Method of calibrating effects of multi-AOI-system for easy changing angles-of-incidence in ellipsometers and the like
First Claim
1. A method of accurately evaluating parameters in parameterized equations in a mathematical model of a system of spatially separated input and output electromagnetic beam intercepting angle-of-incidence changing system elements, said parameterized equations enabling, when parameters therein are properly evaluated, independent calculation of retardation entered by each of said input output electromagnetic beam intercepting angle-of-incidence changing system elements between orthogonal components of a beam of electromagnetic radiation caused to pass through said input and output electromagnetic beam intercepting angle-of-incidence changing system elements, at least one of said input and output electromagnetic beam intercepting angle-of-incidence changing system elements being birefringent, said method comprising, in a functional order, the steps of:
- a. providing spatially separated input and output electromagnetic beam intercepting angle-of-incidence changing system elements, at least one of said input and output electromagnetic beam intercepting angle-of-incidence changing system elements demonstrating birefringence when a beam of electromagnetic radiation is caused to pass therethrough, there being a means for supporting a sample system positioned between said input and output electromagnetic beam intercepting angle-of-incidence changing system elements;
b. positioning an ellipsometer system source of electromagnetic radiation and an ellipsometer system detector system such that in use a beam of electromagnetic radiation provided by said source of electromagnetic radiation is caused to pass through said input electromagnetic beam intercepting angle-of-incidence changing system element, interact with a sample system, in a plane of incidence thereto, and exit through said output electromagnetic beam intercepting angle-of-incidence changing system element and enter said detector system;
c. providing a sample system to said means for supporting a sample system, the composition of said sample system being sufficiently well known so that retardance entered thereby to a polarized beam of electromagnetic radiation of a given wavelength, which is caused to interact with said sample system in a plane of incidence thereto, can be accurately modeled mathematically by a parameterized equation which, when parameters therein are properly evaluated, allows calculation of retardance entered thereby between orthogonal components of a beam of electromagnetic radiation caused to interact therewith in a plane of incidence thereto;
d. in combination with the other steps, providing a mathematical model for said ellipsometer system and said input and output electromagnetic beam intercepting angle-of-incidence changing system elements, in which electromagnetic radiation is caused to pass through said input and output electromagnetic beam intercepting angle-of-incidence changing system elements, and said sample system, comprising separate parameterized equations for independently calculating retardance entered between orthogonal components of a beam of electromagnetic radiation caused to pass through each of said input and output electromagnetic beam intercepting angle-of-incidence changing system elements, and interact with said sample system in a plane of incidence thereto;
such that where parameters in said mathematical model are properly evaluated, retardance entered between orthogonal components of a beam of electromagnetic which passes through each of said input and output electromagnetic beam intercepting angle-of-incidence changing system elements, and interacts with said sample system in a plane of incidence thereto can be independently calculated from said parameterized equations;
e. obtaining a spectroscopic set of ellipsometric data with said parameterizable sample system present on the means for supporting a sample system, utilizing a beam of electromagnetic radiation provided by said source of electromagnetic radiation, said beam of electromagnetic radiation being caused to pass through said input electromagnetic beam intercepting angle-of-incidence changing system element, interact with said parameterizable sample system in a plane of incidence thereto, and exit through said output electromagnetic beam intercepting angle-of-incidence changing system element and enter said detector system, such that a physical concrete and tangible transformation of said electromagnetic beam from one state to another is caused by interaction thereof with said parameterizable sample system and said input and output electromagnetic beam intercepting angle-of-incidence changing system elements;
f. by utilizing said mathematical model provided in step d. and said spectroscopic set of ellipsometric data obtained in step e., simultaneously evaluating parameters in said mathematical model parameterized equations for independently calculating retardance entered between orthogonal components in a beam of electromagnetic radiation caused to pass through said input electromagnetic beam intercepting angle-of-incidence changing system element, interact with said sample system in a plane of incidence thereto, and exit through said output electromagnetic beam intercepting angle-of-incidence changing system element;
to the end that application of said parameterized equations for each of said input and output electromagnetic beam intercepting angle-of-incidence changing system elements and sample system for which values of parameters therein have been determined in step f., enables independent calculation of retardance entered between orthogonal components of a beam of electromagnetic radiation by each of said input and output electromagnetic beam intercepting angle-of-incidence changing system elements, and said sample system, at given wavelengths in said spectroscopic set of ellipsometric data, said calculated retardance values for each of said input electromagnetic beam intercepting angle-of-incidence changing system element, output electromagnetic beam intercepting angle-of-incidence changing system element and sample system being essentially uncorrelated;
said result being useful and the direct result of a physical concrete and tangible transformation of said electromagnetic beam from one state to another caused by interaction thereof with said parameterizable sample system and said input and output electromagnetic beam intercepting angle-of-incidence changing system elements.
