A laser-based inspection tool (LIT) for disks that allows simultaneous inspection of disk surfaces for defects and curvature. The laser beam is directed by a rotating scanner, such as a rotating polygon mirror, to the input of a telecentric lens assembly that provides an output beam parallel to its optical axis as the beam is being scanned. The output beam from the telecentric lens strikes the disk surface substantially perpendicularly. The beam is then reflected from the disk surface and passes back through a collection lens to the sensing surface of an optical detector. The detector outputs analog signals that represent the X and Y positions on the sensing surface where the reflected light beam is incident, which thus correspond to the slope of the disk surface at the point where the laser beam was incident. A mechanical disk lifter moves the disk in a plane parallel to the disk surface so that different scan lines can be generated on the disk surface. A processor, such as a personal computer, receives the output signals from the detector and calculates the slope values, and from the slope values, the curvature of the disk surface. A large number of points on each scan line are sampled, and a large number of scan lines are generated, so that the disk surface curvature can be calculated at various locations and over various ranges of the disk surface. The large number of sample points and the rapid calculation of slope values enables the shape of disk surface defects to be determined, which allows the disk defects to be classified as pits or bumps.
A system and a method for measuring a height of a thin film disk or a silicon wafer having a first and a second electromagnetic signal source for generating a first and a second signal toward a first position on the thin film magnetic disk at two different angles, a first and a second sensitive detector positioned at a right angle from each other to receive a reflected portion of the first and the second signal that reflects off of the object, and to determine a radial portion of the first and the second signals and a circumferential portion of the first and the second signals. The system also includes a processor for determining the height of the first position based upon a difference between the circumferential portion of the second signal and the circumferential portion of the first signal that does not include slope information.
A method for detecting manufacturing marks on sputtered disks includes rotating the disk three hundred and sixty degrees. As the disk rotates, a sensor is used to detect a quantity of manufacturing marks formed on the outer edge of the disk. If there are less than four manufacturing marks on the edge of the disk, a signal is sent to a warning device to indicate that the disk is defective. The lack of a manufacturing mark is an indication that a gripper used to hold the disk within the sputtering chamber during the sputtering process is bent or otherwise misaligned. As such, a signal is also sent to the warning device to indicate that the grippers within the sputtering chamber must be inspected.
Methods of measuring widths of illumination spots and distances between two points, and predicting detected signal widths are provided. Systems, software, and kits for performing the methods of the invention are also provided.
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.
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.
