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Stitching E Beam Patterns in the Absence of Central Registration Marks

IP.com Disclosure Number: IPCOM000068682D
Original Publication Date: 1978-Feb-01
Included in the Prior Art Database: 2005-Feb-20

Publishing Venue

IBM

Related People

Authors:
Michail, MS Moore, RD Ryan, PM [+details]

Abstract

Large chips, i.e., those with greater than a 5 mm dimension, for example must be exposed by 'stitching together' several small electron (E)-beam fields. Accurate overlay and acceptable image quality along the stitched borders require registration. Previously this has required one or more registration marks within the active area of the chip. The presence of these 'central' registration marks is a severe constraint on chip design and makes it difficult to apply E-beam exposure techniques to large