1. Plasma technology : towards industrial feasibility
Antoine Merlo

2. Basics of plasma technology Applications of plasma Surface coating
Presentation summary
Introduction
Basics of plasma technology
Applications of plasma
Surface coating
Traditional methods
Plasma-assisted methods
Conclusions

3. Introduction
Ressources become more scarce and emissions cause an unprecedented crisis for humanity
Need for more efficient and « greener » industrial processes
Which processes?
How to evaluate them?
Transition: C’est bien beau, mais pas si facile, sinon ce serait déjà fait…
Challenges importants:
Limiter CO2
Répondre à la demande énergétique globale, croissante
Sécurité d’approvisionnement dans l’espace et dans le temps
Au final: Garder un coût raisonnable pour l’énergie

4. PULSATEC Interreg project
Metal oxides films synthesis using HiPIMS (Hi-Powered Impulse Magnetron Sputtering)
Evaluate the potential of this technology and scale it up
ULiège : developing a new methodology capable of assessing both feasibility and environmental impacts

5. Basics of plasma technology Applications of plasma Surface coating
Presentation summary
Introduction
Basics of plasma technology
Applications of plasma
Surface coating
Traditional methods
Plasma-assisted methods
Conclusions

6. What is a (cold) plasma? Ionized gas
A non-thermal plasma is NOT in equilibrium, meaning different species (neutrals, ions, electrons) have different speed (=Temperatures)
Typical temperature ranges :
Te = K
Ti = 500 K
Tn = 293 K
 Electrons as excitation carriers!

7. Generating a plasma Usually, through an electric potential
An electron from the cathode causes subsequent ionizations Electron cascade!
With potenial high enough, the plasma maintains itself
Excited species in the plasma emit light

8. Plasma-matter interactions
Many ≠types of interactions depending on :
Gaz composition, pressure, anode and cathode composition and distance, topology, electron and ion temperature, voltage, magnetic field… Flexible technology but can be unreliable

9. Basics of plasma technology Applications of plasma Surface coating
Presentation summary
Introduction
Basics of plasma technology
Applications of plasma
Surface coating
Traditional methods
Plasma-assisted methods
Conclusions

10. Plasma applications
 Lots of different applications… but lack of a large-scale integration !

11. Example : Etching Critical step in micro-electronics
Remove layers of a wafer
Parts protected by a masking material
Process-induced topology on micro-chips

12. Wet etching
In wet etching, the wafer is immersed in etchant (example : Si-on-SiO2 in BHF)
Large amounts of toxic waste
Very serious environmental problem for the industry until early 80’s
Up to 100 million $ cleanup for a site

13. Plasma (Dry) etching
Wafer placed in a low-pressure environment (<100Pa)
Reactive gas flow
Plasma generation with a radio-frequency generator
Plasma species-wafer interaction and matter removal
 No solvent !

14. Example : wool treatment
Treatment to make wool printable
Conventional : chlorination
Unsafe, large amounts of toxic wastes, inefficient process…
Low pressure plasma treatment
For 120 tons of wool : saving of m3 of water, 685 MWh,, 11 tons of sulfuric acid, 16 tons of bisulfate and 44 tons of sodium hypochloride

15. Example : removal of VOC’s
Traditional technologies : regenerative sorption or biofilter
Plasma technology : dielectric barrier discharge
Plasma treatment causes the less impact in all categories

16. Basics of plasma technology Applications of plasma Surface coating
Presentation summary
Introduction
Basics of plasma technology
Applications of plasma
Surface coating
Traditional methods
Plasma-assisted methods
Conclusions

17. Traditional coating techniques
Plating
Dip coating
Spray coating
Chemical vapor deposition
Roll-to-roll processing
Conversion coating
Sol-Gel …
 These methods usually involve the use of solvents, or the need to go at really high temperatures!

18. Example : α - aluminium oxide CVD
4 AlCl3 + 3 O2 + 6H2  2 Al2O3 + 12HCl
Need to go to 1000°C !

19. Basics of plasma technology Applications of plasma Surface coating
Presentation summary
Introduction
Basics of plasma technology
Applications of plasma
Surface coating
Traditional methods
Plasma-assisted methods
Conclusions

20. Plasma enhanced CVD Using plasma to facilitate chemical reactions
For alumina: 1000°C  °C
Less restricting substrate choice V

21. Magnetron sputtering Plasma generation with a DC generator
Magnets near the cathode (target) to increase ionization rate
Target sputtering
Condensation on substrate
 No solvent!

22. Complex surface treatments
Hard to coat complex surfaces
Width film growth
Plasma allows uniform coating
Polarized substrate
Ions follow the plasma “sheath”

23. Pros and cons of plasma technology
Advantages -No solvent -Ease of operation -Low(er) temperatures -Efficiency -No waste -High development potential
Disavantages
High investment costs
Difficulties to scale-up
High maintenance costs
Need for a specifically trained staff
Limited application per equipment
High electricity demand
Limited speed and reactivity

24. Basics of plasma technology Applications of plasma Surface coating
Presentation summary
Introduction
Basics of plasma technology
Applications of plasma
Surface coating
Traditional methods
Plasma-assisted methods
Conclusions

25. Perspectives and outlook
Plasma is a promising technology
Needs to be thoroughly studied to show it’s potential to the industry
PULSATEC and the methodology developed during the project could be the missing link

26. Methodology development
Need to agree on a base case process and functional unit
Process modelling to assess preliminary material inputs, waste, energy consumption
Economic evaluation of the process and alternatives
LCA
Results presentation and discussion

27. Methodology development
Need to agree on a base case process and functional unit
Process modelling to assess preliminary material inputs, waste, energy consumption
Economic evaluation of the process and alternatives
LCA
Results presentation and discussion

28. Thank you for your attention ! Any questions?

29. References
Rakowski, Plasma modification of wool under industrial conditions
Stephanos Konstantinidis’ course, UMONS
Edgar B. Gutoff and Edward D. Cohen, Water- and solvent-based technology
Georg Erkens, Plasma assisted surface coating
G. Bonizzoni, E. Vassallo, Plasma physics and technology; industrial applications
Inga Stasiulaitiene et al., Comparative life cycle assessment of plasma-based and traditional exhaust gas treatment technologies
J. Reece Roth, Industrial Plasma Engineering volume 1&2
Donald M. Mattox, The foundations of vacuum coating
Industrial Plasma Technology : Applications from Environmental to energy technologies

30. Figures Lightning : pixabay.com
Plasma d’argon : Plasma Surface Interactions Research at UW-Madison
Plasma processing : The National Academies Press
VLSI : ICT Academy
Toxic maps :
Plasma etching : RPI SCOREC - Plasma Etch Modeling
Aluminz : Optical microstructure and SEM image of alumina coating.