Substrate target for in-situ lithography metrology, metrology method for in-situ lithography, and method of manufacturing integrated circuit device by using in-situ metrology
A substrate can include a feature pattern included in an integrated circuit on the substrate and an in-situ metrology pattern spaced apart from the feature pattern on the substrate, the in-situ metrology pattern and the feature pattern both configured to have equal heights relative to a surface of the substrate.
1. A substrate target for lithography metrology comprising:
a substrate;
a feature pattern on the substrate; and
a Sub Wavelength Grating (SWG) key on a same level relative to the substrate as the feature pattern, the SWG key comprising a plurality of diffraction patterns spaced apart at a first pitch that is configured to measure a focal variation affecting formation of the feature pattern,
wherein the plurality of diffraction patterns are within a one-time measurement spot, formed by one shot of a radiation beam projected onto the substrate,
wherein the SWG key is configured to measure the focal variation based on a height of the plurality of diffraction patterns, and
wherein the height of the plurality of diffraction patterns is determined based on a phase difference between a transverse electric (TE) polarized radiation component and a transverse magnetic (TM) polarized radiation component included in a zero-order diffracted light beam diffracted by the plurality of diffraction patterns.
2. The substrate target for lithography metrology of claim 1 , wherein the SWG key and the feature pattern comprise the same material.
3. The substrate target for lithography metrology of claim 1 , wherein the first pitch is less than a wavelength of a radiation beam used to measure the focal variation.
4. The substrate target for lithography metrology of claim 1 , wherein each of the diffraction patterns has a rectangular cross-sectional shape.
5. The substrate target for lithography metrology of claim 1 , wherein each of the diffraction patterns has inclined sidewalls.
6. A substrate target for lithography metrology comprising:
a micro-Diffraction Based Overlay (micro-DBO) key on a substrate, wherein the micro-DBO key comprises a plurality of first diffraction patterns each having a first width as a minimum width; and
a SubWavelength Grating (SWG) key on the substrate, wherein the SWG key comprises a plurality of second diffraction patterns each having a second width that is less than the first width,
wherein the plurality of first diffraction patterns and the plurality of second diffraction patterns are within a one-time measurement spot, formed by one shot of a radiation beam projected onto the substrate,
wherein the SWG key is configured to measure a focal variation affecting formation of a plurality of feature patterns based on a height of the plurality of second diffraction patterns, and
wherein the height of the plurality of second diffraction patterns is determined based on a phase difference between a transverse electric (TE) polarized radiation component and a transverse magnetic (TM) polarized radiation component included in a zero-order diffracted light beam diffracted by the plurality of second diffraction patterns.
7. The substrate target for lithography metrology of claim 6 , wherein:
the micro-DBO key is located within a first area on the substrate, and
the SWG key is located in a second area of the substrate within the first area and is surrounded by the plurality of first diffraction patterns.
8. The substrate target for lithography metrology of claim 6 , wherein:
the micro-DBO key is configured to measure an overlay error of a plurality of feature patterns on the substrate, and
the SWG key is configured to measure a focal variation affecting formation of the plurality of feature patterns.
9. The substrate target for lithography metrology of claim 8 , wherein:
the second diffraction patterns have respective line shapes that are parallel to each other, and
the second diffraction patterns and the feature patterns are the same material.
10. A substrate comprising:
a feature pattern included in an integrated circuit on the substrate; and
an in-situ metrology pattern spaced apart from the feature pattern on the substrate,
wherein the in-situ metrology pattern and the feature pattern are both configured to have equal heights relative to a surface of the substrate,
wherein the in-situ metrology pattern is within a one-time measurement spot, formed by one shot of a radiation beam projected onto the substrate,
wherein the in-situ metrology pattern is configured to measure a focal variation based on a height of the in-situ metrology pattern, and
wherein the height of the in-situ metrology pattern is determined based on a phase difference between a transverse electric (TE) polarized radiation component and a transverse magnetic (TM) polarized radiation component included in a zero-order diffracted light beam diffracted by the in-situ metrology pattern.
11. The substrate of claim 10 , wherein the in-situ metrology pattern and the feature pattern are both lithographically configured to have the equal heights relative to the surface of the substrate.
12. The substrate of claim 10 , wherein the in-situ metrology pattern and the feature pattern are commonly formed on the substrate.
13. The substrate of claim 10 , wherein the in-situ metrology pattern comprises a SubWavelength Grating (SWG) key comprising a plurality of diffraction patterns spaced apart at a first pitch on the substrate that is configured to measure focal variation affecting formation of the feature pattern.
14. The substrate of claim 13 , wherein the first pitch is less than a wavelength of a radiation beam configured to measure the focal variation.
15. The substrate of claim 14 , wherein the plurality of diffraction patterns comprises a first plurality of diffraction patterns each having a first width, the substrate further comprising:
a micro-Diffraction Based Overlay (micro-DBO) key on the substrate, the micro-DBO key comprising a plurality of second diffraction patterns each having a second width that is greater than the first width.
16. The substrate of claim 15 , wherein the micro-DBO key is configured to indicate an overlay error associated with formation of the feature pattern responsive to the radiation beam.
17. The substrate of claim 15 , wherein the SWG key is surrounded by separate ones of the plurality of second diffraction patterns included in the micro-DBO key.