Package carrier

Wire Interconnect Materials. Wire-bonding is accompHshed by bringing the two conductors to be joined into such intimate contact that the atoms of the materials interdiffuse (2). Wire is a fundamental element of interconnection, providing electrical connection between first-level (ie, the chip or die) and second-level (ie, the chip carrier, or the leadframe in a single-chip carrier) packages. 

Metal is then deposited into the opened vias (openings) in the oxide layer and over its surface. During the subsequent photolithography process, it is patterned to form the desired electrical interconnections. These two steps are repeated for each succeeding level to produce additional levels of interconnections. Finally, a protective overcoat of oxide/nitride is applied (passivation), and vias are opened so that the wires eonnectlng the IC chip to its carrier package can be bonded to output pads. 

Here the joining of an adhesive bonding a tape carrier package, in which a semiconductor chip has been incorporated, to a liquid crystal display panel through an anisotropic conductive film is shown. 

Vasopressin (antidinretic hormone) is a nonapeptide that controls resorption of water by distal tubules of the kidney to regulate the osmotic pressure of blood. It functions to conserve body water by reducing the output of urine, and thus it is known as an antidiuretic. Vasopressin is synthesized in the supraoptic nucleus of the hypothalamus where it is bound to a neurophysin protein carrier, packaged in granules, and delivered by intracellular transport to nerve terminals in the posterior pituitary. Vasopressin bound to neurophysin is released from the granules in response to increased extracellular osmolarity sensed by hypothalamic osmoreceptors, signaling by atrial stretch receptors or after a rise in angiotensin n levels. Its secretion is increased by dehydration or stress and decreased after alcohol consumption. 

Tape carrier package (TCP) Tape automated bonding (TAB) package has an open circuit (98% vs. 2% misalignment problems) failure mode. 

J leads, leads that are rolled under the body of the package in the shape of the letter J. They are typically used on plastic chip carrier packages. 

Leaded ceramic chip carrier (LDCC), leaded ceramic chip carrier packages include JEDEC types A, B, C, and D. Leaded type B parts are direct soldered to a substrate. Leaded type A parts can be socketed or direct soldered, and include sub-categories leaded ceramic, premolded plastic, and postmolded plastic (which are not designated as LDCC devices). 

Chip on board (COB)—the die is mounted directly on the printed circuit substrate (or board). See also tape automated bonding (TAB) and tape carrier packages (TCB). 

PLASTIC LEADED CHIP CARRIER (PLCC) A chip Carrier packaged in plastic, usually terminating in compliant leads (originally J style) on all four sides. 

Low density Third-party miik runs or LTL carrier LTL or package carrier Package carrier... 

There has recently been a renewed interest in Sn whiskers because of the worldwide conversion to Pb-free solders and finishes in electronic manufacturing. Finishes are applied to printed circuit boards (PCBs) and to the lead frames used to connect device packages to printed circuit boards. Lead frames are typically made of a copper (Cu) or iron-nickel (FeNi) alloy plated with a Sn-Pb alloy. Fig. 5 is a schematic diagram of a lead frame cross section bonded to a chip-carrier package. The surface finish of the lead-frame leg is designed to provide surface passivation and enhanced solderability. Typical Pb-free surface finishes are eutectic Sn-Cu or pure Sn. Tin(Sn) whiskers readily grow on high-Sn content finishes under certain conditions. 

Textile uses are a relatively stable area and consist of the lamination of polyester foams to textile products, usually by flame lamination or electronic heat sealing techniques. Flexible or semirigid foams are used in engineered packaging in the form of special slab material. Flexible foams are also used to make filters (reticulated foam), sponges, scmbbers, fabric softener carriers, squeegees, paint appHcators, and directly appHed foam carpet backing. 

Additive packages have been developed which do an exceUent job of preventing IVD. The key to effective operation is to keep the valve wet so that the additive can prevent deposit buildup. Most packages include a combination of detergent/dispersant and a carrier oil or heavy solvent. If no carrier oil is present, then the fuel may evaporate off the valve too rapidly for the package to be effective. When the valves do not rotate, the portion of the valve which has the highest deposit level is the back side which is not constantly wet. 

These processes are considerably more complex in actual CMOS fabrication. First, the lower layers of a CMOS stmcture typically have a twin-tub design which includes both PMOS and NMOS devices adjacent to each other (see Fig. 3b). After step 1, a mask is opened such that a wide area is implanted to form the -weU, followed by a similar procedure to create the -weU. Isolation between active areas is commonly provided by local oxidation of sihcon (LOCOS), which creates a thick field oxide. A narrow strip of lightly doped drain (LDD) is formed under the edges of the gate to prevent hot-carrier induced instabiUties. Passivation sidewalls are used as etch resists. A complete sequence of fabrication from wafer to packaged unit is shown in Figure 10. 

Electronic-Grade MMCs. Metal-matrix composites can be tailored to have optimal thermal and physical properties to meet requirements of electronic packaging systems, eg, cotes, substrates, carriers, and housings. A controUed thermal expansion space tmss, ie, one having a high precision dimensional tolerance in space environment, was developed from a carbon fiber (pitch-based)/Al composite. Continuous boron fiber-reinforced aluminum composites made by diffusion bonding have been used as heat sinks in chip carrier multilayer boards. 

Fig. 1. The different levels of electronic packaging (0) chip (1) chip carrier (2) printed circuit board (electronic card assembly) (3) rack and (4) system (2).

The formulation of a carrier depends on four considerations (/) the carrier-active chemical compound (2) the emulsifier (J) special additives and (4) environmental concerns. Additional parameters to be considered in the formulation of a carrier product with satisfactory and repeatable performance arise from the equipment in which the dyeing operation is to be carried out. The choice of equipment is usually dictated by the form in which the fiber substrate is to be processed, eg, loose fiber, staple, continuous or texturized filament, woven or knot fabric, yam on packages or in skeins (see Textiles). 

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