Overlay accuracy: a metal layer study

Habermas, Andrew; Ferguson, B. A.; Seligson, Joel L.; Kassel, Elyakim; Izikson, Pavel

doi:10.1117/12.473466

Cited by 1 publication

(1 citation statement)

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“…Various overlay mark designs have been studied to protect from the effects of AlCu PVD induced overlay shift [1][2], but it can't completely remove the PVD process induced error and with the controversy over the trend of measurement targets. APC (Advanced Process Control) is another method to manage the AlCu-PVD induced overlay shift, and model-based APC is usually emphasized by well characterizing the influence factors [3].…”

Section: Introductionmentioning

confidence: 99%

The novel advanced process control to eliminate AlCu-PVD induced overlay shift

Huang

Yang

et al. 2007

SPIE Proceedings

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AlCu PVD (Physical Vapor Deposition) induced overlay shift has been a critical concern for non-damascene metallization process to tackle with the ever decreasing overlay tolerances. In this study, a new approach was demonstrated to effectively eliminate the AlCu PVD induced overlay shift. With measuring the metal-to-contact registration before the metal deposition and feeding forward the values for metal-to-contact overlay compensation at the metal photo process, the metal-induced shift can be optimally managed. Besides, an investigation was also carried out to figure out the suitable measurement target with least sensitive to process parameter variations at after contact etch, after contact W CMP and after metal etch. As a consequence, the conventional wide-trench overlay target has been identified to be the more susceptible to the process variation and easily results in measurement reading error. Compared to the conventional wide-trench target, a 0.2um width narrow trench target performed the better mark integrity for our feedforward compensation approach. Finally, the feed-forward compensation in combination with narrow width overlay mark has demonstrated its effectiveness on managing the AlCu-PVD induced overlay shift.

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Section: Introductionmentioning

confidence: 99%