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Abstract
Disclosed is a system for enabling easy sequential setting of different Angles-of-Incidence of a beam of electromagnetic radiation to a surface of a sample system involving regression based methodology for evaluating and compensating the effects of the presence electromagnetic beam intercepting angle-of-incidence changing systems, including where desired, parameterization of calibration parameters.
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Citations
32 Claims
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1. A method of accurately evaluating parameters in parameterized equations in a mathematical model of a system of spatially separated input and output electromagnetic beam intercepting angle-of-incidence changing system elements, said parameterized equations enabling, when parameters therein are properly evaluated, independent calculation of retardation entered by each of said input output electromagnetic beam intercepting angle-of-incidence changing system elements between orthogonal components of a beam of electromagnetic radiation caused to pass through said input and output electromagnetic beam intercepting angle-of-incidence changing system elements, at least one of said input and output electromagnetic beam intercepting angle-of-incidence changing system elements being birefringent, said method comprising, in a functional order, the steps of:
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a. providing spatially separated input and output electromagnetic beam intercepting angle-of-incidence changing system elements, at least one of said input and output electromagnetic beam intercepting angle-of-incidence changing system elements demonstrating birefringence when a beam of electromagnetic radiation is caused to pass therethrough, there being a means for supporting a sample system positioned between said input and output electromagnetic beam intercepting angle-of-incidence changing system elements; b. positioning an ellipsometer system source of electromagnetic radiation and an ellipsometer system detector system such that in use a beam of electromagnetic radiation provided by said source of electromagnetic radiation is caused to pass through said input electromagnetic beam intercepting angle-of-incidence changing system element, interact with a sample system, in a plane of incidence thereto, and exit through said output electromagnetic beam intercepting angle-of-incidence changing system element and enter said detector system; c. providing a sample system to said means for supporting a sample system, the composition of said sample system being sufficiently well known so that retardance entered thereby to a polarized beam of electromagnetic radiation of a given wavelength, which is caused to interact with said sample system in a plane of incidence thereto, can be accurately modeled mathematically by a parameterized equation which, when parameters therein are properly evaluated, allows calculation of retardance entered thereby between orthogonal components of a beam of electromagnetic radiation caused to interact therewith in a plane of incidence thereto; d. in combination with the other steps, providing a mathematical model for said ellipsometer system and said input and output electromagnetic beam intercepting angle-of-incidence changing system elements, in which electromagnetic radiation is caused to pass through said input and output electromagnetic beam intercepting angle-of-incidence changing system elements, and said sample system, comprising separate parameterized equations for independently calculating retardance entered between orthogonal components of a beam of electromagnetic radiation caused to pass through each of said input and output electromagnetic beam intercepting angle-of-incidence changing system elements, and interact with said sample system in a plane of incidence thereto;
such that where parameters in said mathematical model are properly evaluated, retardance entered between orthogonal components of a beam of electromagnetic which passes through each of said input and output electromagnetic beam intercepting angle-of-incidence changing system elements, and interacts with said sample system in a plane of incidence thereto can be independently calculated from said parameterized equations;e. obtaining a spectroscopic set of ellipsometric data with said parameterizable sample system present on the means for supporting a sample system, utilizing a beam of electromagnetic radiation provided by said source of electromagnetic radiation, said beam of electromagnetic radiation being caused to pass through said input electromagnetic beam intercepting angle-of-incidence changing system element, interact with said parameterizable sample system in a plane of incidence thereto, and exit through said output electromagnetic beam intercepting angle-of-incidence changing system element and enter said detector