Nikon Corporation

Nikon Research Corporation of America

Henry K Chau

Arun Ananth Aiyer

John H McCoy

Kyoichi Suwa

Paul Derek Coon

A method and apparatus for detecting the presence of a thin film such as a photoresist film on a semiconductor wafer or other substrate. Only when a film is present does the surface reflectance (reflective power) of light incident on the wafer surface vary sinusoidally when the incidence angle of the light is varied. This sinusoidal variation in the reflected optical power is due to interference occurring between the film surface and wafer surface reflections. This method and apparatus allows determining whether an undeveloped photoresist layer is present on a wafer; this is not possible using merely visual inspection especially when an underlying pattern is present. The present method and apparatus may also be used to determine the thickness of a particular thin film.

Thin film detection method and apparatus

Macro defects in a processed or partly processed semiconductor wafer, liquid crystal display element, disk drive element or the like, are detected using scattered light. By use of automated image processing techniques, a reference image and a sample image are formed from the scattered light and edge enhanced. A difference image is formed by comparing the edge enhanced reference and sample images. The difference image is evaluated using one or more automated image processing techniques such as thresholding, morphological transformations and blob analysis to identify macro defects.

Method and apparatus for macro defect detection using scattered light

A chemical-mechanical polishing (CMP) optical process monitor apparatus allows in situ measurement of the thickness of a thin film being polished. As the incidence angle of the incident light on the wafer being polished is changed, the reflected intensity of the light from the thin film on the wafer undergoes a variation in local maxima and minima. The angle at which the light intensity is a maximum or minimum determined by the thin film interference equation, thus providing a measurement of the thin film thickness and/or the change in the thin film thickness.

CMP variable angle in situ sensor

Defects in a processed or partly processed semiconductor wafer, or other similar three-dimensional periodic pattern formed on a substrate surface, are detected by light diffraction. Incident monochromatic light is provided from an elongated and extended source to illuminate the entire wafer surface. By use of automated image processing techniques, wafer macro inspection is thereby automated. The elongated and extended light source allows light at different angles to be incident upon each point of the wafer surface, thereby allowing defect detection for an entire wafer surface in a single field of view and reducing inspection time. The particular wavelength of the incident monochromatic light is predetermined to allow optimum detection of defects in the periodic pattern on the wafer, depending on the width and pitch of the features of the periodic pattern.

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Henry K Chau