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.
Generating high-efficiency neutral beams by using negative ions in an inductively coupled plasma source
To minimize radiation damage caused by charge buildup or ultraviolet and x-ray photons during etching, we developed a high-performance neutral-beam etching system. The neutral-beam source consists of an inductively coupled plasma (ICP) source and parallel top and bottom carbon plates. The bottom carbon plate has numerous apertures for extracting neutral beams from the plasma. When a direct current (dc) bias is applied to the top and bottom plates, the generated positive or negative ions are accelerated toward the bottom plate. Most of them are then efficiently converted into neutral atoms, either by neutralization in charge-transfer collisions with gas molecules during ion transport and with the aperture sidewalls in the bottom plate, or by recombination with low-energy electrons near the end of the bottom plate. We found that negative ions are more efficiently converted into neutral atoms than positive ions. The neutralization efficiency of negative ions was almost 100%, and the maximum neutral flux dens...