Pore size distributions in nanoporous methyl silsesquioxane films as determined by small angle x-ray scattering

Abstract

Small angle x-ray scattering ͑SAXS͒ measurements were performed on nanoporous methyl silsesquioxane films that were generated by the incorporation of a sacrificial polymeric component into the matrix and subsequently removed by thermolysis. The average pore radii ranged from 1 to 5 nm over a porosity range of ϳ5-50%. The distribution in pore size was relatively broad and increases in breadth with porosity. The values and observations obtained by SAXS are in good agreement with field emission scanning electron microscopy.

Supercritical CO2extraction of porogen phase: An alternative route to nanoporous dielectrics

“…It is noted that both pore generation methods give similar porosities and pore-size distributions for OS4555, whereas for OS7525 the SCCO 2 process gives broader size distribution than thermal method. As suggested before, 25 this analysis approach employing a spherical model is questionable for films where the pores become interconnected, the 55% loading level films. Therefore, we have also analyzed the SAXS data using a method suited to films with interconnected pores 38 with results described below.…”

“…25 Poly(propylene glycol) {PPG; [-CH(CH 3 )CH 2 O-] n } from Bayer Polymers (Pittsburgh, PA) (AcclaimTM) with a linear structure, M n ‫ס‬ 20,000 g/mol and polydispersity index (PDI) ‫ס‬ 1.05, is chosen as a porogen material. Appropriate quantities of PPG and PMSSQ were dissolved in propylene glycol methyl ether acetate (PGMEA) and the solution was loaded into a disposable syringe before passing through a 0.2-m polytetrafluoroethylene (PTFE) filter and onto silicon substrates.…”

Construction of Representative Pore Morphologies in Disordered Nanoporous Two-Phase Materials

“…Electron microscopies can also be useful for directly determining the morphology of nanoscale heterogeneous materials, but the interpretation of microscopy images is often difficult [15] (due, for example, to limitations in resolution or artifacts created in sample preparation). Here we describe a method for constructing representative real-space morphologies from SAXS [16] data from isotropic two-phase systems with arbitrary phase volume fractions but where the phase morphology is random.…”

X-ray metrology for advanced microelectronics

“…1) and modelled by assuming a distorted wave Born approximation for describing X-rays scattering from imperfect structures. I(q), the X-ray intensity scattered by pores with an average radius r, can be expressed as [48]:…”

“…It is based on two assumptions: (i) all pores have a spherical shape; and (ii) the pore size has a log-normal distribution. This appears to be the best approach to model the GI-SAXS pattern [48]:…”