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Semiconductor Wafer Mask Alignment Fixture

IP.com Disclosure Number: IPCOM000093133D
Original Publication Date: 1967-May-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 53K

Publishing Venue

IBM

Related People

Keller, CJ: AUTHOR

Abstract

This fixture precisely aligns a semiconductor wafer with a mask prior to photoexposure.

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Semiconductor Wafer Mask Alignment Fixture

This fixture precisely aligns a semiconductor wafer with a mask prior to photoexposure.

In drawing A, a wafer is held by vacuum to a pedestal which is connected to a resilient diaphragm. Upon application of air pressure to the lower chamber, the diaphragm is stretched lifting pedestal and wafer toward the glass photomask.

In order to obtain improved alignment and image reproduction, a liquid is introduced in the upper chamber as in drawing B. Now when the wafer and supporting pedestal are raised by the deflection of the diaphragm under air pressure, a thin layer or film of residual liquid separates the wafer from the plate. The hydrostatic forces of this residual liquid film tend to equalize on the surface of the wafer thus resulting in a parallel wafer-mask separation or alignment. This film also permits better resolution of the image on the wafer and, in addition, provides a cushioning effect to prevent wafer damage.

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