Date of Graduation
12-2020
Document Type
Dissertation
Degree Name
Doctor of Philosophy in Engineering (PhD)
Degree Level
Graduate
Department
Mechanical Engineering
Advisor/Mentor
Paul Millett
Committee Member
Min Zou
Second Committee Member
Arun Nair
Third Committee Member
Jim Leylek
Fourth Committee Member
Brian Berry
Keywords
Block co-polymer, cold zone annealing, epitaxial templating, surface engineering
Abstract
Directed self-assembly (DSA) of block copolymers (BCPs) has been shown as a viable method to achieve bulk fabrication of surface patterns with feature sizes smaller than those available through traditional photolithography. Under appropriate thermodynamic conditions, BCPs will self-assemble into ordered micro-domain morphologies, a desirable feature for many applications. One of the primary interests in this field of research is the application of thin-film BCPs to existing photolithography techniques. This “bottom-up” approach utilizes the self-assembled BCP nanostructures as a sacrificial templating layer in the lithographic process.
While self-assembly occurs spontaneously, extending orientational uniformity over centimeter-length scales remains a critical challenge. A number of DSA techniques have been developed to enhance the long range order in an evolving BCP system during micro-phase separation. Of primary interest to this dissertation is the synergistic behavior between chemoepitaxial templating and cold-zone annealing. The first method involves pre-treating a substrate with chemical boundaries that will attract or repel one of the monomer blocks before application of the thin-film via spin-coating. The second method applies a mobile, thermal gradient to induce micro-phase separation in a narrow region within the homogeneous thin-film .
Parametric studies have been performed to characterize the extent of long range order and defect densities obtained by applying various thermal zone velocities and template patterns. These simulations are performed by utilizing a Time-Dependent Ginzburg-Landau (TDGL) model and an optimized phase field (OPF) model. Parallel processing is implemented to allow large-scale simulations to be performed within a reasonable time period.
Citation
Hill, J. (2020). Numerical Simulations of Directed Self-Assembly Methods in Di-block Copolymer Films for Efficient Manufacturing of Nanoscale Patterns with Long-Range Order. Graduate Theses and Dissertations Retrieved from https://scholarworks.uark.edu/etd/3833