| AVS 63rd International Symposium & Exhibition | |
| Plasma Science and Technology | Monday Sessions |
| Session PS+AS+SS-MoA |
| Session: | Plasma Surface Interactions |
| Presenter: | Martin Blake, University of York, UK |
| Authors: | M. Blake, University of York, UK D. O'Connell, University of York, UK A.R. Gibson, LPP, CNRS, Ecole Polytechnique, Université Paris-Saclay, France T. Gans, University of York, UK |
| Correspondent: | Click to Email |
wafer processing is difficult to characterise. However, understanding the plasma dynamics
at this interface is key for further optimisation of industrial plasma processes. Of particular
relevance are the densities of reactive species, such as atomic oxygen, in this region. In this
work a methodology has been developed based on newly augmented fast optical
techniques which can probe reactive species densities in the wafer region without the need
for expensive laser equipment. This technique, known as energy resolved actinometry
(ERA)[1], utilises phase resolved optical emission spectroscopy (PROES) measurements of the
direct and dissociative electron-impact excitation dynamics of three distinct emission lines,
750.4 nm (argon, added in small concentrations as a tracer gas) and 777.4 nm, 844.6 nm
(atomic oxygen). Through the ratio of the excitation functions and their energy dependence
we determine both the atomic oxygen density and the mean electron energy above the
electrode surface.
In this work ERA has been applied to measure atomic oxygen densities and local mean
electron energies in a low pressure (1 – 100 Pa) oxygen plasma produced in a GEC reference
cell system [2], operated at 13.56 MHz in both capacitive and inductive modes at power
inputs ranging from 50 – 500 W. Additional characterisation of the plasma-surface interface
is carried out through the use of a retarding field energy analyser (RFEA) to measure the ion
energy distribution at the surface. The combination of both approaches allows for
information on the neutral and ion dynamics in the surface region, both of which are known
to be important for process outcomes.
A two-dimensional hybrid plasma simulation code is used to simulate the same conditions in
order to improve understanding of the experimental results.
Acknowledgements:
This work has been supported through the UK Engineering and Physical Sciences Research
Council (EPSRC) manufacturing grant EP/K018388/1 and the authors would also like to thank
Intel Ireland, Ltd. for financial support.
References:
[1] Greb, A., Niemi, K., O'Connell, D., Gans, T. 2014; Energy resolved actinometry for
simultaneous measurement of atomic oxygen densities and local mean electron energies in
radio-frequency driven plasmas, Appl. Phys. Lett. 105 234105
[2] P. J. Hargis Jr et al (1994); The Gaseous Electronics Conference radio‐frequency reference
cell: A defined parallel‐plate radio‐frequency system for experimental and theoretical
studies of plasma‐processing discharges, Rev. Sci. Instrum. 65, 140