US Patent 7713753 - 2-level self-assembled patterning

http://www.freepatentsonline.com/7713753.html

Block copolymers have been shown to self-assemble into periodic nanoscale patterns when deposited onto a substrate which can be useful to maskless lithography. This patent from Seagate Technology teaches a multi-layer self-assembly method with block copolymers. Claim 1 reads:

1. A method of fabricating a device comprising:

providing a substrate having a patterned surface;

depositing a first-level block copolymer self-assembled material on at least a portion of the patterned surface, wherein the position and/or orientation of the first-level self-assembled material is directed by the patterned surface, to form a first nanostructure pattern; and

depositing a second-level self-assembled material on at least a portion of the first nanostructure pattern to form an array of nanostructures of the second-level self-assembled material.