Design of silicon-containing block copolymer materials for applications in lithography
Continual advancement in microelectronic performance has made microelectronics essentially ubiquitous, enriching modern life in ways unimaginable even a few decades ago. The advancement in microelectronic devices is made possible by advancements in the manufacturing processes used to make them. Chief among these technologies is lithography, the process by which the individual components on the device are patterned. At present, complex and complicated double-patterning processes are being used to extend the resolution of the lithographic methods used in high-volume manufacturing, but only at great cost. Future generations of microelectronic devices will require even further use of multiple-patterning processes, at which point the economics of manufacturing could prevent the commercialization of such devices. This economic reality has spurred interest in alternative patterning technologies. One of the leading potential methods is to exploit the self-assembly of block copolymers (BCPs). BCPs are a type of polymer consisting of two or more chemically distinct blocks that are covalently joined together. The components of a BCP can phase-separate, and the resultant features form on the 5 to 50 nm length-scale. This size range is coincidentally ideal for next-generation semiconductor devices. However, BCPs on their own do not immediately form device-relevant features. Processes known collectively as directed self-assembly (DSA) are needed to properly guide BCPs. The work in this dissertation focuses on a very specific class of BCPs, those that contain silicon in just one of the blocks. The presence of silicon in the molecule produces many lithographic advantages, but also requires specialized processing steps. Chapter 1 provides an overview of lithography and block copolymer self-assembly. Chapter 2 introduces the materials and techniques needed to control the behavior of silicon-containing BCPs. Chapter 3 presents and characterizes a variety of silicon-containing BCPs. Last, Chapters 4 and 5 describe two implementations of silicon-containing BCP DSA, one for semiconductor patterning, and the other for hard disk drive applications.