Measuring apparatus
AssigneeMetryx Limited
InventorsRobert John Wilby, Adrian Kiermasz
Life of this patent
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Abstract
Measuring apparatus for monitoring the position of the center of mass of a semiconductor wafer is disclosed. The apparatus includes a wafer support (14) with a ledge for supporting an edge of a wafer (2) when it is lifted at a detection point by a probe (16). The probe (16) is connected to a force sensor (18) which senses a force due to a moment of the wafer about a fulcrum (4) on the wafer support (14). Moment measurements are taken at a plurality of detection points and a processing unit calculates the position of the center of mass from the moment measurements. Changes in wafer mass distribution (e.g. due to faulty treatment steps) which cause movement of the center of mass can be detected.
Claims12
Apparatus for monitoring a fabrication process of a semiconductor wafer, the apparatus having:
- a pivot element for providing a plurality of fulcrums about which the wafer is pivotable;
- and
- a weighing unit arranged to measure a force at each of a plurality of detection points on the wafer, the force at each detection point being due to a moment of the wafer about a respective fulcrum.
Dependencies are inferred from the claim text.