Mechanical Properties of Low Dielectric-Constant Organic-Inorganic Hybrids

1999 ◽  
Vol 576 ◽  
Author(s):  
Robert F. Cook

ABSTRACTSpin-on glasses, generated by the condensation of an organic-inorganic hybrid silsesquioxane (SSQ), have great potential as low dielectric-constant semiconductor interconnection materials. After curing and condensation SSQ materials consist of an amorphous, inorganic, –Si–O-Sibridging network with organic, non-bridging –Si–R side groups. Relative dielectric constants in the range 2.5–3.3 are obtained for SSQ materials, depending on the curing conditions, and compare with 4.0 for conventionally-used fused silica. The non-bridging side groups significantly disrupt the SSQ network—occupying more than 25% of the Si bonds—and lead to materials that are considerably less stiff, hard and tough than fused silica. Perhaps more importantly, SSQ materials have thermal expansion coefficients greater than that of the intended Si substrate and therefore finish curing in a state of residual tension, leading to a susceptibility to stress-corrosion cracking. In this paper the development of thermomechanical properties during curing of SSQ spin-on glasses is considered and related to the driving force for film cracking deriving from the residual tension. Various crack suppression schemes involving mechanisms both intrinsic and extrinsic to the base SSQ are discussed.

1986 ◽  
Vol 72 ◽  
Author(s):  
G. V. Chandrashekhar ◽  
M. W. Shafer

AbstractDielectric properties have been measured for a series of porous and fully densified silica glasses, prepared by the sol-gel technique starting from Si-methoxide or Si-fume. The results for the partially densified glasses do not show any preferred orientation for porosity. When fully densified (˜2.25 gms/cc) without any prior treatment of the gels, they have dielectric constants of ≥ 6.5 and loss factors of 0.002 at 1 MHz, compared to values of 3.8 and <0.001 for commercial fused silica. There is no corresponding anomaly in the d.c. resistivity. Elemental carbon present to the extent of 400–500 ppm is likely to be the main cause for this enhanced dielectric constant. Extensive cleaning of the gels prior to densification to remove this carbon were not completely successful pointing to the difficulty in preparing high purity, low dielectric constant glasses via the organic sol-gel route at least in the bulk form.


1986 ◽  
Vol 73 ◽  
Author(s):  
G. V. Chandrashekhar ◽  
M. W. Shafer

ABSTRACTDielectric properties have been measured for a series of porous and fully densified silica glasses, prepared by the sol-gel technique starting from Si-methoxide or Si-fume. The results for the partially densified glasses do not show any preferred orientation for porosity. When fully densified (∼2.25 gms/cc) without any prior treatment of the gels, they have dielectric constants of ≥ 6.5 and loss factors of 0.002 at 1 MHz, compared to values of 3.8 and <0.001 for commercial fused silica. There is no corresponding anomaly in the d.c. resistivity. Elemental carbon present to the extent of 400–500 ppm is likely to be the main cause for this enhanced dielectric constant. Extensive cleaning of the gels prior to densification to remove this carbon were not completely successful pointing to the difficulty in preparing high purity, low dielectric constant glasses via the organic sol-gel route at least in the bulk form.


2018 ◽  
Vol 31 (8) ◽  
pp. 986-995
Author(s):  
Lei Wang ◽  
Guifen Gong ◽  
Junyao Shen ◽  
Jinsong Leng

Polyimide (PI)/titanium dioxide (TiO2) composite nanofibers (NFs) with average diameters of 200–250 nm were synthesized via electrospinning. The total number density of dipoles decreased significantly, owing to the porous structures and compact interface between TiO2 NPs and PI matrix. All PI/TiO2 NFs maintain low dielectric constants and losses. For example, the dielectric constants of PI/TiO2-6% NFs are all lower than 2.6, being exposed to temperatures from 25°C to 200°C. Meantime, the dielectric losses of PI/TiO2-6% NFs are below 0.005. For ultraviolet (UV)-light shielding performance, the PI/TiO2 NFs exhibited good UV-light shielding and corresponding anti-photoaging properties. The reason can be ascribed from high UV-light absorption and scattering ability in the TiO2 NPs. The best UV-light absorption (average: 3.71) and corresponding absorption decay (15.13%) were achieved for optimized PI/TiO2-6% NFs. Other fundamental characteristics, such as the thermal stability, mechanical tensile property, and hydrophobicity, were also investigated. Such low dielectric constant PI/TiO2 composite NFs can be alternatively chosen under a longtime UV-light exposing condition.


