Abstract: Disclosed are mechanisms for selectively filtering spatial portions of light emanating from a sample under inspection within an optical system. In one embodiment, a programmable spatial filter (PSF) is constructed from materials that are compatible with light in a portion of the UV wavelength range. In a specific implementation, the PSF is constructed from a UV compatible material, such as a polymer stabilized liquid crystal material. In a further aspect, the PSF also includes a pair of plates that are formed from a UV grade glass. The PSF may also include a relatively thin first and second ITO layer that results in a sheet resistance between about 100 and about 300 &OHgr; per square.

Abstract: Provided are apparatus and methods for detecting phase defects. The invention relies generally on the distortion of light as it passes through defects in phase shift masks to detect these defects. Light traveling through a defect, such as a bump in an etched area will travel at a different angle than light traveling through air. In order to enhance the signals generated from the defects, the invention in several embodiments provides a multiple element detector having at least four elements, arranged in a radially symmetric configuration. Individual elements of the detector are selected to form a differential signal based on the configuration of pattern lines in the area proximate to the defect. The resulting differential signal is used to generate an image signal and to identify phase defects.

Abstract: The present invention pertains to techniques for increasing the available illumination light, increasing the resolution, and optimizing the spectrum of optical inspection systems. These techniques involve combining the light beams from two or more separate illumination sources. In one embodiment, this performed by utilizing two separate illumination sources wherein one of the illumination sources compensates the other illumination source in the wavelength range where illumination light intensity is low. Specifically, this can be performed by utilizing a broadband illumination source and a narrowband illumination source combined with dichroic beamsplitters.

Abstract: Methods and apparatus are providing for inspecting a test sample. An electron beam is tuned to cause secondary electron emissions upon scanning a target area. Reactive substances are introduced to etch and remove materials and impurities from the scan target. Residual components are evacuated. In one example, a laser is used to irradiate and area to assist in the removal of residual components with poor vapor pressure.

Abstract: Methods and systems for monitoring semiconductor fabrication processes are provided. A system may include a stage configured to support a specimen and coupled to a measurement device. The measurement device may include an illumination system and a detection system. The illumination system and the detection system may be configured such that the system may be configured to determine multiple properties of the specimen. For example, the system may be configured to determine multiple properties of a specimen including, but not limited to, a presence of macro defects and overlay of a specimen. In this manner, a measurement device may perform multiple optical and/or non-optical metrology and/or inspection techniques.

Abstract: The ability to inspect photomasks for errors or defects in phase-shifters is greatly enhanced using optical techniques based on multiple modified radiation collection techniques. In particular, the apparatus and methods of the invention allows for errors in phase-shifters to be more accurately detected, even in the presence of regular amplitude objects such as grid lines. In one embodiment, the intensities of two slightly defocused images of phase objects corresponding to the same photomask location are compared. In a second embodiment, radiation having two Zernike point spread functions is used to obtain two slightly different phase sensitive images. Data collected and analyzed using this method provides much greater sensitivity to phase objects and errors in phase objects than prior art inspection systems. Embodiments include both scanning-type and projector-type optical architectures and may utilize radiation transmitted or reflected by a sample.

Abstract: Disclosed are mechanisms for selectively filtering spatial portions of light emanating from a sample under inspection within an optical system. In one embodiment, a programmable spatial filter (PSF) is constructed from materials that are compatible with light in a portion of the UV wavelength range. In a specific implementation, the PSF is constructed from a UV compatible material, such as a polymer stabilized liquid crystal material. In a further aspect, the PSF also includes a pair of plates that are formed from a UV grade glass. The PSF may also include a relatively thin first and second ITO layer that results in a sheet resistance between about 100 and about 300 &OHgr; per square. The PSF provides selective filtering in two directions. In other words, the PSF provides two dimensional filtering.

Abstract: The disclosure relates to measuring an undercut of a feature on a specimen using a scanning electron microscope (SEM). In accordance with one embodiment, a method for measuring the undercut includes illuminating the feature with a primary electron beam at an incident angle, changing the incident angle of the primary electron beam over a set of angles, measuring an intensity of scattered electrons from the feature for each incident angle in the set of angles, and determining a discontinuity in the intensities as a function of the incident angle.

Abstract: The present invention includes a system for localization of defects in test samples. A sample is scanned using a particle beam. Some particles interact with conductive elements and may cause the emission of x-rays. Other particles can pass through the sample entirely and generate a current that can be measured. A higher current generated indicates less conductive material at the scan target that may mean a void, dishing, or erosion is present. Localization of a defect can be confirmed using an x-ray emission detector.

Abstract: Techniques for increasing the percentage of light that is transmitted through optical inspection systems that operate in or near the ultraviolet and deep ultraviolet electromagnetic spectrums are described. Along with increasing the amount of light transmission, the techniques of the present invention also provide additional advantages such as reduction of ripple, increased ability to match inspection systems, and improving manufacturability. The techniques of the present invention involve using an auto-focus light source near the operational range of the inspection system and slightly raising the lower end of the operational range.

Abstract: Disclosed is a method of inspecting a reticle defining a circuit layer pattern that is used within a corresponding semiconductor process to generate corresponding patterns on a semiconductor wafer. A test image of the reticle is provided, and the test image has a plurality of test characteristic values. A baseline image containing an expected pattern of the test image is also provided. The baseline image has a plurality of baseline characteristic values that correspond to the test characteristic values. The test characteristic values are compared to the baseline characteristic values such that a plurality of difference values are calculated for each pair of test and baseline characteristic values. Statistical information is also collected.

