Patterning of non-convex shaped nanostructures
Methods of making nano-scale structures with geometric cross-sections, including convex or non-convex cross-sections, are described. The approach may be used to directly pattern substrates and/or create imprint lithography templates or molds that may be subsequently used to directly replicate nano-shaped patterns into other substrates, such as into a functional or sacrificial resist to form functional nanoparticles.
1. A method of forming an imprint lithography template having patterning features with non-convex cross-sections, the method comprising:
forming a first material layer on a substrate;
forming a first patterned layer of formable material over the first material layer using an imprint lithography template having a patterning surface of features having convex geometric cross-sections;
removing portions of the first patterned layer and the first material layer to form recesses in the first material layer having convex geometric cross-sections; forming a second patterned layer of formable material over the first layer using an imprint lithography template having a patterning surface of features having convex geometric cross-sections, wherein the template features are displaced relative to the corresponding formed recesses in the first layer;
removing portions of the second patterned layer and the first material layer to form recesses in the first material layer having non-convex geometric cross-sections;
etching the substrate to form recesses in the substrate having non-convex geometric cross-sections;
removing remaining portions of the second patterned layer; and
removing remaining portions of the first material layer, thereby forming the imprint lithography template with patterning features having non-convex cross-sections.
2. The method of claim 1 wherein the geometric cross-sections are polygonal.
3. The method of claim 1 wherein the displacement of the features relative to the corresponding recesses is a rotational displacement.
4. The method of claim 1 wherein the displacement of the features relative to the corresponding recesses is a lateral displacement.
5. The method of claim 1 wherein the features of the imprint template are raised.
6. The method of claim 1 wherein the features of the imprint template are recessed.
7. The method of claim 1 wherein the first material layer and the formable material have different etch characteristics.
8. The method of claim 1 wherein the first material layer contains a metal.
9. The method of claim 1 wherein the first material layer contains chromium.
10. A method of forming an imprint lithography template having patterning features with non-convex cross-sections, the method comprising:
forming a first material layer on a substrate;
forming a first patterned layer of formable material over the first material layer using an imprint lithography template having a patterning surface of features having first convex geometric cross-sections;
removing portions of the first patterned layer and the first material layer to form recesses in the first material layer having first convex geometric cross-sections;
forming a second patterned layer of formable material over the first layer using an imprint lithography template having a patterning surface of features having second convex geometric cross-sections, wherein the template features are aligned with the corresponding formed recesses in the first layer having first convex geometric cross-sections;
removing portions of the second patterned layer and the first material layer to form recesses in the first material layer having non-convex geometric cross-sections;
etching the substrate to form recesses in the substrate having non-convex geometric cross-sections;
removing remaining portions of the second patterned layer; and
removing remaining portions of the first material layer, thereby forming the imprint lithography template with patterning features having non-convex cross-sections.
11. The method of claim 10 wherein the geometric cross-sections are polygonal.
12. The method of claim 10 wherein the features of the imprint template are raised.
13. The method of claim 10 wherein the features of the imprint template are recessed.
14. The method of claim 10 wherein the first material layer and the formable material have different etch characteristics.
15. The method of claim 10 wherein the first material layer contains a metal.
16. The method of claim 10 wherein the first material layer contains a chromium.