High-Rate Bias Sputtering Filling of SiO2 Film Employing Both Continuous Wave and Time-Modulated Inductively Coupled Plasmas

Abstract

The SiO2 film deposition employing inductively coupled plasma (ICP) with SiCl2H2/O2 occurred rapidly in the low-density plasma region due to production of precursors of SiCl2H2Ox (x=1–4). In an ICP CVD apparatus made with optimized distances between the antenna and the stage, and between the SiCl2H2 gas ring and the stage, a SiO2 film was with high deposition rate of more than 1 µm/min, 1.5 times the BHF etch rate of thermal oxide, and low Cl inclusion at a pressure of around 0.1 Torr. To supply ions to the Si wafer located in the ion-deficient plasma region, another time-modulated ICP antenna was set near the stage. Since deposition rate decreased with increasing wafer temperature, the laser the interference measurement of a Si wafer set on an RF-biased stage revealed the importance of the tight adhesion of the wafer to the stage. Ar+ ion bombardment during discharge on and off-time of 5 µs enabled us to fill Si trenches with SiO2 at a V dc of 500 V.