Onto Innovation Inc.
BEAMSPLITTER BASED ELLIPSOMETER FOCUSING SYSTEM
Last updated:
Abstract:
An ellipsometer includes a focusing system that uses an image of the measurement spot to determine a best focal position for the ellipsometer. The focus signal is produced by splitting off the ellipsometer measurement spot before the signal is analyzed by a polarizer thereby avoiding imagining the spot with a modulated intensity. The focus signal is imaged on a sensor array and based on the position of the spot on the sensor array, the focal position of the ellipsometer may be determined. A single image may be used to determine the focal position of the ellipsometer permitting a real time focus position measurement.
Status:
Application
Type:
Utility
Filling date:
1 Oct 2019
Issue date:
1 Apr 2021