Optimized polarization illumination
First Claim
1. An apparatus for increasing a process window associated with imaging a mask design onto a target portion of a substrate, said apparatus comprising:
- a computer system configured to optimize polarization and intensity at each of a plurality of points of an illuminator used to illuminate the mask design by performing the steps of;
(a) determining an illumination intensity for at least one point on the illuminator for at least two polarization states;
(b) determining image log slope (ILS) for the at least one point on the illuminator for the at least two polarization states;
(c) determining a maximum image point where the ILS is at least near zero for the at least one point on the illuminator;
(d) selecting an optimal polarization state corresponding to the maximum ILS for the at least one point on the illuminator; and
(e) repeating steps (a)-(d) for each of the plurality of points on the illuminator.
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Accused Products
Abstract
Disclosed concepts include a method of optimizing polarization of an illumination of a pattern to be formed in a surface of a substrate. Polarized illumination is optimized by determining an illumination intensity for at least one point on an illuminator for at least two polarization states, determining image log slope for the at least one point on the illuminator for the at least two polarization states, determining a maximum image log slope (ILS) where the ILS is near zero for the at least one point on the illuminator, and selecting an optimal polarization state corresponding to the at least two polarization states that minimizes an ILS for the at least one point on the illuminator. This may be repeated for a plurality of points on the illuminator.
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Citations
13 Claims
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1. An apparatus for increasing a process window associated with imaging a mask design onto a target portion of a substrate, said apparatus comprising:
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a computer system configured to optimize polarization and intensity at each of a plurality of points of an illuminator used to illuminate the mask design by performing the steps of; (a) determining an illumination intensity for at least one point on the illuminator for at least two polarization states; (b) determining image log slope (ILS) for the at least one point on the illuminator for the at least two polarization states; (c) determining a maximum image point where the ILS is at least near zero for the at least one point on the illuminator; (d) selecting an optimal polarization state corresponding to the maximum ILS for the at least one point on the illuminator; and (e) repeating steps (a)-(d) for each of the plurality of points on the illuminator.
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2. A method of optimizing polarization of an illumination of a pattern to be formed in a surface of a substrate, comprising the steps of:
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(a) determining an illumination intensity for at least one point on an illuminator having a plurality of illumination points, the illuminator being used to illuminate a mask having the pattern, the illumination intensity being determined for at least two polarization components; (b) generating a contrast image associated with the surface of the substrate relative to the illumination intensity for each of the at least two polarization components; and (c) optimizing the contrast image for each of the at least two polarization components to obtain a better contrast of the pattern to be formed in the surface of the substrate. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification