We are going to buy several plasma cleaners for decontamination of our SEMs and I was wondering if somebody has experience with the two brands at the market, Ibss and Evactron. The ibss downstream asher offers a larger range of pressure and power, but is this really useful and the main argument?
I just would like to hear some experience reports.
By the way: The systems: Tescan Lyra 3, Tescan Mira, FEI Strata 235, Zeiss NVision, Hitachi 4800.
Hi Bjorn, My experience in using oxygen plasma cleaner may not be very rich. However, I used to use 100 W power on a benchtop plasma cleaner (PE-50 XL) Benchtop RF Oxygen Plasma Cleaner, by Plasma Etch Inc., to clean the surface of Si/SiO2 chips from carbon impurities in less than 2 minutes.
Hi Bjorn,
At my last job, at Carl Zeiss, we used Evactrons on all the instruments and also sold it on the microscopes as an option. Recently we tested the IBSS. The operator liked that it was faster in cleaning. An additional advantage is that it runs at better vacuum than the Evactron does, so that there is no need to put chamber pumping into low vac state. Recovery is thus very quick.
PIE Scientific LLC also developed a low pressure remote plasma cleaner for hydrocarbon contamination removal on electron microscopes. SEMI-KLEEN and Tergeo series plasma cleaners can work at a pressure one to two orders of magnitude lower than XEI and IBSS products. It also has many unique features such as: Plasma probe for plasma strength monitor, MFC for gas flow adjustment with pressure sensor feedback control and automatic RF impedance matching. Testing result has shown more than 10 times higher cleaning speed than other plasma cleaners due to superior plasma discharge technology. The SmartSchedule function is especially convenient. Once user set up the recipes and the cleaning schedule, it will automatically take care SEM, FIB and other vacuum systems.
The link to the plasma cleaner is: http://www.piescientific.com/Product_Plasma_Cleaner\
The reason that low pressure operation is better is because:
1) Once reactive radicals are created, they may disappear due to recombination in high pressure. Radical loss in low pressure is much less.
2) If a source can be operated at lower pressure, it means the source is more efficient in creating more radicals. Almost all plasma cleaner can work in pressure range between 100mTorr to 1Torr. But only the highly efficient plasma cleaner can ignite and sustain plasma at pressure below 1mTorr.
3) If the source can be operated at lower pressure, it means source can afford to have larger conductance between the source and the chamber. It helps the radicals to diffuse into the cleaning chamber.
4) Low pressure plasma cleaning is much more efficient and more uniform.
5) Low pressure operation will not overload turbo pump. It improve turbo pump lifetime.
Thank you, Ximan. Your points are exactly what we have experienced with our two new ibss plasma cleaners! :)
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