A Manufacturing Grade, Porous Oxycarbosilane Spin-On Dielectric Candidate with K ≤ 2.0

Isaacson

et al. 2019

Adv Funct Materials

Self Cite

Polymer confinement is realized in hybrid nanocomposites where individual polymer molecules are confined by a nanoporous matrix to dimensions less than the molecular size of the polymer. Here it is shown that by functionalizing the interior pore surfaces of a nanoporous organosilicate matrix, the pores can be filled with polystyrene molecules to achieve extreme levels of molecular confinement not previously possible. This provides opportunities for unique thermal and mechanical properties. It is shown that pore surface functionalization markedly impacts the polymer mobility during polymer infiltration by affecting the polymer-pore surface interaction, addressing the challenge of filling high-molecular-weight polymer molecules into nanoscaleconfined spaces. This allows for achieving extreme levels of molecular confinement with the loss of interchain entanglement and extensive polymer elongation along the pore axis. The glass transition temperature of the polymer is suppressed compared to bulk polymer melt, and is significantly affected by the polymer-surface interaction, which changes the polymer segmental mobility. The polymer-surface interaction also affects the interfacial polymer-pore sliding shear stress during polymer pullout from the nanopores, markedly affecting the fracture resistance of the nanocomposite.of the polymer, which has been shown to reduce entanglements, [4] form ordered morphology, [5] influence T g , [6] improve polymer diffusivity, [7] and enhance fracture resistance of the nanocomposites. [8] A fundamental limit of these studies, however, has been to achieve extreme levels of molecular confinement and the ability to control the interfacial interaction of the confined polymer with the matrix pores.Here we demonstrate that pore surface chemical functionalization allows us to achieve extreme levels of molecular confinement and manipulate the nanocomposite thermal and mechanical properties by controlling the interaction of the polymer with the pore surface (Figure 1). We show that the polymer filling rate can be significantly improved through selection of appropriate surface chemistry, which enables filling polymers with unprecedentedly high molecular weight (M w ) into the porous matrix to create extreme levels of molecular confinement not previously possible. This induces polymer hyperconfinement [[8a]] in which polymer chains entirely lose interchain entanglements and elongate extensively along the pore axis. [9] We also show that T g of the polymer is decreased by hyperconfinement, and can be significantly affected by tuning the polymer-surface interaction to impact the polymer segmental mobility.In addition, we show that the polymer-surface interaction affects the fracture of the nanocomposites where molecular bridging that involves the pullout and stretching of individual confined polymer chains from the nanopores leads to a marked increase in fracture resistance. The surface chemical functionalization significantly changes the sliding shear stress at the polymer/pore surface interfac...

Section: Resultsmentioning

confidence: 99%

“…Surface Functionalization of the Nanoporous Matrix : The Et‐OCS matrix was obtained by spin‐casting and thermally curing a porogen‐containing sol−gel formulation on top of a 200 mm silicon wafer coated with a dense Et‐OCS adhesion layer 8a,10. The silicon wafer substrate was then diced into 50 × 50 mm square coupons.…”

Section: Methodsmentioning

confidence: 99%

Surface Chemical Functionalization to Achieve Extreme Levels of Molecular Confinement in Hybrid Nanocomposites

Isaacson

et al. 2019

Adv Funct Materials

Self Cite

Journal of Applied Physics

“…Film preparation A k ¼ 2.0 spin-on resin derived from an ethylene-bridged organosilicate precursor was selected for this study. 4 porogen in the sol-gel formulation was required. The porogen nature and quantity, along with the sol-gel conditions were optimized to generate k ¼ 2.0 films.…”

Section: Methodsmentioning

confidence: 99%

“…This issue was however addressed by increasing the hybrid silica network connectivity through the use of carbon bridged precursors, leading to improved low-k stiffness, fracture resistance, and interfacial adhesion. [2][3][4][5][6][7][8][9] Second, highly porous low-k materials are a lot more prone to plasma damage due to a huge increase in accessible surface area. [10][11][12][13] Over the past 15 years, a lot of efforts have been devised to either prevent or mitigate plasma damage.…”

Section: Introductionmentioning

confidence: 99%

The efficacy of post porosity plasma protection against vacuum-ultraviolet damage in porous low-k materials

Lionti

Darnon

Volksen

et al. 2015

As of today, plasma damage remains as one of the main challenges to the reliable integration of porous low-k materials into microelectronic devices at the most aggressive node. One promising strategy to limit damage of porous low-k materials during plasma processing is an approach we refer to as post porosity plasma protection (P4). In this approach, the pores of the low-k material are filled with a sacrificial agent prior to any plasma treatment, greatly minimizing the total damage by limiting the physical interactions between plasma species and the low-k material. Interestingly, the contribution of the individual plasma species to the total plasma damage is not fully understood. In this study, we investigated the specific damaging effect of vacuum-ultraviolet (v-UV) photons on a highly porous, k = 2.0 low-k material and we assessed the P4 protective effect against them. It was found that the impact of the v-UV radiation varied depending upon the v-UV emission lines of the plasma. More importantly, we successfully demonstrated that the P4 process provides excellent protection against v-UV damage.

“…[33] Dubois et al have proposed first oxycarbosilane material and then hybrid oxycarbosilane / methylsislsequioxane material as a porous low-k dielectric. [34,35,36] They have shown that the carbon bridges improve the mechanical stability of the material. [35] With their new material, the carbon content increases, and the pore size and porosity decrease.…”

Section: Plasma-resistant Porous Sicohmentioning

confidence: 99%

Prospects for dielectric constant reduction in integrated circuits interconnects

et al. 2014

To improve the integrated circuits' performance and continue the downscaling of dimensions, it is necessary to use low dielectric constant materials as interconnects insulators. Current porous SiCOH low-k dielectrics are now reaching their limits since their porosity enables the diffusion of species that modify the inner surface of the pores. To further reduce the dielectric constant, it is necessary to change paradigm in interconnects fabrication. In this paper, we discuss the most promising innovations in terms of process, materials and architectures to reduce the interconnects insulators dielectric constant.