Direct Printing of Ultrathin Block Copolymer Film with Nano‐in‐Micro Pattern Structures

Abstract Nanotransfer printing (nTP) is one of the most promising nanopatterning methods given that it can be used to produce nano‐to‐micro patterns effectively with functionalities for electronic device applications. However, the nTP process is hindered by several critical obstacles, such as sub‐20 nm mold technology, reliable large‐area replication, and uniform transfer‐printing of functional materials. Here, for the first time, a dual nanopatterning process is demonstrated that creates periodic sub‐20 nm structures on the eight‐inch wafer by the transfer‐printing of patterned ultra‐thin (<50 nm) block copolymer (BCP) film onto desired substrates. This study shows how to transfer self‐assembled BCP patterns from the Si mold onto rigid and/or flexible substrates through a nanopatterning method of thermally assisted nTP (T‐nTP) and directed self‐assembly (DSA) of Si‐containing BCPs. In particular, the successful microscale patternization of well‐ordered sub‐20 nm SiO x patterns is systematically presented by controlling the self‐assembly conditions of BCP and printing temperature. In addition, various complex pattern geometries of nano‐in‐micro structures are displayed over a large patterning area by T‐nTP, such as angular line, wave line, ring, dot‐in‐hole, and dot‐in‐honeycomb structures. This advanced BCP‐replicated nanopatterning technology is expected to be widely applicable to nanofabrication of nano‐to‐micro electronic devices with complex circuits.


Table of contents (ToC)
Figure S1.Sequential process for the fabrication of nano-in-micro pattern structures.

Figure S3 .
Figure S3.Self-assembled BCP on a planar surface.

Figure S4 .
Figure S4.Multiple BCP line patterns consisting of self-assembled SiO x spheres.

Figure S5 .
Figure S5.Sequential cross-sectional SEM images for multi-layered BCP film at 2 wt% before dry-etching process.

Figure S6 .
Figure S6.Ultra-thin replica BCP layer on an adhesive PI film.Figure S7.Temperature dependency on the transfer yield of ultra-thin BCP film.

Figure S8 .
Figure S8.Center-to-center size distribution of transfer-printed nut-shaped SiO x nanodot patterns.

Figure S9 .
Figure S9.Si guiding templates with complex pattern geometries.

Figure S10 .
Figure S10.Unusual and complex nano-in-micro pattern structures by T-nTP of selfassembled BCP.

Figure S11 .
Figure S11.Self-assembled SiO x line structure with a line width of sub-20-nm on a planar surface without a guiding template.

Figure S12 .
Figure S12.Dependency on the annealing time of the self-assembled SiO x line structures.

Figure S13 .
Figure S13.Optimization process of annealing conditions for cylinder-forming SD45BCP.

Figure S14 .
Figure S14.Transfer-printed SiO x lines within the individual microscale line pattern when using a cylinder-forming SD28 BCP.

Figure S15 .
Figure S15.Transfer-printed ring-shaped SiO x lines within the complex microscale dotin-hole pattern when using a cylinder-forming SD28 BCP.

Figure S16 .
Figure S16.Defects on the center and edge sides of the transfer-printed BCP patterns at an eight-inch wafer scale.

Figure S17 .
Figure S17.Procedure for the pattern formation of multi-layered BCP film at an 8-inch wafer scale.

Figure S1 .
Figure S1.Sequential process for the fabrication of nano-in-micro pattern structures.(Step 1: DSA of BCP) The BCP solution is spin-coated onto a Si guiding template fabricated by the conventional photolithography process.The coated BCP thin film is solvothermalannealed at a warm temperature (~ 65℃) using a stainless-steel chamber that can provide solvent vapor into the BCP film.(Step 2: transfer-printing of BCP patterns) A replica BCP pattern is generated by attaching and detaching using an adhesive PI film.The functional BCP pattern is printed onto the target substrate through the T-nTP process, after which transfer-printed replica BCP film is etched by CF 4 plasma followed by O 2 plasma.The oxidized PDMS nanodots-in-unusual micro pattern structure (nano-in-micro pattern) is successfully obtained.

Figure
Figure S2.Transfer-printed ultra-thin BCP lines.SEM image of discrete BCP line patterns with a width of 1 µm.

Figure S4 .
Figure S4.Multiple BCP line patterns consisting of self-assembled SiO x spheres.(a) Schematic images of self-assembled multi-layer PDMS dots.(b) Transfer-printed multi-layer BCP patterns.Multi-layer microscale BCP line patterns can be obtained by controlling the BCP film thickness.

Figure S5 .
Figure S5.Sequential cross-sectional SEM images for multi-layered BCP film at 2 wt% before dry-etching process.(a) Si mold with a depth of 40 nm, (b) After spin coating of BCP, (c) After transfer-printing.When using the SD56 BCP solution with a higher weight percent, the transfer printing result shows an interconnected BCP film rather than individual BCP lines (thickness of transfer-printed BCP film: ~ 80 nm).

Figure S6 .
Figure S6.Ultra-thin replica BCP layer on an adhesive PI film.Photograph of the replicated BCP film from the micro-patterned Si mold.

Figure S7 .
Figure S7.Temperature-dependency on the transfer yield of ultra-thin BCP film.Photographs of transfer-printed BCP films from 25℃ to 150℃.The threshold temperature for the successful patterning of the ultra-thin BCP film is 120℃.

Figure S8 .
Figure S8.Center-to-center size distribution of transfer-printed nut-shaped SiO x nanodot patterns.Mean value of center-to-center distance is 2.51 µm.The error range of the transfer-printed nano-in-micro patterns is less than 0.5%.

Figure S10 .
Figure S10.Unusual and complex nano-in-micro pattern structures by the T-nTP of selfassembled BCP.Transfer-printed microscale (a) dot-in-hole and (b) dot-in-honeycomb patterns composed of self-assembled SiO x nanodots.(c & d) Uniformity of the transfer-printed inner units (dot) and outer units (dot and hexagon), showing mean size values of 901.7 nm (Unit 1, U 1 ), 2.02 µm (U 2 ), 889.7 nm (U 3 ), and 1.97 µm (U 4 ), respectively.The maximum error range of all printed units is less than 0.2%.

Figure S11 .
Figure S11.Self-assembled SiO x line structure with a line width of sub-20-nm on a planar surface without a guiding template.(a) Schematic of cylinder-forming SD45 BCP.(b) SEM image of disordered SiO x lines.

Figure S12 .
Figure S12.Dependency on the annealing time of the self-assembled SiO x line structures.Periodic SD45 line structures were obtained at annealing time of 60 mins.

Figure S13 .
Figure S13.Optimization process of annealing conditions for cylinder-forming SD45 BCP.The self-assembled sub-20 nm SiO x lines within a wave-shaped SD45 BCP pattern at varied annealing times, indicating the optimum annealing time (60 min) and temperature (85℃).

Figure S14 .
Figure S14.Transfer-printed SiO x lines within the individual microscale line pattern when using a cylinder-forming SD28 BCP.

Figure S15 .
Figure S15.Transfer-printed ring-shaped SiO x lines within the complex microscale dotin-hole pattern when using a cylinder-forming SD28 BCP.

Figure S16 .
Figure S16.Defects on the center and edge sides of the transfer-printed BCP patterns at an eight-inch wafer scale.The irregular pattern structures may be due to non-uniform BCP film thickness and/or low solvent injection rate in the annealing process of BCP before transfer-printing process.

Figure S17 .
Figure S17.Procedure for the pattern formation of multi-layered BCP film on the eightinch wafer scale.The depth of micro-patterned Si mold is ~ 250 nm.