Bulk Delivery Systems

One goal of a bulk delivery system is to provide constant pressure to a CMP polisher, so that the peristaltic metering pump in the polisher can provide constant slurry flow to the polisher platen. While many schemes have been devised to minimize the fluctuations in pressure, there are many... 

Historically, bulk delivery systems have used manual diaphragm valves located at the return end of the global piping system, another carryover from high-purity chemical systems. However, the shear sensitivity of many slurries has fostered the creation of other baek-pressure approaches, including... 

J. P. Bare and B. Johl, Aging and Handling Evaluation of Tungsten CMP Slurry in Bulk Delivery System, Proceedings of Fourth Int l Chemical-Mechanical Polish Conference (CMP-MIC) (February 1999). 

Bulk delivery systems are the t3q)ical piped systems. The materials used in the transfer system should be compatible with the materials being transferred. Pressure should not exceed 15 psi. The systems should be equipped with an excess flow valve, secondary containment where spills may occur, manual shutdown at point of dispensing. Redundant fill level monitors and preset meters should also be provided on automated delivery systems. 

Nanomaterials are particles between 1 and 100 nm in diameter. They have properties that differ from the properties of atoms and from those of bulk materials and are used to create miniature circuits and drug delivery systems. 

The need for a reliable source of slurry during CMP stimulated the growth of a whole industry of bulk chemical distribution (BCD) systems. An extended discussion of BCD systems is beyond the scope of this work, but a few words are in order. Slurry distribution systems vary in sophistication from the simple laboratory system consisting of little more than a barrel of slurry and a pump to sophisticated delivery systems designed to supply slurry to tens of CMP tools in a high-volume production environment [56]. 

Self-assembly of polymers in the bulk Polymer micelles, polymero-somes, gelled macromole-cules, nano-tubes, protein fibres/tapes produced by aggregation at low pH, controlled release vehicles, smart delivery systems 50-500 nm Forster and Konrad, 2003 Sanguansri and Augustin, 2006 Dickinson 2006a Graveland-Bikker and de Kruif, 2006 van der Linden, 2006... 

Electrostatic self-assembly of polymers in the bulk Polyelectrolyte capsules controlled release vehicles, smart delivery systems 50-500 nm Anal et al., 2008... 

Specialty Gases. The purity of specialty gases depends on the systems and procedures adopted by the distributors for bulk gas supply and cylinder preparation, filling, and delivery. The distributors need to follow strict cylinder selection, preparation, and filling procedures to ensure the quality of the products. Most of the precautions taken into consideration in the bulk gases delivery system are also applied for specialty gases to eliminate recontamination. 

Conveyor installations may be permanent or a combination of permanent and portable. The latter kind is often mounted on a bulk-delivery vehicle, which permits fast unloading into the customer s silo by the carrier without effort or equipment from the customer. Controls range from simple motor starters and hand-connected hoses to sophisticated, microprocessor-electropneumatic control systems. 

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