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Vacuum Mask Holding Fixture of Photolithographic and Mask Generating Equipment

IP.com Disclosure Number: IPCOM000087306D
Original Publication Date: 1977-Jan-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Jaerisch, W: AUTHOR [+2]

Abstract

In optical instruments where glass masks are used, the masks must be clamped in a fixed position. Presently, segmented rings are used with each segment containing a vacuum port for holding the mask tight against the face of the clamp. However, because each port is separate, the mask is pulled unevenly, and distortion and variations in flatness occur across the mask.

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Vacuum Mask Holding Fixture of Photolithographic and Mask Generating Equipment

In optical instruments where glass masks are used, the masks must be clamped in a fixed position. Presently, segmented rings are used with each segment containing a vacuum port for holding the mask tight against the face of the clamp. However, because each port is separate, the mask is pulled unevenly, and distortion and variations in flatness occur across the mask.

The drawing shows an improved mask clamp which comprises a continuous ring 10 having spaced therein two concentric grooves 11 and 12 provided with via holes 13 and 14, respectively, through which vacuum may be drawn in to the grooves such that when a mask is placed against the face of the clamp, over the grooves, the mask will be held around its entire perimeter. Distortion and variations in flatness in the mask are thus minimized.

The ring is formed by routing out the grooves 11 and 12 and back filling them with an epoxy. After curing the epoxy, the face 15 of the ring is lapped and polished to the desired degree of flatness while under vacuum. Once lapped and polished, the epoxy is removed from the grooves.

Such a ring can flatten glass masks to a flatness of 1 micrometer over a diameter of 100 millimeters.

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