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.
Chemical, biological, and immunological characterization of mono- and diiodothyrotropin releasing factor.
Abstract Iodination of thyrotropin releasing factor (TRF) with chloramine-T and NaI at pH 7.5 produces both mono- and diiodo-TRF as well as unreacted TRF and I − . The four compounds can be separated by ion-exchange chromatography on SP-Sephadex C-25, using a stepwise gradient of 0.01 m MH 4 OAc at pH 3.5, 5.2 and 7.2. The monoiodo-TRF was characterized by nuclear magnetic resonance, mass spectra, and elemental analysis as [Im-5-iodo-His 2 ]-TRF while the diiodo-TRF was similarly characterized as [Im-2,5-diiodo-His 2 ]-TRF. Both iodination products showed no thyrotropin releasing activity at doses up to 1 μg in the in vivo mouse bioassay. The specific binding of mono- and diiodo-TRF was measured against three different TRF antisera. In the absence of TRF, antisera A and C bound more diiodo-TRF than monoiodo-TRF while antiserum B seemed to bind both tracers equally. In all cases steeper curves were produced when diiodo-TRF was displaced by synthetic TRF.