Shrinking integrated circuits
Researchers using the XSD 8-ID-E beamline at the APS are seeking new means to shrink integrated circuits to enable cheaper and more energy-efficient microchips. The team is exploring block copolymer nanolithography as a low-cost strategy to improve fabrication of nanoscale features in semiconductors.
Progress in semiconductor fabrication relies on shrinking the features of integrated circuits, enabling faster, cheaper and more energy-efficient microchips. However, smaller features have traditionally relied on the development of new or improved lithographic techniques. State-of-the-art 193 nm immersion lithography encounters substantial difficulties in accessing sub-30 nm features, and although extreme ultraviolet (EUV) and electron-beam lithographies have demonstrated promising results, the cost and throughput of these methods remain problematic for industrial implementation.
We report herein the modular synthesis and nanolithographic potential of poly(dimethylsiloxane-block-methyl methacrylate) (PDMS-b-PMMA) with self-assembled domains approaching sub-10 nm periods. A straightforward and modular coupling strategy, optimized for low molecular weight diblocks and using copper-catalyzed azide–alkyne “click” cycloaddition, was employed to obtain a library of PDMS-b-PMMA and poly(dimethylsiloxane-block-styrene) (PDMS-b-PS) diblock copolymers.
Flory–Huggins interaction parameters, determined from small-angle X-ray scattering experiments, were high for PDMS-b-PMMA (χ ∼ 0.2 at 150 °C), suggesting this diblock copolymer system has promise for sub-10 nm lithographic applications when compared to the corresponding PDMS-b-PS diblock copolymers (χ ∼ 0.1 at 150 °C). Performance evaluation in thin film self-assembly experiments allowed domain periods as small as 12.1 nm to be obtained, which is among the smallest highly ordered nanoscale patterns reported hitherto for thermally annealed materials.
Yingdong Luo, Damien Montarnal, Sangwon Kim, Weichao Shi, Katherine P. Barteau, Christian W. Pester, Phillip D. Hustad, Matthew D. Christianson, Glenn H. Fredrickson, Edward J. Kramer and Craig J. Hawker, “Poly(dimethylsiloxane-b-methyl methacrylate): A Promising Candidate for Sub-10 nm Patterning,” Macromolecules, Article ASAP. DOI: 10.1021/acs.macromol.5b00518, Published May 19, 2015.