Polyhedral Oligomeric Silsesquioxanes Based Ultralow‐k Materials: The Effect of Cage Size

Abstract

Polyhedral oligomeric silsesquioxanes (POSS) are of considerable interest as building blocks for preparing low‐k materials. To date T8 POSS has been extensively investigated while the potential of larger POSS cages remain an unexplored area. Herein, the first known contribution to map the role of POSS cage size on the dielectric and other comprehensive properties of hybrid materials with identical chemical compositions is described. First, three vinyl POSS (T8, T10, and T12) species are isolated from a commercial POSS mixture. Then, they are converted to benzocyclobutene functionalized and thermo‐crosslinked hybrid materials. It is found that the cage size can strongly affect their k values, more importantly, showing a linear decrease while increasing the cage volumes (k = 2.24, 2.02, and 1.83 for c‐T8B8, c‐T10B10, and c‐T12B12, respectively). This finding highlights a profound influence of POSS cage changes on dielectric properties and could be used to predict ultralow‐k (1.5–1.1) materials by extrapolating to larger T14, T16, and T18 POSS cages. Meanwhile, varying the cage size has no obvious effect on the materials’ other properties, and all of them exhibit good comprehensive properties. Moreover, such low‐k values can persist at high temperature and high humidity conditions, which affords some promising (ultra)low‐k dielectrics for modern integrated circuit development.

Preparation and performance of low‐dielectric benzocyclobutene resins containing dicyclopentadiene

“…[20,21] The introduction of low-polarity, large-volume functional groups into BCB resins can increase the free volume of a polymer, and the introduction of low-polarity, large-volume rigid functional groups can effectively improve the dielectric properties of a resin. [22][23][24][25] Dicyclopentadiene (DCPD) is a very important hydrocarbon cyclodiolefin generated from cyclopentadiene. It is the primary component of the C5 fraction following naphtha cleavage and is therefore cheap to produce and buy.…”

The low dielectric constant hyperbranched polycarbosilane derived resins with spacing groups

“…10 Some materials have a low-k, but their mechanical and thermodynamic properties are not excellent, so their use value is limited. 11,12 Another way is to significantly reduce the k via low-polarity bonds, such as Si C, 13,14 C C, 15,16 C F, 17 and so forth. Compared with other low-k materials, the materials based on carbon-silicon structure can significantly reduce the k and dielectric loss.…”

Construction of porous poly (aryl sulfide sulfone) film with low dielectric constant and excellent mechanical property

“…Over the past decades, lots of efforts have been focused on the fabrication of low dielectric constant film. The main methods include: (1) Designing the molecular structure of the polymer to reduce the polarizability via introducing groups or side chains with strong polar fluorine atoms 5–8 or adding more functional groups with large free volume, 9–12 such as naphthyl, fluorenyl, and spiral ring; 13 (2) Introducing the new component with low dielectric constant by the processing and forming method, such as blending with fluorographene 14–17 or other fillers with low dielectric constant like covalent organic frameworks (COFs) 18 and polyhedral oligomeric silsesquioxane (POSS); 19–25 (3) Fabricating air pore structure in the film due to the dielectric constant of air is only 1, 26 which is the simplest and most versatile method. Wang et al used the delayed phase transformation method to introduce pores to poly (aryl ether nitrile) (PEN) matrix and obtained ultra‐low dielectric constant PEN foam 2 .…”