Plasma Treatment Effects on Molecular Structures at Dense and Porous Low-k SiCOH Film Surfaces and Buried Interfaces
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- 作者：John N. Myers ; Xiaoxian Zhang ; Jeffery D. Bielefeld ; Zhan Chen
- 刊名：Journal of Physical Chemistry C
- 出版年：2015
- 出版时间：October 1, 2015
- 年：2015
- 卷：119
- 期：39
- 页码：22514-22525
- 全文大小：634K
- ISSN：1932-7455
文摘
The effects of oxygen plasma treatment on molecular structures at low-k organosilicate (SiCOH) film surfaces and buried interfaces were investigated using sum frequency generation (SFG) vibrational spectroscopy and Raman spectroscopy. SFG and Raman spectra were acquired from pristine and plasma-treated low-k SiCOH films to characterize the interfacial and bulk molecular structures of the films before and after plasma treatment. Two SiCOH films with similar molecular structures but different porosities were investigated to correlate the effects of plasma treatment to the porosity of low-k films. SFG spectra indicated that the surface molecular structure of dense SiCOH films was more resistant to plasma damage than the surface molecular structure of porous SiCOH films. Furthermore, the ratio of SFG peak intensities before and after plasma treatment enabled quantification of methyl depletion at the surface of SiCOH films after plasma treatment. The molecular structure at buried Si/SiCOH interfaces was characterized by simulating SFG spectra from pristine and plasma-treated SiCOH films. SFG spectra from plasma-treated low-k films were simulated by adjusting the methyl orientation and number density parameters at the low-k/air interface to match experimental results. Simulated SFG spectra indicated that methyl groups at the buried interface of both dense and porous SiCOH films were oriented with a high tilt angle before and after plasma treatment. The developed methodology is general and can be extended to characterize the effects of many different plasma treatments, wet chemical treatments, and surface repair treatments on the interfacial molecular structures of many polymer or organic films.