Importance

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Abstract

A step and repeat mechanism is used with an X-ray lithography system for moving a wafer to be exposed from position to position beneath the source of x-rays. The step and repeat mechanism includes, means for moving the wafer to be exposed with six degrees of freedom. Conventional drive motor means move the step and repeat mechanism, and wafer held thereby, in the X, Y and Z linear directions, as well as rotates, tip and tilt the wafer in the planar direction. In addition, the system includes, three fine Z motor assemblies for moving the wafer in fine increments in the Z direction, which motor assemblies are used to tip and tilt the plane of the wafer. Sensors are included for determining the plane of the mask and the plane of each of the various sections of wafer to be exposed, so that appropriate tip and tilt adjustments by the three fine Z motor assemblies can be made to cause the average plane of each section of the wafer to be exposed to be parallel to the plane of the mask. All of the moving mechanisms, with the exception of the Y direction moving mechanism, are affixed the same level of the step and repeat mechanism. Included in the mechanism is a substage plate which is adjusted by the three triangularly positioned fine Z motor assemblies.

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First Claim