Litho UniversitySM: Directed Self-Assembly 101

July 07,2015

By definition, self-assembly is a phenomenon that occurs when components spontaneously organize themselves into a functional system. Nanotechnology researchers have been studying self-assembly to enable development of electronic devices that are miniscule yet information-rich, such as chemical and biological sensors. Directed self-assembly (DSA) is actively being explored for use in the lithography process of semiconductor manufacturing.

In this series of videos, I will take you on a journey through the amazing world of DSA for microlithography. These videos, developed for Dow’s  Litho University SM, address key challenges and techniques for this emerging technology.

DSA for Advanced Patterning
DSA of block copolymers holds promise for advanced semiconductor patterning. If designed properly, block copolymers can phase separate into a variety of ordered nanostructures that resemble common lithographic features.

Part 1 of this video introduces viewers to block copolymer self-assembly, and two of the pathways that have been developed to direct them into ordered nanostructures.

View Part 1

In Part 2, we discuss PS-PMMA, the leading block polymer for DSA despite the fact that it has a relatively weak driving force for self-assembly, i.e. a low chi parameter. This short video describes the attractive features and limitations of PS-PMMA, and also some considerations for design of new high-chi block copolymer systems.

View Part 2

Brushes and Mats to Enable DSA Chemoepitaxy
Chemoepitaxy is a leading DSA technique in which a chemical contrast on a relatively flat substrate is used to align a lamellar block copolymer to form a line space pattern. In this segment, we provide an in-depth look at the neutral brush or mat. These surface treatment techniques provide control over block copolymer orientation and are a key enabler of these DSA processes.

View the video

Graphoepitaxy with Cylinders
Graphoeptaxy with cylinders enables use of high chi block copolymers, but is currently less common than chemoepitaxy for line/space patterning due to the misconception that feature density is compromised because of the space consumed by the guide structures. This segment dispels these concerns by discussing the keys to enable cylinder graphoepitaxy and demonstrating that 1:1 line space patterns can be achieved.