Claims
- 1. Apparatus for clamping a flat thin conductive workpiece to a mounting member, the mounting member having at least a flat top layer of dielectric material, a conductive sublayer divided into a pattern of at least four electrodes, and an underneath layer of dielectric material wherein the electrodes are all of substantially equal area and are of generally spiral form.
- 2. In a method of electrostatic clamping for providing substantially uniform pressure between a flat thin conductive workpiece and a mounting member, said mounting member comprising at least a top layer composed of flat dielectric, a second layer of metal divided into a pattern of at least four electrodes of substantially equal area, and a third layer of dielectric, the additional steps of:
- arranging that the electrodes extend next to each other in a sequence,
- providing alternating voltages of equal amplitude and of equally spaced phase to each of said electrodes,
- connecting said voltages to the electrodes to introduce electrostatic clamp forces for clamping the workpiece to the mounting member, and
- said electrodes extending in pairs along turning paths to effectively limit magnitude of vibration induced in the workpiece.
- 3. The method of claim 2, wherein the step of arranging includes arranging that said electrodes are patterned electrodes of generally spiral form, thereby reducing magnitude of vibrations induced in the workpiece by said alternating voltages.
- 4. In a method of electrostatic clamping for providing substantially uniform pressure between a flat thin conductive workpiece and a mounting member, said mounting member comprising at least a top layer composed of flat dielectric, a second layer of metal divided into a pattern of at least four electrodes of substantially equal area, and a third layer of dielectric, the additional steps of:
- arranging that the electrodes extend next to each other in a sequence,
- providing alternating voltages of equal amplitude and of equally spaced phase to each of said electrodes,
- connecting said voltages in non-sequential order to the electrodes to introduce a dynamic and non-motoring pattern of electrostatic clamp forces for clamping the workpiece to the mounting member, the step of arranging including arranging that said electrodes are patterned electrodes of generally spiral form, thereby reducing magnitude of vibrations induced in the workpiece by said alternating voltages.
- 5. The method of claim 4 further comprising the step of monitoring current provided to the electrodes to detect presence of the workpiece on said mounting member and to determine its degree of contact therewith.
Parent Case Info
This application is a continuation application of Ser. No. 08/323,764 filed on Oct. 17, 1994, now abandoned. The aforementioned application is hereby incorporated by reference.
US Referenced Citations (6)
Continuations (1)
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Number |
Date |
Country |
Parent |
323764 |
Oct 1994 |
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