2:30 PM - 2:45 PM
[14p-1C-6] Characteristic study of PVD-Co(W) single barrier/liner for highly reliable ULSI Cu interconnects
Keywords:PVD-Co(W),barrier layer,liner layer
In semiconductor device, Cu interconnect is buried in low-dielectric-constant (low-k) materials with interlayers [1]. These are double layers of TaN and Ta, serving as barrier against Cu diffusion and liner, rspectively [2]. With continued downscaling of the device dimensions [3], these layers cause some critical reliability issues such as electromigration (EM) failure, short-circuit failure, and resistive-capacitive (RC) signal delay. Introduction of new materials is beneficial to EM failure and short-circuit failure. However, it cannot relieve RC delay. Meanwhile, single barrier/liner has potential to solve all three issues because transition from double layer to single layer can decrease RC delay as well.
In this context, we previously demonstrated the high performances of ALD-Co(W) superior to PVD-Ta/TaN [5]. More recently, we reported that PVD-Co(W) exhibited these three performances superior to both PVD-Ta/TaN and ALD-Co(W) [4]. However, in the evaluation of diffusion barrier property of PVD-Co(W), we found that we underestimated the barrier property. In this research, we evaluated the barrier property correlctly by employing new measurement method using XPS, that is called back-side measurement.
In this context, we previously demonstrated the high performances of ALD-Co(W) superior to PVD-Ta/TaN [5]. More recently, we reported that PVD-Co(W) exhibited these three performances superior to both PVD-Ta/TaN and ALD-Co(W) [4]. However, in the evaluation of diffusion barrier property of PVD-Co(W), we found that we underestimated the barrier property. In this research, we evaluated the barrier property correlctly by employing new measurement method using XPS, that is called back-side measurement.