Density multiplication and improved lithography by directed block copolymer assembly
Methods to pattern substrates with dense periodic nanostructures that combine top-down lithographic tools and self-assembling block copolymer materials are provided. According to various embodiments, the methods involve chemically patterning a substrate, depositing a block copolymer film on the chemically patterned imaging layer, and allowing the block copolymer to self-assemble in the presence of the chemically patterned substrate, thereby producing a pattern in the block copolymer film that is improved over the substrate pattern in terms feature size, shape, and uniformity, as well as regular spacing between arrays of features and between the features within each array compared to the substrate pattern. In certain embodiments, the density and total number of pattern features in the block copolymer film is also increased. High density and quality nanoimprint templates and other nanopatterned structures are also provided.
1. A method comprising: receiving a first pattern on a substrate, wherein said first pattern comprises pattern features; depositing a block copolymer material on the first pattern; ordering the block copolymer material to form a second pattern comprising pattern features defined by microphase-separated domains of the block copolymer material, wherein feature placement of a subset of the features of the second pattern matches feature placement of the features of the first pattern such that each feature of the first pattern is directly under a feature of the second pattern and only one feature of the second pattern is directly over each feature of the first pattern and wherein the feature density of the second pattern is greater than that of the first pattern.
2. The method of claim 1 wherein the ratio of the feature density of the second pattern to the feature density of the first pattern is at least 2:1.
3. The method of claim 1 wherein the ratio of the feature density of the second pattern to the feature density of the first pattern is at least 4:1.
4. The method of claim 1 wherein the ratio of the feature density of the second pattern to the feature density of the first pattern is at least 9:1.
5. The method of claim 1 wherein the first pattern is a periodic pattern.
6. The method of claim 1 wherein first pattern is an aperiodic pattern.
7. The method of claim 1 further comprising transferring the second pattern to a media disk for magnetic recording.
8. The method of claim 1 wherein the first pattern comprises discrete spots.
9. The method of claim 1 wherein the second pattern features comprise cylinders oriented perpendicular to the substrate.
10. The method of claim 1 wherein the first pattern comprises stripes.
11. The method of claim 1 wherein the second pattern features comprise lamellae oriented perpendicular to the substrate.
12. The method of claim 1 , wherein the feature placement error of the second pattern is less than that of the first pattern, said feature placement error being the deviation in feature placement of a pattern from feature placement of an ideal periodic pattern characterized by a lattice constant L d .
13. The method of claim 12 wherein the standard deviation a of feature placement of the second pattern from the ideal periodic pattern is no more than 1 nm.
14. The method of claim 12 wherein the standard deviation a of feature placement of the second pattern from the ideal periodic pattern is no more than 5% of the L d .
15. The method of claim 12 wherein the standard deviation a of feature placement of the second pattern from the ideal periodic pattern is no more than 2% of the L d .
16. The method of claim 12 wherein the ideal periodic pattern is a 2-dimensional array of dots and the standard deviation of the feature placement of the second pattern from the ideal periodic pattern is no more than 1 nm.
17. The method of claim 12 wherein each feature comprises a top surface having a top surface area, wherein the size distribution of the top surface areas of the second pattern is narrower than the size distribution of the top surface areas of the first pattern.
18. The method of claim 12 wherein each feature comprises a top surface having a lateral dimension, wherein the standard deviation of the lateral dimensions of the second pattern is no more than 5% of the mean lateral dimension.