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

开发了一种新的具有很高流动性的二氧化硅CVD技术，用于平坦化具有窄沟或深沟的极细图案表面。在低于-80ﾟC的衬底温度下，SiH_4和O_2的辉光放电分解沉积了二氧化硅，基本抑制了表面的热反应。当采用三极管型反应器时，生长表面上的离子通量显著减少，氧化物沉积到具有窄特征的表面上是从沟槽或沟槽的底部进行的，并导致表面平坦化。利用Si_2H_6和O_2等离子体或二极管反应器中产生的高分压SiH_4放电也实现了二氧化硅的高流动性沉积。结果表明，尽管生长膜表面有离子辐照，但聚合反应仍在表面促进，生成具有迁移能力的较高的硅烷自由基。这可能是因为聚合物种的寿命受到较高硅烷的缩合速率和表面产物的离子诱导烧蚀/分解速率的控制。利用新开发的FT-IR-ATR系统对SiH4和O2等离子体沉积过程中的表面反应进行了实时监测。在-95ﾟC温度下，吸附物之间的聚合反应在表面进行，形成部分以SiH_3或OH封端的聚硅氧烷(O-SiH_2)_n链。

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.