Seminar Date: Tuesday, February 25, 2025
Time: 11:00 AM PT
Location: 67-3111 & Zoom
Talk Title: Understanding the Role of Entropy in Medium to High-Entropy Oxides and Alloys for Clean Energy Applications
Zoom link
Abstract:
The resolution of extreme ultraviolet (EUV) lithography is limited by stochastic variations, which appear as line roughness and pattern defects. We aim to mitigate these imperfections through the directed self-assembly (DSA) of block copolymers (BCPs), which are thermodynamically driven to smooth interfaces and heal defects. PS-b-PMMA, the most commonly used BCP for lithographic applications, cannot form suitable line features with dimensions below 11 nm, so new BCP chemistries must be developed for DSA at EUV-relevant dimensions. In this work, we study assemblies of A-b-(B-r-C) copolymers with varied segregation strengths. In addition to achieving DSA at small pitch values, this flexible platform provides opportunities to investigate the thermodynamics that dictate self-assembly and pattern quality. Specifically, we use Resonant Soft X-Ray Reflectivity to directly measure the structure of lamellar BCP films, allowing us to uncover relationships between BCP pitch, segregation strength, and interfacial width. We also reconstruct the three-dimensional structure of guided and unguided BCPs using TEM Tomography, providing insights into the full structure of the critical block-block interfaces. In the future, we will connect these studies to the holistic performance of A-b-(B-r-C) BCPs as DSA materials on EUV patterns.