Papers by Keyword: Low Dielectric Constant

Abstract: A kind of MDT polysiloxane was prepared by step hydrolysis and polycondensation of alkoxysilane. It could be cured at elevated temperature with existence of microencapsulated platinum catalyst. The effects of crosslinkable groups’ contents and PhSiO_1.5 content on properties of cured silicone resin were studied in detail. When the contents of crosslinkable groups were 20mol% to 30mol% and the PhSiO_1.5 content was 25mol% to 30mol%, the cured silicone resin had good tensile strength, flexural strength, moderate elasticity, and low viscosity. With the increase of PhSiO_1.5 content from 17mol% to 32mol%, T_g of the silicone resin could be improved by 50°C to 128°C. The thermal stability was explored by thermo gravimetric analysis. The onset temperature of thermal degradation and the center temperature of thermal degradation were 486°C and 548°C, respectively. The average dielectric constant was about 2.45 and the dielectric loss tangent value was less than 0.01. The silicone resin also showed a high-volume resistivity of 5.6×10¹⁶Ω•cm. These results suggest that such silicone resin is suitable for utilization in electronic packaging.

Abstract: Effect of various silicon sources, such as TEOS, MTES mixed with TEOS and 1,3,5-tris(triethoxymethyl) on SiO₂ films was investigated. The synthesized solutions were used as silicon sources to prepare silica-like backbone films. The investigation showed that all precursors can able to produce the flat and uniform films. An FTIR spectrum confirmed the formation of SiO₂ in film matrix. The results indicated that the internal microstructure of each film is different. The incorporation of less polar bonds such as F and C was carried out using various Si sources, while the introduction of these sources confirmed through FTIR spectra. Optical properties of the films were carried out by using ellipsometric porosometry (EP) measurement. The leakage current density for the films prepared by using TEOS, MTES and 135TTEB was observed to be 2.8 × 10^-7 A/cm², 2.9 × 10^-8 A / cm², and 4.1 × 10^-6 A / cm², respectively, at 1 MV/cm electric field strength by the IV curves obtained by semiconductor characterization after fabricating MIS devices. The calculated dielectric constants from RI of the deposited SiO₂ films were 2.0, 1.9 and 2.5 respectively. When the microstructure of the precursor solution changed, the introduction of atomic morphology or terminal inerted group ratio changed the internal bridging mode of SiO₂, and thereby significantly reduced the dielectric constant and improved insulation.

Abstract: The porous silicon nitride ceramics with low dielectric constant and high flexural strength were obtained by adding pore-forming agent through partial sintering technique. The effects of pore-forming agent amount on the properties of porous silicon nitride ceramics were investigated. Microstructure was analyzed by means of scanning electron microscopy. The results show that the porous structure is formed by the overlap of pillar β-Si₃N₄ with high length diameter ratio. The porosity of samples rises with the increase of pore-forming agent content, which leads to the decrease of the dielectric constant and loss, but the decrease of flexural strength. When the pore-forming agent of PMMA with mass fraction of 20% was added, the volume density, porosity, dielectric constant and loss of porous silicon nitride ceramics were 1.17g/cm³, 66.5%, 2.33 and 0.8×10^-3 respectively, with higher flexural strength of 75MPa which is satisfactory as low dielectric material for core layer of broadband radome.

Abstract: A nickel coating on the surface of alumina particles, used as a reinforcement in metal-ceramic composite materials, its dielectric and electromagnetic properties have important application value. In this paper, nickel was deposited on alumina powder surface by the way of hydrothermal and sintering. The results showed that the nickel powders were fcc structure. The size of the crystal grains ranged from 10 nm-50 nm. The electro-magnetic characteristics were measured by HP 8722ES microwave net work analyzer in the band of 2-18 GHz. It was showed that both the Ni-Al203 and Co-Al203 nanopowders had low dielectric constant, low electromagnetic and good properties in microwave absorption.

Abstract: A glass powder of the SiO₂-Al₂O₃-K₂O-Na₂O system was added to fused silica particles to form composite green compacts by tape casting. This procedure was able to lower the sintering temperature of the fused silica particles making the composites suitable for being co-fired with the silver-palladium (Ag-Pd) paste commonly used as a conductive circuit in several microwave applications. The resulting new ceramic composite with the composition of 50 wt% fused silica and 50 wt% glass (brand name: TC-3) had a low dielectric constant and a low loss tangent of 2.7 and 2.5-3.7 x10^-3 , respectively, and was able to be co-fired with the Ag-Pd conductive paste at the temperature of 895 °C, resulting in a potential low temperature co-fired ceramic (LTCC) system for microwave applications.

Abstract: A novel fluorine containing epoxy 4-fluoro-4′,4″-diepoxypropoxy triphenyl methane (FDE) was designed and synthesized. The synthesized epoxy was cured by methyl nadic anhydride (MNA) and diglycidyl ether of bisphenol A (DGEBA) was chosen for comparison. Both glass transfer temperature (Tg) and 5% weight loss degradation temperature (Td5%) of cured FDE are over 60°C higher than that of DGEBA. Dielectric constants of the cured FDE at 106 Hz and 107 Hz are 3.09 and 2.91, comparing to 3.50 and 3.24 of the cured DGEBA, respectively. Furthermore, water absorption of the cured FDE is lower than that of DGBEA.

Abstract: As the integrated circuits developing, the line-width and space between the metal interconnection are shrinking. This increases the RC time delay. To reduce the RC time delay, the low dielectric constant (low-k) material was introduced in the ICs. For process integration considerations, the impact of electronic characters was investigated. In this paper, both static test and CMP(chemical mechanical polishing) process conditions were executed on the low-k material black diamond (BD) with slurry,which was explored by Hebei University of Technology. The slurry was utilized to evaluate the effect on the dielectric properties of BD films. Electrical analyses have shown dielectric properties of BD films would not be degraded during these processes. The static test was dipping the low–k material (BD)in the slurry for 30s and 2minutes, and the results showed the capacitance changed from 3.01to3.40 when dipping in 30s ,and the value reached 3.71 when dipping 2minutes. The resistance changed from 2.9-2.95 to 3.27-3.33 in 30s,and reached 3.57-3.63 in 2 minutes. The result of CMP process showed that the capacitance of five dots , which were selected on the BD film, changed from 2.94-2.98to 2.99-3.05. The dielectric integrity of low k BD films after CMP process remained at an acceptable region to meet requires of multilevel interconnection.

Abstract: The characteristics of plasma are important for the deposition of SiOC(-H) low dielectric thin film. The effect of UV light illumination on the plasma parameter in the capacitive coupled plasma chemical vapor deposition (CCP-CVD) system is investigated. The electron density is almost not changed, but the electron temperature decreases by UV light illumination. The deposition rate increases and the dielectric constant of the film is lowered with UV light.