“Dual-Tone” Area-Selective Deposition: Selectivity Inversion of Polymer on Patterned Si/SiO₂ Starting Surfaces

Area-selective deposition (ASD) has recently emerged as a promising augmentation of lithographic patterning of small device features. However, current ASD processes are restricted to predefined growth and nongrowth surfaces, limiting their flexibility in industrial processing. In this work, we define the concept of “dual-tone ASD,” where a patterned surface is tuned to enable ASD on one of two adjacent surfaces while avoiding growth on the other surface. For the example case in this work, starting with ASD of the poly(3,4-ethylenedioxythipohene) (PEDOT) conjugated polymer on SiO 2 vs on hydrogen-terminated silicon (Si–H), we demonstrate a method to modify a patterned Si–H/SiO 2 surface to invert the selectivity, enabling PEDOT to grow selectively on the modified Si region and not on the modified SiO 2 . The selectivity inversion was achieved by selective modification of the substrate surface energy via treatments with dilute hydrofluoric acid (DHF), (dimethylamino)trimethylsilane (DMATMS), and water. Versatile control over selectivity configurations during ASD has implications for deposition of lateral control layers to reduce overgrowth defects, blocking layers for nonselective deposition steps, and sacrificial layers for recently reported simultaneous deposition and etching processes. Through this study, we identify generalized requirements for selectivity inversion as a patterning strategy in the ASD toolbox and show how this strategy is consistent with previous reports of ASD on metal–dielectric patterned surfaces. Extension of these surface energy treatment strategies to other materials will provide additional opportunities for selectivity inversion, leading to flexible applications of ASD in manufacturing settings.