Apparatus for designing an optical metrology system optimized with signal criteria
AssigneeTokyo Electron Limited
InventorsXinkang Tian, Manuel Madriaga, Ching-Ling Meng, Mihail Mihalov
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Abstract
Provided is an apparatus for designing an optical metrology system for measuring structures on a workpiece wherein the optical metrology system is configured to meet one or more signal criteria. The design of the optical metrology system is optimized by using collected signal data in comparison to set one or more signal criteria. In one embodiment, the optical metrology system is used for stand alone systems. In another embodiment, the optical metrology system is integrated with a fabrication cluster in semiconductor manufacturing.
Claims20
An apparatus for designing an optical metrology system, the optical metrology system measuring structures on a workpiece, the optical metrology system configured to meet one or more signal criteria, the apparatus comprising:
- an optical metrology signal model for an optical metrology system, the optical metrology system designed to measure structures on a workpiece and having an optical path including optical components, the optical metrology signal model configured based on an initial design of the optical metrology system, the initial design based on a range of determined capabilities of the optical metrology system, and configured to store for each optical component in the optical path a corresponding function that determines output signal characteristics based on input signal characteristics;
- an operating data collector configured to collect signal data from input sources and associate the collected signal data to a criterion of the one or more signal criteria;
- and
- a model analyzer configured to develop and store an initial design of the optical metrology system, compare calculated one or more signal criteria using the collected signal data with one or more signal criteria set from input sources, and if the calculated one or more signal criteria do not match the set one or more signal criteria, to determine and implement design modifications of the optical metrology system, and iterate an operation for updating the optical metrology signal model with the design modifications, collecting signal data with the operating data collector, and performing the comparison of collected signal data to the set one or more signal criteria until the calculated one or more signal criteria match the set one or more signal criteria.
The apparatus of claim l wherein the one or more signal criteria comprise a signal-to-noise ratio (SNR) criterion and/or repeatability of measurement criterion.
The apparatus for claim l wherein the workpiece is a wafer in a semiconductor application and wherein the optical metrology system is integrated in a fabrication cluster or the optical metrology system is part of a standalone metrology device.
Dependencies are inferred from the claim text.