Abstract: A two dimensional beam deflector is disclosed which deflects beams from multiple optical assemblies. The input of beams of the multiple optical assemblies follow parallel optical paths until deflection to a wafer. An ellipsometer using a two-dimensional beam deflector is also disclosed.

Abstract: A method is proposed for determining a location on an object and for positioning an object, such as a silicon wafer, which has an array of generally perpendicular grid lines on its surface and a plurality of directional features. The method determines the directions of the grid lines relative to the direction of a reference coordinate system, detects a grid junction and detects a direction of one of the plurality of directional features, thereby providing a location of the grid junction in the reference coordinate system. The object is positioned in accordance with the provided location of the grid junction.

Abstract: An autofocussing mechanism is provided which is useful for all objective lenses and during scanning of the object. The autofocussing mechanism operates with a microscope having a main optical path, an objective lens, an object surface, an image plane and apparatus for changing the distance between the objective lens and the object surface thereby to focus the image of the object. The autofocussing mechanism preferably includes a pattern imaging system, a single image detector and a pattern focus analyzer. The pattern imaging system images at least one pattern through the objective lens along the main optical path and onto the object surface. The image of the pattern is then combined with an image of the object and is reflected along the main optical path towards the image plane. The image detector detects the reflected image and the pattern focus analyzer determines the extent of sharpness of the pattern by analyzing the output of the image detector.

Abstract: A thin film thickness measuring device is disclosed. The device includes an illuminator, a receiver and a beam deflector. The illuminator provides a collimated input light beam along an input axis. The receiver includes a lens and a diaphragm having a pinhole located at a focal point of the lens and receives a collimated output light beam along an output axis parallel to the input axis. The beam deflector is translatable at least along a scanning axis parallel to the input axis. The beam deflector directs the input light beam towards a sample and the output light beam from the sample towards the receiver.