Claims
- 1. A method for optically inspecting a sample, the method comprising:
obtaining empirical optical response information describing the diffraction resulting from the interaction of a probe beam with the sample; defining a model for the sample, where the model includes one or more control points, the control points collectively defining the cross-sectional profile of at least one layer within the sample; evaluating the model to obtain calculated optical response information predicting the diffraction resulting from the interaction of the probe beam with the sample; and comparing the empirical optical response information and the calculated optical response information to determine the accuracy of the model.
- 2. A method as recited in claim 1 where at least one control point is a thickness control point and defines a layer thickness within the model.
- 3. A method as recited in claim 1 where at least one control point is a width control point and at least partially defines the width of the cross-sectional profile.
- 4. A method as recited in claim 1 that further comprises the step of using two or more control points to define a curve, the curve defining at least part of the cross- sectional profile.
- 5. A method as described in claim 1 that further comprises:
redefining the model by adjusting one or more control points; reevaluating the model to minimize the difference between the empirical and calculated optical response information.
- 6. A method as described in claim 1 that further comprises:
providing a user with a visual display that includes a representation of the model as well as the empirical and calculated optical response information; accepting interactive commands from the user to modify the model; reevaluating the interactively modified model to obtain calculated optical response information predicting the diffraction resulting from the interaction of the probe beam with the sample; and updating the visual display to reflect the calculated optical response information associated with the modified model.
- 7. A method as recited in claim 6 in which the user interactively modifies the model by changing the position of control points within the model representation.
- 8. A method for optically inspecting a sample, where the sample has a surface that includes a periodically repeating or isolated surface feature, the method comprising:
defining a cross-sectional profile for the surface feature, the shape of the cross- sectional profile defined by a set of two or more control points; defining the thickness of each layer of materials included in the cross-sectional profile; obtaining calculated optical response information predicting the diffraction resulting from the interaction of the probe beam with the sample by evaluating a model including the cross-sectional profile and defined thicknesses; obtaining empirical optical response information describing the diffraction resulting from the interaction of a probe beam with the sample; and comparing the empirical optical response information and the calculated optical response information to determine the accuracy of the model.
- 9. A method as recited in claim 8 where a thickness control points is used to define a thickness of at least one layer.
- 10. A method as recited in claim 8 that further comprises the step of defining the thickness of each layer of materials that is not included in the cross-sectional profile.
- 11. A method as recited in claim 8 where at least one control point is a width control point and at least partially defines the width of the cross-sectional profile.
- 12. A method as recited in claim 8 that further comprises the step of using two or more control points to define a curve, the curve defining at least part of the cross- sectional profile.
- 13. A method as described in claim 8 that further comprises:
redefining the model by adjusting one or more control points; reevaluating the model to minimize the difference between the empirical and calculated optical response information.
- 14. A method as recited in claim 8 where the steps of defining a cross-sectional profile and defining the thickness of each layer of materials included in the cross-sectional profile are performed by moving control points within a graphic representation of the sample.
- 15. A method for optically inspecting a sample, where the sample has a surface that includes a periodically repeating or isolated surface; the method comprising:
interactively choosing the location of one or more control points within a graphic representation of the model to define to a cross-sectional profile for the surface feature; interactively choosing the location of one or more control points within a graphic representation of the model to define the thickness of each layer of materials included in the cross-sectional profile; obtaining calculated optical response information predicting the diffraction resulting from the interaction of the probe beam with the sample by evaluating a model including the cross-sectional profile and defined thicknesses; obtaining empirical optical response information describing the diffraction resulting from the interaction of a probe beam with the sample; and comparing the empirical optical response information and the calculated optical response information to determine the accuracy of the model.
- 16. An apparatus for optically inspecting a sample, where the sample has a surface that includes a periodically repeating or isolated surface; the apparatus comprising:
a first module configured to allow a user to interactively choose the location of one or more control points within a graphic representation of the model to define to a cross-sectional profile for the surface feature; a second module configured to evaluate the model to obtain calculated optical response information predicting the diffraction resulting from the interaction of the probe beam with the subject; and a third module configured to visually portray the difference between the calculated optical response information and empirical optical response information obtained for the subject.
PRIORITY CLAIM
[0001] The present application claims priority to U.S. Provisional Patent Application Serial No. 60/463,791, filed Apr. 18, 2003, the disclosure of which is incorporated in this document by reference.
Provisional Applications (1)
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Number |
Date |
Country |
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60463791 |
Apr 2003 |
US |