Mechanism of plasma-induced damage to low-k SiOCH films during plasma ashing of organic resists

Abstract

Articles you may be interested inEffects of plasma and vacuum-ultraviolet exposure on the mechanical properties of low-k porous organosilicate glass J. Appl. Phys. 116, 044103 (2014); 10.1063/1.4891501Plasma damage effects on low-k porous organosilicate glass Plasma-induced damage to porous SiOCH ͑p-SiOCH͒ films during organic resist film ashing using dual-frequency capacitively coupled O 2 plasmas was investigated using the pallet for plasma evaluation method developed by our group. The damage was characterized by ellipsometry and Fourier-transform infrared spectroscopy. Individual and synergetic damage associated with vacuum ultraviolet ͑VUV͒ and UV radiation, radicals, and ions in the O 2 plasma were clarified. It was found that the damage was caused not only by radicals but also by synergetic reactions of radicals with VUV and UV radiation emitted by the plasmas. It is noteworthy that the damage induced by plasma exposure without ion bombardment was larger than the damage with ion bombardment. These results differed from those obtained using an H 2 / N 2 plasma for resist ashing. Finally, the mechanism of damage to p-SiOCH caused by O 2 and H 2 / N 2 plasma ashing of organic resist films is discussed. These results are very important in understanding the mechanism of plasma-induced damage to p-SiOCH films.

Plasma etching: Yesterday, today, and tomorrow

“…Since oxygen plasmas can degrade the low-j dielectric, 299 resist ashing is not performed in an oxygen plasma asher, but rather in a medium-density plasma (e.g., capacitively coupled plasma etcher), using plasmas with lowoxygen concentration or other chemistries, such as N 2 /H 2 based chemistry. Regardless of the ashing process used, some degradation of the dielectric is observed, 299,300 which is substantial for ultra low j (j < 2.3) dielectrics. Therefore, newer dual-damascene schemes such as the trench first metal hard mask (TFMHM) approach attempt to minimize exposure of the low-j dielectric to resist-stripping plasmas.…”

Nanoscale chemical structure variations in nano-patterned and nano-porous low-k dielectrics: A comparative photothermal induced resonance and infrared spectroscopy investigation

“…Fortunately, the chemical structure / bonding of low-k dielectrics is ideally suited for characterization by IR spectroscopy due to the strong IR activity of both the organic component (through various C-H stretching and deformation bands) and the inorganic component (through the Si-O and Si-H stretching bands) [42]. Numerous FTIR, GATR and multiple internal reflection IR (MIRIR) spectroscopy investigations of the chemical modification of low-k dielectrics by various nanofabrication processes have been performed on blanket films [43][44][45][46][47][48][49] and in some cases large periodic arrays of m-nm wide patterned features [26,[50][51][52]. These studies have established general trends and correlations between process chemistries and the low-k dielectric chemical bond structure to the susceptibility of process induced chemical modification.…”

Pore sealing mechanism in OSG low‐k films under ion bombardment

“…It was also demonstrated that very short plasma exposures can greatly reduce subsequent carbon loss induced by O atoms. Takeda et al showed that ion bombardment can produce a SiO 2 ‐like overlayer, which inhibits O atom penetration in the low‐ k films.…”