Chemistry studies of SF6/CF4, SF6/O-2 and CF4/O-2 gas phase during hollow cathode reactive ion etching plasma

Autor(es)

Tezani, L. L. ^[1] ; Pessoa, R. S. ^{[1, 2]} ; Maciel, H. S. ^{[1, 2]} ; Petraconi, G. ^[1]

Afiliação do(s) autor(es)

^[1] Inst Tecnol Aeronaut, Dept Fis, Lab Plasmas & Proc, BR-12228900 Sao Jose Dos Campos, SP - Brazil

^[2] Univ Vale Paraiba, IP&D, Lab Nanotecnol & Proc Plasma, BR-12244000 Sao Jose Dos Campos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: VACUUM; v. 106, p. 64-68, AUG 2014.
• Citações Web of Science: 9

Resumo

In this work, mass spectrometry and optical emission spectroscopy techniques were used to monitor the molecular and atomic neutral species during SF6/CF4, SF6/O-2 and CF4/O-2 plasmas generated in a radiofrequency Hollow Cathode Reactive Ion Etching (HCRIE) reactor keeping constant the following operational conditions: total gas flow rate, gas pressure, and discharge power. The investigations were aimed to understand the chemistry behavior of plasmas generated with SF6 and CF4 mixtures or mixed separately with O-2. The neutral mass spectrometry analysis showed a high concentration of gas species namely SFg{''} (Parent specie = SF6), SF3+ (SF4), CF3+ (CF4) and HF+ (HF) in SF6/CF4 plasmas, SF5+, SF3+, O-2(+) (O-2), F+ (F) and HF+ in SF6/O-2 plasmas and CF3+, O-2(+), CO2+ (CO2) and HF+ in CF4/O-2 plasmas. The presence of other species was observed in quantities lower than 1% of total gas pressure. It was used the actinometry method to monitor the atomic fluorine (F) concentration during discharge operation. Higher density of F was observed in all experiments, varying from (2.8-9.5) x 10(19) m(-3) in SF6/CF4 plasmas, (0.2-1.7) x 10(20) m(-3) in SF6/O-2 plasmas and (0.06-1.17) x 1020 m(-3) in CF4/02 plasmas. The addition of CF4 in SF6 plasma reduces monotonically the F concentration when compared with the SF6/O-2 and CF4/O-2 plasmas that promotes an increase of F for low O-2 concentrations. This effect shows the importance of oxygen species in the dissociative processes of the fluorine-based plasma also for this type of plasma reactor. Moreover, it is highlighted the higher concentrations of HF in gas phase that promotes reactions paths that decrease the F species in gas/plasma phase. (C) 2014 Elsevier Ltd. All rights reserved. (AU)

• Processo FAPESP: 11/50773-0 - Núcleo de excelência em física e aplicações de plasmas
• Beneficiário: Ricardo Magnus Osório Galvão
• Modalidade de apoio: Auxílio à Pesquisa - Temático