Abstract: Systems and methods for inspecting a wafer with increased sensitivity are provided. One system includes an inspection subsystem configured to direct light to a spot on the wafer and to generate output signals responsive to light scattered from the spot on the wafer. The system also includes a gas flow subsystem configured to replace a gas located proximate to the spot on the wafer with a medium that scatters less of the light than the gas thereby increasing the sensitivity of the system. In addition, the system includes a processor configured to detect defects on the wafer using the output signals.

Abstract: Various computer-implemented methods are provided. One method for evaluating reticle layout data includes generating a simulated image using the reticle layout data as input to a model of a reticle manufacturing process. The simulated image illustrates how features of the reticle layout data will be formed on a reticle by the reticle manufacturing process. The method also includes determining manufacturability of the reticle layout data using the simulated image. The manufacturability is a measure of how accurately the features will be formed on the reticle. Also provided are various carrier media that include program instructions executable on a computer system for performing a method for evaluating reticle layout data as described herein. In addition, systems configured to evaluate reticle layout data are provided. The systems include a computer system and a carrier medium that includes program instructions executable on the computer system for performing method(s) described herein.

Abstract: Various test structures and methods for monitoring or controlling a semiconductor fabrication process are provided. One test structure formed on a wafer as a monitor for a lithography process includes a bright field target that includes first grating structures. The test structure also includes a dark field target that includes second grating structures. The first and second grating structures have one or more characteristics that are substantially the same as one or more characteristics of device structures formed on the wafer. In addition, the test structure includes a phase shift target having characteristics that are substantially the same as the characteristics of the bright field or dark field target except that grating structures of the phase shift target are shifted in optical phase from the first or second grating structures. One or more characteristics of the targets can be measured and used to determine parameter(s) of the lithography process.

Abstract: Various methods and systems for utilizing design data in combination with inspection data are provided. One computer-implemented method for determining a position of inspection data in design data space includes aligning data acquired by an inspection system for alignment sites on a wafer with data for predetermined alignment sites. The method also includes determining positions of the alignment sites on the wafer in design data space based on positions of the predetermined alignment sites in the design data space. In addition, the method includes determining a position of inspection data acquired for the wafer by the inspection system in the design data space based on the positions of the alignment sites on the wafer in the design data space. In one embodiment, the position of the inspection data is determined with sub-pixel accuracy.

Abstract: Inspection systems, circuits, and methods are provided to enhance defect detection by reducing thermal damage to large particles by dynamically altering the incident laser beam power level supplied to the specimen during a surface inspection scan. In one embodiment, an inspection system includes an illumination subsystem for directing light to a specimen at a first power level, a detection subsystem for detecting light scattered from the specimen, and a power attenuator subsystem for dynamically altering the power level directed to the specimen based on the scattered light detected from the specimen. The power attenuator subsystem may reduce the directed light to a second power level, which is lower than the first, if the detected scattered light exceeds a predetermined threshold level. The systems and methods described herein may also be used to extend the measurement detection range of an inspection system by providing a variable-power inspection system.

Abstract: Methods and systems for inspection of a wafer or setting up an inspection process are provided. One method for inspection of a wafer includes detecting first and second sets of defects on the wafer by performing different scans of the wafer with different focus offsets. The method also includes comparing results of the different scans for a defect of the first set and a defect of the second set that are detected at approximately the same location on the wafer. The method further includes determining if the defect of the first and second sets is a defect of an underlying layer or an uppermost layer formed on the wafer based on results of the comparing step.

Abstract: Computer-implemented methods for detecting defects in reticle design data are provided. One method includes generating a first simulated image illustrating how the reticle design data will be printed on a reticle using a reticle manufacturing process. The method also includes generating second simulated images using the first simulated image. The second simulated images illustrate how the reticle will be printed on a wafer at different values of one or more parameters of a wafer printing process. The method further includes detecting defects in the reticle design data using the second simulated images. Another method includes the generating steps described above in addition to determining a rate of change in a characteristic of the second simulated images as a function of the different values. This method also includes detecting defects in the reticle design data based on the rate of change.

Abstract: Various systems for measurement of a specimen are provided. One system includes an optical subsystem configured to perform measurements of a specimen using vacuum ultraviolet light and non-vacuum ultraviolet light. This system also includes a purging subsystem that is configured to maintain a purged environment around the optical subsystem during the measurements. Another system includes a cleaning subsystem configured to remove contaminants from a specimen prior to measurement. In one embodiment, the cleaning subsystem may be a laser-based cleaning subsystem that is configured to remove contaminants from a localized area on the specimen. The system also includes an optical subsystem that is configured to perform measurements of the specimen using vacuum ultraviolet light. The optical subsystem is disposed within a purged environment. In some embodiments, the system may include a differential purging subsystem that is configured to provide the purged environment for the optical subsystem.

Abstract: Disclosed are techniques and apparatus are provided for determining overlay error or pattern placement error (PPE) across the field of a scanner which is used to pattern a sample, such as a semiconductor wafer or device. This determination is performed in-line on the product wafer or device. That is, the targets on which overlay or PPE measurements are performed are provided on the product wafer or device itself. The targets are either distributed across the field by placing the targets within the active area or by distributing the targets along the streets (the strips or scribe areas) which are between the dies of a field. The resulting overlay or PPE that is obtained from targets distributed across the field may then be used in a number of ways to improve the fabrication process for producing the sample.

