Three-dimensional mask model for photolithography simulation
View Patent ↗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.
1. A method comprising:
applying, by a computer, a thin mask model to a mask design layout to create a thin mask transmission;
obtaining a plurality of edge-based kernels to adapt the thin mask transmission to a mask 3D transmission; and
combining the thin mask transmission and the plurality of edge-based kernels to create a mask 3D transmission corresponding to the mask design layout.
2. The method of claim 1 , wherein the plurality of edge-based kernels are for transverse electric (TE) polarization and transverse magnetic (TM) polarization.
3. The method of claim 1 , wherein obtaining the plurality of edge-based kernels includes:
receiving a mask topography structure for the mask design layout;
performing a rigorous simulation to simulate a near-field; and
deriving the plurality of edge-based kernels from the near-field.
4. The method of claim 1 , wherein the mask 3D transmission is in a spatial domain form.
5. The method of claim 1 , wherein the mask 3D transmission is in a frequency domain form.
6. A non-transitory computer readable medium having instructions stored thereon which, when executed by a computer, cause the computer to perform a method comprising:
applying a thin mask model to a mask design layout to create a thin mask transmission;
obtaining a plurality of edge-based kernels to adapt the thin mask transmission to a mask 3D transmission; and
combining the thin mask transmission and the plurality of edge-based kernels to create a mask 3D transmission corresponding to the mask design layout.
7. The computer-readable medium of claim 6 , wherein the plurality of edge-based kernels are for transverse electric (TE) polarization and transverse magnetic (TM) polarization.
8. The computer-readable medium of claim 6 , wherein obtaining the plurality of edge-based kernels includes:
receiving a mask topography structure for the mask design layout;
performing a rigorous simulation to simulate a near-field; and
deriving the plurality of edge-based kernels from the near-field.
9. The computer-readable medium of claim 6 , wherein the mask 3D transmission is in a spatial domain form.
10. The computer-readable medium of claim 6 , wherein the mask 3D transmission is in a frequency domain form.
11. A method, implemented by a computer, of performing mask topography effect modeling on a mask design layout, the method comprising:
applying, using the computer, a thin mask model to the mask design layout to create a thin mask transmission;
applying a thick mask model to the mask design layout to generate a mask 3D residual, the thick mask model comprising a plurality of edge-based kernels; and
combining the thin mask transmission and the mask 3D residual to create a mask 3D transmission, wherein the mask topography effect modeling on the mask design layout is used to create an improved optical mask for creating an integrated circuit.