Method of determining control parameters of a device manufacturing process
A method including: obtaining an image of at least part of a substrate, wherein the image includes at least one feature manufactured on the substrate by a manufacturing process including a lithographic process and one or more further processes; determining one or more image-related metrics in dependence on a contour determined from the image, wherein one of the one or more image-related metrics is an edge placement error, EPE, of the at least one feature; and determining one or more control parameters of the lithographic process and/or the one or more further processes in dependence on the edge placement error, wherein at least one control parameter is determined so as to minimize the edge placement error of the at least one feature.
1. A method comprising:
obtaining an image of at least part of a substrate, wherein the image comprises at least one feature manufactured on the substrate by a manufacturing process comprising a lithographic process and one or more further processes;
determining, by a hardware computer system, one or more image-related metrics in dependence on a contour determined from the image, wherein one of the one or more image-related metrics is an edge placement error, EPE, of the at least one feature; and
determining one or more control parameters of the lithographic process and/or the one or more further processes, in dependence on the edge placement error, wherein at least one control parameter of the one or more control parameters is determined so as to minimize the edge placement error of the at least one feature.
2. The method according to claim 1 , further comprising controlling a lithographic apparatus used in the lithographic process in dependence on the determined one or more control parameters.
3. The method according to claim 1 , further comprising controlling an etching apparatus used in the one or more further processes in dependence on the determined one or more control parameters.
4. The method according to claim 1 , wherein at least one of the one or more image-related metrics is determined in dependence on a comparison of the contour and a target contour.
5. The method according to claim 1 , further comprising:
determining a plurality of segments of the contour of a feature of the at least one feature;
determining a respective weight for each of the plurality of segments;
determining, for each of the segments, an image-related metric of the segment; and
determining an image-related metric of the feature of the at least one feature in dependence on the weight and image-related metric of each of the segments.
6. The method according to claim 5 , wherein the weight of each segment is dependent on a tolerance value of the image-related metric of the segment.
7. The method according to claim 5 , wherein the one or more control parameters are determined in dependence on a sensitivity of each of the segments.
8. The method according to claim 1 , wherein a plurality of control parameters is determined and at least two of the control parameters are co-determined.
9. The method according to claim 8 , wherein the co-determination of at least two of the control parameters is dependent on:
the combined effect of the at least two control parameters; and/or
the interdependence of the at the least two control parameters.
10. The method according to claim 8 , wherein the at least two co-determined control parameters are focus and dose.
11. The method according to claim 8 , wherein the co-determined control parameters are determined in dependence on CD variation on a small spatial scale or both CD variation on a small spatial scale and CD variation on a large spatial scale.
12. The method according to claim 1 , further comprising:
obtaining a plurality of images of the substrate; and
determining one or more image-related metrics of features in each image.
13. The method according to claim 12 , wherein the one or more image-related metrics include one or more selected from: sizes of block patterns in the images, differences in sizes of block patterns in the images, differences in pitches in gratings in the images, an overall shift of a block layer with respect to a grating layer, or a shift between two LELE layers.
14. The method according to claim 1 , wherein determining the one or more image-related metrics comprises:
determining a contour shape of a structure comprised by the at least one feature in the image;
comparing the determined contour shape with one or more reference contour shapes; and
generating a model of the comparison result.
15. The method according to claim 14 , where the model comprises parameters that represent translation, magnification and/or rotation differences between the determined contour shape and the one or more reference contour shapes.
16. A system for manufacturing devices on a substrate, wherein the system is configured to perform the method of claim 1 .
17. A computer program product comprising a non-transitory computer-readable medium having machine-readable instructions therein, the instructions, when executed by a computer system, configured to cause the computer system to at least:
obtain an image of at least part of a substrate, wherein the image comprises at least one feature manufactured on the substrate by a manufacturing process comprising a lithographic process and one or more further processes;
determine one or more image-related metrics in dependence on a contour determined from the image, wherein one of the one or more image-related metrics is an edge placement error, EPE, of the at least one feature; and
determine one or more control parameters of the lithographic process and/or the one or more further processes, in dependence on the edge placement error, wherein at least one control parameter of the one or more control parameters is determined so as to minimize the edge placement error of the at least one feature.
18. The computer program product of claim 17 , wherein the instructions are further configured to cause the computer system to control a lithographic apparatus used in the lithographic process in dependence on the determined one or more control parameters or control an etching apparatus used in the one or more further processes in dependence on the determined one or more control parameters.
19. The computer program product of claim 17 , wherein at least one of the one or more image-related metrics is determined in dependence on a comparison of the contour and a target contour.
20. The computer program product of claim 17 , wherein the instructions are further configured to cause the computer system to:
determine a plurality of segments of the contour of a feature of the at least one feature;
determine a respective weight for each of the plurality of segments;
determine, for each of the segments, an image-related metric of the segment; and
determine an image-related metric of the feature of the at least one feature in dependence on the weight and image-related metric of each of the segments.