Tessellated patterns in imprint lithography
The present invention is directed towards a choice of the shape of the patterned fields for Level 0 (patterned by imprint or photolithography or e-beam, etc.) and Level 1 (patterned by imprint) such that these shapes when tessellated together eliminate the open areas causes by the moats.
1. An imprint lithography method for forming patterned fields without open areas between the fields, the method comprising:
providing a substrate having a plurality of patterned fields formed thereon, each field having a first field layout, the first field layout having a first active area and a first boundary area having a plurality of first alignment marks, the first field layout further configured such that each field tessellates with each adjacent field;
providing an imprint lithography template configured for imprinting a second field layout, the second field layout having a second active area and a second boundary area having a plurality of second alignment marks and a plurality of dummy grating areas, the second field layout further configured such that adjacent fields imprinted by the imprint lithography template tessellate with each other; and
imprinting second field layouts over first field layouts using the imprint lithography template, wherein such imprinting further comprises imprinting dummy gratings over first alignment marks of first field layouts and wherein such imprinted dummy gratings do not interfere with the alignment of second alignment marks of the template with first alignment marks of the first pattern when imprinting adjacent second field layouts.
2. The method of claim 1 wherein the patterned fields are formed from a method selected from the group of: imprint lithography, photolithography, and e-beam lithography.
3. The method of claim 1 wherein the second active area of the template includes a plurality of features.
4. The method of claim 1 wherein the first alignment marks of the first field layout are checkerboard in design.
5. The method of claim 1 wherein the first boundary includes a test pattern region.
6. The method of claim 1 wherein the dummy grating areas have gratings having a pitch that does not substantially interfere with a signal caused by the alignment marks.
7. The method of claim 1 wherein the dummy grating areas each have gratings having a duty cycle nominally similar to that of features in a region surrounding the dummy grating area.