Novel hexameric tin carboxylate clusters as efficient negative-tone EUV photoresists: high resolution with well-defined patterns under low energy doses

Abstract

Synthesis of two novel tin carboxylate clusters (RSn)6(R’CO2)8O4Cl2 is described, and their structures have been characterized by X-ray diffraction. These clusters have irregular ladder geometry to form very smooth films...

Synthesis of pentameric chlorotin carboxylate clusters for high resolution EUV photoresists under small doses

“…In the O (1s) peak analysis, the component centered at 530.6 eV in Fig. 14 is assignable to inorganic Sn–O species including Sn 2 OH, Sn 2 O and Sn 3 O; 16,30–32 the second component centered at 529 eV is assigned to the t -BuCO 2 Sn oxygen. Previously, Zhang reported 32 that the HRXPS spectra of the [( n -BuSn) 12 O 14 (OH) 6 ] +2 core could be resolved into two components such as Sn 3 O and Sn 2 OH in this 530.0–531.2 eV region.…”

“…The Sn–Cl, Sn–vinyl and Sn–O 2 CBu t cleavages follow the reported mechanisms of tin carboxylate clusters. 14–16 Although the photolytic decomposition of Sn–O 2 CBu t and vinyltin groups also takes place for the blend ( 3 ), their rates are slow because a large proportion still remains at J = 60 mJ cm −2 as shown in Table 3. For the vinyltin groups, radical propagation at this functionality is not supportive.…”

“…Existing reports on metal clusters or nanoparticles predominantly feature oxide or carboxylate ligands owing to their ready availability. 6–25 However, oxide ligands exhibit photochemical inertness toward UV light in addition to their weak EUV absorptions. Although carboxylate ligands can be easily decomposed by EUV light, their sizes are somehow too large to facilitate the molecular aggregation of negative-tone photoresists.…”

Highly hydroxylated hafnium clusters are accessible to high resolution EUV photoresists under small energy doses

“…Nevertheless, very few photoresists can reach high resolution patterns with HP <20 nm. 17,18 Radical chain growth on a MAA ligand may also occur rapidly between exposed and unexposed photoresists due to small kinetic barriers. Negative-tone photoresists are probably a viable route to avoid radical chain growth, although there are no successful examples.…”

Si-Containing Reverse-Gradient Block Copolymer for Inorganic Pattern Amplification in EUV Lithography

“…This innovation facilitates the production of high-resolution patterns beyond the capabilities of other scalable and reliable patterning technologies, positioning EUVL at the forefront of next-generation semiconductor manufacturing. − However, the practical realization of high-NA (numerical aperture) EUVL currently faces a number of technical challenges. One of the most critical challenges is the requirement for a thin photoresist (PR) layer, which leads to low aspect ratios (AR) in the PR etch-mask and, consequently, poor etching performance due to the insufficient endurance of the resist. − Recent studies have focused on mitigating the limitations in pattern resolution and AR encountered in EUVL. These efforts include the development of inorganic-based PRs and the integration of robust hard-mask underlayers to enhance pattern fidelity. − Despite these advancements, the patterns realized under EUV exposure have achieved an AR of only about 2.1, which is suboptimal for reliable pattern transfer during subsequent etching processes …”