Chemical Bonding Structure of Low Dielectric Constant Si:O:C:H Films Characterized by Solid-State NMR

Abstract

Organosilicon films ͑Si:O:C:H͒ have the potential to replace SiO 2 as a lower dielectric constant microelectronic interconnection layer. The structure of Si:O:C:H films was characterized by 1 H, 13 C, and 29 Si solid-state nuclear magnetic resonance ͑NMR͒ and also by X-ray photoelectron and Fourier transform infrared spectroscopies. Spin-coated hydrogen silsesquioxane, methyl silsesquioxane, and surface-modified nanoporous silica films were observed to be more homogeneous in structure than films grown by chemical vapor deposition ͑CVD͒. The CVD films were deposited from N 2 O mixed with either tetramethylsilane, a mixture of tetramethylsilane and silane, trimethylsilane, or methylsilane. The various gas mixtures altered the degree of oxidation and hydrogenation in the resulting films, confirming that the composition of Si:O:C:H can be readily adjusted by CVD. Of all the characterization methods, the 29 Si NMR was most readily able to distinguish differences between the Si:O:C:H films, resolving up to twelve distinct bonding environments. These same bonding configurations are also found in bulk organosilicate glasses. In all films studied, 13 C NMR reveals that methyl is the primary bonding configuration for carbon and no sp 2 -bonded carbon was detected.

Evaluating the gas permeation properties and hydrothermal stability of organosilica membranes under different hydrosilylation conditions

“…After air treatment, the 29 Si NMR spectra showed no change in the T 3 (CSiO 3 ) [26,27] unit with an increased Q 4 unit [26,27] caused by the oxidation of SiH [26] and Si-CH ¼ CH 2 [26] groups, respectively. Thus, the slight increase in gas permeance that was larger than that of CH 4 can be ascribed to the oxidation of unreacted Si-CH ¼ CH 2 groups.…”

“…The peak for unreacted Si-CH ¼CH 2 groups [24,25] disappeared after heat treatment at 500°C under air, but there was no change in the peak for Si-(CH 2 ) 2 -Si [24,25]. The 29 Si NMR spectra showed T 3 (CSiO 3 , HSiO 3 ) [26,27] units with Q 4 units even before air treatment. Hydrosilylation and the following reaction are known to occur simultaneously in the case of Pt-catalyzed hydrosilylation [28].…”

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

“…This exchange increases the average coordination for the local molecules involved in this reaction. Mabboux and Gleason 18 have calculated the average coordination number for the different molecular units, Q, T, D, and M (Table III). He and Thorpe 20 have shown that a phase transformation occurred when the average coordination number, hri, for the material exceeds 2.4.…”

Influence of Tetramethyldisiloxane‐Oxygen Mixtures on the Physical Properties of Microwave PECVD Coatings and Subsequent Post‐Plasma Reactions

“…TMDSO has a similar structure to HMDSO but has two Si-H bonds and has been noted to produce a coating with higher amounts of Si-H bonding, which have been reported to be susceptible to post-plasma reactions. [23] There is limited information on the aging process for TMDSO plasma polymers. Guillou et al [24] deliberately aged pure TMDSO coatings via the combination of an oxygen plasma and thermal treatment and this achieved a largely amorphous SiO 1.8 coating for the barrier protection of steel.…”