Abstract: Systems and methods of observing a sample using a charged-particle beam apparatus in voltage contrast mode are disclosed. The charged-particle beam apparatus comprises a charged-particle source, an optical source, a charged-particle detector configured to detect charged particles, and a controller having circuitry configured to apply a first signal to cause the optical source to generate the optical pulse, apply a second signal to the charged-particle detector to detect the second plurality of charged particles, and adjust a time delay between the first and the second signals. In some embodiments, the controller having circuitry may be further configured to acquire a plurality of images of a structure, to determine an electrical characteristic of the structure based on the rate of gray level variation of the plurality of images of the structure, and to simulate, using a model, a physical characteristic of the structure based on the determined electrical characteristic.

Abstract: A method of measuring a delay time of a propagation of a signal in a line in a circuit structure, the method comprises irradiating the line by pulses of a charged particle beam, wherein a pulse repetition frequency of the pulses of the charged particle beam is varied. The method further comprises measuring, for each of the pulse repetition frequencies, a secondary charged particle emission responsive to the irradiating the line by the pulses of the charged particle beam at the respective pulse repetition frequency, and deriving the delay time of the line based on the secondary charged particle emission responsive to the varying of the pulse repetition frequency.

Abstract: The first layer mark and the second layer mark are adapted to be projected onto each other during the lithographic process. The first layer components and the second layer components are adapted to be arranged in a plurality of different overlay configurations, each overlay configuration comprising a number of the plurality of the first layer components and a number of the plurality of the second layer components, and each overlay configuration having a different overlay distance at which each first layer component is arranged in a first direction of an associated second layer component of the second layer components. The method comprises determining an overlay step which represents a difference between the different overlay distances of the plurality of overlay configurations, determining a largest overlay distance, determining the number of first layer components and/or the number of associated second layer components in each overlay configuration.

Abstract: Optically determining whether metallic features in different layers in a structure are in electrical contact with each other. When the metallic features include different metals and/or have different dimensions, which cause one or more resonances in reflected radiation to be detected, the metallic features in the different layers are determined to be in contact or out of contact with each other based on the spectral positions of the one or more resonances. When the metallic features are formed from the same metal and have the same dimensions, the metallic features in the different layers are determined to be in contact with each other responsive to detection of a single resonance associated with the metallic features and out of contact with each other responsive to detection of two or more resonances associated with the metallic features.