1999 ◽  
Vol 565 ◽  
Author(s):  
T. Aoki ◽  
Y Shimizu ◽  
T. Kikkawa

AbstractA novel spin on material derived from perhydropolysilazane that converts into ultra-low k inorganic films is described in this paper. The obtained films, cured at 400°C in N2 atmosphere, exhibit dielectric constants as low as 1.6 which do not change after holding the wafers in a clean-room mbient for 2 months. Cross-sectional SEM images of the cured films show the aggregation of small granules with diameters ranging from 5 to 30 nm. The films can be obtained by conventional SOG process: spin-coating, baking and curing, without any additional process such as hydrophobic treatment.The average atomic compositions of the films are, Si/O/N/C = 40/55/5/0.5 (atomic %), by XPS analysis. These results indicate that the films have hydrogen silicon oxynitride structures. No evolution of H2O and NH3 was detected by TDS analysis in the temperature range of RT to 800°C. Hydrophobic Si-H and Si-H2 groups remaining in the film might prevent water absorption, resulting in the low dielectric constant.The remainder of Si-H and Si-H2 constituents in the cured films is the result of selective oxidation reactions of perhydropolysilazane in the baking process with the use of a specific catalyst. The structures of the films are tailored by altering the amount of the catalyst. In this study, we also demonstrate the relationship between the effect of the catalyst and the film properties.


1970 ◽  
Vol 23 (5) ◽  
pp. 905 ◽  
Author(s):  
PJ Pearce ◽  
W Strauss

The electrolytic conductance of solutions of potassium chloride and tetrabutyl- ammonium picrate over a range of concentrations have been measured in dioxan-water mixtures containing 0, 25, 50, 70, and 80% dioxan at 25� and pressures up to 1000 and 2500 bars respectively for the two solutes. The solvent concentration range corresponds to a range of dielectric constants of 78.3 (for water) to 11.98 (80% dioxan). The association of KCl in solutions of low dielectric constant is reduced by increasing pressure, so that the conductances of the solutions of finite concentration are not reduced as much by pressure as at infinite dilution. In contrast to this, the solutions of the tetrabutylammonium picrate are wholly dissociated even in very low dielectric constant solvents, as is shown by the limited concentration dependence of the conductance pressure characteristics.


2012 ◽  
Vol 262 ◽  
pp. 448-453 ◽  
Author(s):  
Jian Yong Lv ◽  
Yan Meng ◽  
Li Fan He ◽  
Teng Qiu ◽  
Xiao Yu Li ◽  
...  

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.


1996 ◽  
Vol 443 ◽  
Author(s):  
S. W. Lim ◽  
M. Miyata ◽  
T. Naito ◽  
Y. Shimogaki ◽  
Y. Nakano ◽  
...  

AbstractOne solution to reduce the time constant of ultra large scale integrated circuit (ULSI) is the use of a low dielectric constant intermetal film like fluorinated silicon oxide (SiOF). We could obtain SiOF films with low dielectric constant as low as 2.6 and good step coverage by adding CF4 to SiH4 and N2O in plasma-enhanced chemical vapor deposition (PECVD) process. To investigate the dielectric constants due to each polarization and the reason for the decrease in the dielectric constant, we used capacitance-voltage (C-V) and ellipsometry measurements, and Kramers-Kronig transformation. The decrease in dielectric constant could not be completely explained by the reduction in ionic and electronic polarization. We could detect silanol groups, Si-OH in the films and their decrease with increasing CF4 flow rate. It is suggested that the main polarization component to decrease dielectric constant is such as orientational polarization. The step coverage of film was improved by adding CF4. It is suggested that the reduction in the sticking probability of films forming species due to the change in surface state improved the step coverage.


2020 ◽  
Vol 993 ◽  
pp. 927-932
Author(s):  
Zhi Wei He ◽  
Hong Xiao Lin ◽  
Chun Yan Li ◽  
Ashok M. Mahajan ◽  
Swati A. Gupta ◽  
...  

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.


RSC Advances ◽  
2016 ◽  
Vol 6 (90) ◽  
pp. 87433-87439 ◽  
Author(s):  
Jinmeng Hao ◽  
Yanfeng Wei ◽  
Jianxin Mu

Soluble poly(arylene ether)s with perfluoro-aromatics and POSS in the main chains exhibited ultra low dielectric constants and hydrophobic properties.


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