| 摘要 |
A method of measuring a circular wafer in which the surface (A) of the wafer is divided into a plurality (N) of concentric rings of constant surface area (A/N), and at least one measurement point (P<SUB>n</SUB>) is positioned on each ring. The outside radius (R<SUB>n</SUB>) of each ring is calculated using the following formula: <?in-line-formulae description="In-line Formulae" end="lead"?>R<SUB>n</SUB>=R<SUB>N</SUB>(n/N)<SUP>1/2</SUP><?in-line-formulae description="In-line Formulae" end="tail"?> in which n varies from 1 to N. In this manner, rings are obtained that become narrower with increasing distance from the center of the wafer, thereby providing measurement points that become closer together towards the edge of the wafer, and covering only the useful zone of the wafer to be measured, guaranteeing that no measurement is made in an annular exclusion zone.
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