Molecular bixbyite-like In12-oxo clusters with tunable functionalization sites for lithography patterning applications

Abstract

Indium oxides have been widely applied in many technological areas, but their utilization in lithography has not been developed. Herein, we illustrated a family of unprecedented In₁₂-oxo clusters with a general formula [In₁₂(μ₄-O)₄(μ₂-OH)₂(OCH₂CH₂NHCH₂CH₂O)₈(OR)₄X₄]X₂ (where X = Cl or Br; R = CH₃, C₆H₄NO₂ or C₆H₄F), which not only present the largest size record in the family of indium-oxo clusters (InOCs), but also feature the first molecular model of bixbyite-type In₂O₃. Moreover, through the labile coordination sites of the robust diethanolamine-stabilized In₁₂-oxo core, these InOCs can be accurately functionalized with different halides and alcohol or phenol derivatives, producing tunable solubility. Based on the high solution stability as confirmed by ESI-MS analysis, homogeneous films can be fabricated using these In₁₂-oxo clusters by the spin-coating method, which can be further used for electron beam lithography (EBL) patterning studies. Accordingly, the above structural regulations have significantly influenced their corresponding film quality and patterning performance, with bromide or p-nitrophenol functionalized In₁₂-oxo clusters displaying better performance of sub-50 nm lines. Thus, the here developed bixbyite-type In₁₂-oxo cluster starts the research on indium-based patterning materials and provides a new platform for future lithography radiation mechanism studies.