Surface Degradation Mechanism During the Fluorine-Based Plasma Etching of a Low-<I>k</I> Material for Nanoscale Semiconductors

Abstract

The degradation of a low-k material surface during the exposure to plasma etching is one of the most serious problems to be solved for the realization of high speed semiconductor devices. In this study, the factors causing the degradation of a low-k material surface during the etching using fluorine-based plasma etching have been investigated by using XPS. As the plasma factors, active radicals, bombardment energy, and charge of the ions were considered and, as the low-k material, methyl silsesquioxane (MSQ) has been used. The XPS results showed that the ion bombardment during the plasma etching of MSQ affects the breaking of MSQ bone structure by changing the Si-O bonds and Si-C bonds to Si-F mostly, while fluorine-based radicals in the plasma mostly affect the change of Si-CH3 bonds to Si-CH(x)F(y). By removing the charge of the ions during the bombardment, the MSQ properties were further improved. When F intensity which is related to the damage of the MSQ surface is estimated, the bombardment energy, reactive radical density, and charge of the ions were responsible for -18%, -53%, -19% of the F intensity in the MSQ. Therefore, by using the neutral beam etching instead of a conventional ICP etching, the degradation on the MSQ surface estimated by the F intensity remaining on the MSQ surface could be decreased to 10%.

Low damage etching method of low-k material with a neutral beam for interlayer dielectric of semiconductor device

“…3(b), an increase of the carbon peak intensity near 284.8 eV was observed, possibly due to the formation of the carbon-rich layer. 23 When the MSQ was etched by the ion beam with 280 V of first grid voltage, even though the ion bombardment energy was higher than that of ICP etching while the etch depth of MSQ remained the same, the fluorine peak intensity on the etched MSQ was significantly lower by about 44% than that etched using the ICP. In the case of carbon peak intensity, the peak intensity was slightly decreased compared to that etched by the ICP.…”

Surface plasma modification of cellulose acetate fiber filter for the adsorption of typical components in smoke components

“…Energy particles and energy light radiation can easily cause a series of physicochemical reactions in materials such as desorption, doping, etching, sputtering and degradation, crosslinking, surface graing and interfacial polymerization. [9][10][11] On the one hand, oxygen-containing functional groups such as C-O, C]O and O-H will be introduced into the surface of the material aer plasma treatment to enhance the surface wettability of the material. 12 Meanwhile, the surface structure and composition of the material will be changed, and then the surface energy of the material will be changed, resulting in the increasing of the surface adhesion.…”