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US 4,506,184 AGranted
Deformable chuck driven by piezoelectric means
AssigneeVarian Associates, Inc.
InventorGraham J. Siddall
Life of this patent
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Abstract
A deformable vacuum pin chuck includes a thin silicon chuck for supporting a semiconductor wafer during lithographic processing and a number of piezoelectric transducers for selectively deforming the chuck. Chuck deformation caused by application of electric potentials to selected transducers may be used to correct flatness deviations in the wafer and, thereby, a desired degree of flatness of the semiconductor wafer may be obtained.
Claims6
An apparatus for supporting a workpiece, comprising:
- a deformable chuck having a diameter to thickness ratio greater than or equal to about 40:1.
- a rigid plate;
- and
- a plurality of displacement means, mounted on the rigid plate and attached to the deformable chuck, for selectably displacing portions of the deformable chuck.
1 more element
Dependencies are inferred from the claim text.