Multiple degree of freedom substrate manipulator
AssigneeActive Precision, Inc.
InventorBradley L. Hunter
Life of this patent
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Abstract
A system for manipulating a planar substrate such as a semiconductor wafer is provided. The manipulator is typically used in conjunction with an XY stage to focus and planarize a wafer with respect to a tool. The manipulator employs redundant actuators of different types and a control system that uses low-bandwidth, high efficiency actuators to provide low frequency forces and high-bandwidth, but less efficient, actuators to provide all other forces. The manipulator provides support and manipulation of a substrate while minimizing errors due to thermal distortion.
Claims22
An actuator comprising:
- a piston movably guided by an externally pressurized fluid-bearing;
- a fluid chamber formed at one end of the piston having a chamber pressure controlled by balancing a fluid flowing into the fluid chamber with fluid exiting the chamber through a controllable orifice;
- and
- a voice coil motor disposed to move the piston located within the confines of the piston.
An actuator comprising:
- a piston movably guided by a fluid-bearing;
- a fluid chamber formed at one end of the piston having a chamber pressure controlled by balancing a fluid flowing into the fluid chamber with fluid exiting the chamber through a controllable orifice;
- a voice coil motor disposed to move the piston located within the confines of the piston;
- and
- a control system that supplies large low-frequency forces by modulating the chamber pressure, and supplies low amplitude high-frequency forces via the voice coil motor.
An actuator, comprising:
- a piston movably guided by a fluid-bearing;
- an external source of fluid that supplies the fluid-bearing;
- a fluid chamber formed at one end of the piston having a chamber pressure controlled by balancing the fluid flowing into the fluid chamber from the fluid-bearing with fluid exiting the chamber through a controllable orifice;
- and
- a voice coil motor disposed to move the piston located within the confines of the piston.
An actuator, comprising:
- a piston movably guided by a fluid-bearing;
- an external source of fluid that supplies the fluid-bearing;
- a fluid chamber formed at one end of the piston having a chamber pressure controlled by balancing the fluid flowing into the fluid chamber with fluid exiting the chamber through a controllable orifice;
- a voice coil motor disposed to move the piston located within the confines of the piston;
- and
- an air-bearing pad disposed above the surface of the piston and allowed to pivot with respect to a vertical axis of the piston.
An actuator, comprising:
- a piston movably guided by a fluid-bearing;
- an external source of fluid that supplies the fluid-bearing;
- a fluid chamber formed at one end of the piston having a chamber pressure controlled by balancing the fluid flowing into the fluid chamber with fluid exiting the chamber through a controllable orifice;
- a voice coil motor disposed to move the piston located within the confines of the piston;
- and
- a single valve connected to the pressure chamber and normally operated in a partially open state to regulate the flow of fluid from the pressure chamber to an external source of pressure that is maintained at a pressure substantially below the nominal chamber pressure.
Dependencies are inferred from the claim text.