A method for obtaining texture measurements of a highly-polished surface (110) uses a directed-energy light source (124) to perform the steps of scattering the directed-energy light from a plurality of known texture surfaces. The known texture surfaces have equivalent surface area and dimensions to those of the highly-polished surface (110). A next step is to measure (102 and 130) the scattered light from the directed-energy light source (124) to establish a threshold energy level measurement (48, 50, or 52) above which the measured scattered light varies according to differences in texture among the plurality of known texture surfaces. From variations in the measured scattered light a texture-light relationship (Equation 1) is established that expresses expected changes in measured scattered light according to changes in texture in the plurality of known texture surfaces. Scattered light from the highly-polished surface (110) is then measured. A texture measurement is then generated by applying the texture-light relationship (Equation 1) to the measured scattered light from the highly-polished surface (110).
An image detection apparatus (10) having an illumination system (IS) irradiates light onto the surface (30S) of an object 30 to be inspected for defects. A detection optical system (34) condenses the light from the surface and forms an image of the surface on an image detector (48). The detection optical system includes a receiving mirror (38) having an optical axis (A.sub.38) that intersects the reference optical axis (A.sub.34) of the detection optical system. A processing apparatus (60) includes a processing system (62) that performs image processing based on an output from the detector corresponding to the image. The processing system includes an image distortion correction unit (62a) for eliminating the effects of distortion in the image of the surface generated by the inclination of the surface with respect to the reference optical axis and the receiving mirror.
A surface scanning inspection system that uses a laser to scan the surface of a wafer for defects. The wafers are pre-aligned at a specified angle prior to the scan. This enables maximum light scattered off stacking fault defects, to be directed into a collector, enhancing the abilities of the system to classify the defect from other type of defects.
A non-contacting measuring method for three dimensional micro pattern in a measuring object is disclosed. Three dimensional micro pattern of the surface of the measuring object is measured using blur of light. For measurement, a mechanism of an optical window with a slit is inserted between light source and the measuring object. The blurred image is captured by charge coupled device sensor based image frame grabber, and is analyzed in personal computers. All the values of the relative height differences are obtained in overall scanning measurement area of the measuring object. The relative height differences are the distances from the reference position to the other positions. The reference position is selected when its image is sharp in focus on the screen. At this time, images of the other positions except the reference position are blurred out of focus on the screen. Also, from the law of geometric optics and the geometric similarity of triangles, the relation equation between the height difference and the ratio of blurred image size to sharp image size can be constructed. When the size of the image of the reference position and the sizes of the images with the blurred image of the other positions are measured, all the height differences between the reference position and the other position can be calculated if the coefficients of the relation equation are evaluated.
A method of decorating a semiconductor substrate with an etchant solution is provided for revealing defects, such as microscratches, resulting from an oxide chemical-mechanical planarization (CMP) polishing. An oxide layer is provided over the substrate made from, for example, tetraethylorthosilicate (TEOS). The oxide layer is polished by a CMP process which tends to leave behind microscratches and other defects that can cause conductivity problems on the wafer. To reveal the microscratches, the wafer is decorated or submerged in an etchant, such as an HF etchant, for a period of time. Following the decorating, the wafer is rinsed, dried and inspected. The method improves the ability to identify and optimize steps in a semiconductor fabrication process that cause semiconductor defects.
A surface inspection apparatus of the present invention comprises: an illumination optical system 100 which is fixed at a first predetermined angle with respect to a wafer 3 and which irradiates a substantially parallel illuminating light toward the entire surface of the wafer 3; an image pickup device 6 which is fixed at a second predetermined angle with respect to the wafer 3 and which receives diffracted light or scattered light from the wafer 3 and projects an image of the wafer; and an image processing apparatus 7 which performs a macro inspection by taking the image signal generated by the image pickup device 6 and carrying out image processing, and is further provided with a plurality of interference filters F1.about.F4 to enable the variable setting of the wavelength of the illuminating light from the illumination optical system 100. In this apparatus, macro inspections can be carried out efficiently on a variety of objects while apparatus such as the illumination apparatus and the image projection apparatus are maintained in fixed positions.
