FEI FIBs make use of Gas Injection Systems (GIS) for metal deposition using the ion beam. This technique uses organo-metallic gases that react with the ion beam to deposit metals on the scanned areas. Organic gases are released as a by product and these go on to contaminate the chamber and specimen surface. Using Evactron Anti-Contaminator removes these deposits and restores high resolution imaging capability in the SEM mode. This gas been demonstrated at several sites.

FEI 235 Dual Beam FIB - AMD, Sunnyvale, California
AMD uses the dual beam FIB to study structure of sub 170 nm copper vias for process control. The use of GIS platinum deposition guns had released organics into the chambers creating foggy images of these small structures. The installation of an Evactron System allows for faster and clearer imaging of the these very small structures. The contamination fog in the studied area is now gone.

Jeol 6400: Kimberly Clark, Neenah WI.
Jeol 6400 was used for imaging wood and paper products. Microscope had also a oily window problem on EDS Detector. Installing Evactron system cleaned up chamber and periodic use prevents buildup of contamination on wall of chamber. EDS oil build-up stopped

JEOL 6400 and 845. IBM Canada, Bromont, Canada
This semiconductor research lab had persistent problems with contamination until the Evactron Sem-Clean system was installed on these two SEMs.

Hitachi S-4500 IBM San Jose, CA

User images magnetic disk coated with a lubricant. