Abstract: A device and method for subaperture stray light detection and diagnosis. A test light beam is generated. Stray light is detected. Based on the detected stray light, potential paths that light may have taken to arrive at the detection surface are determined. A testing device comprises a test light beam source whereby the cross sectional area of the test light beam is made less than the cross sectional area of the system aperture. A relative lateral positioning stage and an angular beam directing stage launch the test light beam into the aperture. A detector and a data processing system produce a data set relating the stray light to the location and directional angles of the test light beam to identify the sources of stray light. A light trap and test light beam delivery system are provided.

Abstract: A device and method for subaperture stray light detection and diagnosis in an optical system. A test light beam is generated with a width whose cross sectional area is less than the cross sectional area of a system aperture. Stray light is detected at a system detection surface. Based on the stray light and the location and direction angles of the light beam, potential paths that light may have taken to arrive at the detection surface are determined so as to identify physical features of the optical system that may have produced the stray light. A testing device comprises a test light beam source, preferably including a beam width magnifier, whereby the cross sectional area of the test light beam is made less than the cross sectional area of the system aperture. A relative lateral positioning stage and an angular beam directing stage launch the test light beam into the aperture at a selected position and selected directional angles.

Abstract: A method for mounting a light duty bearing having a groove defined in an outer arcuate surface thereof for receiving a metallic tolerance ring placed therein which includes protruding waves extending radially outwardly from the groove while the main band of the bearing is positioned preferably completely within the groove such that the bearing can be placed into a workpiece aperture to be movably mounted therein in a frictionally resisted manner such as required in light-duty applications where slight restricted movement between the bearing and the mounting aperture of the workpiece is desirable. The bearing assembly can be mounted in the workpiece aperture by exerting axial force against the inner race member or the outer race member to achieve the frictionally resisted mounting therebetween. The groove defined in the outer portion of the bearing is designed to receive and retain the tolerance ring therein during mounting in the workpiece aperture for greatly facilitating mounting.

Abstract: In a method for depositing particles onto a substrate a flow of gas containing particles is provided along a flow path that bypasses a deposition chamber. The flow path may direct the flow of the gas containing the particles to a vacuum. To deposit particles onto a substrate in the deposition chamber, the flow path of the gas containing the particles is diverted into the deposition chamber so that particles are deposited onto the substrate. After a desired amount of particles have been deposited onto the substrate, the flow path of the flow of the gas containing the particles is changed to the flow path that bypasses the deposition chamber. A particle deposition system and a method for maintaining particle diameter during deposition of particles onto a substrate also are described.

Abstract: In an optical inspection system, defects such as particles, pits, subsurface voids, mounds, or other defects occurring at or near the smooth surface of a substrate are classified by type and size based on the magnitude S of a signal produced by collected light for each of a plurality N of different test configurations, yielding a plurality of signal magnitudes S1 through SN. A database is consulted, comprising a relationship of S versus defect size d for each test configuration and for each of a plurality of idealized defect types, so as to determine a defect size d corresponding to each measured signal magnitude S, and an average defect size is determined for each defect type. Signal magnitudes <S1> through <SN> that would be produced by a defect of the average size are determined for each defect type, and defect type is determined based on a smallest deviation between the measured magnitudes and the determined magnitudes.

Abstract: A surface inspection system and method is provided which detects defects such as particles or pits on the surface of a workpiece, such as a silicon wafer, and also distinguishes between pit defects and particle defects. The surface inspection system comprises an inspection station for receiving a workpiece and a scanner positioned and arranged to scan a surface of the workpiece at the inspection station. The scanner includes a light source arranged to project a beam of P-polarized light and a scanner positioned to scan the P-polarized light beam across the surface of the workpiece. The system further provides or detecting differences in the angular distribution of the light scattered from the workpiece and for distinguishing particle defects from pit defects based upon these differences.

