Dresden 2009 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 21: Devices
HL 21.6: Vortrag
Dienstag, 24. März 2009, 15:30–15:45, BEY 81
E-Beam alignment markers for high overlay accuracy — •Jürgen Moers1,2, Julian Gerharz1,2, Stefan Trellenkamp1,2, and Detlev Grützmacher1,2 — 1Institute for Bio- and Nanosystems, Research Center Jülich, D-52425 Jülich, Gemany — 2JARA Jülich Aachen Research Alliance
In recent years the dimensions of semiconductor devices have been decreased to the deep sub-100nm range with an overlay requirement of 10nm and below. In research e-beam lithography is used to meet those requirements. The key issue for achieving the overly accuracy is the quality of the alignment markers. For this purpose square holes etched into the silicon substrate are used.
The e-beam tool triggers on the contrast transition between the marker and the surrounding area. The position of this transition is the marker edge. Its position is determined by averaging over several measurements of the contrast transition. The marker position is given by the center of the positions of the four marker edges.
While with new markers an intrinsic overlay of 10nm can be achieved, the quality of the markers deteriorate during processing. In this work the effect of layer deposition, epitaxial growth and etching steps on the overlay accuracy is investigated. It can be shown, that the standard deviation of the determined position of the marker edge increases, while the determined center of the marker is till found in good agreement with its designed position. Hence an overlay of 10 nm can still be achieved.