Abstract: The present invention is directed to a high speed, spinning chuck for use in a semiconductor wafer inspection system. The chuck of the present disclosure is configured with a turbulence-reducing lip. Spinning of the chuck produces radial airflows proximal to a surface of the wafer and proximal to the bottom of the chuck. The turbulence-reducing lip of the chuck of the present disclosure directs the radial airflows off of the top surface of the wafer and the bottom surface of the chuck in a manner that minimizes the size of the low pressure zone formed between these radial airflows. The minimization of the low pressure zone reduces air turbulence about the periphery of the chuck and substrate, thereby reducing the possibility of contaminants in the system being directed onto the surface of the substrate by such air turbulence.

Abstract: An inspection system may include, but is not limited to: an illumination subsystem for directing light to an inspection specimen comprising: a power attenuator subsystem configured for altering the power level of a light beam emitted by the illumination subsystem; and a power attenuation control subsystem configured to provide control signals to the power attenuator subsystem according to a detected level of light scattering by the inspection specimen upon illumination by the illumination subsystem. A method for scatterometry inspection may include, but is not limited to: directing light having a power level to an inspection specimen from a light source; detecting light scattered from the specimen; and modifying a power level of one or more intermediate light beams within the light source according to a level of light scattering by the specimen upon illumination by the light source.

Abstract: An inspection tool embodiment includes an illumination source for directing a light beam onto a workpiece to generate scattered light that includes the ordinary scattering pattern of the workpiece as well as light scattered from defects of the workpiece. The embodiment includes a programmable light selection array that receives light scattered from the workpiece and selectively directs the light scattered from defects onto a photosensor which detects the defect signal. Processing circuitry receives the defect signal and conducts surface analysis of the workpiece that can include the characterizing of defects of the workpiece. The programmable light selection arrays can include, but are not limited to, reflector arrays and filter arrays. The invention also includes associated surface inspection methods.

Abstract: An inspection tool embodiment includes an illumination source for directing a light beam onto a workpiece to generate scattered light that includes the ordinary scattering pattern of the workpiece as well as light scattered from defects of the workpiece. The embodiment includes a programmable light selection array that receives light scattered from the workpiece and selectively directs the light scattered from defects onto a photosensor which detects the defect signal. Processing circuitry receives the defect signal and conducts surface analysis of the workpiece that can include the characterizing of defects of the workpiece. The programmable light selection arrays can include, but are not limited to, reflector arrays and filter arrays. The invention also includes associated surface inspection methods.

Abstract: A surface inspection method of the invention includes scanning an inspection surface taking surface measurements. Determinations of various noise levels in the surface are made based on variations in the surface measurements. A dynamic threshold is then determined. The dynamic threshold adapts to the noise levels in the inspection surface to provide a varying threshold that can provide areas of high and low defect sensitivity on the same inspection surface. Defects are then identified by comparing surface measurements with the dynamic threshold. Additionally, the invention includes a surface inspection method that uses signal-to-noise ratios to identify defects. Such a method scans an inspection surface to obtain surface measurements. Noise levels associated with the inspection surface are then determined. Signal-to-noise ratios are determined for the surface measurements. The signal-to-noise ratios are compared with a signal-to-noise ratio threshold value.

Abstract: A surface inspection method of the invention includes scanning an inspection surface taking surface measurements. Determinations of various noise levels in the surface are made based on variations in the surface measurements. A dynamic threshold is then determined. The dynamic threshold adapts to the noise levels in the inspection surface to provide a varying threshold that can provide areas of high and low defect sensitivity on the same inspection surface. Defects are then identified by comparing surface measurements with the dynamic threshold. Additionally, the invention includes a surface inspection method that uses signal-to-noise ratios to identify defects. Such a method scans an inspection surface to obtain surface measurements. Noise levels associated with the inspection surface are then determined. Signal-to-noise ratios are determined for the surface measurements. The signal-to-noise ratios are compared with a signal-to-noise ratio threshold value.

Abstract: An optical surface scanner for semiconductor wafers and like substrates having one channel with a detector receiving collected scattered light and another channel with a detector receiving reflected light. The scattered light signal is indicative of surface haze, particle count and size, while the reflected light signals are indicative of film thickness and/or surface properties as in the case of an opaque or absorbing layer. The latter signal may be used to correct the particle count and size determination and may also be used simultaneously for thin film measurement. The reflectivity or thin film measurement signals may be used to characterize a film layer controller to improve the accuracy of the deposited thickness of the layer.

Abstract: A particle detection method for matching particles detected in two scans of a surface taken at different times in which particles having a light scattering intensity above a collection threshold are first detected and the measured position and scattering intensity therefor stored in a computer memory. Corresponding first and second measured positions from the respective first and second scans are determined by forming a triangle from selected first detected particles and finding those second detected particles which form a variant triangle with matching perimeter and area. From these matching first and second particles a transformation is found for mapping first measured positions to corresponding second positions and vice versa. Areas around corresponding positions of particles having a scattering intensity above a display threshold are examined for matching particles. If not found, the area is reexamined at a reduced threshold.

