IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Plasma Science Thursday Sessions
       Session PS-ThP

Paper PS-ThP14
Trench Etch Characteristics of Via-first Dual Damascene Process on 0.15µm SRAM Technology.

Thursday, November 1, 2001, 5:30 pm, Room 134/135

Session: Plasma Etching Poster Session
Presenter: W.-S. Kim, Hynix Semiconductor Inc., South Korea
Authors: W.-S. Kim, Hynix Semiconductor Inc., South Korea
J.-I. Cho, Hynix Semiconductor Inc., South Korea
I.-S. Choi, Hynix Semiconductor Inc., South Korea
J.-J. Lee, Hynix Semiconductor Inc., South Korea
H.-S. Shin, Hynix Semiconductor Inc., South Korea
H.-S. Yang, Hynix Semiconductor Inc., South Korea
Correspondent: Click to Email
Recently, via-first dual damascene process with cost-effectiveness and fabrication complexity reduction has been proposed as an alternative to get over the limitation of conventional interconnection processes. However, it has some problems such as the formation of the fence and the facet around the via hole in the trench etching process. Especially, the fence can cause bad via hole filling and the incomplete removal of resist residues. In this study, we investigated the effect of CH2F2 and CO addition into C4F8 plasma on fence formation, and also relationship between organic ARC fill thickness and fence formation. Physical features were analyzed with SEM and TEM. And electrical characteristics were examined with continuity/bridge patterns. For the surface analysis, the etched oxide films with C4F8/CH2F2 and C4F8/CO, respectively, were characterized with XPS. In the trench etching with C4F8/CH2F2 plasma, the fence height was increased with organic ARC thickness. Since the organic ARC on the sidewall of the via hole played a role as the etch barrier during trench etching, fence-shaped oxide residue was occurred around the via hole. Moreover, in this study, we could also observe the fence profile in a condition of no organic ARC with C4F8/CH2F2 plasma because the polymer deposited at the top edge of the via hole prevented oxide etching around the via hole whereas fence free with C4F8/CO plasma. The XPS surface analysis data clearly showed that C4F8/CH2F2 plasma had higher intensity for C-C bonds and C-H bonds in comparison with C4F8/CO plasma. Therefore, in order to obtain fence-free trench profiles, optimization of ARC thickness and also use of low polymerizing plasma were simultaneously needed. Consequently, for 0.15µm SRAM technology, the fence-free trench etching was achieved with low polymerizing C4F8/CO plasma and optimum ARC fill thickness which was slightly lower than the etch stopper in the via hole.