Block copolymer (BCP) lithography has emerged as a promising strategy to create highly regular and dense dot or line arrays at the sub-50 nm length scale. [1][2][3][4][5][6] Block copolymer lithography refers to the use of self-assembled domain structures, typically spheres, cylinders, and lamellas in thin-film form as a template for the addition and subtraction nanofabrication processes. [5] Mainly two pattern geometries have been studied extensively: dense arrays of dots and dense arrays of lines and spaces. The former can be generated from sphereforming BCP or from cylinder-forming BCP with domains oriented perpendicular to the substrate, and the latter from cylinder-forming BCP with domains oriented parallel to the substrate or lamella forming BCP with domains oriented vertically to the substrate. These periodic arrays based on self-assembly in BCP thin films have been examined for fabrication of magnetic storage media, quantum dot arrays, photonic crystals, and nanowire transistors. [4,[7][8][9][10] Vertically oriented domain structures have distinct advantages in terms of pattern transfer to the underlying substrate and fabrication of high-aspect ratio features.[11] In the case of perpendicular cylinder or perpendicular lamellae, the orientation of the BCP microdomains can be controlled by solvent evaporation, electric fields, directional crystallization, [12][13][14][15] physical constraints (topography), or chemical patterns. [16][17][18][19] Perhaps the most common means to induce perpendicular domain orientation, however, is to chemically modify and control the interaction between the BCP and the substrate. [20,21] For example, the substrate can be chemically modified by using self-assembled monolayers (SAMs) or random copolymer brush. SAMs of alkylthiols (on gold) or alkylsiloxanes (on Si/SiO 2 ) with polar or non-polar terminal groups have been utilized to modify the substrate. [22][23][24] Exposure to different doses of X-ray in the presence of oxygen can further alter the polarity and hence the wetting behavior of the SAM resulting in a symmetric, neutral or asymmetric BCP morphology. [25] Mansky and coworkers demonstrated that the interfacial energies between the PS and PMMA blocks of P(S-b-MMA) and the substrate can be carefully balanced by grafting an end-hydroxy functionalized P(S-r-MMA) polymer on the SiO x /Si substrate. [20,26,27] Covalent grafting of P(S-r-MMA)having f St (where f st is the styrene fraction) of 0.58 resulted in the neutral wetting behavior and the vertical orientation of lamellar or cylindrical domains. In this original report covalent grafting is usually achieved through the dehydration reaction between the end-hydroxy functionalized P(S-r-MMA) and the native oxide layer of silicon substrate. Ryu et. al recently reported an elegant chemistry to create substrate independent neutral surface through the self thermal crosslinking reaction of benzocyclobutene (BCB)-containing random copolymers at temperatures above 200°C.[28] The high temperature required for efficient cross-lin...