Rotatable and translatable mounting mechanism for a specimen pattern in

Abstract

A translatable and rotatable mechanism is employed in optical processing apparatus for exposing a specimen pattern and inspecting light pattern or image developed from it. The mounting mechanism includes a plate that is rotatably mounted on a linear positioning table assembly. The plate includes a substrate arm and a camera arm that extend in opposite directions from the axis of rotation of the plate. The specimen pattern, such as a photomask, is positioned on the free end of the substrate arm, and a video camera is positioned on the free end of the camera arm. Whenever the plate is rotated to an exposure orientation, the photomask diffracts light rays emanating from a laser. The diffracted light rays interfere with a reference beam to form a hologram. Whenever the plate is rotated 180.degree. to an inspection orientation, a reconstructed imate of the photomask appears at the location where the photomask was positioned during exposure. The video camera is positioned directly beneath the reconstructed image and scans it by the translational movement of the positioning table. A microscope is mounted to a stationary support and is positioned over the photomask. The video camera and the microscope observe corresponding regions of the image and the photomask, respectively, in synchronism for all translational movements of the plate.