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 self-assembled 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.

In this work, we connected the analytical determination of the EUV Dill C parameter for different photodecomposable base quencher (PDB) architectures using a standard addition method, the influence of the underlying hardmask on postdevelop EUV resist residue formation, and the vertical PAG and PDB concentration profile throughout the depth of the film determined by GCIB-TOF- SIMS for a model EUV resist system. The collected experimental data was used to feed a resist patterning simulation engine, in order to understand the additive effect of component distribution and efficiency on EUV stochastics and its potential impact on defect control. Our results unveiled a link between PDB quantum yield and nanoscopic material distribution uniformity. In parallel, a differentiating behavior was observed among inorganic underlayers: metal oxide hardmasks (HMs) invariably induced more resist residue than non-metallic HMs. Last, a specific example of joint PAG and PDB concentration depletion at the resist-substrate interface was related to a potential increase in microbridge defectivity as a result of poor stochastic counts.

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.

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.

At IBM, one of the focus items for EUV patterning development is to enable the fullest extent of scaling to a second EUV node while maintaining single-exposure levels. The challenge for the next node of EUV patterning has been with attaining acceptable defectivity levels that can enable electrical yield at pitches 32nm and below. For single-expose EUV, the primary detractors to sub-32nm pitch yield are typically microbridging and line break defects, which have different root causes but can exist in the same dose range. Since the etch strategies for mitigating one of these defect types will result in exacerbating the other, the burden to improve defectivity cannot be placed solely on the pattern transfer process. Resist scumming, which is the root cause of microbriging, can be modulated through interactions with the resist-hardmask interface. The lack of acid at the substrate interface causes resist scumming, and therefore increasing the acidity at the resist hardmask interface can be expected to mitigate post-litho microbridge defects. As the number of EUV photons are significantly less compared to DUV exposures due to the high energy contained in each photon, an extra acid boost can also help to address the stochastics failures that dominate EUV patterning. This paper will demonstrate the concept of modulating the resist-hardmask interaction through surface activation layers, and show the subsequent effects on patterning process window and microbridging defectivity toward yield at pitches <32nm.

Four halogen and hydrogen bonding rotaxane host systems featuring pyridinium bis-amide-iodotriazole/prototriazole and pyridinium bis-amide-iodotriazolium/prototriazolium axle components have been synthesized by CuAAC-mediated mono-stoppering chloride anion templation and post-rotaxanation methylation reactions. In competitive 45 : 45 : 10 CDCl3-CD3OD-D2O aqueous solvent media, the dicationic halogen bonding rotaxane displayed a notable enhanced binding affinity and marked selectivity for Br- over other halides and nitrate and dihydrogen phosphate oxoanions in contrast to an all hydrogen bonding counterpart which is attributed to chelated charge assisted halogen bonding interactions.