Abstract: A method for detecting the presence of a workpiece on a polishing pad of a chemical mechanical polishing (CMP) machine applies an optical interrogation signal to a workpiece during the CMP process. An optical probe assembly produces a light signal that communicates with the polishing pad; portions of the light signal reflect from the polishing pad in a scattered manner. A light receptor receives reflected light associated with the interrogation signal, and the characteristics of the received light are analyzed and processed by a suitable processor. By analyzing the scattered light signals, the method distinguishes the reflective characteristics of the polishing pad from the reflective characteristics of the workpiece. Thus, the method may be used to detect a lost or broken workpiece in a fast and effective manner.

Abstract: A method for use with a chemical mechanical planarization (CMP) system includes an infrared LED emitter that generates an interrogation signal and directs the interrogation signal toward a polishing pad configured to process a workpiece during the CMP procedure. A reflected signal produced in response to the interrogation signal is received by a detector, and the reflected signal is processed by a converter to produce a control signal having an analog voltage. The control signal is processed and an output is produced indicative of the presence of extraneous material proximate an area of the polishing pad when the analog voltage is measured within a predetermined range. The predetermined voltage range is established such that a variety of polishing pads having different physical characteristics may be employed without altering the position of the emitter or the operating parameters of the apparatus.

Abstract: An apparatus for use with a chemical mechanical planarization (CMP) system includes an infrared LED emitter that generates an interrogation signal and directs the interrogation signal toward a polishing pad configured to process a workpiece during the CMP procedure. A reflected signal produced in response to the interrogation signal is received by a detector, and the reflected signal is processed by a converter to produce a control signal having an analog voltage. The control signal is processed and an output is produced indicative of the presence of extraneous material proximate an area of the polishing pad when the analog voltage is measured within a predetermined range. The predetermined voltage range is established such that a variety of polishing pads having different physical characteristics may be employed without altering the position of the emitter or the operating parameters of the apparatus.

Abstract: An apparatus for detecting the presence of a workpiece on a polishing pad of a chemical mechanical polishing (CMP) machine employs an optical interrogation signal that is applied during the CMP process. An optical probe assembly produces a light signal that communicates with the polishing pad; portions of the light signal reflect from the polishing pad in a scattered manner. A light receptor receives reflected light associated with the interrogation signal, and the characteristics of the received light are analyzed and processed by a processor used by the apparatus. By analyzing the scattered light signals, the apparatus distinguishes the reflective characteristics of the polishing pad from the reflective characteristics of the workpiece. Thus, the apparatus is capable of detecting a lost or broken workpiece in a fast and effective manner.