Metrology method and apparatus, computer program and lithographic system
AssigneeASML Netherlands B.V.
InventorsThomas THEEUWES, Hugo Augustinus Joseph CRAMER
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Abstract
A method of reconstructing a characteristic of a structure formed on a substrate by a lithographic process, and an associated metrology apparatus. The method includes combining measured values of a first parameter associated with the lithographic process to obtain an estimated value of the first parameter; and reconstructing at least a second parameter associated with the characteristic of the structure using the estimated value of the first parameter and a measurement of the structure. The combining may involve modeling a variation of the first parameter to obtain a parameter model or fingerprint of the first parameter.
Claims20
A method of reconstructing a characteristic of a structure formed on a substrate by a semiconductor manufacturing process, the method comprising:
- combining measured values of a first parameter associated with the semiconductor manufacturing process to obtain an estimated value of the first parameter, wherein the first parameter is associated with a first layer formed during the semiconductor manufacturing process;
- and
- reconstructing at least a second parameter associated with the characteristic of the structure using the estimated value of the first parameter and a measurement of the structure, wherein the second parameter is associated with a second layer formed during the semiconductor manufacturing process, the second layer being formed subsequent to the first layer.
A metrology apparatus comprising:
- an illumination system configured to illuminate with radiation at least a structure produced using a semiconductor manufacturing process on a substrate;
- a detection system configured to detect scattered radiation arising from illumination of the structure;
- and
- a processor operable to at least:
- combine measured values of a first parameter associated with the semiconductor manufacturing process to obtain an estimated value of the first parameter, wherein the first parameter is associated with a first layer formed during the semiconductor manufacturing process;
- and
- reconstruct at least a second parameter associated with the characteristic of the structure using the estimated value of the first parameter and a measurement of the structure, wherein the second parameter is associated with a second layer formed during the semiconductor manufacturing process, the second layer being formed subsequent to the first layer.
A non-transitory computer program product comprising processor readable instructions which, when run on a suitable processor-controlled apparatus, cause the processor:
- controlled apparatus to at least:
- combine measured values of a first parameter associated with a semiconductor manufacturing process to obtain an estimated value of the first parameter, wherein the first parameter is associated with a first layer formed during the semiconductor manufacturing process;
- and
- reconstruct at least a second parameter associated with a characteristic of a structure formed on a substrate by the semiconductor manufacturing process using the estimated value of the first parameter and a measurement of the structure, wherein the second parameter is associated with a second layer formed during the semiconductor manufacturing process, the second layer being formed subsequent to the first layer.
Dependencies are inferred from the claim text.