Three-dimensional mask model for photolithography simulation
AssigneeAsml Netherlands B.V.
InventorsPeng Liu, Yu Cao, Luoqi Chen, Jun Ye
Life of this patent
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Abstract
A three-dimensional mask model that 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.
Claims11
A method comprising:
- simulating, by a hardware computer, 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 image;
- 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 a thin-mask transmission function to produce a near-field image.
A method comprising:
- simulating, by a hardware computer, 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 thin-mask transmission functions to produce a near-field image.
A non-transitory computer-readable medium including instructions configured to cause a hardware computer to perform a method comprising:
- 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 a thin-mask transmission function to produce a near-field image.
Dependencies are inferred from the claim text.