Three-dimensional mask model for photolithography simulation
First Claim
1. A photolithography simulation system implemented by a computer, the system comprising:
- a three-dimensional mask model of a type of photolithography mask, the three-dimensional mask model comprising one or more of;
a correction factor configured to modify a mathematical transform of a mask transmission function of a mask;
a correction factor configured to modify a mathematical transform of a horizontal mask-edge function of the mask;
a correction factor configured to modify a mathematical transform of a vertical mask-edge function of the mask; and
a correction factor configured to modify a mathematical transform of a mask-corner function of the mask,wherein the correction factors represent one or more effects of the topography of the type of photolithography mask on light passing through a mask of that type; and
simulating a near-field image expected to be produced by a photolithographic tool using the mask, using the computer executing a software tool using the three dimensional mask model.
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Accused Products
Abstract
A three-dimensional mask model of the invention provides a more realistic approximation of the three-dimensional effects of a photolithography mask with sub-wavelength features than a thin-mask model. In one embodiment, the three-dimensional mask model includes a set of filtering kernels in the spatial domain that are configured to be convolved with thin-mask transmission functions to produce a near-field image. In another embodiment, the three-dimensional mask model includes a set of correction factors in the frequency domain that are configured to be multiplied by the Fourier transform of thin-mask transmission functions to produce a near-field image.
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Citations
46 Claims
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1. A photolithography simulation system implemented by a computer, the system comprising:
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a three-dimensional mask model of a type of photolithography mask, the three-dimensional mask model comprising one or more of; a correction factor configured to modify a mathematical transform of a mask transmission function of a mask; a correction factor configured to modify a mathematical transform of a horizontal mask-edge function of the mask; a correction factor configured to modify a mathematical transform of a vertical mask-edge function of the mask; and a correction factor configured to modify a mathematical transform of a mask-corner function of the mask, wherein the correction factors represent one or more effects of the topography of the type of photolithography mask on light passing through a mask of that type; and simulating a near-field image expected to be produced by a photolithographic tool using the mask, using the computer executing a software tool using the three dimensional mask model. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A photolithography simulation system implemented by a computer, the system comprising:
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a three-dimensional mask model of a type of photolithography mask, the mask model comprising one or more of a linear and a bilinear filtering kernel, the one or more filtering kernels being configured to represent one or more effects of the topography of the type of photolithography mask on light passing through a mask of that type; and simulating a near-field image expected to be produced by a photolithographic tool using the mask, using the computer executing a software tool using the mask model, wherein the simulation includes convolving the one or more filtering kernels with one or more representations of the mask. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method implemented by a computer for creating a three-dimensional mask model, the method comprising:
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simulating the effect of light passing through a mask using three-dimensional mask topography information to produce a theoretical image; determining initial filtering kernels for a three-dimensional mask model using the theoretical; and modifying the initial filtering kernels until a total difference between the theoretical image and a simulated image is minimized or below a predetermined threshold to produce final filtering kernels, wherein the final filtering kernels are configured to be convolved with one or more mask transmission functions to produce a near-field image, and wherein the simulating, determining and modifying steps are implemented using the computer. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A method implemented by a computer for creating a three-dimensional mask model, the method comprising:
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simulating the effect of light passing through a mask using three-dimensional mask topography information to produce a theoretical image; determining initial correction factors for a three-dimensional mask model using the theoretical image; and modifying the initial correction factors until a total difference between the theoretical image and a simulated image is minimized to produce final correction factors, wherein the final correction factors are configured to be multiplied by a Fourier transform of one or more mask transmission functions to produce a near-field image, and wherein the simulating, determining and modifying steps are implemented using the computer. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36)
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37. A non-transitory computer-readable medium including instructions for performing:
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determining initial filtering kernels for a three-dimensional mask model using a theoretical image produced by simulating the effect of light passing through a mask using three-dimensional mask topography information; and modifying the initial filtering kernels until a total difference between the theoretical image and a simulated image is minimized or below a predetermined threshold to produce final filtering kernels, wherein the final filtering kernels are configured to be convolved with one or more mask transmission functions to produce a near-field image. - View Dependent Claims (38, 39, 40, 41)
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42. A non-transitory computer-readable medium including instructions for performing:
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determining initial correction factors for a three-dimensional mask model using a theoretical image produced by simulating the effect of light passing through a mask using three-dimensional mask topography information; and modifying the initial correction factors until a total difference between the theoretical image and a simulated image is minimized to produce final correction factors, wherein the final correction factors are configured to be multiplied by a Fourier transform of one or more mask transmission functions to produce a near-field image. - View Dependent Claims (43, 44, 45, 46)
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Specification