Rotational flexure stage

• US 5,083,757 A
• Filed: 07/05/1990
• Issued: 01/28/1992
• Est. Priority Date: 07/05/1990
• Status: Expired due to Fees

• Current Assignee: Ultratech Stepper East, Inc. (Veeco Instruments Incorporated), Ultratech Stepper, Inc. (Veeco Instruments Incorporated)
• Original Assignee: General Signal Corporation (SPX Corporation)
• Inventors: Barsky, Samuel M.
• Primary Examiner(s): HALVOSA, GEORGE
• Application Number:
  US07/548,081
• Time in Patent Office: 572 Days
• Field of Search: 267/181, 267/160, 267/161, 267/162, 267/163, 248/184, 248/476, 137/845, 137/852, 137/855
• US Class Current: 267/181
• CPC Class Codes: B23Q 1/36 Springs
• CPC Class Codes: F16F 1/02 made of steel or other material having low internal friction characterised by their special construction from fibre-reinforced plastics F16F1/366; spring units consisting of several springs F16F3/02; making springs from wire B21F35/00; Wound, torsion, leaf, cup, ring or the like springs, the material of the spring not being relevant
• CPC Class Codes: F16F 1/32 Belleville-type springs friction-clutch diaphragm springs F16D13/583
• CPC Class Codes: G03F 7/70716 Stages
• CPC Class Codes: H01L 21/682 Mask-wafer alignment in general G03F7/70, G03F9/70

Abstract

The flexure stage disclosed herein is useful in aligning a semiconductor wafer during microlithographic exposure to define circuit elements on the surface of the wafer. The stage is a unitary structure which permits essentially lossless small angle relative rotation of a central portion of the stage with respect to an outer, annular portion of the stage. Three pairs of slots define three links extending radially with respect to the axis of rotation and, radially outwardly from each pair of slots, a respective transverse slot in the outer portion provides radial compliance for the outer end of the respective link.

Claims

1. A unitary flexure stage permitting essentially lossless relative small angle rotation around a central axis, said stage comprising a body of elastic material having therein:

three pairs of parallel slots defining three links extending radially with respect to said axis from respective points of attachment to a central portion of said body;

cylindrical bores at each end of each of the slots of said pairs, the adjacent bores at corresponding ends of each pair being closely adjacent thereby providing a necked down region at the respective end of the link establishing a compliant region;

located radially outwardly from each pair of slots in an outer, annular portion of said body, a respective relief slot, said relief slot extending transversely of the respective pair of radial slots and closely adjacent the respective pair of bores at substantially radially outer ends of said slots thereby to provide radial compliance for the respective link; and

peripheral slot segments separating said central portion from said outer annular portion between said links.

2. A stage as set forth in claim 1 further including a cylindrical bore at each end of each of said transverse relief slots.

3. A unitary flexure stage permitting essentially lossless relative small angle rotation of a central portion of the stage with respect to an outer, annular portion of the stage around a central axis, said stage comprising a generally flat metal body having therein:

three pairs of parallel slots defining three links extending radially with respect to said axis from respective points of attachment to said central portion;

at each end of each of said slots, a cylindrical bore, the adjacent bores at corresponding ends of each pair being closely adjacent thereby providing a necked down region at the respective end of the respective link;

radially outwardly from the bores at an outer end of each pair of slots, a respective transverse slot in said outer portion passing closely adjacent the respective pair of bores at substantially radially outer ends of said slots providing radial compliance for the respective link; and

peripheral slot segments separating said central portion from said outer annular portion between said links.

4. A stage as set forth in claim 3 wherein said metal is aluminum.