Methods of determining stress in a substrate, control system for controlling a lithographic process, lithographic apparatus and computer program product
AssigneeASML Netherlands B.V.
InventorsRichard Johannes Franciscus VAN HAREN, Leon Paul VAN DIJK, Ilya MALAKHOVSKY, Ronald Henricus Johannes OTTEN
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Abstract
A method and control system for determining stress in a substrate. The method includes determining a measured position difference between a measured position of at least one first feature and a measured position of at least one second feature which have been applied on a substrate, and determining local stress in the substrate from the measured position difference.
Claims20
A method of determining stress in a substrate, the method comprising:
- determining a measured position difference between a measured position of at least one first feature and a measured position of at least one second feature which have been applied on a substrate, wherein the first feature and the second feature are located within a single exposure image field of a lithographic apparatus used to measure the measured positions;
- and
- determining local stress in the substrate from the measured position difference.
A control system for controlling a lithographic process, the control system comprising:
- storage for receiving metrology data comprising a plurality of measured position differences from a plurality of feature pairs, each feature pair being located at a different location on a substrate, and each feature pair comprising a first feature and a second feature;
- and
- a processor configured to at least:
- determine a local stress in the substrate from each of the measured position differences;
- determine a stress fingerprint describing stress variation over the substrate, based on the measured position differences;
- determine in-plane distortion of the substrate from the stress fingerprint;
- and
- determine, using the determined in-plane distortion, a correction for performing a subsequent patterning step on the substrate.
A non-transitory computer program product containing one or more sequences of machine-readable instructions therein, the instructions, upon execution by a computer system, configured to cause the computer system to a least:
- determine a measured position difference between a measured position of at least one first feature and a measured position of at least one second feature which have been applied on a substrate, wherein the first feature and the second feature are located within a single exposure image field of a lithographic apparatus used to measure the measured positions;
- and
- determine local stress in the substrate from the measured position difference.
Dependencies are inferred from the claim text.