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: A method and system of using exposure control to inspect a surface, such as a wafer. One inspection system comprises charge coupled devices (CCDs) as detectors. The exposure control function of each CCD is used to adjust integration times on individual taps of the CCD such that light scattered from the surface, which may contain multiple scattering regions, is within a dynamic range of the CCD during inspection.

Abstract: One embodiment disclosed relates to a method for electron beam inspection of a semiconductor circuit to identify a defect path using a hyper-extracting field. The method includes scanning the semiconductor circuit with a primary electron beam, applying a hyper-extracting field sufficient to achieve a junction breakdown, detecting intensities of electrons hyper-extracted from the semiconductor circuit during the scanning, and identifying a defect path from the hyper-extracted intensities. Another embodiment disclosed relates to a method that includes identifying both a normally extracting voltage contrast defect and a normally retarding voltage contrast defect by using the hyper-extracting field. Another embodiment disclosed relates to an apparatus for electron beam inspection of a semiconductor circuit to identify a defect path using a hyper-extracting field.

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 apparatus for measuring a thickness of a substrate having an upper surface, without contacting the upper surface of the substrate. A platen having a base surface receives the substrate, and a reference surface is disposed at a known first height from the platen surface. A non contact sensor senses the known first height of the reference surface without making physical contact with the reference surface. The non contact sensor further senses a relative difference between the known first height of the reference surface and a second height of the upper surface of the substrate without making physical contact with the upper surface of the substrate. A controller controls the sensor and determines the thickness of the substrate based at least in part on the known first height of the reference surface and the relative difference between the known first height of the reference surface and the second height of the upper surface of the substrate.

Abstract: Misalignment error between two periodic structures such as two overlay targets placed side-by-side is measured. The two structures are illuminated by coherent radiation and the positive and negative diffraction beams of the input beam by the two structures are detected to discover the optical phase difference between the positive and negative diffraction beams. The misalignment between the two structures may then be ascertained from the phase difference.

Abstract: An apparatus adapted for sensing characteristics of a layer disposed substantially within a plane, without making physical contact with the layer. An x-ray source produces x-rays, where the x-ray source has an axis disposed substantially perpendicular to the plane of the layer. An x-ray reflector has an axis disposed substantially perpendicular to the plane of the layer. The x-ray reflector receives the x-rays from the x-ray source and directs the x-rays received to a target spot on the layer at angles whereby the x-rays reflect off of the layer as reflected x-rays at a reflection angle. The reflected x-rays have properties that are indicative of the characteristics of the layer. A first x-ray blocking barrier is disposed substantially perpendicular to the plane of the layer, above the target spot. The first x-ray blocking barrier blocks at least a portion of the x-rays director toward and reflected off of the layer.

Abstract: An objective lens system having reconfigurable optical components that enable the inspection of inspection surfaces in the absence of a pellicle or through a thin membrane pellicle, and using the same system, also enabling the inspection of inspection surfaces through a thick pellicle. An objective lens system includes a first group and a second group of optical elements. The first group of optical elements enables high numerical aperture and beam contraction. The second group of optical elements is capable of two mode operation enabling, in one mode, inspection through a thin membrane pellicle or in the absence of a pellicle and in another mode, enabling inspection through a thick pellicle. The system can also be enhanced through the use of an interposable aberration corrector plate that is used to correct optical aberrations caused by the presence, absence, or thickness of pellicles.

Abstract: A compact and versatile multi-spot inspection imaging system employs an objective for focusing an array of radiation beams to a surface and a second reflective or refractive objective having a large numerical aperture for collecting scattered radiation from the array of illuminated spots. The scattered radiation from each illuminated spot is focused to a corresponding optical fiber channel so that information about a scattering may be conveyed to a corresponding detector in a remote detector array for processing. For patterned surface inspection, a cross-shaped filter is rotated along with the surface to reduce the effects of diffraction by Manhattan geometry. A spatial filter in the shape of an annular aperture may also be employed to reduce scattering from patterns such as arrays on the surface. In another embodiment, different portions of the same objective may be used for focusing the illumination beams onto the surface and for collecting the scattered radiation from the illuminated spots simultaneously.

Abstract: Techniques for detecting endpoints during semiconductor dry-etching processes are described. The dry-etching process of the present invention involves using a combination of a reactive material and a charged particle beam, such as an electron beam. In another embodiment, a photon beam is used to facilitate the etching process. The endpoint detection techniques involve monitoring the emission levels of secondary electrons and backscatter electrons together with the current within the sample. Depending upon the weight given to each of these parameters, an endpoint is identified when the values of these parameters change more than a certain percentage, relative to an initial value for these values.

