Traitement en cours

Veuillez attendre...

Paramétrages

Paramétrages

Aller à Demande

1. WO2020156738 - PROCÉDÉS ET APPAREIL POUR COMMANDER UN PROCESSUS LITHOGRAPHIQUE

Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

[ EN ]

CLAIMS

1. A method of determining a control parameter for a lithographic process, the method comprising: obtaining a substrate model for representing a process parameter fingerprint across a substrate, the substrate model being defined as a combination of basis functions including at least one basis function suitable for representing variation of the process parameter fingerprint between substrates and/or batches of substrates;

receiving measurements of the process parameter across at least one substrate;

determining substrate model parameters using the measurements and the basis functions; and determining the control parameter based on the substrate model parameters and a similarity of the at least one basis function to a process parameter fingerprint variation between substrates and/or batches of substrates.

2. The method of claim 1, wherein the at least one basis function is suitable to represent an edge fingerprint variation between substrates and/or batches of substrates.

3. The method of claim 1, wherein the basis functions are polynomials, for example Zernike polynomials.

4. The method of claim 1, wherein the control parameter is a weighted function of the substrate model parameters, wherein the weights are based on the similarity of the basis functions associated with the substrate model parameters to process parameter fingerprint variations between substrates and/or batches of substrates.

5. The method of claim 4, wherein the weight of a substrate model parameter associated with a basis function exceeding a measure of similarity to a process parameter fingerprint variation between substrates and/or batches of substrates is reduced or nulled.

6. The method of claim 1, wherein the control parameter is an automatic process control, APC, model parameter, for example a smoothing parameter associated with an exponentially weighted moving average, EWMA, filter utilized in the APC model.

7. The method of claim 6, wherein the APC model comprises a plurality of smoothing parameters and at least two smoothing parameters out of said plurality of smoothing parameters have a different functional dependency to the substrate model parameters.

8. The method of claim 1, wherein the control parameter is configured to control a lithographic apparatus on a per substrate basis.

9. The method of claim 1, wherein individual substrate model parameters are correlated to context information associated with the substrates used for providing the measurement data.

10. The method of claim 1, further comprising keeping the control parameter up to date by using a learning model keeping track of evolution of measurement data and determining adequate modification of the control parameter to achieve stable control of the lithographic process.

11. A computer program comprising instructions which, when executed on at least one processor, cause the at least one processor to carry out a method according to claim 1.

12. An apparatus for determining a control parameter for a lithographic process, the apparatus comprising one or more processors configured to execute computer program code to undertake the method as set out in any of claims 1 to 10.

13. A metrology apparatus comprising an apparatus according to claim 12.

14. A lithographic apparatus comprising an apparatus according to claim 12.