Patent ID: 7413497

Claim:
A chemical mechanical polishing monitoring system, comprising: a peristaltic pump operable to deliver a slurry to a polishing pad; a controller operable to send a drive voltage to the peristaltic pump based on a desired volumetric flow rate for the slurry; a rotation sensing device coupled to a rotating shaft of the peristaltic pump and operable to sense a rotation of the peristaltic pump, the rotation sensing device further operable to generate a voltage indicative of the rotation of the peristaltic pump, and a computer coupled to the rotation sensing device and the controller, the computer operable to: receive the drive voltage from the controller; receive the voltage from the rotation sensing device; and compare the voltage to a threshold voltage that is based, in part, on the drive voltage in order to monitor the peristaltic pump during use; wherein the computer is further operable to generate a message based on the comparison.