Three-dimensional mask model for photolithography simulation

Patent metadata

Field	Value
Publication number	US-2016357900-A1
Application number	US-201615174732-A
Country	US
Kind code	A1
Filing date	Jun 6, 2016
Priority date	Aug 14, 2007
Publication date	Dec 8, 2016
Grant date	—

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.

First claim

What is claimed is:

1 . 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.

2 . The method of claim 1 , wherein the thin-mask transmission functions includes a standard thin-mask transmission function and derivatives of the standard thin-mask transmission function.

3 . The method of claim 1 , wherein the final filtering kernels are independent of the layout of any particular mask.

4 . The method of claim 1 , wherein the final filtering kernels include a linear filtering kernel and at least one bilinear filtering kernel.

5 . The method of claim 1 , wherein the three-dimensional mask topography information was produced by inspecting a manufactured calibration mask.

6 . The method of claim 1 , wherein rigorously simulating the effect of light passing through a mask includes simulating a plane wave of light and oblique waves of light passing through the mask.

7 . 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.

8 . The method of claim 7 , wherein the final correction factors are independent of the layout of any particular mask.

9 . The method of claim 7 , wherein the three-dimensional mask topography information was produced by inspecting a manufactured calibration mask.

10 . The method of claim 7 , wherein rigorously simulating the effect of light passing through a mask includes simulating a plane wave of light and oblique waves of light passing through the mask, and each of the final correction factors models oblique incidence effects.

11 . 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.

Assignees

• Asml Netherlands Bv

Inventors

• Liu Peng
• Cao Yu
• Chen Luoqi
• Ye Jun

Classifications

• G03F7/705

  Modelling or simulating from physical phenomena up to complete wafer processes or whole workflow in wafer productions · CPC title

• G06F30/39

  Circuit design at the physical level (physical level design for reconfigurable circuits G06F30/347) · CPC title

• G06F30/398 Primary

  Design verification or optimisation, e.g. using design rule check [DRC], layout versus schematics [LVS] or finite element methods [FEM] (optical proximity correction [OPC] design processes G03F1/36) · CPC title

• G03F1/36 Primary

  Masks having proximity correction features; Preparation thereof, e.g. optical proximity correction [OPC] design processes · CPC title

• G06F17/5009

  Physics · mapped topic