Abstract: A wafer handler featuring a carriage movable along a rail path, the carriage supporting an upright rotatable arm with a cantilevered wafer chuck. Elevators for raising and lowering trays containing wafer stacks are disposed on either side of the rail path. Each elevator has a curved track section which may be interposed along the rail path. The upright arm has a track follower, parallel to a boom supporting the wafer chuck and freely movable along the rail path, except when it encounters a curved track section. In this instance, the track follower will follow the curved track section, causing rotation of the arm, boom and wafer chuck, bringing the chuck into the wafer stack at an elevation determined by the elevator. In this manner, motion in the X, Y and Z planes may be provided for stacked wafers over extended distances.

Abstract: A wafer orienting apparatus having inwardly biased rollers, spaced about the circumferential edge of a wafer in contact with the edge. Two of the rollers are spaced apart a distance less than the dimension of a primary flat registration edge and are mounted to follow the wafer edge upon rotation of the wafer. When a flat registration edge passes these closely spaced rollers they move inwardly, activating switches associated with a coincidence circuit. When both switches are simultaneously activated, the coincidence circuit produces a signal which stops wafer rotation, thereby orienting the wafer. The rollers are mounted so that they can be moved from the path of wafer travel after wafer orientation, permitting a queue of wafers to be oriented, one after the other.

Abstract: An instrument for computing resistivity based upon measurements of thickness and conductance. A conductance transducer is a solenoid in an annular ferrite cup connected to a tank circuit for an eddy current measurement of conductance. Within the center of the annular ferrite cup concentric acoustic wave sending and receiving channels are disposed for making an acoustic pressure wave measurement which is used for a thickness measurement using two gauge heads, spaced on opposite sides of an article to be measured. Each gauge head contains identical conductance and thickness transducers. The thickness measurement is divided by the conductance measurement to derive resistivity.

Abstract: A gauge for measuring variations in distance of a surface relative to a reference by means of phase shifts in a zone of high acoustic impedance. A gauge head is provided with a first orifice for emitting acoustic waves, driven by a reference signal, toward a surface positioned very close to the gauge head, forming a high impedance zone. A second orifice in the gauge head picks up acoustic waves subjected to the zone and these waves are converted to electrical signals for comparison to the reference signal in a phase detector. The phase error between the two signals is indicative of surface distance variations.

Abstract: A probe for determining the p or n-type of semiconductor material wherein a conductive wire is positioned for point contact with the semiconductor, forming a diode. The wire is energized by r.f. current passing through a capacitor so that the current is rectified at the diode, charging the capacitor. A voltage comparator is connected to the capacitor for determining the polarity of charge on the capacitor and hence the p or n-type of the semiconductor wafer. The semiconductor is supported on a non-diffusing dielectric over a conductive carrier such that r.f. current passes through the dielectric to the carrier, thereby completing the circuit.

Abstract: A measurement system wherein an acoustic distance measuring transducer is moved over a flat reference surface, measuring the distance from the transducer to a calibration surface and then to a test surface. The transducer is moved along a path within a ring while the top edge of the ring is used to support the calibration surface and then the test surface. The ring is mounted for rotation so that the transducer can scan a supported surface at a locus of points. Scans across the calibration surface and then the test surface are compared to measure deviations of the test surface from calibration surface.

Abstract: Apparatus for measuring distance between a gauge head orifice, and the front planar surface of an object by sensing acoustic pressure near the gauge head orifice. The acoustic pressure is initially generated by an audio oscillator activating a speaker which emits acoustic waves through a first orifice. Acoustic pressure is sensed through a second orifice, proximate to the first, and the pressure is converted to an electrical signal which is processed to yield a distance signal for a display. Two similar distance gauges spaced apart on opposite sides of a planar member at a known distance are used to compute the thickness of the planar member.

Abstract: A surface profile measuring instrument, which has a stylus supported on a counterbalanced scanner arm, in turn supported in a gimbal mounting having two axes, one of which is adjustable by a servo. A connected electronics package provides axis compensation for levelling through the servo, as well as zero adjustment of a display device and discrimination against small, unwanted slops. Stylus motion is translated into an analog signal by a linear position differential transformer. To achieve slope discrimination, the analog signal is differentiated and compared in a comparator to a reference for rejection of signals corresponding to small slopes. The signal is then integrated and displayed, with reference to a selected zero of a display device.

Abstract: A small diameter transparent visible fluid flow indicator suitable for mounting behind an opening in an instrument panel contains a six-bladed paddle wheel pivoted for rotation by the flow of fluid passing through orifices in the indicator housing. Each of the six blades of the wheel contains a small magnet oppositely polarized from the magnets in the adjacent blades to create alternate magnetic fields that pass through a pickup coil embedded in the housing. The resulting coil voltage is amplified and rectified to control a relay switch. Thus, the liquid flow indicator provides both a visible indication of fluid flow and also controls a switching circuit that may be used as an alarm if the fluid flow stops or varies from some predetermined value.