Importance

Loading Importance Indicators...

Abstract

A system and method for calibrating scanning beam systems, such as electron beam systems, so that a plurality of such systems are compatible one with another, thereby allowing an object that is scanned on one system to be transferred to another system while still maintaining proper alignment between the pattern(s) scanned on the object by one system and the pattern(s) scanned on the object by another system. A calibration plate, having an array of calibration marks thereon at prescribed locations, is made on a first system. This plate is then transferred to a second system where the location of the calibration marks is measured. The measured locations are fitted mathematically to the prescribed locations in order to minimize error. Nonetheless, some error will be present due to the slight misalignments and nonlinearities, such as mirror distortion, that are present between any two scanning beam systems. This error is determined by comparing the fitted measured locations to the prescribed locations. An error map is created that characterizes this error by location, for the particular scanning beam system being calibrated. The information contained in this error map is used to subsequently compensate the movement of the calibrated system, using interpolation when necessary, so that the movements of the calibrated system accurately track, and hence are aligned with, the movements of the first system. Internal compensation may also be performed on each system to account for known errors and nonlinearities associated with the operation of the individual system.

Loading the Abstract Image...

First Claim