Development of selective deposition technique of sillicon dioxideinto extremely fine patterned structure and its application to G-bit memory wiring

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A novel CVD technique of silicon dioxide with a very high fluidity has been developed for planarizing extremely fine patterned surfaces with narrow grooves or deep trenches. Silicon dioxide has been deposited by the glow discharge decomposition of SiH_4 and O_2 at substrate temperatures below-80ﾟC,where the thermal reaction on the surface was basically suppressed. When ion flux onto the growth surface was significantly reduced by employing a triode-type reactor, oxide deposition onto surfaces with narrow features proceeds from the bottom of a trench or groove and result in planarization of the topography. High-fluidity deposition of silicon dioxide was also achieved by employing a Si_2H_6 and O_2 plasma or a high partial pressure SiH_4 discharge generated in a diode-type reactor. It is shown that the polymerization reaction is promoted on the surface to form higher silane radicals with migration capability despite the ion irradiation to the growth film surface. This is presumably because the life time of polymerized species is controlled the condensation rate of higher silanes and ion-induced ablation/decomposition rate of surface products. Real time monitoring of surface reactions during deposition from siH_4 and O_2 plasma was performed by employing a newly developed FT-IR-ATR system. At temperature of -95ﾟC,polymerization reactions among adsorbates proceeds on the surface to form polysiloxene (O-SiH_2)_n chains partially terminated with SiH_3 or OH.