Array Based Test Structure for Optical-Electrical Overlay Calibration

Published

March 22, 2007

Author(s)

Byron J. Shulver, Richard A. Allen, Anthony Walton, Michael W. Cresswell, J. T. Stevenson, S Smith, Andrew S. Bunting, P. Durgapal, Alan Gundlach, Les I. Haworth, Alan W. Ross, Anthony J. Snell

Abstract

The novel overlay test structure reported in this paper was purposely designed to serve as an application specific reference material. It features standard frame-in-frame optical overlay targets which are embedded in electrical test structures and fabricated by the same process as the parts being manufactured. The electrical overlay of the targets is established by electrical testing of the test structures in which they are embedded. Their corresponding optical overlay is then measured by the same tool that is being used in the manufacturing process being controlled. Thus it is straightforward to construct an application-specific calibration curve relating optical overlay measurements to the functionally-relevant electrical overlay which can not be routinely measured during the manufacturing operation. It allows optical overlay readings that are normally extracted from product testing according to existing sampling protocols to be converted immediately to electrical overlay for processevaluation and control purposes.

Proceedings Title

IEEE ICMTS International Conference on Microelectronic Test Structures

Conference Dates

March 19-22, 2007

Conference Location

Tokyo, 1, JA

Pub Type

Conferences

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Keywords

box-in-box, electrical test structure metrology, overlay, semiconductor process control

Citation

Shulver, B. , Allen, R. , Walton, A. , Cresswell, M. , Stevenson, J. , Smith, S. , Bunting, A. , Durgapal, P. , Gundlach, A. , Haworth, L. , Ross, A. and Snell, A. (2007), Array Based Test Structure for Optical-Electrical Overlay Calibration, IEEE ICMTS International Conference on Microelectronic Test Structures, Tokyo, 1, JA, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=32594 (Accessed October 17, 2025)