Computational metrology
A method, involving determining a first distribution of a first parameter associated with an error or residual in performing a device manufacturing process; determining a second distribution of a second parameter associated with an error or residual in performing the device manufacturing process; and determining a distribution of a parameter of interest associated with the device manufacturing process using a function operating on the first and second distributions. The function may include a correlation.
1. A method comprising:
obtaining an underlying contribution of a lithographic apparatus to overlay as part of a patterning process; and
combining, by a hardware computer, the underlying contribution with a further contribution to overlay of a substrate to obtain an estimate of overlay for the substrate.
2. The method of claim 1 , wherein the further contribution comprises a contribution of a substrate surface height of the substrate to overlay.
3. The method of claim 1 , wherein the further contribution comprises a contribution of a substrate servo error of the substrate to overlay.
4. The method of claim 1 , wherein the further contribution comprises a contribution of an alignment and/or projection system model residual.
5. The method of claim 1 , further comprising combining, with the underlying contribution and the contribution of the substrate surface height, a contribution of an etch process to overlay of the substrate.
6. The method of claim 5 , wherein the etch process contribution is specific to the patterning process but not specific to any particular substrate processed using the patterning process.
7. The method of claim 1 , wherein the underlying contribution is specific to a particular patterning process but not specific to any particular substrate processed using the patterning process.
8. The method of claim 1 , wherein the obtaining the underlying contribution further comprises obtaining measured overlay data and removing therefrom a contribution of a particular component of the lithographic apparatus to overlay.
9. The method of claim 8 , wherein the contribution of the particular component comprises one or more selected from: a contribution of a servo error, a contribution of alignment model residual, a contribution of a projection system aberration, a contribution of a projection system model residual, and/or a contribution of a substrate surface height.
10. The method of claim 1 , wherein the contribution comprises a spatial substrate fingerprint.
11. The method of claim 1 , further comprising using the estimate to perform any one or more selected from: predict a defect for the substrate, control the patterning process, monitor the patterning process, design an aspect of the patterning process, and/or calibrate a mathematical model.
12. A computer program product comprising a non-transitory computer readable medium having instructions therein, the instructions, when executed by a computer system, configured to cause the computer system to perform the method of claim 1 .
13. A method comprising:
obtaining an alignment data distribution across at least part of a substrate processed using a patterning process, based on measured alignment data; and
combining, by a hardware computer, the alignment data distribution with an alignment fingerprint attributable to a processing parameter other than measured alignment to obtain an estimate of alignment data for the substrate.
14. The method of claim 13 , wherein the alignment fingerprint comprises a contribution of a substrate height or unflatness of the substrate to alignment.
15. The method of claim 13 , wherein the alignment fingerprint comprises a contribution of a process effect, due to a part of the patterning process other than a lithography pattern transfer, of the substrate to alignment.
16. The method of claim 13 , wherein the alignment fingerprint comprises a contribution of heating of the substrate to alignment.
17. The method of claim 13 , wherein the alignment fingerprint is specific to the patterning process but not specific to any particular substrate processed using the patterning process.
18. The method of claim 13 , wherein the alignment fingerprint is specific to a particular substrate processed using the patterning process but not generic to other substrates processed using the patterning process.
19. The method of claim 13 , wherein the alignment fingerprint is derived from a measurement of the processing parameter.
20. The method of claim 13 , wherein the alignment fingerprint comprises a spatial substrate fingerprint.
21. The method of claim 13 , further comprising using the estimate to perform any one or more selected from: predict a defect for the substrate, control the patterning process, monitor the patterning process, design an aspect of the patterning process, and/or calibrate a mathematical model.
22. A computer program product comprising a non-transitory computer readable medium having instructions therein, the instructions, when executed by a computer system, configured to cause the computer system to perform the method of claim 13 .