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Electro-Damp® is the first commercial, active, vibration isolation system designed specifically to increase throughput, resolution, and yield in semiconductor manufacturing applications. The Electro-Damp II is a complete redesign of the original system, adding modularity, digital control, feedforward, high-force/high-clearance actuators, and multiple digital user interfaces specifically designed for use in OEM applications such as microlithography, inspection, and metrology tools.
Semiconductor manufacturing tools place conflicting demands on their vibration isolation system. In response to floor noise, the system must be soft to effectively filter floor vibration from reaching the isolated surface. Simultaneously, the system must be stiff in response to stage forces such that stage motion induces minimal displacement of the isolated surface and settles rapidly.
In addition to employing inertial, active feedback damping, Electro-Damp II uses information feedforward to further improve system response. Feedforward works by taking information from a stage controller about the stage’s position and acceleration, then processes that data to provide force actuation to the payload, greatly reducing stage-induced payload motion. The system can read the feedforward information digitally, as bipolar analog signals, or by reading the output of quadrature encoders. The DC-2000 Digital Controller can also automatically adjust the parameters required by feedforward using a stage test pattern. This makes setup on initial installations, or after changes to the payload, quick and easy.
Electro-Damp II’s modularity allows the system to be used with electronic servo valves alone (for heavy, low-acceleration applications like CMMs), with electromagnetic actuation only (for lighter stages which use high rates of acceleration), or a combination of both for the most demanding applications.