POSITION DETECTION SYSTEM FOR USE IN LITHOGRAPHY EQUIPMENT

摘要

PROBLEM TO BE SOLVED: To provide a reference system which enables reference repeatable with a precision of mobile object, preferably, a submicrometer regarding to a reference frame. SOLUTION: The position detector comprises a radiation source mounted on an isolated reference frame and a two-dimensional sensor mounted close to the said radiation source. An object for positional detection is topped with a regressive reflector so as to reflect light radiated from the radiation source along a return path which is in parallel with an incident light path but displaced from it. The quantity of displacement depends on the position of the object and is measured by the two-dimensional sensor. Such three devices are combined into a system to measure the position of the object at total six degrees of freedom.