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Array Based Test Structure for Optical-Electrical Overlay Calibration



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


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


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


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], (Accessed April 13, 2024)
Created March 21, 2007, Updated October 12, 2021