MULTI-PROBE ERROR SEPARATION APPLIED TO ROUNDNESS CIRCULAR FLATNESS AND ANGULARITY

摘要

Multi-probe error separation has particular utility for Reflective Electron Beam Lithography (REBL), a new technology being developed at KLA-Tencor under DARPA contract HR0011-07-9-0007. The REBL architecture features a continuously rotating platter of wafers which also slowly translates under a digital e-beam projector similar in concept to a digital light projector (DLP). Within a small (100 urn × 6 urn) stationary field, it projects a dynamic, digital pattern that exposes patterns that are stationary relative to the moving wafers. The motion of the rotary-linear stage must be measured in six degrees of freedom in real-time to provide both feedback for controlling stage motion, including the magnetic spindle bearings, and feed forward for steering the e-beam. Ultimately the planar motion of each wafer must be tracked to the nanometer level with a portion allocated to stage metrology and error separation.