Experimental and DFT study of nitrogen atoms interactions with SiOCH low-

Damage of porous organosilicate glass (OSG) films with low dielectric constants (low-κ films) in plasma processing is a critical problem for modern microelectronics. For this problem, understanding and revealing of basic reaction steps for radicals etching and damage are of importance. Previously we have studied experimentally and theoretically the etching and damage of low-κ dielectric films under oxygen and fluorine atoms. Here the effects of N atoms on OSG films are studied experimentally by Fourier Transform InfraRed (FTIR) spectroscopy method and theoretically by density functional theory (DFT) method. Experimental FTIR spectra are compared with calculated vibrational spectra to reveal the relevant surface SiCHxNy groups which could be produced in multi-step reactive collisions of N atoms in ground and lower metastable states with OSG low-κ dielectric films

Data publication: Modification of Porous Ultralow‑k Film by Vacuum Ultraviolet Emission

Modification of spin-on-deposited porous PMO (periodic mesoporous organosilica) ultralow-k (ULK) SiCOH films (k = 2.33) containing both methyl terminal and methylene bridging groups by vacuum ultraviolet (VUV) emission from Xe plasma is studied. The temporal evolution of chemical composition, internal defects, and morphological properties (pore structure transformation) is studied by using Fourier transform infrared spectroscopy, in situ laser ellipsometry, spectroscopic ellipsometry, ellipsometric porosimetry (EP), positron-annihilation lifetime spectroscopy (PALS), and Doppler broadening positron-annihilation spectroscopy. Application of the different advanced diagnostics allows making conclusions on the dynamics of the chemical composition and pore structure. The time frame of the VUV exposure in the current investigation can be divided into two phases. During the first short phase, film loses almost all of its surface methyl and matrix bridging groups. An increase of material porosity due to removal of methyl groups with simultaneous matrix shrinkage is found by in situ ellipsometry. The removal of bridging bonds leads to an increase of matrix intrinsic porosity. Nevertheless, when the treated material is exposed to the ambient air, the sizes of micro- and mesopores and pores interconnectivity decrease with the VUV exposure time according to PAS and EP data. The last is the result of the additional film shrinkage caused by atmosphere exposure. During the second phase the increase of mesopore size is detected by both EP and PAS. The increase of mesopore size goes all the time as it is expected from in situ ellipsometry, but it is masked by the air exposure