system, such that a physical concrete and tangible transformation of said electromagnetic beam from one state to another is caused by interaction thereof with said parameterizable sample system and said input and output electromagnetic beam intercepting angle-of-incidence changing system elements; f. by utilizing said mathematical model provided in step d. and said spectroscopic set of ellipsometric data obtained in step e., simultaneously evaluating parameters in said mathematical model parameterized equations for independently calculating retardance entered between orthogonal components in a beam of electromagnetic radiation caused to pass through said input electromagnetic beam intercepting angle-of-incidence changing system element, interact with said sample system in a plane of incidence thereto, and exit through said output electromagnetic beam intercepting angle-of-incidence changing system element; to the end that application of said parameterized equations for each of said input and output electromagnetic beam intercepting angle-of-incidence changing system elements and sample system for which values of parameters therein have been determined in step f., enables independent calculation of retardance entered between orthogonal components of a beam of electromagnetic radiation by each of said input and output electromagnetic beam intercepting angle-of-incidence changing system elements, and said sample system, at given wavelengths in said spectroscopic set of ellipsometric data, said calculated retardance values for each of said input electromagnetic beam intercepting angle-of-incidence changing system element, output electromagnetic beam intercepting angle-of-incidence changing system element and sample system being essentially uncorrelated; said result being useful and the direct result of a physical concrete and tangible transformation of said electromagnetic beam from one state to another caused by interaction thereof with said parameterizable sample system and said input and output electromagnetic beam intercepting angle-of-incidence changing system elements. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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11. A method of accurately evaluating parameters in parameterized equations in a mathematical model of a system of spatially separated input and output electromagnetic beam intercepting angle-of-incidence changing system elements, said parameterized equations enabling, when parameters therein are properly evaluated, independent calculation of retardation entered by each of said input electromagnetic beam intercepting angle-of-incidence changing system element and said output electromagnetic beam intercepting angle-of-incidence changing system to at least one orthogonal component(s) of a beam of electromagnetic radiation caused to pass through said input and output electromagnetic beam intercepting angle-of-incidence changing system elements, at least one of said input and output electromagnetic beam intercepting angle-of-incidence changing systems being birefringent, said method comprising, in a functional order, the steps of:
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a. providing spatially separated input and output electromagnetic beam intercepting angle-of-incidence changing systems, at least one of said input and output electromagnetic beam intercepting angle-of-incidence changing system elements demonstrating birefringence when a beam of electromagnetic radiation is caused to pass therethrough, there being a means for supporting a sample system positioned between said input and output electromagnetic beam intercepting angle-of-incidence changing system elements; b. positioning an ellipsometer system source of electromagnetic radiation and an ellipsometer system detector system such that in use a beam of electromagnetic radiation provided by said source of electromagnetic radiation is caused to pass through said input electromagnetic beam intercepting angle-of-incidence changing system element, interact with a sample system, in a plane of incidence thereto, and exit through said output electromagnetic beam intercepting angle-of-incidence changing system element and enter said detector system; c. providing a sample system to said means for supporting a sample system; d. in conjunction with other steps, providing a mathematical model for said ellipsometer system and said input and output electromagnetic beam intercepting angle-of-incidence changing system elements and said sample system, comprising, for each of said input electromagnetic beam intercepting angle-of-incidence changing system and said output electromagnetic beam intercepting angle-of-incidence changing system element, separate parameterized equations for retardance for at least one orthogonal component in a beam of electromagnetic radiation provided by said source of electromagnetic radiation, which orthogonal component is directed out-of-a-plane of incidence which