paper we present technical design issues and metrological capabilities of the device. The interferometer is supplied with new automated analysis software which automatically detects defects on the disk surface (pockets) as small as 0.5 micrometer in depth and performs shape categorization.
© (1999) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Artur G. Olszak, Ken Stumpe, Raymond M. Copenhaver, and George Z. Angeli "High-speed interferometric aluminum disk blank tester", Proc. SPIE 3619, Surface Characterization for Computer Disks, Wafers, and Flat Panel Displays, (29 March 1999); https://doi.org/10.1117/12.343703
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KEYWORDS
Interferometers

Mirrors

Aluminum

Zernike polynomials

Data acquisition

Metrology

Beam splitters

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