Slurry Filtration

Filters generally achieve a lower final moisture content than obtained by gravity sedimentation and are often fed from thickeners, as indicated in the schematic particulate process shown in Figure 9.2. In this chapter the principles of slurry filtration will be described and certain simplified filter design equations derived. For more complex derivations the reader is referred to specialist texts e.g. Coulson and Richardson (1991), Wakeman (1990a) and Purchas (1981). 

A blend of Polywax 500 and 655 (81.3 and 18.7 wt%, respectively) with a CO-activated ultrafine iron catalyst was used for the evaluation of catalyst/ wax slurry filtration performance of the filter module with and without an alcohol compound. All of the filtration tests were conducted with a TMP of... 

On-site filtration of CMP slurry is one of the remedial approaches used to reverse the effects of changes to slurry particles between manufacture and delivery to the polisher platen. Figure 11 shows the locations that can be considered for slurry filtration. The candidate locations include... 

Capitanio et al, Defect Reduction During Chemical Mechanical Planarization by Incorporation of Slurry Filtration, Proceedings of SEMICONlWest Contamination in Liquid Chemical Distribution Systems Workshop (July 1998). 

The chemistry of Rh(DIPAMP) and mechanism has been reviewed.914 1617 2 28 Marginally higher catalyst efficiencies are observed with higher alcohols compared to methanol, whereas the presence of water can result in the reduction of slurries. Filtration of the product can improve the % ee while the catalyst and D,L-product remain in the mother liquor. The catalyst stereoselectivities decrease as hydrogen pressure increases. [Rh(COD)(R,W-DIPAMP) +BF4 (13) affords the. S -con-figuration of amino acids on reduction of the enamide substrate. Reduction of enamides in the presence of base eliminates the pressure variances on the stereoselectivities, but the rate of reaction under these conditions is slow.17... 

In the submicron range of particle sizes, there are at least two media types to consider depth and microporous membrane. Typically, depth media is melt-blown fibrous nonwoven type (Fig. 18.13). Membranes are basically cast or expanded microporous films. Depth filters with a wrapped or pleated construction are used for slurry filtration (see Fig. 18.14a and b). Membrane... 

FIGURE 18.13 Typical graded-density depth media for CMP slurry filtration. 

Information on typical filtration products used for CMP slurry filtration follows. 

PUMP HANDLING EFFECTS ON CMP SLURRY FILTRATION—CASE STUDIES 603... 

Discuss various filtration approaches used in CMP slurry abrasive particle management. How are the requirements of new slurries filtration likely to change for future low-defectivity CMP processes What considerations should be made to get stable and extended lifetime from CMP slurry filters How may next-generation slurries low abrasive content and/or complex abrasives change filtration optimization ... 

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