The area selective growth of polymers and their use as inhibiting layers for inorganic film depositions may provide a valuable self-aligned process for fabrication. Polynorbornene (PNB) thin films were grown from surface-bound initiators and show inhibitory properties against the atomic layer deposition (ALD) of ZnO and TiO2. Area selective control of the polymerization was achieved through the synthesis of initiators that incorporate surface-binding ligands, enabling their selective attachment to metal oxide features versus silicon dielectrics, which were then used to initiate surface polymerizations. The subsequent use of these films in an ALD process enabled the area selective deposition (ASD) of up to 39 nm of ZnO. In addition, polymer thickness was found to play a key role, where films that underwent longer polymerization times were more effective at inhibiting higher numbers of ALD cycles. Finally, while the ASD of a TiO2 film was not achieved despite blanket studies showing inhibition, the ALD deposition on polymer regions of a patterned film produced a different quality metal oxide and therefore altered its etch resistance. This property was exploited in the area selective etch of a metal feature. This demonstration of an area selective surface-grown polymer to enable ASD and selective etch has implications for the fabrication of both micro- and nanoscale features and surfaces.

The combination of area-selective deposition (ASD) with a patternable organic monolayer provides a versatile additive lithography platform, enabling the generation of a variety of nanoscale feature geometries. Stearate hydroxamic acid selfassembled monolayers (SAMs) were patterned with extreme ultraviolet (λ = 13.5 nm) or electron beam irradiation and developed with ASD to achieve line space patterns as small as 50 nm. Density functional theory was employed to aid in the synthesis of hydroxamic acid derivatives with optimized packing density to enhance the imaging contrast and improve dose sensitivity. Near-edge X-ray absorption fine structure spectroscopy and infrared spectroscopy reveal that the imaging mechanism is based on improved deposition inhibition provided by the cross-linking of the SAM to produce a more effective barrier during a subsequent deposition step. With patterned substrates composed of coplanar copper lines and silicon spacers, hydroxamic acids selectively formed monolayers on the metal portions and could undergo a pattern-wise exposure followed by ASD in the first combination of a patternable monolayer with ASD. This material system presents an additional capability compared to traditional ASD approaches that generally reflect a starting patterned surface. Furthermore, this bottoms-up additive approach to lithography may be a viable alternative to subtractive nanoscale feature generation.

As the semiconductor community continues scaling, area selective atomic layer deposition (ASD) offers the potential to relax down stream processing steps by enabling self-aligned processes (e.g., self-aligned vias). Otherwise, conventional means of lithography face increasingly difficult challenges such as patterning and overlay errors as resolution improves. ASD can be achieved under a variety of conditions, and with the use of organic inhibiting materials, it can exhibit some of the highest levels of selectivity. However, the structure property relationship of these inhibiting materials is not completely understood, and therefore the relationship between a materials chemical functionality and its inhibiting properties remains largely unexplored. This was explored with polymeric materials that served as a versatile materials platform allowing a broad variation of chemical functional groups and physical properties that may then enable the ASD community to extend the number and types of films that can be selectively deposited. Initially, hydrophobic polymers including polystyrene (PS) and polyvinyl chloride (PVC), as well as an oleophobic polymer, poly[difluoro-bis(trifluoromethyo)-dioxole-co-tetrafluoroethylene] (PTFE-AF), were surveyed for their inhibitory properties toward the atomic layer deposition of industry relevant metal oxides such as Al2O3 and TiO2, which heavily feature as etch masks and other functional nanostructures. Despite blanket deposition of Al2O3 being observed, even when using an oleophobic polymer such as PTFE-AF, TiO2 deposition was notably inhibited by blanket films of PVC, PS, and PTFE-AF. In light of these results, the functionalization of PVC and PS with selective area substrate anchoring groups such as phosphonic acids (targeting copper oxide surfaces) was conducted to investigate whether grafting selectivity of these polymer films to their intended surface could be inhibited, thereby achieving film growth in the proximal uninhibited area. Two methods of polymer functionalization were evaluated: phosphonic acid groups distributed randomly throughout the polymer backbone of PVC and a single phosphonic acid group localized at the chain end of PS. Notably, the PVC multidentate derivatives and the PS monodentate type polymers exhibited effective inhibition of TiO2.