Effects of Crystallinity in Spin‐On Pure‐Silica‐Zeolite MFI Low‐Dielectric‐Constant Films

Abstract

Low‐dielectric‐constant (low‐κ) materials are a critical requirement for future generations of computer microprocessors. As a unique class of porous silicas, pure silica zeolites (PSZs) have been shown to be a promising low‐κ material with excellent mechanical strength (e.g., elastic modulus of 16–18 GPa) due to their crystalline nature. In the present study, we show for the first time that higher crystallinity of spin‐on PSZ MFI films leads to lower κ values and less moisture sensitivity—two critical properties of a porous low‐κ material. We have also advanced the two‐stage synthesis method to produce zeolite nanoparticles with high yield (77 %) and a small diameter (< 80 nm). A κ value of 1.6 is obtained from the silylated highly crystalline PSZ MFI film and the κ value only increases by 12.5 % after exposure to ambient conditions for a period of 24 h.

Evidence of Large Voids in Pure‐Silica‐Zeolite Low‐k Dielectrics Synthesized by Spin‐on of Nanoparticle Suspensions

“…[8][9][10] The isotherms typically show a low pressure uptake in micropores and adsorption in the region P/ P 0 ¼ 0.85-1, [8,10] which reveals the presence of mesopores. The isotherms show hysteresis and a sudden nitrogen desorption in the relative pressure range 0.40-0.50, which has been interpreted in terms of capillary desorption from pores with diameters of 2.6-4 nm.…”

“…0.5 nm and interstitial voids with diameters smaller than 4 nm located between the Silicalite-1 nanocrystals. [8][9][10] This bimodal pore model has been adopted in several studies and reviews. [3,4,[7][8][9][10][11][12][13][14][15][16][17] With Silicalite-1, ultralow k values (k < 2.4) can be achieved for the highest ever reported elastic moduli.…”

Low‐kMaterials: Recent Advances

“…Using a two-stage hydrothermal synthesis method, the yield of nanocrystals for a given particle size can be increased in the solution used for film preparation. A direct effect is observed on the dielectric constant of the films with higher crystallinity, leading to lower k values [141,142]. At the same relative level of crystallinity, changing the nature of the zeolite nanocrystals from MFI to MEL also results in a lower dielectric constant.…”

“…Because all the films above are composed of a mixture of amorphous silica and silicalite nanocrystals, not only the overall ratio of one silica component versus the other (in other words the total level of film crystallinity) [141] but also the nature of the zeolite (MFI or MEL, zeolites with a two-dimensional 10-ring pore structure) [142] influence the dielectric properties of the material. Using a two-stage hydrothermal synthesis method, the yield of nanocrystals for a given particle size can be increased in the solution used for film preparation.…”

Layer‐by‐Layer Approach to Superhydrophobic Zeolite Antireflective Coatings

“…[10,11] Orderly arrayed channels, high pore volume and highly crystalline walls in their structures make them suitable for potential applications in the fields of low-k materials, [12,13] catalysis, [14,15] separation and adsorption, [16][17][18] and optics. [19][20][21] However, very limited works were reported on the synthesis of super hydrophilic AR zeolite coatings.…”