Chemical Modification Mechanisms in Hybrid Hafnium Oxo-methacrylate Nanocluster Photoresists for Extreme Ultraviolet Patterning

et al. 2019

Eur J Inorg Chem

Metal‐containing molecular hybrid compounds, such as metal oxoclusters (MOCs), are promising materials for extreme ultraviolet (EUV) lithography. The solubility, processability, and reactivity towards EUV photons in these compounds are mostly determined by the composition of their organic shells. Therefore, gaining molecular control on the composition of the shell is crucial to tune their lithographic performance of sensitivity, resolution, and line‐edge roughness. In this work, a new method to prepare MOCs that feature two types of carboxylate ligands is presented. In this method, amine‐functionalized resins are used for the purification step. By using this protocol, Ti‐ and Zr‐based MOCs with mixed‐ligands organic shells were synthesized. The new compounds showed clear differences in the processability and sensitivity as EUV resists compared to their analogues featuring only one type of ligand. The results validate this new synthetic approach for the preparation of custom‐made EUV resists towards better lithographic performance.

Section: Introductionmentioning

confidence: 99%

Hybrid EUV Resists with Mixed Organic Shells: A Simple Preparation Method

Liu

et al. 2019

Eur J Inorg Chem

“…The latter is highly relevant since EUV exposure is performed under high vacuum, which may act as a driving force for ligands loss and undesired aggregation of the inorganic clusters. 16,22 The evolution of the thin films after different treatments was analysed by UV-vis absorption and FTIR spectroscopy. Figure 6.…”

Section: Stability Studiesmentioning

confidence: 99%

“…On the other hand, the introduction of MA ligands having a terminal double bond is anticipated to provide an effective solubility switch arising from the cross-linking of these double bonds. 4,16 The study of the EUV lithographic performance on Zn-based oxoclusters featuring both types of ligands, as well as their shelf life, will be used to shed light on importance of the selection of proper ligands for an optimal design of hybrid EUV resists. New developers that can have specific interactions with this type of hybrid materials are also explored to improve the contrast of the material.…”

Section: Introductionmentioning

confidence: 99%

Zinc-based metal oxoclusters: towards enhanced EUV absorptivity

Thakur

Extreme Ultraviolet (EUV) Lithography X

Ekinci

et al. 2019

The cost-effectiveness and future progress of EUV (13.5 nm) lithography will largely depend on the resist technology development. Hybrid inorganic-organic photoresists have emerged as promising materials of EUV and have gained increasing attention in recent years. A crucial aspect for hybrid materials is their stability and the preservation of their molecular integrity when deposited as thin films. In this work, we study novel zinc (Zn) oxoclusters as molecular hybrid photoresists. Our aim is to combine the reactivity of methacrylate organic ligands with an inorganic cluster with high EUV photon absorption cross-section arising from this metal. To gain understanding on the shelf life of this material, changes in their structure under different conditions were monitored employing a combination of different spectroscopic techniques. The sensitivity of these oxoclusters under EUV light was investigated and their patterning performance is evaluated using EUV interference lithography. Our results indicate that these novel Zn-based oxoclusters are promising candidates for EUV lithography owing to their high dose sensitivity. Nevertheless, the labile nature of the methacrylate ligands has an important impact in the development process which seems to hamper their reproducibility. This work contributes to the understanding of the pitfalls and advantages of hybrid molecular resists.

“…[5][6][7] However, some works have evidenced that the organic shell can play a more active role in the patterning mechanism. 2,[8][9][10][11] The organic moieties can also promote the formation of new bonds, especially when they have terminal double bonds that are prone to undergo radical polymerization. This phenomenon was observed in molecular metallorganic resists (MORE) 8 and in oxoclusters.…”

Section: Introductionmentioning

confidence: 99%

“…This phenomenon was observed in molecular metallorganic resists (MORE) 8 and in oxoclusters. 9,10 Ober's group proposed that EUV irradiation can induce the replacement of ligands in ZrO 2 and HfO 2 nanoparticles by the sulphonic acid generated in the process, thus rendering the solubility switch. 11 Recently, this concept was also applied to smaller molecules based on Zn-dimers where, as a result of EUV exposure, ligands with positive charge density at their terminal positions where replaced with by ligands with terminal negative charge density, leading to a solubility switch due to a change in the molecular polarity.…”

Section: Introductionmentioning

confidence: 99%

The role of the organic shell in hybrid molecular materials for EUV lithography

Wu¹,

Extreme Ultraviolet (EUV) Lithography X

Ekinci

et al. 2019

As EUV lithography is being introduced into the market, the need for resists that can satisfy the exigent requirements of sensitivity, resolution, and line-edge roughness requires the development of guidelines for new generations of materials. In this work, we aim for gaining more understanding on the contribution of the organic components in inorganic-organic hybrid molecular resists to their sensitivity. A method to investigate the effect of specific functionalities on the sensitivity of metal oxo clusters is presented, which consists in the "doping" of the methacrylate shell through the introduction of fluorinated, iodinated and extended aromatic ligands. By introducing each of these functionalities in small ratios to the methacrylate ligand (1:11 and 2:10) the main chemical properties of the materials (solubility and molecular packing in the thin film) are expected to be unaltered. Our investigations show that the sensitivity is enhanced in the presence of halogens and drastically decreased when extended aromatic compounds are introduced. The trends are uncorrelated with the absorptivity estimated for each material, which seems to indicate that the doping functionalities might interfere with the cross-linking of the methacrylate ligands or introduce new chemical pathways. Our results indicate that specific organic functionalities can be used to tune the reactivity of hybrid compounds for EUV light by introducing them in doping amounts, thus preserving the processability of the initial material.