Large-Scale Formation of a Close-Packed Monolayer of Spheres Using Different Colloidal Lithography Techniques

The possibility of using colloidal lithography at the industrial level depends on the ability to form defect-free coatings over large areas. The spin-coating method has not yet shown acceptable results, but a more detailed studying of the regularities of this process may improve the quality of masks. The Langmuir–Blodgett method is expected to be the most preferable for forming high-quality large-scale monolayers. Real-time controlling the surface pressure of the monolayer can allow to obtain close-packed arrays with long-range order. In this work, to develop the spin-coating technology, the influence of technological parameters (spin-coating speed and time, concentrations of components in suspension) on the substrate coverage area with a monolayer of polystyrene spheres (1.25 μm) was studied. An original automated Langmuir–Blodgett system was developed to study the influence of the monolayer surface pressure on its quality using polystyrene spheres (1.25, 1.8, 2.1 μm). The developed spin-coating technology resulted in a record coverage area (90%) of Si substrate (76 mm) and a defect-free hexagonally ordered domain area of 500 μm2. As a result of the developed Langmuir–Blodgett technique, a close-packed monolayer coating was obtained over the entire substrate area (coverage area 99.5%, defect-free domain area 3000 μm2) without the use of any surfactants.