Abstract: A surface inspection system and method is provided which detects defects such as particles or pits on the surface of a workpiece, such as a silicon wafer, and also distinguishes between pit defects and particle defects. The surface inspection system comprises an inspection station for receiving a workpiece and a scanner positioned and arranged to scan a surface of the workpiece at the inspection station. The scanner includes a light source arranged to project a beam of P-polarized light and a scanner positioned to scan the P-polarized light beam across the surface of the workpiece. The system further provides for detecting differences in the angular distribution of the light scattered from the workpiece and for distinguishing particle defects from pit defects based upon these differences.

Abstract: A surface inspection system and method is provided which detects defects such as particles or pits on the surface of a workpiece, such as a silicon wafer, and also distinguishes between pit defects and particle defects. The surface inspection system comprises an inspection station for receiving a workpiece and a scanner positioned and arranged to scan a surface of the workpiece at the inspection station. The scanner includes a light source arranged to project a beam of P-polarized light and a scanner positioned to scan the P-polarized light beam across the surface of the workpiece. The system further provides for detecting differences in the angular distribution of the light scattered from the workpiece and for distinguishing particle defects from pit defects based upon these differences.

Abstract: P-polarized light or having a strong P-polarized component is directed onto a filmed substrate at two (or more) different incidence angles, one angle being relatively large and the other angle being relatively small as measured from a surface normal. Light that is scattered into a back region of the hemispherical space above the substrate surface is collected and the intensity of the collected light is measured for each of the two incident angles. A defect can be classified as either a hole in the film or a particle on the film based on the relative intensities of the collected light.

Abstract: In an optical inspection system, defects such as particles, pits, subsurface voids, mounds, or other defects occurring at or near the smooth surface of a substrate are classified by type and size based on the magnitude S of a signal produced by collected light for each of a plurality N of different test configurations, yielding a plurality of signal magnitudes S1 through SN. A database is consulted, comprising a relationship of S versus defect size d for each test configuration and for each of a plurality of idealized defect types, so as to determine a defect size d corresponding to each measured signal magnitude S, and an average defect size is determined for each defect type. Signal magnitudes <S1> through <SN> that would be produced by a defect of the average size are determined for each defect type, and defect type is determined based on a smallest deviation between the measured magnitudes and the determined magnitudes.

Abstract: A surface inspection system and method is provided which detects defects such as particles or pits on the surface of a workpiece, such as a silicon wafer, and also distinguishes between pit defects and particle defects. The surface inspection system comprises an inspection station for receiving a workpiece and a scanner positioned and arranged to scan a surface of the workpiece at the inspection station. The scanner includes a light source arranged to project a beam of P-polarized light and a scanner positioned to scan the P-polarized light beam across the surface of the workpiece. The system further provides for detecting differences in the angular distribution of the light scattered from the workpiece and for distinguishing particle defects from pit defects based upon these differences.

Abstract: A surface inspection system and method is provided which detects defects such as particles or pits on the surface of a workpiece, such as a silicon wafer, and also distinguishes between pit defects and particle defects. The surface inspection system comprises an inspection station for receiving a workpiece and a scanner positioned and arranged to scan a surface of the workpiece at the inspection station. The scanner includes a light source arranged to project a beam of P-polarized light and a scanner positioned to scan the P-polarized light beam across the surface of the workpiece. The system further provides for detecting differences in the angular distribution of the light scattered from the workpiece and for distinguishing particle defects from pit defects based upon these differences.

Abstract: Particles are distinguished from pits, voids, scratches, and other subsurface defects in a surface of a substrate by impinging the defect with polarized light and integrating light scattered by the defect over a wide angular range to produce a total integrated response. Using a P-polarized incident light beam, particles are distinguished from subsurface defects by comparing the total integrated responses, which vary with changes in the incident angle. Alternatively, the defect is impinged with a P-polarized incident beam at a defined incident angle, and is then impinged with an S-polarized beam at the same incident angle. Total integrated responses are measured for both beams and a P-to-S ratio of the responses is calculated. Particles are distinguished from subsurface defects by comparing the P-to-S ratio to a predetermined threshold value which separates particles from subsurface defects.