Abstract: A calibration standard which may be used to calibrate lateral dimensional measurement systems is provided. The calibration standard may include a first substrate spaced from a second substrate. In addition, the calibration standard may include at least one layer disposed between the first and second substrates. The layer may have a traceably measured thickness. For example, a thickness of the layer may be traceably measured using any measurement technique in which a measurement system may be calibrated with a standard reference material traceable to a national testing authority. The calibration standard may be cross-sectioned in a direction substantially perpendicular to an upper surface of the first substrate. The cross-sectioned portion of the calibration standard may form a viewing surface of the calibration standard. In this manner, a lateral dimensional artifact of the calibration standard may include the traceably measured thickness of at least the one layer.

Abstract: Methods and systems for monitoring semiconductor fabrication processes are provided. A system may include a stage configured to support a specimen and coupled to a measurement device. The measurement device may include an illumination system and a detection system. The illumination system and the detection system may be configured such that the system may be configured to determine multiple properties of the specimen. For example, the system may be configured to determine multiple properties of a specimen including, but not limited to, critical dimension and a thin film characteristic. In this manner, a measurement device may perform multiple optical and/or non-optical metrology and/or inspection techniques.

Abstract: Disclosed are mechanisms for selectively filtering spatial portions of light emanating from a sample under inspection within an optical system. In one embodiment, a programmable spatial filter (PSF) is constructed from materials that are compatible with light in a portion of the UV wavelength range. In a specific implementation, the PSF is constructed from a UV compatible material, such as a polymer stabilized liquid crystal material. In a further aspect, the PSF also includes a pair of plates that are formed from a UV grade glass. The PSF may also include a relatively thin first and second ITO layer that results in a sheet resistance between about 100 and about 300 &OHgr; per square.

Abstract: Disclosed are methods and apparatus for simultaneously flooding a sample (e.g., a semiconductor wafer) to control charge and inspecting the sample. The apparatus includes a charged particle beam generator arranged to generate a charged particle beam substantially towards a first portion of the sample and a flood gun for generating a second beam towards a second portion of the sample. The second beam is generated substantially simultaneously with the inspection beam. The apparatus further includes a detector arranged to detect charged particles originating from the sample portion. In a further implementation, the apparatus further includes an image generator for generating an image of the first portion of the sample from the detected particles. In one embodiment, the sample is a semiconductor wafer. In a method aspect, a first area of a sample is flooded with a flood beam to control charge on a surface of the sample. A second area of the sample is inspected with an inspection beam.

Abstract: Disclosed is a method of inspecting a sample. The sample is scanned in a first direction with at least one particle beam. The sample is scanned in a second direction with at least one particle beam. The second direction is at an angle to the first direction. The number of defects per an area of the sample are found as a result of the first scan, and the position of one or more of the found defects is determined from the second scan. In a specific embodiment, the sample includes a test structure having a plurality of test elements thereon. A first portion of the test elements is exposed to the beam during the first scan to identify test elements having defects, and a second portion of the test elements is exposed during the second scan to isolate and characterize the defect.

Abstract: The present invention pertains to an optical inspection system capable of obtaining very high signal-to-noise ratio data and that is capable of high speed scanning rates. The ability to obtain high signal-to-noise data is obtained by selecting parts of the scattering hemisphere where signal from a defect is high and noise due to scattering from wafers structures is low. One embodiment of the optical inspection system includes a set of lenses used to form an image of the inspected specimen at a Fourier plane with telecentric-in-object space imaging. Another embodiment of the optical inspection system includes a substantially hemispherical shaped mirror system that provides a large collection numerical aperture that allows for the collection of substantially all of the hemisphere of scattered light from an inspected specimen. The present invention also discloses techniques for enhancing the signal-to-noise ratio of image data received from the optical inspection system.

Abstract: The present invention includes a system for efficient and effective detection and characterization of dishing and/or erosion. An x-ray emission inducer is used to scan a target on a sample. The target can be scanned at an acute incident angle to allow characterization of the dishing and/or erosion and analysis of the metallization or thin film layer topology.

Abstract: A reusable circuit design for use with electronic design automation EDA tools in designing integrated circuits is disclosed, as well as reticle inspection and fabrication methods that are based on such reusable circuit design. The reusable circuit design is stored on a computer readable medium and contains an electronic representation of a layout pattern for at least one layer of the circuit design on an integrated circuit. The layout pattern includes a flagged critical region which corresponds to a critical region on a reticle or integrated circuit that is susceptible to special inspection or fabrication procedures. In one aspect of the reusable circuit design, the special analysis is performed during one from a group consisting of reticle inspection, reticle production, integrated circuit fabrication, and fabricated integrated circuit inspection.

Abstract: Systems and methods for determining the height of a surface of a specimen, such as a surface of a semiconductor device wafer are provided. A system may be configured to generate a comparison signal that may used to alter a Z-axis fine height adjustment of the system. The system may include for example, a processing tool, a metrology tool, or an inspection tool that may be used in semiconductor device fabrication. In this manner, the system may be configured to maintain a constant working distance between the wafer surface and an optical column of the system. A system may include an off-axis dual beam symmetric height sensor due to mechanical constraints of the system. The dual beam symmetric height sensor may provide automatic focusing of the wafer with high precision by substantially eliminating wafer pattern-induced error in comparison signals generated by the system.