Abstract:
Disclosed are methods and apparatus for inspecting a photolithographic reticle. A near field reticle image is generated via a deep learning process based on a reticle database image produced from a design database, and a far field reticle image is simulated at an image plane of an inspection system via a physics-based process based on the near field reticle image. The deep learning process includes training a deep learning model based on minimizing differences between the far field reticle images and a plurality of corresponding training reticle images acquired by imaging a training reticle fabricated from the design database, and such training reticle images are selected for pattern variety and are defect-free. A test area of a test reticle, which is fabricated from the design database, is inspected for defects via a die-to-database process that includes comparing a plurality of references images from a reference far field reticle image to a plurality of test images acquired by the inspection system from the test reticle. The reference far field reticle image is simulated based on a reference near field reticle image that is generated by the trained deep learning model.
Abstract:
Disclosed are methods and apparatus for qualifying a photolithographic reticle. A reticle inspection tool is used to acquire images at different imaging configurations from each of a plurality of pattern areas of a test reticle. A reticle near field for each of the pattern areas of the test reticle is recovered based on the acquired images from each pattern area of the test reticle. A lithography model is applied to the reticle near field for the test reticle to simulate a plurality of test wafer images, and the simulated test wafer images are analyzed to determine whether the test reticle will likely result in an unstable or defective wafer.
Abstract:
Apparatus and methods for inspecting a specimen are disclosed. An inspection tool is used at one or more operating modes to obtain images of a plurality of training regions of a specimen, and the training regions are identified as defect-free. Three or more basis training images are derived from the images of the training regions. A classifier is formed based on the three or more basis training images. The inspection system is used at the one or more operating modes to obtain images of a plurality of test regions of a specimen. Three or more basis test images are derived from to the test regions. The classifier is applied to the three or more basis test images to find defects in the test regions.
Abstract:
Apparatus and methods for inspecting a photolithographic reticle are disclosed. A reticle inspection tool is used at one or more operating modes to obtain images of a plurality of training regions of a reticle, and the training regions are identified as defect-free. Three or more basis training images are derived from the images of the training regions. A classifier is formed based on the three or more basis training images. The inspection system is used at the one or more operating modes to obtain images of a plurality of test regions of a reticle. Three or more basis test images are derived from to the test regions. The classifier is applied to the three or more basis test images to find defects in the test regions.
Abstract:
Disclosed is test structure for measuring wave-front aberration of an extreme ultraviolet (EUV) inspection system. The test structure includes a substrate formed from a material having substantially no reflectivity for EUV light and a multilayer (ML) stack portion, such as a pillar, formed on the substrate and comprising a plurality of alternating pairs of layers having different refractive indexes so as to reflect EUV light. The pairs have a count equal to or less than 15.
Abstract:
Methods and systems for performing measurements of semiconductor structures and materials based on scatterometry measurement data are presented. Scatterometry measurement data is used to generate an image of a material property of a measured structure based on the measured intensities of the detected diffraction orders. In some examples, a value of a parameter of interest is determined directly from the map of the material property of the measurement target. In some other examples, the image is compared to structural characteristics estimated by a geometric, model-based parametric inversion of the same measurement data. Discrepancies are used to update the geometric model of the measured structure and improve measurement performance. This enables a metrology system to converge on an accurate parametric measurement model when there are significant deviations between the actual shape of a manufactured structure subject to model-based measurement and the modeled shape of the structure.
Abstract:
Disclosed is test structure for measuring wave-front aberration of an extreme ultraviolet (EUV) inspection system. The test structure includes a substrate formed from a material having substantially no reflectivity for EUV light and a multilayer (ML) stack portion, such as a pillar, formed on the substrate and comprising a plurality of alternating pairs of layers having different refractive indexes so as to reflect EUV light. The pairs have a count equal to or less than 15.
Abstract:
Methods and systems for generating an indication of a changing electrostatic field between a sense electrode of a capacitance sensing integrated circuit and a specimen under inspection are presented. The capacitance sensing integrated circuit is an integrated circuit that includes a number of sense electrodes and sense electronics. By fabricating the elements of the capacitance sensing integrated circuit as a single microelectronic chip, the sense electrodes can be miniaturized to sizes that enable inspection of fine line patterns common in modern semiconductor manufacturing. In one embodiment, the sense electrodes are metallic contacts. In another embodiment the sense electrodes are field effect transistors (FETs) with a floating gate. The sense electronics generate an indication of the changing electrostatic field between each sense electrode and a specimen under inspection as the specimen is scanned relative to the capacitance sensing integrated circuit.
Abstract:
In one embodiment, disclosed are apparatus, methods, and targets for determining a phase shift of a photomask having a phase-shift target. An inspection or metrology system is used to direct an incident beam towards the target and then detect a plurality of intensity measurements that are transmitted through the target in response to the incident beam. A phase shift value for the target may then be determined based on the intensity measurements.
Abstract:
Disclosed is a system that includes a light source for generating an illumination beam and an illumination lens system for directing the illumination beam towards a sample. The system further includes a collection lens system for directing towards a detector output light from the sample in response to the illumination beam and a detector for receiving the output light from the sample. The collection lens system includes a fixed-design compensator plate having individually selectable filters with different configurations for correcting system aberration of the system under different operating conditions. The system also includes a controller operable for: (i) generating and directing the illumination beam towards the sample, (ii) selecting operating conditions and a filter for correcting the system aberration under such selected operating conditions, (iii) generating an image based on the output light, and (iv) determining whether the sample passes inspection or characterizing such sample based on the image.