CMP slurry mixing system

11/01/1996

CMP slurry mixing system

The SMS-102 CMP polishing slurry system mixes an alumina slurry with ferric nitrate for polishing a tungsten metal layer on a wafer and can also be used for other mixing applications. The system automatically mixes the slurry with the desired chemical to a programmable mix ratio; it then recirculates the slurry mix to a loop that supplies the polishing machine. SMS-102 uses load cells to measure by weight the quantities of slurry and chemical that are to be mixed. The mix ratio can be easily changed by adjusting the weight set point of either of the components. Mechanical stirrers accelerate the mixing, and continuous recirculation of the slurry mix prevents settling of the slurry particles. One automatic and two operator-controlled cleaning processes are used to clean the containers, pumps, valves, and fluid lines to remove any slurry particles from the system during periods of non-use. The system`s footprint is 28 ? 28 in. Semco Corp., Santa Clara, CA; ph 408/748-2650, fax 408/496-1279.