Abstract: A chemical-mechanical abrasive composition for use in semiconductor processing uses abrasive particles having a non-spherical morphology.

Abstract: A method of determining a quantity of amorphous SiC2-containing impurities in a montmorillonite clay sample comprising the steps of: (a) analyzing the clay sample to determine the weight percent of SiO2 contained in the clay sample; (b) analyzing the clay sample for non-montmorillonite SiO2-containing crystalline components; (c) calculating the weight percent of SiO2 from step (a) that is derived from the montmorillonite and amorphous SiQ2-containing impurities by lowering the weight percent of SiO2 in step (a) based on the non-montmorillonite SiO2-containing crystalline impurities found in step (b); and (d) determining the amorphous SiO2-containing impurity portion of the SiO2 calculated in step (c) by further lowering the amount of SiO2 from step (c) until the amount of montmorillonite-derived SiO2 is consistent with one or more properties of the clay sample, the amount of further lowering being proportional to an amount of amorphous SiO2-containing impurities contained in the clay sample.

Abstract: A hydrothermal reaction which dissolves the amorphous silica and the crystalline silica impurities contained in a recovered, naturally occurring montmorillonite clay, and subsequently converts the dissolved silicas into a dioctahedral and/or trioctahedil smectite clay. The dissolution of silica is accomplished by adjusting the pH of an aqueous slurry of the recovered clay to a value of about 8.5 to about 10.0, preferably about 9.0 to about 9.5, at a temperature of at least about 150.degree. C., preferably about 180.degree. C. to about 250.degree. C., more preferably about 190.degree. C. to about 235.degree. C. Dissolved silica reacts with stoichiometric amounts of aluminum and/or magnesium and/or sodium added to the slurry, while at a temperature of at least about 150.degree. C., preferably about 185.degree. C. to about 250.degree. C.

Abstract: A clay purification process, for removing impurities recovered with the clay, particularly a montmorillonite clay, includes the steps of separating the clay from rocks and other large non-clay impurities; dispersing the clay and smaller impurities in water, preferably at a concentration of at least about 4% by weight clay, based on the total weight of clay and water, more preferably about 6-10% by weight clay in water, to provide a clay slurry; passing the clay slurry through a series of hydrocyclones to remove the larger particles (impurities) while retaining clay particles having a size of about 100 microns or less, particularly about 80 microns or less; ion exchanging the clay to remove at least about 95% of the interlayer, multivalent (e.g.