A defect detection optical system includes a light receiving system including n light receiving elements arranged in a direction perpendicular to a main scan direction, for focusing an image thereon such that the image becomes in the arranging direction of the light receiving elements, in which, when a width of the image focused thereon in the main scan direction is equal to or smaller than the width of the light receiving elements, light reflected from a recessed or protruded defect is swung in the width direction of the light receiving elements and a light receiving area of the light receiving elements is reduced. When the reflection light from the recessed or protruded defect is; swung in sloped portions of the defect, an amount of light received by the light receiving elements is at least reduced, so that two detection signals having levels lower than those when there is no defect are obtained.
An image of a scanning position on a faceplate on a light receiving region defined by an arrangement of n light receiving elements such that an amount of light received by the light receiving region becomes a peak at a center of the light receiving region in an arranging direction of the light receiving elements and is gradually reduced substantially symmetrically toward both ends thereof in the same direction. Therefore, if there is no defect in the surface of the faceplate, levels of light receiving signals of the light receiving elements arranged substantially symmetrically in position on both sides of the light receiving region with respect to the center thereof as a reference are substantially equal and there is no substantial difference therebetween. When there is a recessed or protruded defect in a scan position of the faceplate surface, the image on the light receiving region is shifted in either direction from the center by light reflected by a side slope portion of the recessed or protruded defect and the difference of the levels of the light receiving signals in symmetrical positions becomes large. The defect is detected when the difference is larger than a predetermined value.
An automated, non-invasive method for classifying, detecting, and counting micropipes contained within silicon wafers, and generally any assortment of transparent wafers. Classifying, detecting, and counting micropipes takes place through the use of a data processing algorithm that incorporates information regarding: defect size; pit signature; area of pit signature when comparing a topography, specular, or scatter images; and detecting a tail within the standard pit signature. The method of the present invention teaches the development of a topography defect map, specular defect map, and scatter defect map for a complete analysis of the surface of a particular transparent wafer. Conventional detection, classification, and counting of micropipes involve characterization of micropipes in a manual fashion and rely upon an extremely invasive form of sample preparation. The method disclosed in the present invention is completely automated and non-invasive with regards to the treatment of the transparent wafer to be analyzed.
A system and method for measuring a phase difference between first and second reflected polarized light signal components, including transmitting a first incident light signal toward a first object, wherein the first object is a magnetic disk and/or a glass substrate. Seperating from a reflected light signal, a first mixed reflected polarized light signal component having a first phase and a second mixed reflected polarized light signal component having a second phase that is different from said first phase, wherein said mixed reflected polarized light signal components comprises both P-polarized and S-polarized light relative to a plane of incidence of said reflected light signal. Detecting the intensities of said first and second mixed reflected polarized light signal components, and determining a difference in phase between said first and second mixed reflected polarized light signal component based upon said first and second intensities.
A system and method for performing a magnetic imaging, optical profiling, and measuring lubricant thickness and degradation, carbon wear, carbon thickness, and surface roughness of thin film magnetic disks and silicon wafers at angles that are not substantially Brewster's angle of the thin film (carbon) protective overcoat is provided. The system and method involve a focused optical light whose polarization can be switched between P or S polarization is incident at an angle to the surface of the thin film magnetic disk. This generates both reflected and scattered light that may be measured to determine various values and properties related to the surface of the disk, including identifying the Kerr-effect in reflected light for determination of point magnetic properties. In addition, the present invention can mark the position of an identified defect.
