High-Precision Solvent Vapor Annealing for Block Copolymer Thin Films

Micromachines

ChloeS. Drapes¹  MeaganA. Grant¹  Jeffrey Wong¹  Ryan Gnabasik¹  Andrew Baruth¹  Gunnar Nelson¹ 

[1] Department of Physics, College of Arts and Sciences, Creighton University, 2500 California Plaza, Omaha, NE 68178, USA;

关键词: block polymers;    self-assembly;    thin films;    solvent vapor annealing;    nanolithography;   

DOI  :  10.3390/mi9060271

来源: DOAJ

【 摘 要 】

Despite its efficacy in producing well-ordered, periodic nanostructures, the intricate role multiple parameters play in solvent vapor annealing has not been fully established. In solvent vapor annealing a thin polymer film is exposed to a vapor of solvent(s) thus forming a swollen and mobile layer to direct the self-assembly process at the nanoscale. Recent developments in both theory and experiments have directly identified critical parameters that govern this process, but controlling them in any systematic way has proven non-trivial. These identified parameters include vapor pressure, solvent concentration in the film, and the solvent evaporation rate. To explore their role, a purpose-built solvent vapor annealing chamber was designed and constructed. The all-metal chamber is designed to be inert to solvent exposure. Computer-controlled, pneumatically actuated valves allow for precision timing in the introduction and withdrawal of solvent vapor from the film. The mass flow controller-regulated inlet, chamber pressure gauges, in situ spectral reflectance-based thickness monitoring, and low flow micrometer relief valve give real-time monitoring and control during the annealing and evaporation phases with unprecedented precision and accuracy. The reliable and repeatable alignment of polylactide cylinders formed from polystyrene-b-polylactide, where cylinders stand perpendicular to the substrate and span the thickness of the film, provides one illustrative example.

【 授权许可】

Unknown