Abstract: An apparatus and method for use is described which permits real time monitoring of build-up of particulate contamination in a wafer processing chamber. The apparatus is capable of monitoring particle build up in regions of a processing chamber which are not accessible by traditional optical particle scanners. An accelerometer is fastened to a body in the chamber upon which the contamination is deposited. The body is subjected to vibrations and produces a vibration signal which is detected by the accelerometer. The signal is filtered, digitized, and processed by a digital signal analyzer which computes a frequency spectrum of vibration amplitudes. Frequencies in a selected band of the frequency spectrum are directly proportional to the degree of particulate build up on the body. The invention is applied to a wafer annealing tool which has a rotatable wafer platform wherein particles deposit on the exposed back side of the wafer during processing. The particles emanate from bearings in the rotation drive.

Abstract: CMP pad conditioning processes have been monitored and controlled by detecting the vibrational spectrum of a sensor mounted on the conditioner support arm. An accelerometer is used as the detector so that vibrational velocity (which correlates with pad wear) can be measured, rather than displacement or acceleration. After the vibrational spectrum has been transformed to its frequency domain equivalent, it is monitored for the presence of abnormal peaks in order to control the conditioning process.

Abstract: The present invention uses a method of processing signals in which signals received from an array of sensors are subject to system having a first adaptive filter arranged to enhance a target signal and a second adaptive filter arranged to suppress unwanted signals. The output of the second filter is converted into the frequency domain, and further digital processing is performed in that domain. The invention is further enhanced by incorporating a third adaptive filter in the system and a novel method for performing improved signal processing of audio signals that are suitable for speech communication.