Determination of stack difference and correction using stack difference
AssigneeASML Netherlands B.V.
InventorsArie Jeffrey Den Boef, Kaustuve Bhattacharyya
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Abstract
A method including: obtaining a measurement of a metrology target on a substrate processed using a patterning process, the measurement having been obtained using measurement radiation; and deriving a parameter of interest of the patterning process from the measurement, wherein the parameter of interest is corrected by a stack difference parameter, the stack difference parameter representing an un-designed difference in physical configuration between adjacent periodic structures of the target or between the metrology target and another adjacent target on the substrate.
Claims20
A method comprising:
- obtaining first values of a stack difference parameter and second values of a stack difference parameter for a plurality of adjacent periodic structures of a measurement target or for a plurality of adjacent measurement targets, the first values of the stack difference parameter and second values of the stack difference parameter having been obtained with, respectively, measurements using first measurement radiation and second measurement radiation and the stack difference parameter representing an un-designed difference in physical configuration between adjacent periodic structures of a measurement target or between adjacent measurement targets on a substrate;
- obtaining first values of a target parameter and second values of the target parameter for the plurality of adjacent periodic structures of the measurement target or for the plurality of adjacent measurement targets, the first values of the target parameter and second values of the target parameter having been obtained with, respectively, the first measurement radiation and the second measurement radiation and wherein the target parameter value comprises a part which is independent of the un-designed difference in physical configuration, and a part due to the un-designed difference in physical configuration;
- and
- determining a relationship function describing a relationship between the first and/or second values of stack difference parameter and the difference of the first values of the target parameter and the second values of the target parameter;
- and
- determining a part of a target parameter value which is independent of the un-designed difference in physical configuration from the relationship function.
A non-transitory computer program product comprising machine-readable instructions therein that, when executed by a processor system, are configured to cause the processor system to at least:
- obtain first values of a stack difference parameter and second values of a stack difference parameter for a plurality of adjacent periodic structures of a measurement target or for a plurality of adjacent measurement targets, the first values of the stack difference parameter and second values of the stack difference parameter having been obtained with, respectively, measurements using first measurement radiation and second measurement radiation and the stack difference parameter representing an un-designed difference in physical configuration between adjacent periodic structures of a measurement target or between adjacent measurement targets on a substrate;
- obtaining first values of a target parameter and second values of the target parameter for the plurality of adjacent periodic structures of the measurement target or for the plurality of adjacent measurement targets, the first values of the target parameter and second values of the target parameter having been obtained with, respectively, the first measurement radiation and the second measurement radiation and wherein the target parameter value comprises a part which is independent of the un-designed difference in physical configuration, and a part due to the un-designed difference in physical configuration;
- and
- determining a relationship function describing a relationship between the first and/or second values of stack difference parameter and the difference of the first values of the target parameter and the second values of the target parameter;
- and determining a part of a target parameter value which is independent of the un-designed difference in physical configuration from the relationship function.
Dependencies are inferred from the claim text.