Small angle x-ray scattering for measuring pore-size distributions in porous low-κ films

Abstract

A small-angle x-ray scattering technique has been applied for characterizing pore-size distribution in porous low-κ dielectric films. The data are collected in reflection geometry using offset θ/2θ scans for avoiding strong specular reflections from the film surface and its substrate. The effects of refraction and reflection at the film surface and interface are corrected by the distorted wave Born approximation. A Γ-distribution mode is used to determine the pore-size distribution in a film. The technique has been used to analyze porous methyl silsesquioxane films. The pore sizes were found to disperse in the range from subnanometer to several nanometers, and the results agree well with those obtained by the N2 gas adsorption technique.

Thickness dependence of the porosity of PPy/DDS films

“…The volume distribution function of pore sizes was calculated by the program NANO-Solver (version 3.6, Rigaku™) by least squares fitting of measured GISAXS curves. GISAXS curves were simulated using X-ray scattering theory [25]. Reflection and refraction effects owing to grazing incidence geometry were taken into account by distorted wave Born approximation.…”

An Organic/Inorganic Nanocomposite Consisting of Polymuconate and Silver Nanoparticles

“…Data analysis was performed using a previously reported method. [13,14] The scattering intensity I(q, D 0 , M) was analyzed using the following equation:…”

SANS and XRR Porosimetry of a Polyphenylene Low-k Dielectric

“…It is important to note that the Kelvin equation does not apply for pore radii smaller than about 5 Å. 27 The molecular radius of toluene is ∼3 Å. 6 Small-Angle Neutron Scattering.…”

“…2,3 The tandem of X-ray reflectivity (XRR) and smallangle neutron scattering (SANS) represents a powerful methodology for characterizing pore volume fraction (porosity) and pore size distribution in thin films. [4][5][6][7][8][9] Nondestructive techniques used to investigate the pore size distribution in nanoporous low-k materials include ellipsometric porosimetry, [10][11][12][13][14][15] XRR porosimetry, [16][17][18] SANS porosimetry, [19][20][21][22] positronium annihilation lifetime spectroscopy (PALS), [23][24][25] small-angle X-ray scattering (SAXS), 26,27 and neutron reflectivity. 28 Ellipsometry, XRR, and PALS have been used to characterize a set of samples, yielding similar pore sizes, and the advantages and disadvantages of the techniques have been discussed in recent reviews.…”