Structure-Designable Formation-Method of Super Low-k SiOC Film (k=2.2) by Neutral-Beam-Enhanced-CVD
Ar neutral beam enhanced chemical vapor deposition can control the dielectric constant and film modulus of low-k SiOC deposited on Si substrates precisely because it avoids precursor dissociation due to electron collisions and UV photons in plasma. Optimizing the ratio between Si-O and Si-(CH3)x as well as the proportions of linear, network, and cage Si-O structures by changing the precursor, we obtained a k of 2.2 and a reasonable modulus by using either dimethyl diethoxy silane or dimethyl dimethoxy silane as a precursor.
Evaluation of interconnection capacitances in IC's with heterogeneous isolating materials
Parameters of interconnection lines have an effect on the electrical parameters of modern VLSI chips, so precise models of interconnection capacitances are indispensable in verification of the design. In our previous works we have shown importance of geometric configuration of the interconnection bus, taking into account further neighbourhood, and proposed a model of corresponding capacitances, verified numerically and experimentally [1], [2]. Our model was developed for technologies using only SiO2 as the isolation material between interconnection lines and metal layers. In most advanced technologies low-k materials displace SiO2, as they enable to reduce capacitances significantly. In this paper we present results of our studies on usability of our model in the cases of technologies using different and heterogeneous isolating materials in respect of dielectric permittivity.
Irradiation Damage in SiO2/Si System Induced by Photons and/or Ions in Photo-Oxidation and Plasma-Oxidation
Irradiation damage in an SiO2/Si system induced by photons and/or ions was evaluated. The flat-band voltage (Vfb) was not shifted and the interface density of states (Dit) was increased by irradiation of 172-nm-wavelength light, which corresponds to a photo-oxidation condition. Surface wave plasma (SWP) excited using microwave with Kr gas has an electron temperature less than 1 eV. However, Vfb was shifted and Dit was increased by the irradiation of photons from Kr plasma, which corresponds to a plasma-oxidation condition. Vfb was not shifted and Dit was increased by the irradiation of ions from Kr plasma. However, the SiO2/Si interface formed by photo-oxidation had a Dit of 3×1010 cm-2eV-1, which is equal to that of a SiO2/Si interface formed by a thermal-oxidation. This means that photo-oxidation forms the SiO2/Si interface by a concerted reaction of the photo-oxidation and the irradiation.