Metrology method, target and substrate
First Claim
Patent Images
1. A method, comprising:
- illuminating at least a first periodic structure of a metrology target with radiation having a first polarization;
illuminating at least a second periodic structure of the metrology target with radiation having a second different polarization, wherein the radiation having the first polarization and the radiation having the second polarization form a single beam spot on the metrology target or form respective beam spots that overlap on the metrology target;
combining radiation diffracted from the first periodic structure with radiation diffracted from the second periodic structure to cause interference;
detecting the combined radiation using a detector; and
determining a parameter of interest from the detected combined radiation.
1 Assignment
0 Petitions
Accused Products
Abstract
A method, involving illuminating at least a first periodic structure of a metrology target with a first radiation beam having a first polarization, illuminating at least a second periodic structure of the metrology target with a second radiation beam having a second different polarization, combining radiation diffracted from the first periodic structure with radiation diffracted from the second periodic structure to cause interference, detecting the combined radiation using a detector, and determining a parameter of interest from the detected combined radiation.
-
Citations
20 Claims
-
1. A method, comprising:
-
illuminating at least a first periodic structure of a metrology target with radiation having a first polarization; illuminating at least a second periodic structure of the metrology target with radiation having a second different polarization, wherein the radiation having the first polarization and the radiation having the second polarization form a single beam spot on the metrology target or form respective beam spots that overlap on the metrology target; combining radiation diffracted from the first periodic structure with radiation diffracted from the second periodic structure to cause interference; detecting the combined radiation using a detector; and determining a parameter of interest from the detected combined radiation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A metrology apparatus comprising:
-
an optical system configured to provide radiation having a first polarization onto at least a first periodic structure of a metrology target and radiation having a second polarization onto at least a second periodic structure of the metrology target, wherein the optical system is configured to provide the radiation having the first polarization and the radiation having the second polarization as a single beam spot on the metrology target or as respective beam spots that overlap on the metrology target; a detector configured to detect radiation from the radiation having the first and second polarizations diffracted by the respective first and second periodic structures, wherein the diffracted radiation from the first and second periodic structures is combined and interferes; and a control system configured to determine a parameter of interest from the detected combined diffracted radiation. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
-
-
18. A non-transitory computer program product comprising machine-readable instructions that, when executed by a computer system, are configured to cause the computer system to at least:
-
enable illumination of at least a first periodic structure of a metrology target with radiation having a first polarization; enable illumination of at least a second periodic structure of the metrology target with radiation having a second different polarization, wherein radiation diffracted from the first periodic structure combines with radiation diffracted from the second periodic structure to cause interference; enable detection of the combined radiation using a detector; and determine a parameter of interest from a value of an intensity difference or ratio determined using the detected combined radiation. - View Dependent Claims (19, 20)
-
Specification