said electromagnetic beam makes with said sample system in use, such that retardation entered to said out-of-plane orthogonal component can, for each of said input and output electromagnetic beam intercepting angle-of-incidence changing system, be separately calculated by said parameterized equations, where parameters in said parameterized equations are properly evaluated; e. obtaining a spectroscopic set of ellipsometric data with said sample system present on the means for supporting a sample system, utilizing a beam of electromagnetic radiation provided by said source of electromagnetic radiation, said beam of electromagnetic radiation being caused to pass through said input electromagnetic beam intercepting angle-of-incidence changing system element, interact with said sample system in a plane of incidence thereto, and exit through said output electromagnetic beam intercepting angle-of-incidence changing system, and enter said detector system, such that a physical concrete and tangible transformation of said electromagnetic beam from one state to another is caused by interaction thereof with said parameterizable sample system and said input and output electromagnetic beam intercepting angle-of-incidence changing system elements; f. by utilizing said mathematical model provided in step d. and said spectroscopic set of ellipsometric data obtained in step e., simultaneously evaluating sample system DELTA'"'"'S in correlation with in-plane orthogonal component retardation entered to said beam of electromagnetic radiation by each of said input and output electromagnetic beam intercepting angle-of-incidence changing system elements, and parameters in said mathematical model parameterized equations for out-of-plane retardance entered by said input electromagnetic beam intercepting angle-of-incidence changing system element and said output electromagnetic beam intercepting angle-of-incidence changing system element to a beam of electromagnetic radiation caused to pass through said input electromagnetic beam intercepting angle-of-incidence changing system, interact with said sample system in said plane of incidence thereto, and exit through said output electromagnetic beam intercepting angle-of-incidence changing system element; to the end that application of said parameterized equations for out-of-plane retardance entered by said input electromagnetic beam intercepting angle-of-incidence changing system element and said output electromagnetic beam intercepting angle-of-incidence changing system element to a beam of electromagnetic radiation caused to pass through said input electromagnetic beam intercepting angle-of-incidence changing system, interact with said sample system in said plane of incidence thereto, and exit through said output electromagnetic beam intercepting angle-of-incidence changing system element, for which values of parameters therein are determined in step f., enables independent calculation of retardance entered to said out-of-plane orthogonal component of a beam of electromagnetic radiation by each of said input and output electromagnetic beam intercepting angle-of-incidence changing systems; said result being useful and the direct result of a physical concrete and tangible transformation of said electromagnetic beam from one state to another caused by interaction thereof with said parameterizable sample system and said input and output electromagnetic beam intercepting angle-of-incidence changing system elements. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
to the end that application of said parameterized equations for each of said input electromagnetic beam intercepting angle-of-incidence changing system element, output electromagnetic beam intercepting angle-of-incidence changing system and sample system for which values of parameters therein have been determined in step h., enables independent calculation of retardance entered to both said out-of-plane and said in-plane orthogonal components of a beam of electromagnetic radiation by each of said input and output electromagnetic beam intercepting angle-of-incidence changing systems, and retardance entered by said sample system to said in-plane orthogonal component of said beam of electromagnetic radiation, at given wavelengths in said spectroscopic set of ellipsometric data.
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14. A method of accurately evaluating parameters in parameterized equations in a mathematical model of a system of spatially separated input and output electromagnetic beam intercepting angle-of-incidence changing system elements, as in claim 13, in which the step h. simultaneous evaluation of parameters in said mathematical model parameterized equations for said in-plane retardation entered by said parameterized sample system, and said input and output electromagnetic beam intercepting angle-of-incidence changing system elements, is achieved by a square error reducing mathematical curve fitting procedure.
