Directed Self-assembly
As of 2010, much progress was reported on the use of PMMA-PS block copolymers to define sub-20 nm patterns by means of self-assembly, guided by surface topography and/or surface chemical patterning. The key benefit is the relatively simple processing, compared to multiple exposures or multiple depositions and etching. The main drawback of this technique is the relatively limited range of feature sizes and duty cycles. Nevertheless, the timing for sub-20 nm node ~2013 is currently being targeted. Typical applications have been regular lines and spaces as well as arrays of closely packed holes. However, random, aperiodic patterns may also be generated using carefully defined guiding patterns.
Read more about this topic: Multiple Patterning
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