Advances in nanolithography using molecular rulers
Anderson, M.E.; Tan, L.P.; Tanaka, H.; Mihok, M.; Lee, H.; Horn, M.W.; Weiss, P.S. Advances in Nanolithography Using Molecular Rulers. J. Vac. Sci. Technol., B: Microelectron. Nanometer Struct. -- Process., Meas., Phenom.2003,21, 3116-3119.
The combination of conventional lithographic techniques with chemical self-assembly allows for the creation of nanostructures whose spacing and edge resolution reach nanometer-scale precision. The controlled placement and thickness of self-assembled multilayers composed of alternating layers of α,ω-mercaptoalkanoic acids and coordinated metal ions form precise “molecular ruler” resists that enable the production of tailored and lithographically defined metal patterns. Initial structures created by conventional techniques are referred to as parents and subsequent structures generated by the molecular ruler process are identified as daughters. We report the further creation of subsequent generation structures (granddaughters) that have sub-100 nm dimensions. The granddaughter structures are created by forming molecular rulers on parent and daughter structures, and can be isolated by removing sacrificial parent and/or daughter structures. This process has also been utilized in combination with parent structures created by the process of nanosphere lithography to produce arrays of metal features with 10 nm spacings. Since our original report, we have improved the throughput and reproducibility of the molecular ruler process by automating its iterative nature and by utilizing appropriate chemical lift-off solutions.
Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena