Insulators Dielectric materials

Copper is going to replace aluminum as the material of choice for semiconductor interconnects due to its low electrical resistance and high electromigration resistance (1-4). An inlaid interconnect is used for copper metallization in which the insulating dielectric material is deposited first, trenches and vias are formed by patterning and selective dielectric etching, and then diffusion barrier and copper seed layer are deposited into the trenches and vias (5). 

Pyroelectric transducers are constructed from single crystalline wafers of pyroelectric materials, which are insulators (dielectric materials) with very special thermal and electrical properties. Triglycine sulfate (NH7CH2COOH), H. SOt (usually dcutcraicd or with a fraction of the glycines replaced with alanine), is the most important pyroelectric material used for IR-detcction systems. 

The two following effects help to make the PECVD process within the trenches uniform and conformal, to avoid formation of the keyholes, and to permit complete filling of the trench with insulating dielectric material (Si02) ... 

Dielectric breakdown The conversion of an insulating dielectric material to an electrically conductive material, typically as a direct result of high applied electric field. 

Dielectrics used to satisfy the first and the second requirements are electric insulators with relatively low dielectric constants (less than 15). Capacitor dielectrics with dielectric constants greater than 20 are used as charge storage devices. Thus, thick-film dielectric formulations can be broadly categorized as either insulator or capacitor dielectrics. Insulator dielectric materials can be further categorized as sealing glasses, crossover dielectrics, and multilayer dielectrics. 

Here A is the area of the capacitor plates and d is their separation or the thickness of the insulating (dielectric) material between them. 

Dielectric films Dielectric fluids Dielectric insulators Dielectric masking Dielectric materials Dielectric permittivity Dielectrics... 

Two parallel plates of conducting material separated by an insulation material, called the dielectric, constitutes an electrical condenser. The two plates may be electrically charged by connecting them to a source of direct current potential. The amount of electrical energy that can be stored in this manner is called the capacitance of the condenser, and is a function of the voltage, area of the plates, thickness of the dielectric, and the characteristic property of the dielectric material called dielectric constant. 

Another important use of dielectrics is as intermetal dielectrics (IMDs), where the dielectrics insulate metal lines from each other. The dielectric material must fill small gaps with high aspect ratios (depth to width) while maintaining all other dielectric properties. It is essential that the IMDs are void-free at submicrometer dimensions for both performance and rehabiUty. 

Electrical Properties. AH polyolefins have low dielectric constants and can be used as insulators in particular, PMP has the lowest dielectric constant among all synthetic resins. As a result, PMP has excellent dielectric properties and alow dielectric loss factor, surpassing those of other polyolefin resins and polytetrafluoroethylene (Teflon). These properties remain nearly constant over a wide temperature range. The dielectric characteristics of poly(vinylcyclohexane) are especially attractive its dielectric loss remains constant between —180 and 160°C, which makes it a prospective high frequency dielectric material of high thermal stabiUty. 

The contact ends of printed circuit boards are copper. Alloys of nickel and iron are used as substrates in hermetic connectors in which glass (qv) is the dielectric material. Terminals are fabricated from brass or copper from nickel, for high temperature appHcations from aluminum, when aluminum conductors are used and from steel when high strength is required. Because steel has poor corrosion resistance, it is always plated using a protective metal, such as tin (see Tin and tin alloys). Other substrates can be unplated when high contact normal forces, usually more than 5 N, are available to mechanically dismpt insulating oxide films on the surfaces and thereby assure metaUic contact (see Corrosion and corrosion control). 

The insulating properties of polyethylene compare favourably with those of any other dielectric material. As it is a non-polar material, properties such as power factor and dielectric constant are almost independent of temperature and frequency. Dielectric constant is linearly dependent on density and a reduction of density on heating leads to a small reduction in dielectric constant. Some typical data are given in Table 10.6. 

The early development of modern plastic materials (over a century) can be related to the electrical industry. The electronic and electrical industry continues to be not only one of the major areas for plastic applications, they are a necessity in many applications worldwide (2,190). The main reasons is that plastic designed products are generally basically inexpensive, easily shaped, fast production dielectric materials with variable but controllable electrical properties, and jn most cases the plastics are used because they are good insulators (Chapter 5, ELECTRICAL PROPERTY). 

The dielectric materials interact with the electrical fields and alter the characteristics of the electrical field. In some cases this is desirable and in others it is deleterious to the operation of the system and must be minimized. This is done by both the selection of the material and the configuration of the dielectric. To see how these concepts are applied, an example is presented of one of the major applications of plastics materials, i.e., to insulate wires, and show how a dielectric is designed to meet the service requirements. The specific requirements on a standard wire are ... 

A number of areas in which plastics are used in electrical and electronic design have been covered there are many more. Examples include fiber optics, computer hardware and software, radomes for radar transmitters, sound transmitters, and appliances. Reviewed were the basic use and behavior for plastics as an insulator or as a dielectric material and applying design parameters. The effect of field intensity, frequency, environmental effects, temperature, and time were reviewed as part of the design process. Several special applications for plastics based on intrinsic properties of plastics materials were also reviewed. 

The possibility of realizing via percolated w/o microemulsion conductor/insulating composite materials with very large dielectric constant and exotic optical properties has been pointed out [284],... 

By the nature of conduction and values of conductivity, materials can be classified as conductors, semiconductors, or insulators (dielectrics). It is a special attribute of conductors that free electric charges are present in them. The migration of these free charges in an applied electric field manifests itself as electric current. 

Synthetic polymers are best known for their insulating dielectric properties which have been exploited for numerous applications in both the electrical and electronic industries. It was found recently that some polymers can also be rendered conductive by an appropriate treatment, thus opening the way to a new field of applications of these materials (2, 3). Usually, electrical conductivity is obtained by doping a neutral polymer, rich in unsaturation, with donor or acceptor molecules. These polymers are rather difficult to synthesize, which makes them very expensive besides they are often sensitive to environmental agents, like oxygen or humidity, thus restricting their practical use to oxygen-free systems. 

These postulated mechanisms3 are consistent with the observed temperature dependence of the insulator dielectric properties. Arrhenius relations characterizing activated processes often govern the temperature dependence of resistivity. This behavior is clearly distinct from that of conductors, whose resistivity increases with temperature. In short, polymer response to an external field comprises both dipolar and ionic contributions. Table 18.2 gives values of dielectric strength for selected materials. Polymers are considered to possess... 

The ratio of permittivity with the dielectric to the permittivity in vacuum, e/eo, is called the relative permittivity, s, or dielectric constant. The dielectric constant is a material property. Some values of dielectric constants for common ceramic and glass insulators are given in Table 6.3. Since a polarizable material causes an increase in charge per unit area on the plates of a capacitor, the capacitance also increases, and it can be shown that the dielectric constant is related to the capacitance and displacement in vacuum and with the dielectric material as follows ... 

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