We have developed a patterning method which combines the alignment capabilities of optical lithography with the intrinsic nanometer-scale dimensions of self-assembled diblock copolymer films. We use surface topography to direct the assembly of cylindrical copolymer domains so as to subdivide larger patterns defined using optical lithography, in the process precisely registering the location of each 20 nm polymer domain to the lithographic pattern. In this way self assembly techniques can be used together with optical lithography in order to pattern complex, multi-level, aligned circuit elements at sub-lithographic dimensions with a minimal increase in processing complexity.
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| Lithographically- patterned 0.28um line. | Lithographic line subdivided by self assembly process into 18nm line/space pattern. |
The self-aligned self assembly process can be used to subdivide more complex patterns such as the
doughnut-shaped pattern on the left. The image on the right shows lithographically-defined circles which have been subdivided into bullseye patterns.