Recipe selection based on inter-recipe consistency
A method including: determining recipe consistencies between one substrate measurement recipe of a plurality of substrate measurement recipes and each other substrate measurement recipe of the plurality of substrate measurement recipes; calculating a function of the recipe consistencies; eliminating the one substrate measurement recipe from the plurality of substrate measurement recipes if the function meets a criterion; and reiterating the determining, calculating and eliminating until a termination condition is met. Also disclosed herein is a substrate measurement apparatus, including a storage configured to store a plurality of substrate measurement recipes, and a processor configured to select one or more substrate measurement recipes from the plurality of substrate measurement recipes based on recipe consistencies among the plurality of substrate measurement recipes.
1. A method for a measurement procedure, the method comprising:
determining recipe consistency within each of a plurality of subsets of substrate measurement recipes selected from a plurality of substrate measurement recipes based on values of a characteristic at a plurality of areas on a substrate obtained using the plurality of substrate measurement recipes;
selecting a substrate measurement recipe from the plurality of substrate measurement recipes based on the recipe consistency; and
setting or modifying a physical configuration of a physical measurement process according to at least the selected substrate measurement recipe and/or communicating data to a physical system in order to set or modify a physical configuration of a measurement or inspection apparatus according to at least the selected substrate measurement recipe.
2. The method of claim 1 , wherein the characteristic comprises overlay error or a relative position of the substrate.
3. The method of claim 1 , further comprising obtaining the values of the characteristic by measuring or simulating diffracted radiation from the areas.
4. The method of claim 3 , wherein obtaining the values comprises measuring or simulating a difference between amplitudes of two diffraction orders of the diffracted radiation from the areas.
5. The method of claim 1 , wherein each of the areas comprises a target structure, the target structure comprising overlaid periodic structures having a known overlay error bias.
6. The method of claim 1 , wherein the plurality of substrate measurement recipes differ in one or more parameters selected from: wavelength of radiation used in a measurement or simulation to arrive at the values, polarization of radiation used in a measurement or simulation to arrive at the values, targets within the areas used in a measurement or simulation to arrive at the values, or angle of incidence of radiation used in a measurement or simulation to arrive at the values.
7. The method of claim 1 , wherein the recipe consistency within each subset is a function of differences of the values measured by or simulated for, at the plurality of areas, one substrate measurement recipe of the subset and the values measured by or simulated for, at the plurality of areas, another substrate measurement recipe of the subset.
8. The method of claim 7 , wherein the recipe consistency is a function of the sum of squares of the differences.
9. The method of claim 7 , wherein the recipe consistency is a covariance.
10. The method of claim 1 , wherein the recipe consistency within each subset is a function of regression between the values measured by or simulated for, at the plurality of areas, one substrate measurement recipe of the subset and the values measured by or simulated for, at the plurality of areas, another substrate measurement recipe of the subset.
11. The method of claim 1 , wherein the recipe consistency within each subset is a function of cosine similarities and Euclidian distances of the values of a spatial characteristic.
12. The method of claim 1 , wherein selecting the substrate measurement recipe comprises calculating a sum of recipe consistencies within all subsets that have a substrate measurement recipe in common.
13. The method of claim 1 , wherein selecting the substrate measurement recipe comprises eliminating a substrate measurement recipe from the plurality of substrate measurement recipes based on the recipe consistency.
14. The method of claim 1 , further comprising eliminating a substrate measurement recipe that does not meet one or more detectability criteria.
15. The method of claim 1 , further comprising inspecting the substrate using a selected substrate measurement recipe.
16. The method of claim 1 , further comprising, prior to determining the recipe consistency, determining detectability of a substrate measurement recipe and if the detectability for the substrate measurement recipe crosses a threshold, excluding that substrate measurement recipe from the plurality of substrate measurement recipes.
17. A computer program product comprising a non-transitory computer readable medium having instructions recorded thereon, the instructions when executed by a computer configured to cause at least:
determination of recipe consistency within each of a plurality of subsets of substrate measurement recipes selected from a plurality of substrate measurement recipes based on values of a characteristic at a plurality of areas on a substrate obtained using the plurality of substrate measurement recipes;
selection of a substrate measurement recipe from the plurality of substrate measurement recipes based on the recipe consistency; and
setting or modifying of a physical configuration of a physical measurement process according to at least the selected substrate measurement recipe and/or communication of data to a physical system in order to set or modify a physical configuration of a measurement or inspection apparatus according to at least the selected substrate measurement recipe.
18. The computer program product of claim 17 , wherein the recipe consistency within each subset is a function of differences of the values measured by or simulated for, at the plurality of areas, one substrate measurement recipe of the subset and the values measured by or simulated for, at the plurality of areas, another substrate measurement recipe of the subset.
19. The computer program product of claim 18 , wherein the recipe consistency is a function of the sum of squares of the differences.
20. The computer program product of claim 18 , wherein the recipe consistency is a covariance.
21. The computer program product of claim 17 , wherein the recipe consistency within each subset is a function of regression between the values measured by or simulated for, at the plurality of areas, one substrate measurement recipe of the subset and the values measured by or simulated for, at the plurality of areas, another substrate measurement recipe of the subset.
22. The computer program product of claim 17 , wherein the recipe consistency within each subset is a function of cosine similarities and Euclidian distances of the values of a spatial characteristic.
23. The computer program product of claim 17 , wherein selection of the substrate measurement recipe comprises calculation of a sum of recipe consistencies within all subsets that have a substrate measurement recipe in common.
24. The computer program product of claim 17 , wherein selection of the substrate measurement recipe comprises elimination of a substrate measurement recipe from the plurality of substrate measurement recipes based on the recipe consistency.
25. The computer program product of claim 17 , wherein the instruction are further configured to cause inspection of the substrate using a selected substrate measurement recipe.
26. A substrate measurement apparatus configured to measure a substrate, the substrate measurement apparatus comprising:
a storage configured to store a plurality of substrate measurement recipes, and
a processor configured to at least:
determine recipe consistency within each of a plurality of subsets of substrate measurement recipes selected from the plurality of substrate measurement recipes based on values of a characteristic at a plurality of areas on a substrate obtained using the plurality of substrate measurement recipes;
select a substrate measurement recipe from the plurality of substrate measurement recipes based on the recipe consistency; and
set or modify a physical configuration of a physical measurement process using the substrate measurement apparatus according to at least the selected substrate measurement recipe and/or communicate data to a physical system in order to set or modify a physical configuration of the substrate measurement apparatus according to at least the selected substrate measurement recipe.
27. The substrate measurement apparatus of claim 26 , wherein the recipe consistency within each subset is a function of differences of the values measured by or simulated for, at the plurality of areas, one substrate measurement recipe of the subset and the values measured by or simulated for, at the plurality of areas, another substrate measurement recipe of the subset.
28. The substrate measurement apparatus of claim 26 , wherein the recipe consistency within each subset is a function of regression between the values measured by or simulated for, at the plurality of areas, one substrate measurement recipe of the subset and the values measured by or simulated for, at the plurality of areas, another substrate measurement recipe of the subset.
29. The substrate measurement apparatus of claim 26 , wherein the recipe consistency within each subset is a function of cosine similarities and Euclidian distances of the values of a spatial characteristic.