Volcano reactions in oxide vias between tungsten CVD and bias sputtered TiN/Ti films

Tungsten chemical vapor deposition (CVD) remains the preferred method to make vertical metal interconnects in oxide vias on silicon integrated circuits. Vias are lined with thin titanium films, protected by a TiN diffusion barrier deposited on top followed by tungsten CVD. 'Volcano' reacti...

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Veröffentlicht in:Journal of the Electrochemical Society 2000-05, Vol.147 (5), p.1982-1987
Hauptverfasser: HERNER, S. B, TANAKA, Y, ZHANG, H, GHANAYEM, S. G
Format: Artikel
Sprache:eng
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Zusammenfassung:Tungsten chemical vapor deposition (CVD) remains the preferred method to make vertical metal interconnects in oxide vias on silicon integrated circuits. Vias are lined with thin titanium films, protected by a TiN diffusion barrier deposited on top followed by tungsten CVD. 'Volcano' reactions, which result in rupture of the TiN barrier and electrical failure of the interconnect, remains an integration difficulty of great interest. Four parameters are found to strongly influence volcano reactions: the mixture of WF sub 6 and SiH sub 4 gases during tungsten nucleation film deposition, TiN barrier thickness, use of plasma preclean before Ti/TiN deposition, and a rapid thermal anneal after Ti/TiN deposition and before tungsten CVD. We describe process methods to avoid volcano reactions with thin TiN barrier films, maintaining low resistivity in the via. The influence of varying these parameters on overall step coverage is also discussed.
ISSN:0013-4651
1945-7111
DOI:10.1149/1.1393471