Abstract: A method and apparatus for inspecting a surface of a semiconductor wafer having repetitive patterns for contaminant particles using scattered light which involves directing two beams of light at different approach angles onto the surface in a manner so as to illuminate two intersecting stripe shaped regions on the surface. An imaging lens collects scattered light from the surface as the semiconductor wafer is moving and then images the scattered light collected onto a CCD camera having a square array sensor and arranged to operate in a time delayed integration (TDI) mode. The field of view of the CCD camera is centered at the intersection of the two striped regions. Each light beam striking the surface produces a Fourier diffraction pattern of scattered light in the back focal plane of the imaging lens. In setting up the apparatus, the angle of incidence of one of the light beams is adjusted to shift one of the diffraction patterns, if necessary, so that it overlaps the other diffraction pattern.

Abstract: A method and apparatus for inspecting a surface of a semiconductor wafer having repetitive patterns for contaminant particles using scattered light by illuminating an area on the surface with two beams of light at different approach angles which are independent from each other and then imaging the area illuminated onto a camera positioned above the surface using an imaging lens. Each light beam striking the surface of the semiconductor wafer produces a Fourier diffraction pattern of light scattered from the surface in the back focal plane of the imaging lens. The two diffraction patterns are offset from each other if the two approach angles are not symmetrically disposed relative to an axis of the wafer. In setting up the apparatus, the angle of incidence of one of the beams is adjusted to shift one of the diffraction patterns, if necessary, so that it overlaps the other diffraction pattern.

Abstract: An apparatus and method are disclosed for detecting the presence of particles on the surface of an object such as the front side of a patterned semiconductor wafer. A collimated beam of light is directed onto an area on the surface of the object at a grazing angle of incidence. A detector positioned above the surface detects light scattered from any particles which may be present on the surface, but not specularly reflected light. The output of the detector is fed into a computer where the information is processed and then displayed on a display. The surface is prepositioned relative to the incident light beam so that the diffracted light from the surface and the pattern on the surface is at a minimum. The object is then moved translationally to expose another area to the incident light beam so that the entire surface of the object or selected portions thereof can be examined, an area at a time.

Abstract: An apparatus and method are disclosed for detecting the presence of particles on the surface of an object such as the front side of a patterned semiconductor wafer. A vertically expanded, horizontally scanning, beam of light is directed onto an area on the surface of the object at a grazing angle of incidence. A video camera positioned above the surface detects light scattered from any particles which may be present on the surface, but not specularly reflected light. The surface is angularly prepositioned (rotated) relative to the incident light beam so that the diffracted light from the surface and the pattern of lines on the surface is at a minimum. The object is then moved translationally to expose another area to the incident light beam so that the entire surface of the object or selected portions thereof can be examined, an area at a time.