Materials and methods for creating imaging layers
The present invention provides patterned features of dimensions of less than 50 nm on a substrate. According to various embodiments, the features may be “Manhattan” style structures, have high aspect ratios, and/or have atomically smooth surfaces. The patterned features are made from polymer brushes grafted to a substrate. In some embodiments, the dimensions of the features may be determined by adjusting the grafting density and/or the molecular weight of the brushes. Once the brushes are patterned, the features can be shaped and reshaped with thermal or solvent treatments to achieve the desired profiles. The chemical nature of the polymer brush is thus independent of the patterning process, which allows for optimization of the polymer brush used for specific applications. Applications include masks for pattern transfer techniques such as reactive ion etching.
1. A method of transferring a pattern to a substrate comprising:
a) patterning polymer brushes on the substrate to create an etch mask; wherein the etch mask comprises a feature having an aspect ratio of at least 1:100, the feature comprising a plurality of polymer brushes attached to the substrate and having a height of at least 2.5 nm and wherein the width of the feature is no more than about 50 nm; and
b) etching the unmasked areas of the substrate.
2. The method of claim 1 wherein patterning the polymer brushes comprises creating patterned initiation sites on a substrate and growing polymer brushes at the patterned sites.
3. The method of claim 1 wherein patterning the polymer brushes comprises growing polymer brushes on the surface of the substrate and selectively removing some of the grown polymer brushes.
4. The method of claim 1 wherein patterning the polymer brushes comprises growing polymer brushes on the surface of the substrate and annealing the polymer brushes.
5. The method of claim 1 wherein patterning the polymer brushes comprises growing polymer brushes on the surface of the substrate and exposing the polymer brushes to a solvent.
6. The method of claim 1 wherein the substrate comprises a silicon wafer.
7. The method of claim 1 wherein the patterned is transferred to a dielectric layer on the substrate.
8. The method of claim 1 wherein the polymer brushes comprise silanes.
9. The method of claim 1 wherein the polymer brushes comprise siloxanes.
10. The method of claim 1 wherein the aspect ratio of the feature is at least 1:10.
11. The method of claim 1 wherein the aspect ratio of the feature is at least 1:1.
12. The method of claim 1 wherein the aspect ratio of the feature is at least 2:1.
13. The method of claim 1 wherein the height of the feature is at least 5 nm.
14. The method of claim 1 wherein the height of the feature is at least 10 nm.
15. The method of claim 1 wherein the width of the feature is no more than about 25 nm.
16. The method of claim 1 wherein the width of the feature is no more than about 10 nm.
17. The method of claim 1 wherein the feature has substantially vertical sidewalls.
18. The method of claim 1 wherein the feature has a line edge roughness of no more than 10 nm.
19. The method of claim 1 wherein the etching unmasked areas of the substrate comprises reactive ion etching.
20. The method of claim 1 further comprising, after etching, removing the polymer brushes from the substrate.