Applejack 199 L.p.

Wei-Chun Hung

Wojciech Jan Walecki

Raphael Morency

A method and apparatus for non-contact measurement of stress in a thin-film deposited on a substrate is disclosed. The method may include positioning a substrate on a plurality of support-elements, the substrate having a thin-film deposited thereupon. A first-polynomial may be defined for representing a surface of the substrate that is in contact with the support elements. A second-polynomial may be determined based on an optimization determination of potential-energy acting upon the substrate. A finite-order polynomial may be created by calculating a product of the first and second polynomials to represent a shape of the surface of the substrate as a model of the surface. Thereafter, stress in the substrate may be determined based on fitting the model of the surface with a measured topographical data of the surface.

Non-contact measurement of a stress in a film on substrate

The present subject matter at-least provides a system for measurement of topography of specular surfaces. The system comprises a set of indexed light-sources and a controller configured to drive the set of light-sources for irradiating a specular-surface by sequentially illuminating a plurality of sub-sets of the light-sources in accordance with a pre-defined encoding criteria. Further, at least one camera is provided to capture reflected light-radiation from the specular-surface and thereby generate a plurality of images in accordance with the sequential-illumination, such that each of the generated-image corresponds to a particular sub-set of illuminated light sources. Further, a processing system is configured to process each generated image in accordance with an image-processing criteria specific to the encoding-criteria to determine one or more index of light-sources and thereby identify the light-sources within the images; and determine topography of the specular-surface at-least based on calculation of spatial-coordinates and the determined identity of each light-source.

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San Jose, CA, United States of America

Wei-Chun Hung