Superior etch performance of Ar/N₂/F₂ for PECVD chamber clean

Abstract

F 2 gas mixtures offer ideal properties to be employed as chamber cleaning gas: low dissociation energy and high reactivity, which leads to superior efficiency and ease of abatement. In this work, a new F 2 gas mixture was used with a combination ratio of 10% Ar, 20% F 2 and 70% N 2 in order to obtain a maximum of 20% fluorine in inert gases. This novel Ar/N 2 /F 2 gas mixture has been evaluated as a candidate to replace conventional cleaning gases, like NF 3 , C 2 F 6 and CF 4 in an industrial AMAT P5000 CVD chamber tool. Standard equipment has been used, showing complete compatibility with the new gas. The tested Ar/N 2 /F 2 mixture shows improvements in both parameters, cleaning at a faster rate (up to more 27%), even requiring a lower amount of gas (minus 96% versus NF 3 ). The higher etching rate and the lower gas consumption assure a sensible CoO (Cost of Ownership) advantage to any potential user. The superior etch rate performance of the Ar/N 2 /F 2 gas mixture was combined with excellent etch non uniformities values, of ±3% (1sigma) on SiO 2 and of ±8% (1sigma) on Si 3 N 4 , respectively. Also amorphous Silicon (a-Si) was etched completely and uniformly. The particle performance data showing in average just 14 particle adders (0.25µm), indicating that no significant particle contamination was induced by the process and Ar/N 2 /F 2 can be used as a highly clean and efficient etching gas as well as an ideal drop-in replacement for the conventional cleaning gases.

Environmental-Friendly Fluorine Mixture for CVD Cleaning Processes to Replace C2F6, CF4 and NF3

“…3 ad show the SiO2 etching rate depending on parameter variation of chamber pressure, total amount of gas flow, RF-power and spacing. Etching uniformity of all etched SiO2-films was well below ±5% max/min of the removed film thickness, in good agreement to previously reported data (9). The Ar-gas in the Solvaclean TM P mixture is needed for a safe and stable plasma ignition; at the same time the SiO2 etch non-uniformity is kept below ±8%, which otherwise would rise up to values of high as ±40% (9).…”

Investigation of the Abstraction and Dissociation Mechanism in the Nitrogen Trifluoride Channels: Combined Post-Hartree–Fock and Transition State Theory Approaches

“…The decomposition of nitrogen trifluoride (NF 3 ) is currently a topic of major concern for environmentalists, scientists, and members of civil society worried about climate change issues. Besides the aforementioned use in the BN growth process, NF 3 is regularly applied in the cleaning of plasma-enhanced chemical vapor deposition chambers, which are widely used in the production of liquid-crystal displays, thin-film solar cells, and several other electronic devices. Although NF 3 is usually said to be a less harmful substitute of sulfur hexafluoride or perfluorocarbons for these tasks, it is still a powerful greenhouse gas.…”