Abstract: Methods and systems for generating bright-field ellipsometric images indicative of structural defects sized below the optical resolution limit are presented herein. In some examples, bright-field ellipsometric images offer a higher signal to noise ratio of small defect signals to nuisance pattern noise signals compared to dark-field imaging at the null condition. Various ellipsometric imaging techniques are employed to generate images of a wafer or reticle under inspection. The images provide intensity contrast that is indicative of phase differences induced by the scattering response of different structures in the imaging field of the ellipsometric imaging system. In one aspect, an ellipsometric imaging system employs a polarizer in the illumination path and an analyzer and at least one waveplate in the imaging path. The ellipsometric imaging system generates images having intensity differences that differentiate defects of interest from nuisance pattern noise with relatively high signal to noise ratio.

Abstract: A system includes a processing unit communicatively coupled to a detector array of an optical wafer characterization system. The processing unit is configured to perform one or more steps of a method or process including the steps of acquiring one or more target images of a target location on a wafer from the detector array, applying a de-noising filter to at least the one or more target images, determining one or more difference images from one or more reference images and the one or more target images, and up-sampling the one or more difference images to generate one or more up-sampled images. One or more wafer defects are detectable in the one or more difference images or the up-sampled images.

Abstract: A system includes a processing unit communicatively coupled to a detector array of an optical wafer characterization system. The processing unit is configured to perform one or more steps of a method or process including the steps of acquiring one or more target images of a target location on a wafer from the detector array, applying a de-noising filter to at least the one or more target images, determining one or more difference images from one or more reference images and the one or more target images, and up-sampling the one or more difference images to generate one or more up-sampled images. One or more wafer defects are detectable in the one or more difference images or the up-sampled images.

Abstract: A system is disclosed. In one embodiment, the system includes a scanning electron microscopy sub-system including an electron source configured to generate an electron beam and an electron-optical assembly including one or more electron-optical elements configured to direct the electron beam to the specimen. In another embodiment, the system includes one or more grounding paths coupled to the specimen, the one or more grounding paths configured to generate one or more transmission signals based on one or more received electron beam-induced transmission currents. In another embodiment, the system includes a controller configured to: generate control signals configured to cause the scanning electron microscopy sub-system to scan the portion of the electron beam across a portion of the specimen; receive the transmission signals via the one or more grounding paths; and generate transmission current images based on the transmission signals.

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: 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.