Kla Tencor Corporation

Yanwei Liu

Daniel C Wack

Abdurrahman Sezginer

Daimian Wang

Li Wang

Carl Hess

Yalin Xiong

Oleg Khodykin

Qiang Q Zhang

Eric Vella

Alan Aindow

Hawren Fang

Balaji Ganapathy

Disclosed are methods and apparatus for inspecting a photolithographic reticle. Modeled images of a plurality of target features of the reticle are obtained based on a design database for fabricating the reticle. An inspection tool is used to obtain a plurality of actual images of the target features of the reticle. The modelled and actual images are binned into a plurality of bins based on image properties of the modelled and actual images, and at least some of the image properties are affected by one or more neighbor features of the target features on the reticle in a same manner. The modelled and actual images from at least one of the bins are analyzed to generate a feature characteristic uniformity map for the reticle.

Critical dimension uniformity enhancement techniques and apparatus

A reticle is inspected with an imaging system to obtain a measured image of a structure on the reticle, and the structure has an unknown critical dimension (CD). Using a model, a calculated image is generated using a design database that describes a pattern used to form the structure on the reticle. The model generates the calculated image based on: optical properties of reticle materials of the structure, a computational model of the imaging system, and an adjustable CD. A norm of a difference between the measured and calculated images is minimized by adjusting the adjustable CD and iteratively repeating the operation of generating a calculated image so as to obtain a final CD for the unknown CD of the structure. Minimizing the norm of the difference is performed simultaneously with respect to the adjustable CD and one or more uncertain parameters of the imaging system.

Techniques and systems for model-based critical dimension measurements

Disclosed are methods and apparatus for inspecting a photolithographic reticle. An inspection tool is used to obtain a plurality of patch area images of each patch area of each die of a set of identical dies on a reticle. An integrated intensity value for each patch area image is determined. A gain is applied to the integrated intensity value for each patch area image based on a pattern sparseness metric of such patch area image and its relative value to other patch area images' pattern sparseness metric. A difference between the integrated intensity value of each patch of pairs of the dies, which each pair includes a test die and a reference die, is determined to form a difference intensity map of the reticle. The difference intensity map correlates with a feature characteristic variation that depends on feature edges of the reticle.

Delta die and delta database inspection

Photoelectron emission mapping systems for use with EUV (extreme ultraviolet) mask inspection and lithography systems are described. The mapping systems may be used to provide photoelectron emission maps for EUV photolithography masks and/or EUV mirrors. The systems use EUV photoelectron sources used for mask inspection or photolithography to impinge EUV light on the masks and/or mirrors. The EUV light generates photoelectron on the surfaces of the mask and/or mirrors and the photoelectrons are collected and analyzed by detectors placed away from optical spaces of the EUV chamber.

Photoemission monitoring of EUV mirror and mask surface contamination in actinic EUV systems

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.

Wave front aberration metrology of optics of EUV mask inspection system

Spectral Purity Filters, or SPFs, are disclosed. Such SPFs are designed to block out the 1030 nm drive laser and other undesired out of band light in a EUV mask inspection system. Different phase grating configurations for near normal incidence and grazing incidence are provided in the present disclosure and are configured specifically for EUV mask inspection.

Phase grating for mask inspection system

A compact synchrotron radiation source includes an electron beam generator, an electron storage ring, one or more wiggler insertion devices disposed along one or more straight sections of the electron storage ring, the one or more wiggler insertion devices including a set of magnetic poles configured to generate a periodic alternating magnetic field suitable for producing synchrotron radiation emitted along the direction of travel of the electrons of the storage ring, wherein the one or more wiggler insertion devices are arranged to provide light to a set of illumination optics of a wafer optical characterization system or a mask optical characterization system, wherein the etendue of a light beam emitted by the one or more wiggler insertion devices is matched to the illumination optics of the at least one of a wafer optical characterization system and the mask optical characterization system.

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Danville, CA, United States of America

Yanwei Liu