1 research outputs found
Ultrathin and Conformal Initiated Chemical-Vapor-Deposited Layers of Systematically Varied Surface Energy for Controlling the Directed Self-Assembly of Block CoPolymers
Directed self-assembly
(DSA) of block copolymer (BCP) thin films
is a promising approach to enable next-generation patterning at increasingly
smaller length scales. DSA utilizes interfacial wetting layers to
force the BCP domains to self-assemble with the desired orientation
with respect to the substrate. Here, we demonstrate that initiated
chemical-vapor-deposited (iCVD) polydivinylbenzene (pDVB) ultrathin
films can direct the self-assembly of poly(styrene-<i>block</i>-methylmethacrylate). We found that the methyl radicals formed at
increased filament temperatures during the iCVD process result in
the backbone methylation of pDVB. By tuning the degree of backbone
methylation, we systematically changed the wetting properties of the
iCVD pDVB from a slight poly(methylmethacrylate) preference to complete
poly(styrene) preference. Additionally, we utilize the conformal nature
of the iCVD to form a wetting layer over a topographical line and
space pattern, which is subsequently used to produce self-assembled
BCP films with both perpendicular orientation and long-range alignment