Damage to OSG low‐k films during IPVD deposition of the Ta barrier layer

Abstract

The degradation of a porous organosilicate glass low-k dielectric during the ionized physical vapor deposition of tantalum coating is studied. The main contribution to the damage is made by vacuum UV flux (10 14 -10 15 s -1 cm -2 ) from the argon inductively coupled plasma of the ionizer, and the effect of the direct current magnetron sputter plasma is small. The damage by

Challenges in scaling of IPVD deposited Ta barriers on OSG low‐k films: Carbonization of Ta by CHx radicals generated through VUV‐induced decomposition of carbon‐containing groups

“…However, the dissociation of Si-CH 3 bonds from the triplet state is also energetically favorable, as demonstrated in our previous work. [33] In the cases of structures c and d (see Figure 14a), the triplet state is far more stable. However, the optimized triplet state can further undergo energetically favorable intramolecular rearrangement through an H-shift to the aromatic ring, as shown in Figure 14a, followed by Si-C bond dissociation.…”

“…The main contribution to the VUV radiation reaching the samples comes from the ICP discharge, while the effect of the more distant magnetron discharge plasma is minimal. [33,60] A preliminary discussion of the observed phenomena was presented in the description of the FTIR spectra, and a final conclusion will be drawn in the discussion section.…”

“…[31,32] Most damage is caused by 13-150 nm radiation since the photoabsorption cross section and the quantum yield of methyl group detachment and breakage of bridging carbon groups reach their maximum values in this wavelength range. [27][28][29][30]33] The Ar plasma emits high-energy photons (corresponding to atomic resonance lines at 104.8 and 106.7 nm and ion lines at 92.0 and 93.2 nm), which have the energies sufficient to break the chemical bonds between silicon and carbon groups, making the low-k film hydrophilic. This increases the leakage current and reduces the breakdown field strength.…”

“…[ 31,32 ] Most damage is caused by 13–150 nm radiation since the photoabsorption cross section and the quantum yield of methyl group detachment and breakage of bridging carbon groups reach their maximum values in this wavelength range. [ 27–30,33 ]…”

“…In our previous work, [ 33 ] we investigated the degradation of methylene bridged OSG film exposed to VUV radiation of IPVD plasma under barrier coating deposition conditions, focusing on the structural changes of the bulk dielectric material. The current study focuses on the stability of PMO films with methyl terminal and benzene bridging groups and the modification of the barrier layer by hydrocarbon radicals released as byproducts of OSG film damage.…”