Three-dimensional mask model for photolithography simulation

A method implemented by a computer for creating a three-dimensional mask model, the method comprising:

• 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 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 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.