Effectiveness of Dimethyl Carbonate and Dipivaloyl Methane Chemicals for Internal Repair of Plasma-Damaged Low-k Films

Abstract

We propose the use of methylating chemicals to repair plasma-damaged sites in low-k films. Dimethyl carbonate (DMC) and dipivaloyl methane (DPM) were selected as the methylating chemicals to supply methyl (CH3) groups into the bulk of damaged porous SiOCH films. The absorption of water into the damaged films was fully suppressed by the DMC repair treatment. The relative dielectric constant, which was increased from the value of 2.4 in the as-grown porous SiOCH film to 3.1 by plasma processes, recovered to 2.6 owing to the DMC treatment. In the case of the DPM repair treatment, the relative dielectric constant showed an almost full restoration from a value of 3.8 in the damaged film. To discuss the chemical reaction during the DMC repair treatments, SiO2 and the damaged porous SiOCH films subjected to the treatments were analyzed using time-of-flight secondary ion mass spectrometry and Fourier-transform infrared spectroscopy. The results can be explained using the model showing that the methyl and methoxy groups generated via the decomposition of DMC molecules react with silicon and oxygen sites in the films.

Plasma-Enhanced Atomic Layer Deposition Sealing Property on Extreme Low-k Film with k = 2.0 Quantified by Mass Metrology

“…[7][8][9] For this challenge, repair processes for plasma-induced damage on the surface of porous SiOCH films as well as on internal pore walls are needed. Many approaches such as silylation [10][11][12][13][14][15][16][17][18][19][20] and UV-assisted restoration 21,22) have been studied to restore the k-value of damaged porous SiOCH films. Recently, a UV-assisted restoration process that can restore the k-value of damaged porous SiOCH films with k ¼ 2:0 has been developed.…”

Impact of Hydrocarbon Control in Ultraviolet-Assisted Restoration Process for Extremely Porous Plasma Enhanced Chemical Vapor Deposition SiOCH Films with k = 2.0

“…10,11) As an alternative approach to this challenge, the repair processes of plasma-induced damage on the surface of the porous SiOCH film as well as the internal pore walls with remethylating compound have been attracting much attention. Many approaches such as silylation [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] and UV-assisted restoration 27,28) have been studied to restore the k-value of the damaged porous SiOCH film.…”