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Stereoscopic Mask To Wafer Registration

IP.com Disclosure Number: IPCOM000080292D
Original Publication Date: 1973-Nov-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Wojcik, WJ: AUTHOR

Abstract

Mask-to-wafer registration is accomplished using three-dimensional alignment targets, formed by making the mask and wafer patterns in stereo pairs.

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Stereoscopic Mask To Wafer Registration

Mask-to-wafer registration is accomplished using three-dimensional alignment targets, formed by making the mask and wafer patterns in stereo pairs.

In Fig. 1, mask 1 contains a pair of spaced, two-dimensional alignment patterns 2 and 3 which when viewed in stereo, for example, by the use of a stereo microscope or three-dimensional television, form a cone 4. Wafer 5 contains a pair of corresponding alignment patterns 6 and 7, which when viewed in stereo form a toroid 8. Alignment is accomplished by the operator changing the position of mask 1 and wafer 5 until cone 4 is aligned within toroid 8. Other pattern configurations can be used.

Various configurations of the stereo pairs are useful. As shown in Fig. 1, the mask left and mask right are fused in stereo and aligned to a wafer left and wafer right stereo pair. Another configuration is mask left and wafer right stereo pair, aligned to wafer left and mask right stereo pair. Another is to have mask left and wafer left collectively form one member of a stereo pair, and mask right and wafer right form the second member of the stereo pair. Registration occurs when a symmetrical three-dimensional shape is formed, as shown in Fig. 2.

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