AVS 49th International Symposium
    Plasma Science Friday Sessions
       Session PS-FrM

Paper PS-FrM1
Study of SiO@sub 2@ Etching with Plasma-beam Irradiation

Friday, November 8, 2002, 8:20 am, Room C-103

Session: Plasma Surface Interactions II
Presenter: K. Kurihara, Association of Super-Advanced Electronics Technologies (ASET), Japan
Authors: K. Kurihara, Association of Super-Advanced Electronics Technologies (ASET), Japan
A. Egami, Association of Super-Advanced Electronics Technologies (ASET), Japan
M. Nakamura, Association of Super-Advanced Electronics Technologies (ASET), Japan
Correspondent: Click to Email
Fluorocarbon gases are widely used for Si/SiO@sub 2@/SiN etching to achieve high etching performance. A study of the SiO@sub 2@ etching mechanism has been still needed to construct a process simulator without experiments of trial and error. A plasma-beam irradiation apparatus, which can control plasma parameters, such as ion energy and radical/ion composition, is very useful to examine the plasma-surface interactions under a real etching environment. We measured Si containing desorbed products from the SiO@sub 2@ substrate by quadrupole mass spectrometer during @super 13@CF@sub 4@/Ar gas mixture plasma beam irradiation. Furthermore we analyzed a surface reaction layer by a quasi-in situ X-ray photoelectron spectroscopy analysis after the plasma-beam irradiation. Composition of the desorbed products was almost independent on the ion energy under the condition that the ratio of the radical flux to the ion flux was small (1~2:1). Major desorbed products were SiF@sub 2@ and SiF@sub 4@. The thickness of the surface reaction layer including Si-F bond increased with increase in the ion energy, but bonding state in the reaction layer did not change. At the relatively high ion energy above 500 eV and ion rich condition, ions play an important role in etching. On the other hand, under the condition that the ion energy was low (~300eV) and the ratio of the radical flux to the ion flux was about 10:1, the relative ratio of highly fluorinated species (SiF@sub 4@) increased slightly. Radical species may affect the production of desorbed products at the low ion energy. We will discuss mechanisms of selective etching of SiO@sub 2@ to Si or SiN under these conditions, which leads the achievement of the high selectivity for sub-100nm LSI circuit production. This work was funded by NEDO.