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15. A method of accurately evaluating parameters in parameterized equations in a mathematical model of a system of spatially separated input and output electromagnetic beam intercepting angle-of-incidence changing system elements, as in claim 11, which further comprises the steps of:
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g. removing the sample system from said means for supporting a sample system positioned between said input and output electromagnetic beam intercepting angle-of-incidence changing systems, and positioning in its place an alternative sample system for which a parameterized equation for calculating in-plane retardance entered to a beam of electromagnetic radiation, can be provided; h. providing a parameterized equation for retardation entered in-plane to an orthogonal component of a beam of electromagnetic radiation by said alternative sample system which is then positioned on said means for supporting a sample system positioned between said input and output electromagnetic beam intercepting angle-of-incidence changing system elements, and as necessary similar parameterized equations for retardation entered by each of said input and output electromagnetic beam intercepting angle-of-incidence changing systems to the in-plane orthogonal component of a beam of electromagnetic radiation; i. obtaining a spectroscopic set of ellipsometric data with said alternative sample system present on the means for supporting a sample system, utilizing a beam of electromagnetic radiation provided by said source of electromagnetic radiation, said beam of electromagnetic radiation being caused to pass through said input electromagnetic beam intercepting angle-of-incidence changing system element, interact with said alternative sample system in a plane of incidence thereto, and exit through said output electromagnetic beam intercepting angle-of-incidence changing system element and enter said detector system; j. by utilizing said parameterized mathematical model for said input electromagnetic beam intercepting angle-of-incidence changing system element, and said output electromagnetic beam intercepting angle-of-incidence changing system element, provided in step d. and said parameterized equation for retardation entered by said alternative sample system provided in step h., and said spectroscopic set of ellipsometric data obtained in step i., simultaneously evaluating parameters in said mathematical model parameterized equations for independent calculation of retardance entered to an in-plane orthogonal component of said beam of electromagnetic radiation by said alternative sample system and by said input electromagnetic beam intercepting angle-of-incidence changing system element and said output electromagnetic beam intercepting angle-of-incidence changing system element, such that correlation between DELTA'"'"'S entered by said alternative sample system and retardance entered by said in-plane orthogonal component of said beam of electromagnetic radiation, by each of said input and output electromagnetic beam intercepting angle-of-incidence changing system elements, at given wavelengths in said spectroscopic set of ellipsometric data, is broken, said simultaneous evaluation optionally providing new values for parameters in parameterized equations for calculation of retardance entered in said out-of-plane components of said beam of electromagnetic radiation by each of said input electromagnetic beam intercepting angle-of-incidence changing system element and said output electromagnetic beam intercepting angle-of-incidence changing system element; to the end that application of said parameterized equations for each of said input electromagnetic beam intercepting angle-of-incidence changing system element, output electromagnetic beam intercepting angle-of-incidence changing system and alternative sample system, for each of which values of parameters therein have been determined in step j., enables independent calculation of retardance entered to both said out-of-plane and said in-plane orthogonal components of a beam of electromagnetic radiation by each of said input electromagnetic beam intercepting angle-of-incidence changing system and said output electromagnetic beam intercepting angle-of-incidence changing system element, and retardance entered by said alternative sample system to said in-plane orthogonal component of a beam of electromagnetic radiation, at given wavelengths in said spectroscopic set of ellipsometric data.
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16. A method of accurately evaluating parameters in parameterized equations in a mathematical model of a system of spatially separated input and output electromagnetic beam intercepting angle-of-incidence changing system elements as in claim 15, in which the step j. simultaneous evaluation of parameters in said mathematical model parameterized equations for said in-plane retardation entered by said parameterized sample system, and at least said in-plane input electromagnetic beam intercepting angle-of-incidence changing system element and output electromagnetic beam intercepting angle-of-incidence changing system element, is achieved by a square error reducing mathematical curve fitting procedure.
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17. A method of accurately evaluating parameters in parameterized equations in a mathematical model of a system of spatially separated input and output electromagnetic beam intercepting angle-of-incidence changing system elements as in claim 11, in which the step b. positioning of an ellipsometer system source of electromagnetic radiation and an ellipsometer system detector system includes positioning a polarizer between said source of electromagnetic radiation and said input electromagnetic beam intercepting angle-of-incidence changing system, and the positioning of an analyzer between said output electromagnetic beam intercepting angle-of-incidence changing system and said detector system, and in which the step e. obtaining of a spectroscopic set of ellipsometric data involves obtaining data at a plurality of settings of at least one component selected from the group consisting of:
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said analyzer; and said polarizer.
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18. A method of accurately evaluating parameters in parameterized equations in a mathematical model of a system of spatially separated input and output electromagnetic beam intercepting angle-of-incidence changing system elements, as in claim 15, in which the step b. positioning of an ellipsometer system source of electromagnetic radiation and an ellipsometer system detector system includes positioning a polarizer between said source of electromagnetic radiation and said input electromagnetic beam intercepting angle-of-incidence changing system, and the positioning of an analyzer between said output electromagnetic beam intercepting angle-of-incidence changing system and said detector system, and in which the step i. obtaining of a spectroscopic set of ellipsometric data involves obtaining data at a plurality of settings of at least one component selected from the group consisting of:
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said analyzer; and said polarizer.
