Lithographic apparatus, device manufacturing method and associated data processing apparatus and computer program product
A lithographic process includes clamping a substrate onto a substrate support, measuring positions across the clamped substrate, and applying a pattern to the clamped substrate using the positions measured. A correction is applied to the positioning of the applied pattern in localized regions of the substrate, based on recognition of a warp-induced characteristic in the positions measured across the substrate. The correction may be generated by inferring one or more shape characteristics of the warped substrate using the measured positions and other information. Based on the one or more inferred shape characteristics, a clamping model is applied to simulate deformation of the warped substrate in response to clamping. A correction is calculated based on the simulated deformation.
1. A device manufacturing method for applying patterns in one or more layers on a substrate clamped to a substrate support, the device manufacturing method comprising:
determining a height map of a region of the substrate, wherein the region is determined based on a characteristic of the substrate support; and
determining a correction to the device manufacturing method based on the height map and the characteristic of the substrate support.
2. The method as claimed in claim 1 , wherein the height map is determined from an interferometric measurement of a free forced shape of the substrate.
3. The method as claimed in claim 1 , wherein the height map is determined from measurements by a height sensor on the substrate when the substrate is clamped on the substrate support.
4. The method as claimed in claim 1 , wherein the correction is based on calculation of an in-plane-distortion of the region of the substrate.
5. The method as claimed in claim 1 , wherein the correction is based on calculation of an out-of-plane-distortion of the region of the substrate.
6. The method as claimed in claim 1 , further comprising applying patterns to the substrate while using the correction for positioning of the substrate and/or adjusting a projection system setting.
7. The method as claimed in claim 1 , wherein the characteristic is associated with an extension of one or more support structures provided to the substrate support.
8. The method as claimed in claim 1 , wherein the characteristic is associated with a distribution of support structures provided to the substrate support.
9. The method as claimed in claim 1 , wherein the region of the substrate is associated with sub-optimal clamping or sub-optimal support provided by the substrate support to the substrate.
10. The method as claimed in claim 1 , wherein the region of the substrate comprises an edge region of the substrate.
11. The method as claimed in claim 1 , further comprising determining a radial profile associated with the height map.
12. The method as claimed in claim 11 , wherein an in-plane-distortion of the region of the substrate is calculated from the radial profile.
13. The method as claimed in claim 11 , wherein an out-of-plane-distortion of the region of the substrate is calculated from the radial profile.
14. The method as claimed in claim 11 , wherein the characteristic of the substrate support is determined from the radial profile.
15. A lithographic apparatus for applying a pattern onto a substrate, the apparatus including:
a substrate support configured to clamp the substrate;
a height sensor configured to measure a height map of the clamped substrate; and
a patterning system configured to apply the pattern to the clamped substrate while or after positioning the applied pattern, wherein the patterning system is configured to apply a correction to the positioning of the applied pattern based on the height map and a characteristic of the substrate support.
16. The lithographic apparatus of claim 15 , wherein the height map is determined from an interferometric measurement of a free forced shape of the substrate.
17. A non-transitory computer program product comprising machine-readable instructions, when executed, configured to cause one or more processors to at least:
determine a height map of a region of a substrate, wherein the region is determined based on a characteristic of a substrate support of the substrate; and
determine a correction to a device manufacturing method for applying patterns in one or more layers on the substrate when clamped on the substrate support, based on the height map and the characteristic of the substrate support.
18. The computer program product of claim 17 , wherein the machine-readable instructions are further configured to cause the one or more processors to control a patterning system of a lithographic apparatus to recognize the characteristic and apply the correction.
19. The computer program product of claim 17 , wherein the height map is determined from an interferometric measurement of a free forced shape of the substrate.
20. The computer program product of claim 17 , wherein the correction is based on calculation of an in-plane-distortion of the region of the substrate.