Metal–Organic Framework-Inspired Metal-Containing Clusters for High-Resolution Patterning

Abstract

We report the preparation of discrete nanometer-scale zinc-based clusters and use them to form sub-15 nm structures by means of extreme ultraviolet lithography. By taking advantage of a metal-containing building unit derived by a metal–organic frameworkMOF-2, we found the 3-methyl-phenyl-modified Zn-mTA cluster that formed is well-defined with controlled size and structure and demonstrates extremely high solubility. Progress in recent years in metal–organic frameworks has created a rich variety of metal-containing structures that are useful for numerous applications. Substitution of the bridging ligands with monovalent ligands produces a discrete metal–organic cluster that strongly interacts with soft X-rays at a wavelength of 13 nm. Here we describe the design, preparation, computational modeling, and physical characterization of these new materials. Such metal-containing structures may form the basis of photoresists that enable the next generation of microelectronic devices.

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

“…Metal oxoclusters (MOCs) are molecular hybrid compounds with inorganic core‐organic shell structures,, which are ideal platforms as EUV photoresist , . They have well‐defined inorganic cores and organic shells and, as a result of their molecular nature, they are small and have homogeneous (monodisperse) sizes by definition.…”

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

“…Inorganic resists are typically based on discrete entities (molecules or nanoparticles) that can act as small voxels in the lithographic progress, which is seen as favorable for the reduction of pattern roughness. [1][2][3] They are also not relying on an amplification mechanism (or at least, not one based on photoacid generators), which simplifies the system and reduces stochastic sources. In addition, inorganic resists are expected to present less electron blur due to the different scattering of electrons when the inorganic units are present in the thin film compared to polymeric materials.…”

“…[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.…”

“…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. 2 Therefore, the design of new EUV photoresists materials that can meet all the requirements to keep up with Moore's law demands the understanding of the role of both inorganic and organic components in this new types of hybrid resist. With this in mind, we performed a study on the effect of small variations in the organic shell of a series of molecular hybrid compounds that shared a common inorganic core.…”

Zinc-based metal oxoclusters: towards enhanced EUV absorptivity

“…Recently, molecular materials based on Zn have been investigated and have shown promising results. 11,14,15 In our approach, a denser Zn metallic oxo core is used as the building block in order to enhance the EUV absorbance of the material. The organic ligands surrounding a condensed EUV absorbing core are envisioned as the main factor for the solubility properties and play a major role in the reactivity of the material, which determines in turn the solubility switch upon exposure.…”