Analysis of Ultraviolet Curing Effect on the Dielectric Constant and Molecular Structure of a Porous Dielectric Film

Abstract

In this work, we investigated the role of ultraviolet (UV) curing on the dielectric constant (k) and molecular structure of a porous organosilicate glass (p-OSG) dielectric with k of approximately 2.5. The dielectric constant was investigated in a fundamental manner by quantifying its polarizability components: electronic, ionic, and dipolar. A method involving the KramersKronig relations was formulated to separate the ionic and electronic polarizabilities. After quantifying the polarizability components, the evolution of the molecular structure with UV curing was investigated by Fourier-transform infrared spectroscopy (FTIR) and x-ray photoelectron spectroscopy (XPS). The results from the molecular structure investigation were used to explain the observed trends in polarizability.

Comprehensive Study of the Chemical, Physical, and Structural Evolution of Molecular Layer Deposited Alucone Films during Thermal Processing

“…The density evolution of the alumina and alucone films after thermally processing from 150 to 350 °C at 100 °C intervals in both the presence and absence of UV light in N 2 ambient was also probed using ex-situ heating and subsequent XRR to elucidate the role of short wavelength (172 nm) UV on the annealing process (Figure S3). − The density of the alucone films increased with annealing temperature similar to the in-situ experiment in air, although slightly higher densities were measured in the ex-situ processed samples. These slight differences may be ascribed to the different heating rate and ambient atmosphere between the measurements.…”

Dielectric Constant of Porous Ultra Low-κ Thin Films

“…More recently, Smith et al have extended this investigation to porous SiOCH films deposited using DEMS and a porogen, then cured with a UV assisted thermal treatment. 10 They also showed the presence of an ionic contribution which increases when the UV curing time increases while the dipolar contribution remains close to 0.17.…”

“…But according to Table I, it seems very -Porous SiOCH deposited by PECVD using a porogen approach: this work, DEMS and NBD UV cured, this work, DEMS and ATRP UV cured, this work, DEMS and NBD thermally cured, 1,3,5trimethyl-1,3,5-trivinylcyclotrisiloxane and Methylmethacrylate, 31 Diethoxymethyloxiranylsilane and Norbornene, 28 Tetramethylcyclotetrasiloxane and porogen, 29,30 Precursors unknown, 34 Precursors unknown, 32 DEMS and porogen, 11,25,33 DEMS and porogen. 10 -Porous SiOCH deposited by PECVD using a non-porogen approach: Bis-trimethylsilylmethane, 7 Methyltriethoxysilane, 36 Vinyltrimethylsilane. 37 -Porous SiOCH deposited by spin-coating:…”

“…9 In porous SiOCH, Smith et al have investigated the impact of the UV curing on the different contributions to the dielectric constant for κ higher than 2.5. 10 In this work, we have investigated the different contributions to the dielectric constant of porous SiOCH thin films by combining capacitance measurements as function of the temperature and refractive index measurements. These contributions (electronic, ionic, dipolar) are linked to the porosity content and the chemical nature of the film.…”

Effects of cesium ion-implantation on mechanical and electrical properties of organosilicate low-k films

“…In addition, carbon loss, which results in an increase in defect concentration, also occurs simultaneously. [10][11][12] In this work, the effects of a "dry" Cs ion-implantation in SiCOH are investigated. The goal is to determine whether the advantages previously obtained using wet chemistry could be obtained using Cs ion-implantation, thus being a potential supplement to or even a substitution for the incumbent UV curing method.…”