Vertical translation stage features submicron resolution

Paul Boughton

Aerotech's new Airlift 115 is a submicron resolution vertical translation stage that maintains an almost perfect straight-line performance over a travel range up to 150mm at speeds to 50mm/s. Aimed at demanding application areas such as semiconductor testing, nanoscale metrology, optical inspection and laser micromachining, the stage features a fully preloaded vertical air bearing in combination with a servomotor-driven precision ground ball screw in a compact design that includes an innovative drive mechanism without the need for a load counterbalance system.
Unlike conventional wedge-style designs for vertical translation that offer limited Z-direction angular performance and a restricted travel range (typically of just a few millimetres), the Airlift 115 maintains an angular performance of better than +/-1 arc-sec in pitch, yaw and roll for the 50mm travel version. The range also includes 100mm and 150mm travel versions where angular accuracy performance is still within +/-2 arc-sec. Positioning resolution across the range is 50nm with repeatability within +/-0.5um. Overall calibrated positional accuracy for the 50mm travel version is within +/-1.0um and, for the 150mm travel version, +/-1.5um.
Such impressive specifications allow positioning and micromanipulation of workpieces to be held to remarkably high levels of flatness for applications where an unobstructed view of the work plane is required - such as wafer inspection or laser processing. The long travel range, high bearing stiffness and high speed capability also combine for rapid workpiece loading well away from the work area with the added bonus that the horizontal footprint is also relatively small in comparison to tradition vertical stage designs.
The Airlift 115 includes a BSM series brushless and cogless rotary servomotor for ultra-smooth motion, with submicron position feedback from a linear encoder mounted directly on the air bearing plane. An integral brake is included and there are options for perpendicular or parallel mounting; the complete assembly includes motor, feedback and brake connectors.
Aerotech says the Airlift 115 may be used as a single ultra-high-precision lift mechanism or as part of a complete multi-axis positioning system with Aerotech's wide range of linear and rotary translation stages, drives and motion controls. Complete positioning sub-systems may include standard components or custom engineered products with modified mechanics, integral machine base, full cable management and advanced motion and machine controls specifically aimed at improving both the precision and production throughput performance for applications across manufacturing and research.
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