Chemical-mechanical-polishing system with continuous filtration

摘要

A chemical-mechanical-polishing system having a slurry distribution system, a polisher, a deionized water supply, and a drain, includes a slurry filtration system. The filtration system has two filters for alternately filtering particles in slurry and being backflushed with deionized water. Two input valves have input ports connected to the slurry distribution system and output ports respectively connected to the filters for filtering. Two output valves have input ports respectively connected to the filters for receiving filtered slurry and output ports connected to the polisher. Two backflush valves have input ports connected to the deionized water supply and output ports respectively connected to backflush with deionized water; the output ports are also respectively connected to the input ports of the two output valves. Two drain valves have input ports respectively connected to the filters for receiving backflushed fluid and output ports connected to the drain. A pressure sensor disposed to sense pressure of slurry across the filters provide pressure indications which are used by control circuitry to open and close said valves to filter slurry or backflush the filters.