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: Disclosed are methods and apparatus for analyzing the quality of overlay targets. In one embodiment, a method of extracting data from an overlay target is disclosed. Initially, image information or one or more intensity signals of the overlay target are provided. An overlay error is obtained from the overlay target by analyzing the image information or the intensity signal(s) of the overlay target. A systematic error metric is also obtained from the overlay target by analyzing the image information or the intensity signal(s) of the overlay target. For example, the systematic error may indicate an asymmetry metric for one or more portions of the overlay target. A noise metric is further obtained from the overlay target by applying a statistical model to the image information or the intensity signal(s) of the overlay target. Noise metric characterizes noise, such as a grainy background, associated with the overlay target.

Abstract: Techniques for efficiently setting up inspection, metrology, and review systems for operating upon semiconductor wafers are described. Specifically, this involves setting up recipes that allows each system to accurately inspect semiconductor wafers. The invention gathers pertinent information from these tools and presents the information to users in a way that greatly reduces the time required to complete a recipe. One system embodiment includes an inspection system and a review station that is communicatively linked such that the review station can read from and write to an entire set of data stored at the inspection system. The set of data includes image files of features detected by the inspection system.

Abstract: Disclosed are methods and apparatus for analyzing the quality of overlay targets. In one embodiment, a method of extracting data from an overlay target is disclosed. Initially, image information or one or more intensity signals of the overlay target are provided. An overlay error is obtained from the overlay target by analyzing the image information or the intensity signal(s) of the overlay target. A systematic error metric is also obtained from the overlay target by analyzing the image information or the intensity signal(s) of the overlay target. For example, the systematic error may indicate an asymmetry metric for one or more portions of the overlay target. A noise metric is further obtained from the overlay target by applying a statistical model to the image information or the intensity signal(s) of the overlay target. Noise metric characterizes noise, such as a grainy background, associated with the overlay target.

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, at least four properties of a specimen such as critical dimension, overlay, a presence of macro defects, and thin film characteristics. In this manner, a measurement device may perform multiple optical and/or non-optical metrology and/or inspection techniques.

Abstract: A system and method for reducing peak power of a laser pulse and reducing speckle contrast of a single pulse comprises a plurality of beamsplitters, mirrors and delay elements oriented to split and delay a pulse or pulses transmitted from a light emitting device. The design provides the ability to readily divide the pulse into multiple pulses by delaying the components relative to one another. Reduction of speckle contrast entails using the same or similar components to the power reduction design, reoriented to orient received energy such that the angles between the optical paths are altered such that the split or divided light energy components strike the target at different angles or different positions. An alternate embodiment for reducing speckle contrast is disclosed wherein a single pulse is passed in an angular orientation through a grating to create a delayed portion of the pulse relative to the leading edge of the pulse.

Abstract: Techniques for utilizing a microscope inspection system capable of inspecting specimens at high throughput rates are described. The inspection system achieves the higher throughput rates by utilizing more than one detector array and a large field of view to scan the surface of the semiconductor wafers. The microscope inspection system also has high magnification capabilities, a high numerical aperture, and a large field of view. By using more than one detector array, more surface area of a wafer can be inspected during each scanning swath across the semiconductor wafers. The microscope inspection system is configured to have a larger field of view so that the multiple detector arrays can be properly utilized. Additionally, special arrangements of reflective and/or refractive surfaces are used in order to fit the detector arrays within the physical constraints of the inspection system.

Abstract: Methods and systems for evaluating and controlling a lithography process are provided. For example, a method for reducing within wafer variation of a critical metric of a lithography process may include measuring at least one property of a resist disposed upon a wafer during the lithography process. A critical metric of a lithography process may include, but may not be limited to, a critical dimension of a feature formed during the lithography process. The method may also include altering at least one parameter of a process module configured to perform a step of the lithography process to reduce within wafer variation of the critical metric. The parameter of the process module may be altered in response to at least the one measured property of the resist.

Abstract: A technique for measuring the chemical composition of surface particles or other small features which may be present on semiconductor wafers or other substrates. A particle is irradiated with a variable energy, focused incident electron beam. X-ray or electron emissions from the particle are monitored to detect an increase in output indicating the ionization threshold of the materials in the particle. The incident beam energy is correlated with the thresholds detected to determine the species present in the particle.

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.