Lucid Treatment Systems, Inc.

Glenn A Roberson, Jr

Gary L Corlett

Abrasive components and water are recovered from an aqueous chemical mechanical slurry used for planarization of semiconductor materials. The slurry effluent is preferably brought to a neutral pH, and cooled to a temperature between about 0.degree. C. and about 15.degree. C. An electrical potential can be applied to the slurry effluent to facilitate agglomeration and separation of particles of abrasive material in the slurry effluent. In one embodiment, the slurry effluent is introduced into a process chamber at ambient temperature and pressure, and supernatant liquid separated from the process chamber is then subjected to a reduction of pressure in a vacuum chamber to cause gas entrapped in the supernatant liquid to bubble to the surface of the supernatant liquid for further separation and collection of water and abrasive particles from the slurry effluent. In another embodiment, slurry effluent is filtered through one or more self-cleaning reversible gross particle filter assemblies.

Method and apparatus for recovery of water and slurry abrasives used for

The apparatus for the continuous separation of liquid and relatively fine particles from a liquid slurry includes one or more centrifuge vessels disposed about a longitudinal axis of rotation, and a driver for rotating the centrifuge vessel or vessels. A feed inlet introduces the liquid slurry into each centrifuge vessel, each of which extends at an oblique angle to the axis. A first outlet is provided adjacent to the inner end for the lighter liquid component, and a second outlet is provided adjacent to the outer end for the heavier solid particle component. The inlet of the each centrifuge vessel is preferably located between the first end and the second end, and the second outlet preferably comprises a plurality of solids removal capillary passages connected to a continuous solids removal tube, which can be connected to a source of vacuum to form a vacuum chamber for withdrawing the solids. A supernatant liquid collection chamber is also connected to the first outlet for receiving the supernatant liquid.

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Carmel, CA, United States of America

Glenn A Roberson, Jr