Overlay error correction
A calibration curve for a wafer comprising a layer on a substrate is determined. The calibration curve represents a local parameter change as a function of a treatment parameter associated with a wafer exposure to a light. The local parameter of the wafer is measured. An overlay error is determined based on the local parameter of the wafer. A treatment map is computed based on the calibration curve to correct the overlay error for the wafer. The treatment map represents the treatment parameter as a function of a location on the wafer.
1. A method to correct an overlay error, comprising:
determining a first calibration curve for a first wafer comprising a first layer on a substrate, the first calibration curve representing a local parameter change as a function of a first treatment parameter associated with a wafer exposure to a light;
measuring the local parameter of the first wafer;
determining a first overlay error based on the local parameter; and
computing a first treatment map based on the first calibration curve to correct the first overlay error for the first wafer, the first treatment map representing the first treatment parameter as a function of a location on the first wafer.
2. The method of claim 1 , further comprising processing the first wafer using the first treatment map.
3. The method of claim 1 , further comprising
re-measuring the local parameter of the first wafer;
determining a second overlay error based on the re-measured local parameter;
determining if the second overlay error is greater than a predetermined threshold; and
computing a second treatment map for the first wafer based on the second overlay error, if the second overlay error is greater than the predetermined threshold.
4. The method of claim 1 , further comprising measuring a response of the local parameter of a reference wafer to a plurality of treatment conditions associated with a plurality of treatment parameters;
generating a plurality of calibration curves based on measuring;
determining a process window for each of the calibration curves, wherein the first calibration curve is selected from the plurality of calibration curves stored in a memory based at least on the process window.
5. The method of claim 1 , wherein the first layer is a mask layer, and wherein the substrate comprises a multilayer stack.
6. The method of claim 1 , wherein the first calibration curve is determined based on a characteristic of the first wafer.
7. The method of claim 1 , wherein the first treatment parameter comprises a dose, a power, a fluence, a pulse width, a beam shape, a beam size, a wavelength, an exposure repetition rate, an exposure time, a scan speed, a number of flashes, a zone temperature, an ambient condition, an exposure mode, an exposure sequence, an exposure pattern, or any combination thereof.
8. The method of claim 1 , wherein the local parameter comprises a local stress curvature.
9. A non-transitory machine readable medium comprising instructions that cause a data processing system to perform operations comprising:
determining a first calibration curve for a first wafer comprising a first layer on a substrate, the first calibration curve representing a local parameter change as a function of a first treatment parameter associated with a wafer exposure to a light;
measuring the local parameter of the first wafer;
determining a first overlay error based on the local parameter; and
computing a first treatment map based on the first calibration curve to correct the first overlay error for the first wafer.
10. The non-transitory machine readable medium of claim 9 , further comprising instructions that cause the data processing system to perform operations comprising processing the first wafer using the first treatment map.
11. The non-transitory machine readable medium of claim 9 , further comprising instructions that cause the data processing system to perform operations comprising re-measuring the local parameter of the first wafer;
determining a second overlay error based on the re-measured local parameter;
determining if the second overlay error is greater than a predetermined threshold; and
computing a second treatment map for the first wafer based on the second overlay error, if the second overlay error is greater than the predetermined threshold.
12. The non-transitory machine readable medium of claim 9 , further comprising instructions that cause the data processing system to perform operations comprising measuring a response of the local parameter of a reference wafer to a plurality of treatment conditions associated with a plurality of treatment parameters;
generating a plurality of calibration curves based on measuring;
determining a process window for each of the calibration curves, wherein the first calibration curve is selected from the plurality of calibration curves stored in a memory based at least on the process window.
13. The non-transitory machine readable medium of claim 9 , wherein the first layer is a mask layer, and wherein the substrate comprises a multilayer stack.
14. The non-transitory machine readable medium of claim 9 , wherein the first calibration curve is determined based on a characteristic of the first wafer.
15. The non-transitory machine readable medium of claim 9 , wherein the first treatment parameter comprises a dose, a power, a fluence, a pulse width, a beam shape, a beam size, a wavelength, an exposure repetition rate, an exposure time, a scan speed, a number of flashes, a zone temperature, an ambient condition, an exposure mode, an exposure sequence, an exposure pattern, or any combination thereof.
16. The non-transitory machine readable medium of claim 9 , wherein the local parameter comprises a local wafer curvature.