Abstract: Particles generated within a semiconductor wafer process chamber are monitored by emitting a rastered laser beam into the process chamber and detecting a two-dimensional image of scattered radiant energy within the process chamber. A video frame representing a matrix array of pixel intensities is produced and processed by a processor. The processor receives first and second video frames, the first frame representing a matrix array of pixels of a background image of the process chamber before a wafer processing is started and the second frame representing a matrix array of corresponding pixels of a target image of the process changer after a wafer processing is started. Differential intensities between the pixels of the background image and corresponding pixels of the target image are detected and a decision is made on the detected intensities to produce an output signal representing presence or absence of the particles.

Abstract: A part of the outer wall of the processing chamber supplied with an active gas for an intended processing forms a protruding section extending out from the outer wall into the air. An incident side window through which laser light is guided is mounted to the protruding portion. A baffle is provided inside the protruding portion for intercepting unnecessary portion of light guided in the processing chamber even if irregularly reflecting light arises, when laser light is guided into the window. An antireflection coating is coated on the air side surface of the window. A purge gas inlet port for blowing out a purge gas along the inside surface of the window is formed in the protruding portion.

Abstract: A particle monitor includes a light source for transmitting a light into a space over a wafer in wafer processing equipment to irradiate particles floating above the wafer for causing a scattered light; a photo-detector for detecting the scattered light to generate output signals corresponding to the intensity of the scattered light; a signal intensity judgment device for receiving the output signals from the photo-detector and comparing the output signals with a predetermined reference value already set in the signal intensity judgment device so as to judge whether the intensity of the scattered light is higher or lower than the predetermined reference value; and a display for displaying the intensity of the scattered light and luminance and distribution in intensity thereof or displaying distributions in size and the number of particles.

Abstract: When a intensity of a signal from a light detector 14 to measure a scattered light exceeds a predetermined value, a motion of a particle 20 is displayed as a locus of the scattered light, by means of extending an exposure time of the scattered light to the light detector, or by means of increasing a pulse oscillation frequency of a laser beam 13, or by means of extending a pulse width of the laser light. And then a straight line connecting start and terminal points of the locus is displayed to superimpose on the locus. An origin of the particle is estimated by extending the straight line beyond the start point, and a destination point of the particle is estimated by extending the straight line beyond the terminal point. A mass of the particle is estimated by dividing a projective length of the straight line in a vertical direction by the exposure time of the scattered light.

Abstract: The capacitance type acceleration sensor disclosed is one in which a variation in a distance between first and second electrodes caused by acceleration is measured as an electrostatic capacity variation. The acceleration sensor includes a fixed electrode, a movable electrode and a reference electrode. The fixed electrode constitutes the first electrode or the second electrode, and a movable electrode constitutes the other of the first or second electrodes. The reference electrode is such that its distance with respect to the first and second electrodes is not caused to be changed by acceleration. The fixed electrode and the movable electrode are disposed in an overlapping position in a direction in which the acceleration is detected. Thus, it is possible to scale down the sensor chip area by the magnitude of the area of the reference electrode.