A Lithographer’s Guide to Patterning CMOS Devices with Directed Self-Assembly

Advances in lithography have always been critical in the drive toward each subsequent semiconductor node. By anticipating limitations in the scaling ability of immersion lithography, the industry has been pursuing next-generation lithography techniques beyond multiple patterning. Several techniques have been proposed, including extreme-ultraviolet (EUV) lithography, multibeam electronbeam lithography, nanoimprint lithography, and directed self-assembly (DSA) of block copolymers (BCPs). DSA has attracted a great deal of interest from major semiconductor manufacturers for several years following its initial demonstrations in the early 2000s. Since then, several methods or process flows for using DSA have been proposed by various groups. The purpose of this Spotlight is to compile various methods in one publication. The acronyms and naming conventions used in various publications can also be confusing for anyone who needs a concise description of the methods available. Another goal of this publication is to provide an easy-to-follow reference for lithographers who are interested in learning or using DSA for patterning. It is written for the nonchemist in mind or someone who has no familiarity with the DSA process; however, sufficient details are provided to follow and understand the steps.