Temperature-resolved Fourier transform infrared study of condensation reactions and porogen decomposition in hybrid organosilicon-porogen films

Abstract

Composite organosilicon/porogen thin films were deposited via pulsed-plasma chemical vapor deposition. The organosilicon monomer was polymerized using water as the oxidant, allowing incorporation of silanol (Si–OH) moieties for subsequent condensation reactions and crosslinking for enhanced mechanical properties. The porogen monomer [methylmethacrylate (MMA)] was codeposited in the same step, and the degree of MMA incorporation was shown to scale with both the peak plasma power and porogen flow rate. Fourier transform infrared (FTIR) spectroscopy spectra of the composite material show features from both the organosilicon precursor and the porogen species, indicating that both materials are successfully incorporated into the thin film. The kinetics of both the condensation reaction and porogen removal were determined by a temperature/time-resolved FTIR method. The condensation reaction and crosslinking events occur between 100 and 425 °C. Porogen decomposition occurs simultaneously between approximately 325 and 400 °C, which is consistent with the decomposition of poly(methylmethacrylate). Using these data, the activation energy for the primary decomposition mode was found to be approximately 53.6 kJ/mol (12.8 kcal/mol). Both the index of refraction and the dielectric constant scale with the degree of porogen removal, suggesting the formation of free volume in the films. The lowest index of refraction and dielectric constant obtained was 1.404 and 2.3, respectively, for a 1 h anneal at 425 °C. Worst-case thickness loss for the films was approximately 36% of the as-deposit thickness.

Photoinitiated chemical vapor deposition of cytocompatible poly(2‐hydroxyethyl methacrylate) films

“…Regions to note are the broad peak between 3100 and 3600 cm 21 , attributed to the hydroxyl (OH) group; the two peaks between 2800 and 3000 cm 21 , attributed to the symmetric and antisymmetric stretch of CH 2 / CH 3 , groups; a strong peak between 1725 and 1750 cm 21 , attributed to the carbonyl group; and the triplets between 1050 and 1300 cm 21 , attributed to the ester. 44 The precursor (HEMA) is the only species introduced into the reactor, as in previously described piCVD processes. 40 As there is no separate photoinitiator required, it is concluded that polymerization is initiated by UV irradiation of the HEMA monomer itself.…”

Characterization of oxygen and nitrogen rapid thermal annealing processes for ultra-low-k SiCOH films

“…No O-H (∼3400 cm −1 ) peak was observed for as-deposited SiCOH films. 11,12 As the treatment temperature was increased, the intensities of the CH x stretching peaks and Si-CH 3 bending peaks were decreased notably for both the RTN-and RTO-treated films, indicating removal of organic fragments in Figs. 5(a) and 5(b), respectively.…”

“…The reduction of CH x and Si-CH 3 peak intensity is considered as an evidence for the removal of the thermally unstable hydrocarbon fragments. 3,12,14 Up to 450°C, the reduction in the dielectric constant k is due mainly to hydrocarbon removal in the film. We believe that the higher k values of RTO films than in RTN films were due to the large O-H peak contained in the FTIR spectra.…”

The impact of the nano-pore filling on the performance of organosilicon-based moisture barriers

“…This stretching band is characterized by a higher wavenumber (1080 cm −1 ) shoulder associated with short, linear siloxane chains [41,46,47], and by the presence of the O y Si\ \H x stretching at 2100 cm − 1 [42,47]. The broadening and decrease in intensity of the Si-(CH 3 ) x related signal at 1260 cm − 1 reveals a shift towards a O x Si-(CH 3 ) y chemistry [47][48][49], due to the fragmentation occurring in the plasma phase.…”