| AVS 64th International Symposium & Exhibition | |
| Plasma Science and Technology Division | Thursday Sessions |
| Session PS-ThM |
| Session: | Plasma Sources |
| Presenter: | Shuo Huang, University of Michigan |
| Authors: | S. Huang, University of Michigan V. Volynets, Samsung Electronics Co. Ltd., Republic of Korea S. Lee, Samsung Electronics Co. Ltd., Republic of Korea S. Nam, Samsung Electronics Co. Ltd., Republic of Korea S. Lu, Samsung Electronics Co. Ltd., Republic of Korea M.J. Kushner, University of Michigan |
| Correspondent: | Click to Email |
Remote plasma sources (RPS) are being used to achieve isotropic etching with high selectivity by avoiding charging, energetic ion bombardment and UV/VUV radiation using long distance and discriminating barriers between the RPS and the substrate. By using multiple plasma sources or multiple gas inlets at different locations, the reaction pathway can be optimized for producing desirable process radicals. NF3 and HBr are frequently used sources of F and Br atoms, the main etchants of silicon-containing materials, by electron impact dissociative attachment and excitation. NFx (x = 1 – 3) and HBr can exothermically react with other neutral species to produce F, Br and OH radicals, which also enables customizing the reaction pathway by flowing gases downstream of the RPS.
In this paper, we report on results from a computational investigation of an inductively coupled RPS having multiple gas inlets with the goal of determining strategies for selectively producing reactive fluxes. The investigation was performed using the plug flow mode of 0-dimensional model, Global_Kin and in 2-dimensions using the Hybrid Plasma Equipment Model (HPEM). With NF3/N2/O2 mixtures flowed through the RPS from an upstream inlet, the dominant radicals flowing downstream are F and O formed through dissociative excitation and attachment of NF3 and O2. NO molecules were formed through endothermic reactions among N2, N, O2 and O species. With HBr injected downstream of the plasma source, mixing with the plasma produced radicals enable another level of selectivity. Due to lack of electrons and low gas temperature (~ 350 K) downstream, HBr reacts with F and O through exothermic reactions (HBr + F > HF + Br, HBr + O > OH + Br and HBr + OH > H2O + Br) and the dominant downstream radicals transition from F and O to Br and HF. Vibrationally excited HF(v), a highly polar molecule, may be formed through reactions having a larger exothermicity than the vibrational quanta, and so may produce a significant flux of activation energy to the wafer
Work was supported by Samsung Electronics, DOE Office of Fusion Energy Science and the National Science Foundation.