advances.sciencemag.org/cgi/content/full/1/10/e1500751/dc1 Supplementary Materials for Uniform metal nanostructures with long-range order via three-step hierarchical self-assembly The PDF file includes: Denise J. Erb, Kai Schlage, Ralf Röhlsberger Published 6 November 2015, Sci. Adv. 1, e1500751 (2015) DOI: 10.1126/sciadv.1500751 Fig. S1. AFM micrographs illustrating the dependence of the degree of lateral domain ordering on the ratio of diblock copolymer film thickness to substrate facet height. Fig. S2. Large-area AFM scans of highly ordered metal nanostructure patterns. Fig. S3. Experimental data and simulations of GISAXS patterns for hexagonal Fe nanodot array growing at room temperature. Fig. S4. Experimental data and simulations of GISAXS patterns for hexagonal Fe nanodot array growing at 170 C. Table S1. Compositional properties of the diblock copolymers used. Table S2. List of apparatus and duration of individual process steps. Discussion of nanopattern yield.
Fig. S1. AFM micrographs illustrating the dependence of the degree of lateral domain ordering on the ratio of diblock copolymer film thickness and substrate facet height. If d/h is too low, the substrate facets deform the surface of the diblock copolymer film. If d/h is too high, the guiding effect of the substrate topography and thus the long-range lateral domain ordering in the copolymer film is lost. Insets show fast Fourier transformations of the height information.
Fig. S2. Large-area AFM scans of highly ordered metal nanostructure patterns. Large-area AFM micrographs of a) nanofaceted substrate surface and b) d) Fe nanostructure patterns grown on symmetric and asymmetric diblock copolymer templates. Long range lateral ordering is induced by the substrate; the different nanostructure patterns illustrate some of the morphological options and the scalability of the domain size of the diblock copolymer templates.
Fig. S3. Experimental data and simulations of GISAXS patterns for hexagonal Fe nanodot array growing at room temperature. Sections in qy and qz direction through a sequence of GISAXS patterns, recorded in-situ during Fe nanodot growth at room temperature, with simulations (red solid lines). Labels indicate the elapsed Fe deposition time.
Fig. S4. Experimental data and simulations of GISAXS patterns for hexagonal Fe nanodot array growing at 170 C. Sections in qy and qz direction through a sequence of GISAXS patterns, recorded in-situ during Fe nanodot growth at 170 C, with simulations (red solid lines). Labels indicate the elapsed Fe deposition time.
Reference domain total volume poly- equilibrium name morphology molecular fraction of PS dispersity domain mass period D0 BCP-L lamellar 100 kg/mol 47 % 1.12 48 nm BCP-C1 cylindrical 94 kg/mol 28 % 1.18 48 nm BCP-C2 cylindrical 205 kg/mol 31 % 1.08 83 nm Table S1. Compositional properties of the diblock copolymers used. All listed copolymers are linear PS-b-PMMA diblock copolymers, commercially purchased from Polymer Source, Inc.
Apparatus Purpose Duration of process step ultrasonic acetone bath chamber furnace scale, shaker spin coater oven screw cap glass, custommade sample holder custom-made UHV chamber cleaning of α-al2o3 substrates (15 x 15 mm² or 20 x 20 mm²) faceting of α-al2o3 substrates by high-temperature annealing in air preparation of copolymer solution (3 ml per solution) preparation of copolymer thin films drying of copolymer thin films at 50 C in air chemical microphase separation by solvent vapor annealing nanostructure growth by metal deposition and selective diffusion 15 minutes (up to four substrates in parallel) 18 to 20 hours (up to ten substrates in parallel) usually overnight, min. 3 hours (up to four solutions in parallel) 1 minute (per film, no parallel processing) 2.5 hours (up to ten samples in parallel) 2 to 3 hours (up to ten samples in parallel) about 3 hours (per sample of up to 20 x 20 mm²) Table S2: List of apparatus and duration of individual process steps. Discussion of nanopattern yield. α-al2o3 substrates were commercially purchased (CrysTec GmbH) and cleaned in an ultrasonic acetone bath at 50 C. They were then annealed in air in a chamber furnace (borel MO-1800) with heating rates of 300K/h and passive cooling after annealing. To achieve the desired facet dimensions, substrates were annealed at temperatures between 1300 C and 1400 C for 8 to 10 hours. Including heating and cooling, the annealing procedure thus took about 18 to 20 hours. We prepared the substrates in batches of up to ten pieces (15 x 15 mm² or 20 x 20 mm²) and stored them in large quantities for later use. Solutions of PS-b-PMMA were prepared from commercially purchased PS-b-PMMA (Polymer Source, Inc.) within 3 hours and can be stored for several months in a cool place protected from exposure to UV radiation. Depositing and processing the diblock copolymer thin films to obtain the chemically nanopatterned templates is accomplished within about 6 hours. The templates, too, can be stored for many months at ambient conditions without deterioration. The stated duration for metal nanostructure growth is very specific for our custom-made UHV chamber. It includes loading and evacuating the UHV chamber, heating the sample, interrupting the deposition to cool down the sputtering source, the actual metal deposition (about 5 minutes for Fe, duration varies for different materials), and venting the UHV chamber. An explicit comparison of the patterning throughput of the proposed self-assembly method with the throughput of state-of-the-art lithographical nanostructure fabrication is not instructive: We present a laboratory-scale demonstration of a new routine, while some lithography-based techniques were introduced decades ago and have meanwhile reached high degrees of up-scaling and automation. Nevertheless, some quantitative values for process durations and patterned areas in our specific case may give an impression of the efficiency of nanopatterning by hierarchical self-assembly. The possibility to store substrates, solutions, and templates, reduces the metal nanopattern fabrication time to the time required for metal deposition typically a few hours for our setup. The nanostructure patterns presented here cover areas of 3 cm². This results in patterning rates of about 1 cm² per hour. The sample size was chosen for ease of handling and accounted for the
dimensions of the available fabrication and characterization devices. Since the proposed routine employs exclusively self-assembly processes, the samples can in principle be scaled up to much larger sizes, achieving even larger patterning rates without increasing duration or complexity of the preparation procedure. On a laboratory scale, sample sizes of about 10 x 10 cm² are conceivable. In an industrial context, technical equipment optimized for high throughput, such as automated spin coaters, large-volume furnaces, or inline sputtering systems would further increase the patterning rate. Combining both approaches increasing the sample size and employing high-throughput fabrication devices can result in an increase of the patterning rate to the order of magnitude of 1000 cm² per hour or more.