Method of predicting patterning defects caused by overlay error

1. A method comprising:

determining a first color pattern and a second color pattern associated with a hot spot of a design layout pattern, the design layout pattern configured for transfer to a substrate; and

predicting, by a hardware computer system, whether there would be a defect at the hot spot on the substrate caused by overlay error, based at least in part on a measured overlay error between the first color pattern and the second color pattern from a physical substrate.

2. The method of claim 1 , wherein the predicting comprises:

obtaining an overlay error threshold;

comparing the measured overlay error with the overlay error threshold; and

predicting whether there would be the defect at the hot spot based on a result of the comparing.

3. The method of claim 2 , wherein a value of the measured overlay error is equal to or greater than the amplitude of the overlay error threshold and the defect is predicted at the hot spot responsive to the value of the measured overlay error being equal to or greater than the amplitude of the overlay error threshold.

4. The method of claim 2 , wherein a value of the measured overlay error is smaller than or equal to the amplitude of the overlay error threshold and no defect is predicted at the hot spot responsive to the value of the measured overlay error being smaller than or equal to the amplitude of the overlay error threshold.

5. The method of claim 2 , wherein obtaining the overlay error threshold comprises determining a value of an overlay error between the first color pattern and the second color pattern such that a distance or overlap amount between a simulated first color pattern and a simulated second color pattern based on the overlay error satisfies a defect threshold.

6. The method of claim 5 , wherein the simulated first color pattern is obtained by performing a simulation of the first color pattern based on different values of a processing variable of a patterning process used to transfer the first color pattern to the substrate and/or wherein the simulated second color pattern is obtained by performing a simulation of the second color pattern based on different values of a processing variable of a patterning process used to transfer the second color pattern to the substrate.

7. The method of claim 1 , wherein the predicting results in a prediction that there would be the defect and further comprising, responsive to the prediction there would be the defect, adjusting a processing variable for producing the first color pattern and/or the second color pattern, based on the overlay error.

8. The method of claim 7 , wherein the processing variable comprises one or more selected from: a dose for producing the first color pattern, a focus for producing the first color pattern, an optical aberration associated with producing the first color pattern, a dose for producing the second color pattern, a focus for producing the second color pattern, and/or an optical aberration associated with producing the second color pattern.

9. The method of claim 1 , wherein the first color pattern is for a different layer on the substrate than a layer for the second color pattern.

10. A method comprising:

obtaining an overlay error threshold between a first color pattern and a second color pattern by simulation of the first color pattern and the second color pattern; and

predicting, by a hardware computer system, existence of a defect caused by overlay error, based at least in part on the overlay error threshold and a measured overlay error between the first color pattern and the second color pattern from a physical substrate.

11. The method of claim 10 , wherein the predicting comprises:

selecting one of a plurality of overlay error thresholds, the selected overlay error threshold having at least a directional component in the same direction as that of the measured overlay error;

comparing the measured overlay error with the selected overlay error threshold; and

predicting whether there would be the defect based on a result of the comparing.

12. The method of claim 10 , wherein obtaining the overlay error threshold comprises determining a value of an overlay error between the first color pattern and the second color pattern such that a distance or overlap amount between the simulation of the first color pattern and the simulation of the second color pattern based on the overlay error satisfies a defect threshold.

13. The method of claim 10 , wherein the simulation of the first color pattern is obtained by performing a simulation of the first color pattern based on different values of a processing variable of a patterning process used to transfer the first color pattern to the substrate and/or wherein the simulation of the second color pattern is obtained by performing a simulation of the second color pattern based on different values of a processing variable of a patterning process used to transfer the second color pattern to the substrate.

14. The method of claim 10 , wherein the predicting results in a prediction that there would be the defect and further comprising, responsive to the prediction that there would be the defect, adjusting a processing variable for producing the first color pattern and/or the second color pattern, based on the overlay error.

15. A non-transitory computer program product comprising machine-readable instructions therein, the instructions, upon execution by a processor system, are configured to cause the processor system to at least:

obtain a first color pattern and a second color pattern associated with a hot spot of a design layout pattern, the design layout pattern configured for transfer to a substrate; and

predict whether there would be a defect at the hot spot on the substrate caused by overlay error, based at least in part on a measured overlay error between the first color pattern and the second color pattern taken from a physical substrate.

16. The computer program product of claim 15 , wherein the instructions are further configured to, responsive to a prediction there would be the defect, adjust a processing variable for producing the first color pattern and/or the second color pattern so that the defect caused by the overlay error is expected to be reduced.

17. The computer program product of claim 16 , wherein the processing variable comprises one or more selected from: a dose for producing the first color pattern, a focus for producing the first color pattern, an optical aberration associated with producing the first color pattern, a dose for producing the second color pattern, a focus for producing the second color pattern, and/or an optical aberration associated with producing the second color pattern.

18. The computer program product of claim 15 , wherein the instructions configured to predict whether there would be a defect at the hot spot are further configured to:

obtain an overlay error threshold by determining a value of an overlay error between the first color pattern and the second color pattern such that a distance or overlap amount between a simulated first color pattern and a simulated second color pattern based on the overlay error satisfies a defect threshold;

compare the measured overlay error with the overlay error threshold; and

predict whether there would be the defect at the hot spot based on a result of the comparison.

19. The computer program product of claim 18 , wherein the instructions are further configured to perform a simulation of the first color pattern based on different values of a processing variable of a patterning process used to transfer the first color pattern to the substrate to obtain the simulated first color pattern and/or perform a simulation of the second color pattern based on different values of a processing variable of a patterning process used to transfer the second color pattern to the substrate to obtain the simulated second color pattern.

20. The computer program product of claim 15 , wherein the first color pattern is for a different layer on the substrate than a layer for the second color pattern.

21. A non-transitory computer program product comprising machine-readable instructions therein, the instructions, upon execution by a processor system, are configured to cause the processor system to at least:

obtain an overlay error threshold between a first color pattern and a second color pattern by simulation of the first color pattern and the second color pattern; and

predict existence of a defect caused by overlay error, based at least in part on the overlay error threshold and a measured overlay error between the first color pattern and the second color pattern taken from a physical substrate.