Terminator technology

Fig. 16.1 The terminator technology which can be used to prevent the growth of volunteer plants from dispersed transgenic seed.

RIPP separation sequence (removal of insolubles isolation purification polishing), 5 781-782 RISC enzyme, 27 620 Riser termination technologies, 22 685 Risk... 

Gledhill, D., and Pedersen, J. Operating Experience with the New Riser Termination Technology. Grace Davison FCC Technology Conference, Lisbon, Portugal, September 1-4, 1998, Paper 14. 

The strategy described below involves direct cycle sequencing of the PCR product, using the Dye Terminator technology for an ABI automated sequencer (ABI PRISM Dye Terminator Cycle Sequencing Core Kit, Perkin-Elmer). 

Terminator Technology Genetic modification of food crops to produce seed sterility. 

An appropriate combination of a basic structure and supplemental stmctures should be chosen according to the reqnirements of the apphcation. Also, appropriate termination technologies and suitable circuit constructions must be considered together. 

Appropriate surface treatments for the bare conductors after the coverlay construction should be chosen according to termination technologies. Several examples are listed in Table 62.4. Details are explained in Chap. 64. 

Because the flying leads are basically bare conductors, suitable surface treatments should be conducted according to termination technologies. 

All of the termination technologies of flexible circuits have both advantages and disadvantages. 

To determine the optimal cost-performance combination, one first must establish the requirements from the assembly side and the capabihty of the termination technologies. Table 64.2 lists the critical items that are required to design a suitable termination. 

TABLE 64.1 Termination Technologies for High-Density Flexible Circuits... 

Newly developed anisotropic conductive resins have generated several new termination technologies for high-density flexible circuits. Film-type and paste-type anisotropic materials are developed with suitable applicators. The film-type material, called anisotropic conductive film (ACF), has been widely used for the mounting of driver IC chips on the flexible substrate and connections between the flexible substrates and the glass substrates of the LCD devices. The latest material has 30 m pitch connections in one direction for the IC chips on the gold-plated pads of the flexible circuits. Examples of the basic properties are provided in Table 64.5... 

Semipermanent connections have been required for rework, replacement of components and modules, and repeated connections. Realistic assembly processes for most electronic prodncts are not perfect, so semipermanent terminations are required for rework and replacement of electronic components or modules in standard assembly processes to increase final manufacturing yields. Also, temporary connections are required for testing and adjusting electronic products and modules. These often need 5 to 10 reconnections, with as many as 100 reconnections required in extreme cases. Basic data on typical semipermanent termination technologies are summarized in Tables 64.6 through 64.8. 

TABLE 64.8 Items to Be Considered in Semipermanent Termination Technologies... 

The basic idea of pressure contact termination technology is very simple and is not new. Pad patterns of the same pitch plated with gold are generated on a flexible circuit and opposite circuits, and they are attached to each other with uniform pressure using a suitable rubber strip (see Fig. 64.14). There is no high-temperature process to complete the coimectiou polyester base materials are available. The maximum conuection number and density depend on the capability of dimension control and uniformity of the circuits. It is possible to make 200 connections with 150 /tm pitch because of the processes all take place at room temperature. Neither special application equipment nor special constructions on flexible circuits are... 

There have been two kinds of approaches to reahzing high-density nonpermanent flex circuits. The first is improvement in connection densities of traditional termination technologies. Crimp tabs, pressure contacts, key contacts, and FFC connectors could be categorized in this group. 

No perfect termination technology can satisfy all requirements, especially for high-density connections with high pin counts. On the other hand, higher performances are required for the new portable electronics to complete reliable terminations in limited spaces. Accordingly, many new termination technologies with flexible circuits have been developed to satisfy many requirements. Nevertheless, it is still difficult to use one termination technology to satisfy... 

Termination technology Termination density (fim pitch) Repeatability Requirement for flex circuits... 

Several high density, but reliable termination technologies such as Ball Grid Array (BGA) and Flip Chip Bonding have been intrO duced for the high density rigid/flex. 

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