A new class of materials for nanoscale patterning

The microscopic components that make up computer chips must be made at staggering scales. With billions of transistors in a single processor, each made of multiple materials carefully arranged in patterns as thin as a strand of DNA, their manufacturing tools must also operate at a molecular level.

Typically, these tools involve using stencils to selectively pattern or remove materials with high fidelity, layer after layer, to form nanoscale electronic devices. But as chips must fit more and more components to keep up with the digital world's growing computational demands, these nanopatterning stencils must also become smaller and more precise.

Now, a team of Penn Engineers has demonstrated how a new class of polymers could do just that. In a new study, the researchers demonstrated how "multiblock" copolymers can produce exceptionally ordered patterns in thin films, achieving spacings smaller than three nanometers.

The team, led by Karen Winey, Harold Pender Professor in the Departments of Materials Science and Engineering and Chemical and Biomolecular Engineering, and Jinseok Park, a graduate student in her lab, published these findings in the journal ACS Central Science. They collaborated with Anne Staiger and Professor Stefan Mecking of the University of Konstanz, Germany.

The stencils used in fabricating chips have nanoscale patterns that can be produced by a variety of methods. For example, fine lines and small dots can be produced by a technique known as directed self assembly (DSA), where the polymer chemistry is designed such that it automatically produces the desired geometry.

Current DSA methods use "diblock" copolymers, named for having two long blocks of different polymers bonded end to end, which then assemble to produce the necessary patterns.

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