Simple orientational control over cylindrical organic–inorganic block copolymer domains for etch mask applications

• Published in: Thin solid films 2009-06, Vol.517 (15), p.4474-4478
• Main Authors: Ramanathan, Muruganathan, Nettleton, Elizabeth, Darling, Seth B.
• Format: Article
• Language: English
• Subjects: Atomic force microscopy (AFM); Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Lithography; Materials science; Methods of nanofabrication; Nanoscale materials and structures: fabrication and characterization; Nanoscale pattern formation; Other topics in nanoscale materials and structures; Physics; Polymers; Self-assembly; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2009.02.078

Bottom-up patterning methodologies, predicated on chemical self-assembly, have the potential to transcend limitations associated with more traditional lithographies. By controlling the domain orientation of a cylinder-forming organic–inorganic block copolymer, poly(styrene-block-ferrocenyldimethylsilane), it is possible to straightforwardly fabricate massive arrays of either nanoscale dots or wires out of a film composed of a wide variety of materials. In the work reported here, orientational control is achieved by manipulating the polymer film thickness in concert with the annealing treatment. For films much thinner than the equilibrium periodicity of the microdomains, the cylinders spontaneously orient themselves perpendicular to the substrate. Films with thickness close to the equilibrium periodicity exhibit the more common in-plane orientation following thermal annealing. Solvent annealing leads to an in-plane orientation for the full range of film thicknesses studied. As a demonstration of the effectiveness of this method, semiconductor substrates were patterned with arrays of posts and wires, respectively, using the same starting polymeric material as the etch mask. Compatibility of this polymer with various substrate materials is also demonstrated.