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19. A method of accurately evaluating parameters in parameterized equations in a mathematical model of a system of spatially separated input and output electromagnetic beam intercepting angle-of-incidence changing system elements as in claim 11, in which the step of providing separate parameterized mathematical model parameterized equations for enabling independent calculation of out-of-plane retardance entered by said input and said output electromagnetic beam intercepting angle-of-incidence changing system elements to said beam of electromagnetic radiation caused to pass through said input and output electromagnetic beam intercepting angle-of-incidence changing system elements, involves parameterized equations having a form selected from the group consisting of:
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ret(λ
)=(K1/λ
)
ret(λ
)=(K1/λ
)*(1+(K2/λ
2))
ret(λ
)=(K1/λ
)*(1+(K2/λ
2)+(K3/λ
4)).
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20. A method of accurately evaluating parameters in parameterized equations in a mathematical model of a system of spatially separated input and output electromagnetic beam intercepting angle-of-incidence changing system elements as in claim 13, in which the step of providing separate parameterized mathematical model parameterized equations for retardance entered to the out-of-plane and in-plane orthogonal components of a beam of electromagnetic radiation caused to pass through said input and output electromagnetic beam intercepting angle-of-incidence changing system elements, thereby enabling independent calculation of out-of-plane and in-plane retardance entered by said input and said output electromagnetic beam intercepting angle-of-incidence changing system elements to out-of-plane and in-plane orthogonal components of a beam of electromagnetic radiation caused to pass through said input and output electromagnetic beam intercepting angle-of-incidence changing system elements, and the step of providing a parameterized equation for in-plane retardance entered by interaction of said bean of electromagnetic radiation with said sample system involve, for each input and output electromagnetic beam intercepting angle-of-incidence changing systems orthogonal retardation component and for said sample system retardation, parameterized equations having a form selected from the group consisting of:
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ret(λ
)=(K1/λ
)
ret(λ
)=(K1/λ
)*(1+(K2/λ
2))
ret(λ
)=(K1/λ
)*(1+(K2/λ
2)+(K3/λ
4)).
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21. A method of accurately evaluating parameters in parameterized equations in a mathematical model of a system of spatially separated input and output electromagnetic beam intercepting angle-of-incidence changing system elements as in claim 15, in which the step of providing separate mathematical model parameterized equations for retardance entered to the out-of-plane and in-plane orthogonal components of a beam of electromagnetic radiation caused to pass through said input and output electromagnetic beam intercepting angle-of-incidence changing system elements, thereby enabling independent calculation of out-of-plane and in-plane retardance entered by said input and said output electromagnetic beam intercepting angle-of-incidence changing system elements to out-of-plane and in-plane orthogonal components of a beam of electromagnetic radiation caused to pass through said input and output electromagnetic beam intercepting angle-of-incidence changing systems, and the step of providing a parameterized equation for in-plane retardance entered by interaction of said bean of electromagnetic radiation with said alternative sample system involve, for each input and output electromagnetic beam intercepting angle-of-incidence changing system elements orthogonal retardation component and for said alternative sample system retardation, parameterized equations having a form selected from the group consisting of:
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ret(λ
)=(K1/λ
)
ret(λ
)=(K1/λ
)*(1+(K2/λ
2))
ret(λ
)=(K1/λ
)*(1+(K2/λ
2)+(K3/λ
4)).
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22. A method of accurately evaluating parameters in parameterized equations in a mathematical model of a system of spatially separated input and output electromagnetic beam intercepting angle-of-incidence changing system elements as in claim 11, in which the step a. providing of spatially separated input and output electromagnetic beam intercepting angle-of-incidence changing system elements involves providing input and output electromagnetic beam intercepting angle-of-incidence changing system elements which are mounted on an X, Y, Z orientation control system.
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23. A method of accurately evaluating parameters in parameterized equations in a mathematical model of a system of spatially separated input and output electromagnetic beam intercepting angle-of-incidence changing system elements as in claim 15, in which the step a. providing of spatially separated input and output electromagnetic beam intercepting angle-of-incidence changing system elements involves providing input and output electromagnetic beam intercepting angle-of-incidence changing system elements which are mounted on an X, Y, Z orientation control system.
Specification