Dielectrics applications

The first term represents the forces due to the electrostatic field, the second describes forces that occur at the boundary between solute and solvent regime due to the change of dielectric constant, and the third term describes ionic forces due to the tendency of the ions in solution to move into regions of lower dielectric. Applications of the so-called PBSD method on small model systems and for the interaction of a stretch of DNA with a protein model have been discussed recently ([Elcock et al. 1997]). This simulation technique guarantees equilibrated solvent at each state of the simulation and may therefore avoid some of the problems mentioned in the previous section. Due to the smaller number of particles, the method may also speed up simulations potentially. Still, to be able to simulate long time scale protein motion, the method might ideally be combined with non-equilibrium techniques to enforce conformational transitions. 

Finally, the dielectric properties of a nonpolar polymer are modified by inclusion of even small amounts of a polar comonomer. In coatings applications the presence of polar repeat units in an otherwise nonpolar polymer reduces the tendency for static buildup during manufacture, printing, and ultimate use. On the other hand, in dielectric applications this increases the power loss and must be kept to a minimum, even to the exclusion of polar initiator fragments. 

The glass transition temperature in the polymer containing a few percent of 5-triethoxysilanenorbomene for dielectric applications can be lowered by increasing the amount of 5-decylnorbomene (see Figure 10.33). 

Because of the high functional values that polyimides can provide, a small-scale custom synthesis by users or toll producers is often economically viable despite high cost, especially for aerospace and microelectronic applications. For the majority of industrial applications, the yellow color generally associated with polyimides is quite acceptable. However, transparency or low absorbance is an essential requirement in some applications such as multilayer thermal insulation blankets for satellites and protective coatings for solar cells and other space components (93). For interlayer dielectric applications in semiconductor devices, polyimides having low and controlled thermal expansion coefficients are required to match those of substrate materials such as metals, ceramics, and semiconductors used in those devices (94). 

Policastro PP, Lupinski JH, Hernandez PK (1988) Siloxane polyimides for interlayer dielectric applications, Polymeric materials Science Engineering 59 209... 

Yang, W. L. and Wolden, C. A. (2006). Plasma-enhanced chemical vapor deposition of Ti02 thin films for dielectric applications. Thin Solid Films 515(4), 1708-1713. 

Solution processability — For cost reasons, it is desirable to have a printable dielectric. Therefore, as with the semiconductors discussed above, it is desirable to have solution processable dielectric materials. In particular, for dielectric applications, it is crucial that the solution processing technology be extremely robust and not result in any pinholes, cracks, etc., since these would form points through which electrical shorts might form. 

Ceramic Ablators, Several types of subliming or melting ceramic ablators have been used or considered tor use in dielectric applications particulady with quartz or boron nitride [10043-11-5] fiber reinforcements to form a nonconductive char. Fused silica is available in both nonporous (optically transparent) and porous (slip cast) forms. Ford Aerospace manufactures a 3D silica- fiber-reinfo reed composite densified with colloidal silica (37). The material, designated AS-3DX, demonstrates improved mechanical toughness compared to monolithic ceramics. Other dielectric ceramic composites have been used with performance improvements over monolithic ceramics (see Composite materials, ceramic matrix). 

Mueller B, Lawing AS, Flanagan P, Yu C, Lane S, Huynh D. Challenges for CMP slurries in next generation STI and dielectric applications. Proceedings AVS First International Conference on Mircoelectronics and Interfaces, Santa Clara, CA 2000. 

Electro-insulation materials. The retention of dielectric properties in a high-temperature environment, coupled with good corrosion resistance in contact with certain reactive chemicals, suggests excellent possibilities of polybenzimidazole use in electrical insulation and other dielectric applications at high operating temperatures and/or in aggressive chemical environments. Typical applications, hence, can be foimd in special cable and wire insulation, in the manufacture of circuit boards and radomes for supersonic aircraft, as battery and electrolytic cell separators, and as fuel cell frame structural materials. Some recent publications in the patent and technical report literature may serve to illustrate such applications. 

R. J. Sheppard, "Least-Squares Analysis of Complex Weighted Data with Dielectric Applications," Journal of Physics D—Applied Physics, 6 (1973) 790-794. 

Applications are for use as lightweight filler materials for syntactic foam shapes or for parts for dielectric applications. 

Avatrel Dielectric Polymers (low-k dielectric applications such as interlayer dielectrics, passivation layers, die attach adhesives, chip encapsulants (both molding and adhesive) and underfill materials). 

Because of the improved thermal stability for PADS containing polyimides vis a vis other available siloxane polyimides, a screening program to correlate properties such as Tg, solubility, thermal stability, adhesion properties, and water absorption characteristics to structure was undertaken. Several copolymers were prepared from diamines and co-dianhydrides. An ODAN/ ODA copolymer in which 30 mole % PADS was substituted for ODAN, was prepared and TGA analysis at 450°C indicated that the material was the first siloxane containing polyimide identified that exceeded the established thermal stability criteria for interlevel dielectric applications. Stability and solubility of these materials as a function of PADS concentration is illustrated in Table VI. 

Bisquaric acid was also studied by 13C CPMAS NMR between 123 and 523 K, with powdered crystals.173 This material has also potential for nonlinear optical and dielectric applications. The low-temperature spectra resolve three peaks instead of four in SQA. This compound has no dipole moment, and no phase transition was detected in the studied temperature range, although the lineshape suggests the occurrence of a phase transition below 373 K. An explanation proposed by the authors is the lack of resolution due to the accidental overlapping of the two resonances of the C OH and C — O carbons participating to the HBs, an interpretation also supported by GIAO ab initio chemical shift calculations. 

The development of new materials possessing low dielectric constant (k) is crucial for applications in miniaturized integrated circuits (sub-lOOnm technology). Porous thin films with low k dielectric could provide solutions to the problems of signal delays caused by interconnect resistance-capacitance, signal crosstalk, and power consumption. Suggest a thin film material that would be suitable for low k dielectric applications. 

Lee, B. H. Kang, L. Qi, W. J. Nieh, R. Jeon, Y Onishi, K. Lee, J. C. 1999. Ultrathin hafnium oxide with low leakage and excellent reliability for alternative gate dielectric application. Electron Devices Meeting, 1999. lEDM Technical Digest International, Washington DC, December 5-6, pp. 133-136. 

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