Electro-Damp^® PLS is a new approach to the height control of pneumatic vibration isolation systems.

Typically, air isolators are self-leveling and rely upon mechanical valves and a mechanical linkage to sense and maintain the position of an isolated surface. TMC's EPPSand PEPS^® were the first non-contacting height control systems to incorporate electronic height control valves and analog controls. The approach of using non-contacting height control systems has become an attractive method for metrology and microlithography tool designers to control static and dynamic position. Non-contacting control eliminates wear issues and maintains a high level of repeatability over long periods of time while providing the highest possible level of vibration isolation.

The Electro-Damp PLS builds upon TMC's PEPS^® technology by incorporating our DC-2000 Digital Controller to greatly expand the available options and interfaces. In particular, the Electro-Damp PLS incorporates an Information Feedforward function allowing for dramatically less vertical displacement of the isolated surface and improved leveling times in response to weight shifts caused by stage motion. Feedforward is a technique in which information controlling the position of a motorized stage is used to "anticipate" stage motion and the corresponding change in pressure required in each pneumatic isolator required to offset this motion. Typically, such information is taken from the stage motion controller. This technique is simple, requires no additional sensors, has no feedback (making it inherently stable), and is relatively inexpensive. Feedforward can often achieve up to a five-fold improvement in displacement and leveling time.

Furthermore, since Electro-Damp^® is a modular system, an Electro-Damp^® PLS can be upgraded to an Electro- Damp II System (with inertial damping) by simply adding force motors and a power amplifier should increased performance become necessary.

• Faster settling time of X-Y stage-induced motion
• Non-contacting, electronic height control using proportional valves
• DC-2000 Digital Controller
• Informational feedforward anticipates stage position and acceleration
• Compatible with all TMC pneumatic isolators including the Gimbal Piston™, MaxDamp^®, and Compact Sub-Hertz Pendulum (CSP^®)

• Reduced payload motion and leveling time for stage-induced motion
• Higher throughput and yield
• Position repeatability to within 20 µm eases docking

Electropolished  Stainless Steel Acoustic Enclosure with Integrated

TMC Electro-Damp^® II Vibration Isolation System for Veeco Process Metrology AFM.