Abstract: An apparatus for monitoring particle fallout incorporates a particle flux monitor and a tubular structure. The tubular structure is positioned over an aperture in the housing of the monitor to provide a still air condition so that the particles that descend to the monitor and pass through the light net of the monitor are precluded from being carried back to the light net, which would result in an erroneous count.

Abstract: A surface scanner useful for detecting defects on the surface of a water that is being processed in a vacuum equipment employs a light beam that scans the wafer surface in an arc. The scanning light beam impinges on the wafer surface at a low angle of incidence which permits the beam to pass under photosensing elements disposed in an arcuate array substantially congruous with the arc defined by the scanning light beam. The photosensing elements are patterned close to the wafer surface to receive light scattered by defects on the wafer surface.

Abstract: A compact particle flux monitor is formed with an enclosure through which a laser beam is directed by a lens. An aperture in the enclosure allows free particles which are to be detected to pass through a sensing area at a limiting acceptance angle thereby providing an indication of direction of particle flow. Photodiodes mounted at the sensing area detect the particles, including relatively small particles, by means of the high intensity beam portion at the region of the focal point of the light beam. The response region along the diverging beam is relatively long so that the response as a function of particle size is above background noise level.

Abstract: A system for detection of extremely small particles in a low pressure environment or vacuum includes a vapor column in which a diffusion oil is vaporized, a saturation column in which vaporized oil is cooled and supersaturated, and means for directing a low pressure gas into the saturation column. An optical detector senses the oil droplets that grow around extremely small particles which are introduced in the saturation column by the gas and fall past the detector.

Abstract: A system for detecting contaminant particles in a liquid, such as used for processing wafers during the manufacture of integrated circuits, distinguishes non-contaminant bubbles generally found in liquids from contaminant particles. The system provides a controlled laminar fluid flow of the liquid through a pipe, and the substantially spherical bubbles in the flow path are detected by symmetrically spaced photodiodes. The irregularly shaped contaminant particles are detected, whereas the presence of bubbles are negated by the detection system by virtue of the balanced photodiode assembly.

Abstract: A particle detector includes a laser, a beam shaping lens, and a pair of mirrors which reflect the shaped laser beam back and forth between the mirrors a selected number of times in order to create a sheet of light or light net between the mirrors. The path of the beam is terminated by a beam stop which contains a photodiode to monitor beam intensity and thereby system alignment. Light scattered by a particle falling through the sheet of light is gathered and transmitted to a photodiode. A peak detector provides a measure of the peak intensity of light scattered by such a particle to a microprocessor, which counts the number of particles falling through the light net in a selected time interval. The microprocessor also uses the peak intensity to estimate the size of the particle.