| AVS 55th International Symposium & Exhibition | |
| Plasma Science and Technology | Monday Sessions |
| Session PS-MoM |
| Session: | Plasma Etching for Advanced Interconnects |
| Presenter: | A. Suzuki, Osaka University, Japan |
| Authors: | A. Suzuki, Osaka University, Japan M. Isobe, Osaka University, Japan S. Kobayashi, Sony Corp., Japan M. Fukasawa, Sony Corp., Japan T. Tatsumi, Sony Corp., Japan S. Hamaguchi, Osaka University, Japan |
| Correspondent: | Click to Email |
Highly accurate control of plasma etching processes of low-dielectric-constant (i.e., low-k) insulating materials for interconnects of semiconductor chips has become increasingly important as the dimensions of transistors and interconnect wires in planer technologies diminish. In this work, in an attempt to clarify etching characteristics of SiOCH films, which are widely used as low-k materials for interconnect insulator, we have studied interaction of SiOCH films with impinging fluorocarbon beams, using molecular dynamics (MD) simulations. The simulation code and interatomic potential functions for Si, O, C, F, and H atoms are the same as those used in Ref. 1. In the simulation study presented here, we have first created model SiOCH films by depositing various monomers consisting of Si, O, C, and H atoms with low incident energies. In the numerical process of film deposition, film properties such as density, atomic composition, and porosity vary greatly, depending on the conditions used in the process. The numerical deposition processes used here were not intended to simulate actual SiOCH film formation processes but simply used to prepare model substrates that are similar to porous SiOCH films used in actual semiconductor chip manufacturing. In etching simulations, the injection energies examined in this work have been 100, 200, and 300eV. Unlike SiO2, which has the sputtering yield threshold energy at around 250eV for CF3 ion injections, numerically obtained sputtering yields for SiOCH films are significantly higher. For example, the numerically obtained Si sputtering yield (defined here as the number of Si atoms removed from the substrate surface per injection) by CF3 injections at 100eV is about 0.48. The sputtering yields for SiOCH films have been also confirmed to be an increasing function of the incident energy. We have also examined the sputtering yield dependence on (1) the film density and also (2) incident beam species varying from F to CFx with x = 1~4. For the latter, at 100eV, the dependence on the value x is found to be rather weak.
1T. Takizawa, et al., AVS 54th International Symposium & Exhibition, October 14-19, 2007, PS1-MoM2.