Interferometric analysis method for the manufacture of nano-scale devices
View Patent ↗The present invention features a method to determine relative spatial parameters between two coordinate systems, which may be a mold and a region of a substrate in which mold is employed to generate a pattern. The method includes sensing relative alignment between the two coordinate systems at multiple points and determines relative spatial parameters therebetween. The relative spatial parameters include a relative area and a relative shape.
1. A method to determine relative spatial parameters between two substrates in a process of alignment comprising:
collecting multiple alignment data from phase information using a moiré based pair of overlaying alignment marks, one of the pair disposed on each of the two substrates;
capturing moiré first order microscope images by diffracted light from one of the alignment marks, while a normal distance between the pair of alignment marks changes from 100 microns to less than 10 nm,
wherein all microscopes used for capturing the first order microscope images for the alignment process are positioned outside of a beam path from a UV source focused through a template positioned on one of the two substrates; and,
determining relative spatial parameters between the two substrates using the moiré first order microscope images.
2. The method as recited in claim 1 where the two substrates are a template and a wafer where the wafer is the substrate disposed under the template.
3. The method as recited in claim 1 where a gap between the two substrates is filled with air or imprinting fluid.
4. The method as recited in claim 1 where spatial parameters include alignment, magnification and distortion parameters.
5. The method as recited in claim 2 , wherein the template is an imprint lithography template for imprinting a pattern in a fluid deposited on one of the substrates that is then cured by the UV source.
6. The method as recited in claim 5 , wherein the beam path of the UV source is directed through the imprint lithography template.
7. A method to determine relative spatial parameters between two substrates in a process of alignment comprising:
collecting multiple alignment data from phase information using a moiré based pair of overlaying substrate alignment marks, one of the pair disposed on each of the two substrates;
capturing moiré first order microscope images by diffracted light from an alignment mark on the substrate farther from a microscope capturing the moiré first order microscope images;
controlling each microscope, capturing the first order microscope images, in a closed loop position feedback using alignment marks on the substrate containing patterns to be transferred to the other substrate, wherein a normal distance between the pair of overlapping substrate alignment marks changes from 100 microns to less than 10 nm; and
determining relative spatial parameters between two substrates using the first order microscope images.
8. The method as recited in claim 7 where the two substrates are a template and a wafer where the wafer is the farther substrate.
9. The method as recited in claim 7 where a gap between the two substrates is filled with air or imprinting fluid.
10. The method as recited in claim 7 where the relative spatial parameters include alignment, magnification and distortion parameters.
11. The method as recited in claim 8 , wherein the template is an imprint lithography template for imprinting a pattern in a fluid deposited on one of the substrates that is then cured by a UV source.
12. The method as recited in claim 11 , wherein the beam path of the UV source is directed through the imprint lithography template.