Abstract: The composition of a particle occurring on the surface of a smooth substrate is identified by impinging the surface with a light beam having a strong P-polarized component at an oblique angle of incidence to the surface, and collecting light scattered from the surface at forward, center, and back locations relative to the portion of the surface impinged by the incident beam. The intensities of the light collected at these locations are measured by detectors and converted into signals, and the magnitudes of the signals are compared to correlations of particle material as a function of the relative magnitudes of the forward-, center-, and back-scatter signals so as to identify the material whose correlation most nearly matches the measured detector signals. Preferably, a ratio of the back detector signal magnitude to forward detector signal magnitude is correlated with particle material and back detector signal magnitude.

Abstract: A surface inspection system and method is provided which detects defects such as particles or pits on the surface of a workpiece, such as a silicon wafer, and also distinguishes between pit defects and particle defects. The surface inspection system comprises an inspection station for receiving a workpiece and a scanner positioned and arranged to scan a surface of the workpiece at the inspection station. The scanner includes a light source arranged to project a beam of P-polarized light and a scanner positioned to scan the P-polarized light beam across the surface of the workpiece. The system further provides for detecting differences in the angular distribution of the light scattered from the workpiece and for distinguishing particle defects from pit defects based upon these differences.

Abstract: The method of the present invention accurately measures the diameter of a particle resting on a surface through use of a beam of known wavelength being directed at the surface at an incident angle. Scattered light measurements are taken as the beam contacts the surface and the particle. Scattered light measurements are separated into their respective P and S power components. During all measurements, the beam source remains constant in that it is not moved or adjusted for intensity or polarization. The P and S power components of the background measurements are subtracted from the P and S power components of the particle measurements to give net P and S power components. From the net P and S power components the net P and S components of the differential scatter cross section may be derived as is known in the art. Different ratios may be formed from the differential scatter cross section to eliminate many of the intensity errors inherent in the use of scattered light measurements.

Abstract: A metrology standard that is useful for calibrating instruments for the levels of microroughness encountered in semiconductor, disk drive, and related industries today. In advanced applications, this level is about 5 .ANG. rms in a 0.01-1.0 .mu.m.sup.-1 spatial bandwidth range. This standard uses a one-dimensional square wave pattern etched in a silicon wafer to reduce the effects of instrument spatial bandwidth. The standard has approximately a 20 .mu.m pitch with feature depths as small as 8 .ANG..

Abstract: A hand-held apparatus and process for measuring the gap and mismatch of two adjacent surfaces. The apparatus includes two strobe lights positioned within a hand-held housing. An optical interface within the housing directs a portion of the light generated by each light source into substantially parallel planes which are projected out of the opening of the housing at converging angles onto the surfaces to be measured. A camera within the housing captures the resulting image and generates a signal corresponding to the image. A signal processor which includes a frame grabber card processes the signal generated by the array of detectors to thereby calculate the amount of gap and mismatch between the surfaces being measured.

Abstract: An optical measurement device produces quality light scatter measurements using Bidirectional Reflective Distribution Function (BRDF) techniques to analyze data generated from an accurate, portable, relatively inexpensive scatterometer. The scatterometer is provided with interchangeable scanning heads, each scanning head being equipped with ROM data storage containing certain configuration information about the scanning head. The use of the interchangeable scanning heads allows the present invention to make measurements of light scatter for a wide variety of applications and samples under a variety of environmental conditions where scatter measurement has previously not been feasible.

Abstract: The electric heater herein disclosed is particularly adapted to heat a fluid and to provide a broad, substantially flat heater surface exposed to the fluid to be heated. The heating element is well adapted for deep fat frying use in that it is of high voltage and is economical to manufacture. The invention makes use of standard elongated, tubular, metal-sheathed heaters which are produced in large quantities for a multitude of uses. Such elements are slid into a metal tube of selected diameter and wall thickness, and the assembly is flat-pressed in appropriate sections with the ends round for termination with such fittings as are required. The assembly may then be bent to produce a desired configuration.