| AVS 66th International Symposium & Exhibition | |
| Plasma Science and Technology Division | Thursday Sessions |
| Session PS-ThM |
| Session: | Plasma Diagnostics and Sources II |
| Presenter: | Jianping Zhao, Tokyo Electron America, Inc. |
| Authors: | J.P. Zhao, Tokyo Electron America, Inc. P.L.G. Ventzek, Tokyo Electron America, Inc. C. Schlechte, Tokyo Electron America, Inc. M. Burtner, Tokyo Electron America, Inc. D. Li, The University of Texas at Austin J.G. Ekerdt, The University of Texas at Austin T. Iwao, Tokyo Electron Technology Solutions Limited, Japan K. Ishibashi, Tokyo Electron Technology Solutions Limited, Japan |
| Correspondent: | Click to Email |
Atomic precision plasma processes for logic and memory fabrication are in increasing demand due to the shrink of critical dimensions to near physical limits and increase in stack complexity. Meeting dimensionality requirements is not enough. Infinite selectivity and damage-free process with sub-angstrom control are sought to deliver high quality films with productivity worthy yields. Plasma enhanced processes, particularly plasma enhanced atomic layer deposition (ALD) rely on plasma generated radicals for much of their perceived benefit. Furthermore, low energy ions are required to mitigate damage. Large-area plasma processing systems capacitively driven at very high frequencies (VHF, e.g. 100MHz) have attracted much interest for semiconductor device and flat panel display processing. VHF has the advantage of generating plasma with more efficiency as power is coupled more into electrons and less into ions in the sheath. Depending on the film and process, benefits are reduced ion energy and high radical and ion fluxes. It remains the case that it is difficult to relate the role of the combination of species flux and energy exactly to film growth mechanisms or material properties. Ideally, both species flux and film properties would be measured simultaneously (and in real time) as the surface state from ALD is changing continuously. A significant challenge is that it is difficult to measure the absolute density of neutral species in industrially relevant plasmas reliably especially at high pressure. In order to understand the fundamental plasma chemistry property of VHF plasma, we present here the measurement of the neutral species with a line-of-sight threshold ionization mass spectrometry (LS-TIMS) technology in VHF Ar/NH3 plasmas. Ar/NH3 plasma has been widely used in plasma enhanced ALD and CVD. Systematic measurements were performed in a 100 MHz plasma source with a wide RF power, pressure, Ar to NH3 flow ratio range. Plasma chemistry properties of Ar/NH3 plasma are derived after a careful background subtraction and mass-to-charge ratio dependent sensitivity calibration. Density of NH3 and various amine dissociation products are determined as a function of plasma discharge conditions. The LS-TIMS results are also compared to those from other optical based neutral diagnostics.