Lithographic apparatus and device manufacturing method

A method of controlling a lithographic apparatus, the method comprising:

• obtaining a density distribution of a pattern on a patterning device for use in the lithographic apparatus;
• receiving radiation data characterizing a radiation beam to be applied by the lithographic apparatus;
• receiving measurement data representative of a temperature of the patterning device and setting a parameter of a thermo-mechanical model of the patterning device based on the measurement data, the thermo-mechanical model further comprising one or more variables in addition to the parameter and wherein the thermo-mechanical model comprises a three-dimensional finite element model of the patterning device;
• determining a spatial distribution of dissipation of the pattern based on the density distribution of the pattern and the received radiation data;
• determining a deformation of the pattern by applying the dissipation distribution in the thermo-mechanical model of the patterning device;
• and
• determining a control signal to control a component of the lithographic apparatus based on the deformation of the pattern.

A computer program product comprising a set of computer readable instructions stored on a non-transitory computer readable medium, the set of instructions configured to, when run on a computer system, enable the computer system to at least:

• obtain a density distribution of the pattern of a pattern on a patterning device for use in a lithographic apparatus;
• receive radiation data characterizing a radiation beam to be applied by the lithographic apparatus;
• receive measurement data representative of a temperature of the patterning device and set a parameter of a thermo-mechanical model of the patterning device based on the measurement data, the thermo-mechanical model further comprising one or more variables in addition to the parameter and the thermo-mechanical model comprising a three-dimensional finite element model of the patterning device;
• determine a spatial distribution of dissipation of the pattern based on the density distribution of the pattern and the received radiation data;
• determine a deformation of the pattern by applying the dissipation distribution in the thermo-mechanical model of the patterning device;
• and
• determine a control signal to control a component of the lithographic apparatus based on the deformation of the pattern.

A computer program product comprising a set of computer readable instructions stored on a non-transitory computer readable medium, the set of instructions configured to, when run on a computer system, enable the computer system to at least:

• obtain a density distribution of a pattern on a patterning device for use in a lithographic apparatus;
• receive radiation data characterizing a radiation beam to be applied by the lithographic apparatus;
• determine a spatial distribution of dissipation of the pattern based on the density distribution of the pattern and the received radiation data;
• determine a deformation of the pattern by applying the dissipation distribution as in a thermo-mechanical model of the patterning device, wherein the thermo-mechanical model is configured to determine deformation in each of at least three orthogonal dimensions;
• and
• determine a control signal to control a component of the lithographic apparatus based on the deformation of the pattern.