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Browse Prior Art Database

Elimination of Operator Bias in a Visual Alignment System

IP.com Disclosure Number: IPCOM000083699D
Original Publication Date: 1975-Jul-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Karlson, K: AUTHOR

Abstract

In the fine alignment of objects such as exposure masks with resist coated semiconductor wafers having device patterns formed thereon, misalignments can occur due to operator bias. This bias is illustrated in Figs. 1 and 2 and is a result of how the operator responds to the series of images which are presented.

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Elimination of Operator Bias in a Visual Alignment System

In the fine alignment of objects such as exposure masks with resist coated semiconductor wafers having device patterns formed thereon, misalignments can occur due to operator bias. This bias is illustrated in Figs. 1 and 2 and is a result of how the operator responds to the series of images which are presented.

The effects of the bias are removed by optical processing as illustrated in Fig. 3, in which two alignment channels 1 and 2 present images to the operator of mask marks 3 and 4 and wafer marks 5 and 6 through relay optics 7 and 8. The image of channel 2 is rotated 180 degrees. by the use of a 1X lens or prism 9. The operator is caused to compensate for any systematic bias during the aligning of the images of the mask and wafer marks 3,4 and 5,6, respectively, by attempting to align to a symmetry condition.

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