Abstract: A method and apparatus for inspecting patterned substrates, such as photomasks, for unwanted particles and features occurring on the transmissive as well as pattern defects. A transmissive substrate is illuminated by a laser through an optical system comprised of a laser scanning system, individual transmitted and reflected light collection optics and detectors collect and generate signals representative of the light transmitted and reflected by the substrate. The defect identification of the substrate is performed using transmitted and reflected light signals from a baseline comparison between two specimens, or one specimen and a database representation, to form a calibration pixelated training set including a non-defective region. This calibration pixilated training set is compared to a transmitted-reflected plot map of the subject specimen to assess surface quality.

Abstract: Methods and systems for binning defects detected on a specimen are provided. One method includes comparing a test image to reference images. The test image includes an image of one or more patterned features formed on the specimen proximate to a defect detected on the specimen. The reference images include images of one or more patterned features associated with different regions of interest within a device being formed on the specimen. If the one or more patterned features of the test image match the one or more patterned features of one of the reference images, the method includes assigning the defect to a bin corresponding to the region of interest associated with the reference image.

Abstract: Methods and systems for generating an inspection process for an inspection system are provided. One computer implemented method includes generating inspection data for a selected defect on a specimen at different values of one or more image acquisition parameters of the inspection system. The method also includes determining which of the different values produces the best inspection data for the selected defect. In addition, the method includes selecting the different values determined to produce the best inspection data as values of the one or more image acquisition parameters to be used for the inspection process.

Abstract: Various methods and systems for utilizing design data in combination with inspection data are provided. One computer-implemented method for binning defects detected on a wafer includes comparing portions of design data proximate positions of the defects in design data space. The method also includes determining if the design data in the portions is at least similar based on results of the comparing step. In addition, the method includes binning the defects in groups such that the portions of the design data proximate the positions of the defects in each of the groups are at least similar. The method further includes storing results of the binning step in a storage medium.

Abstract: Methods and apparatus, including computer program products, implementing and using techniques for optimizing feature printability on a semiconductor wafer. A reticle with a quasi-periodic structure is provided. The quasi-periodic structure includes several elements that each contribute to the printed feature to be printed on the wafer. Each element exhibits a slight variation in a reticle feature characteristic compared to an adjacent other element in the quasi-periodic structure. The reticle with the quasi-periodic structure is used to print several printed features on the semiconductor wafer. Each printed feature corresponds to a specific element in the quasi-periodic structure. A metrology process is performed on the semiconductor wafer to generate a signature for each of the printed features. The signature is used to determine an optimum reticle feature characteristic that results in an optimum printed feature.

Abstract: Various systems for measurement of a specimen are provided. One system includes a first optical subsystem, which is disposed within a purged environment. The purged environment may be provided by a differential purging subsystem. The first optical subsystem performs measurements using vacuum ultraviolet light. This system also includes a second optical subsystem, which is disposed within a non-purged environment. The second optical subsystem performs measurements using non-vacuum ultraviolet light. Another system includes two or more optical subsystems configured to perform measurements of a specimen using vacuum ultraviolet light. The system also includes a purging subsystem configured to maintain a purged environment around the two or more optical subsystems. The purging subsystem is also configured to maintain the same level of purging in both optical subsystems.

Abstract: Disclosed is a combined scatterometry mark comprising a scatterometry critical dimension (CD) or profile target capable of being measured to determine CD or profile information and a scatterometry overlay target disposed over the scatterometry CD or profile target, the scatterometry overlay target cooperating with the scatterometry CD or profile target to form a scatterometry mark capable of being measured to determine overlay.

Abstract: Disclosed are apparatus and methods for finding lithographically significant defects on a reticle. In general, at least a pair of related intensity images of the reticle in question are obtained using an inspection apparatus. The intensity images are obtained such that each of the images experience different focus settings for the reticle so that there is a constant focus offset between the two focus values of the images. These images are then analyzed to obtain a transmission function of the reticle. This transmission function is then input into a model of the lithography system (e.g., a stepper, scanner, or other related photolithography system) to then produce an aerial image of the reticle pattern. The aerial image produced can then be input to a photoresist model to yield a “resist-modeled image” that corresponds to an image pattern to be printed onto the substrate using the reticle. This resist-modeled image can then be compared with a reference image to obtain defect information.

Abstract: Methods and systems for inspection of a wafer are provided. One method includes illuminating the wafer with light at a first wavelength that penetrates into the wafer and light at a second wafer that does not substantially penetrate into the wafer. The method also includes generating output signals responsive to light from the wafer resulting from the illuminating step. In addition, the method includes detecting defects on the wafer using the output signals. The method further includes determining if the defects are subsurface defects or surface defects using the output signals.

Abstract: In one embodiment, a system includes a beam generator for directing at least one incident beam having a wavelength ? towards a periodic target having structures with a specific pitch p. A plurality of output beams are scattered from the periodic target in response to the at least one incident beam. The system further includes an imaging lens system for passing only a first and a second output beam from the target. The imaging system is adapted such that the angular separation between the captured beams, ?, and the pitch are selected to cause the first and second output beams to form a sinusoidal image. The system also includes a sensor for imaging the sinusoidal image or images, and a controller for causing the beam generator to direct the at least one incident beam towards the periodic target or targets, and for analyzing the sinusoidal image or images.

Abstract: Methods and systems for determining drift in a position of a light beam with respect to a chuck are provided. One method includes illuminating a surface with the light beam. The surface has a predetermined position with respect to the chuck during illumination. The method also includes generating signals responsive to the illumination of the surface and determining the drift in the position of the light beam with respect to the chuck using the signals. One system includes an illumination subsystem configured to illuminate a fiduciary with the light beam. The fiduciary has a predetermined position with respect to the chuck during illumination. This system also includes a detector configured to generate signals responsive to the illumination of the fiduciary and a processor configured to use the signals to determine the drift in the position of the light beam with respect to the chuck.