Development of Nickel-Based Negative Tone Metal Oxide Cluster Resists for Sub-10 nm Electron Beam and Helium Ion Beam Lithography

Abstract

Hybrid metal−organic cluster resist materials, also termed as organo-inorganics, demonstrate their potential for use in next-generation lithography owing to their ability for patterning down to ∼10 nm or below. High-resolution resist patterning is integrally associated with the compatibility of the resist and irradiation of the exposure source. Helium ion beam lithography (HIBL) is an emerging approach for the realization of sub-10 nm patterns at considerably lower line edge/width roughness (LER/ LWR) and higher sensitivity as compared to electron beam lithography (EBL). Here, for the first time, a negative tone resist incorporating nickel (Ni)-based metal−organic clusters (Ni-MOCs) was synthesized and patterned using HIBL and EBL at 30 keV. This resist comprises a nickel-based metal building unit covalently linked with the organic ligand: m-toluic acid (C 8 H 8 O 2 ). Dynamic light scattering confirmed a narrow size distribution of ∼2 nm for metal−organic cluster (MOC) formulations. High-resolution ∼9 nm HIBL line patterns were well developed at a sensitivity of 22 μC/cm 2 and at a significantly low LER and LWR of 1.81 ± 0.06 and 2.90 ± 0.06 nm, respectively. Analogous highresolution patterns were also observed in EBL with a sensitivity of 473 μC/cm 2 . Hence, the Ni-MOC-based resist investigated using HIBL and EBL elucidates the ability of its potential for the sub-10 nm technology node, under standard processing conditions.

Organoiodine Functionality Bearing Resists for Electron-Beam and Helium Ion Beam Lithography: Complex and Sub-16 nm Patterning

“…For the current research, we have fixed 500 nm square boxes with a base dose of 100 μC/cm 2 . 29 Apart from the variable dose, the beam energy was also varied to analyze the energy dispersion inside the 40 nm-thick 3b. The beam energies (E Beam ) were 1, 2, 5, 10, and 20 keV.…”

Integration of High‐Performance Cost‐Effective Copper‐Metal‐Organic‐Nanocluster‐based Gate Dielectric for Next‐Generation CMOS Applications

“…The first step‐1 weight loss is mainly attributed to the removal of solvents trapped in the material and the unbound moisture. [ 44 ] The second step‐2 of weight loss is unclear while the third step‐3 of weight loss is due to the loss of organic ligands attached in the Cu‐MOCs dielectric material. The total weight loss attributed to 73 wt% in Cu‐MOCs, thereby, leading to 27 wt% of dielectric material remains in the form of inorganic copper oxide counterparts.…”

Scalable Fabrication of Metallic Nanogaps at the Sub‐10 nm Level

“…Consequently, the spot size remains small for considerable distances above and below the focal plane, which allows for high‐resolution patterning even on tilted surfaces. [ 62 , 63 ]…”

“…The degree of distortion is affected by the presence of nearby patterned features in the resist; distortions arising from scattering events are consequently known as “proximity effects.” Compared to electron beams, ion beams are far less susceptible to scattering and so exhibit much weaker proximity effects, making them a better choice for high density nanoscale patterning. [ 63 ]…”