In:
Japanese Journal of Applied Physics, IOP Publishing, Vol. 51, No. 4S ( 2012-04-01), p. 04DB06-
Abstract:
To understand the electromigration degradation in Cu interconnects that utilize the TiO x self-formed barrier (SFB) probably due to Cu oxidation at the Cu/barrier interface, Cu films deposited on TiO x SFB and conventional Ta/TaN barriers were annealed in atmospheres of various oxygen concentrations. The Ta layer was preferentially oxidized to give Ta 2 O 5 , and contained a large amount of oxygen. The barrier layer, which consisted of Ta 2 O 5 and Ta(O), could not suppress Cu diffusion. The TaN layer seemed to remain even after annealing at 400 °C in 10 ppm O 2 , and still suppressed Cu diffusion. This suggests that the TaN layer plays a key role to suppress barrier failure induced by oxygen originating from pores in dielectrics. On the other hand, the oxygen-induced barrier failure was observed in the TiO x SFB after annealing at 500 °C in 5 ppm O 2 and more. Oxygen facilitated Cu 2 O formation above the TiO x SFB, and the Cu 2 O formation caused discontinuity of the TiO x SFB, leading to the barrier failure. The less oxidized Ti 2 O 3 and TiO in the TiO x SFB were not further oxidized to TiO 2 by oxygen in atmospheres, and thus they would not be oxygen absorbers suppressing the Cu 2 O formation above the barrier. Thus, for suppressing the Cu 2 O formation, it is essential to increase oxygen barrier ability of the TiO x SFB (probably increasing Ti concentration of the TiO x SFB).
Type of Medium:
Online Resource
ISSN:
0021-4922
,
1347-4065
DOI:
10.1143/JJAP.51.04DB06
Language:
Unknown
Publisher:
IOP Publishing
Publication Date:
2012
detail.hit.zdb_id:
218223-3
detail.hit.zdb_id:
797294-5
detail.hit.zdb_id:
2006801-3
detail.hit.zdb_id:
797295-7
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