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US 6,659,848 B1Granted
Slurry dispenser that outputs a filtered slurry to a chemical-mechanical polisher at a constant flow rate over the lifetime of the filter
AssigneeNational Semiconductor Corporation
InventorsDavid Linn Craig, Matthew Gautreau
Life of this patent
Estimating the term…
Abstract
The slurry used in a chemical-mechanical polisher is passed through a filter, and output at a constant flow rate throughout the lifetime of the filter by measuring the flow rate of the slurry, comparing the measured flow rate to a reference set point rate, and adjusting the pump speed of a slurry pump when the measured flow rate differs from the reference set point rate.
Claims17
A slurry dispenser that dispenses slurry onto a pad of a chemical-mechanical polisher, the slurry dispenser comprising:
- a pump that receives a slurry from a slurry supply, and outputs a pumped slurry, the pump outputting the pumped slurry with a flow rate at a pump speed, the pump speed being controlled by a pump speed control signal;
- a slurry filter that removes oversized particles from the pumped slurry, the slurry filter having an input and an output;
- a flow meter that measures a flow rate of the pumped slurry, and outputs a measured flow signal that indicates a measured flow rate;
- and
- a flow controller that receives the measured flow signal, compares the measured flow rate to a reference set point rate, and controls a value of the pump speed signal in response to the difference between the measured flow rate and the reference set point rate.
2 more elements
A method of dispensing slurry onto a pad of a chemical-mechanical polisher comprising the steps of:
- pumping a slurry from a slurry supply to output a pumped slurry, the pumped slurry having a flow rate at a pump speed, the pump speed being controlled by a pump speed control signal;
- filtering the pumped slurry with a filter to remove oversized particles from the pumped slurry;
- measuring a flow rate of the pumped slurry, and outputting a measured flow signal that indicates a measured flow rate;
- and
- receiving the measured flow signal, comparing the measured flow rate to a reference set point rate, and controlling a value of the pump speed control signal in response to the difference between the measured flow rate and the reference set point rate.
2 more elements
Dependencies are inferred from the claim text.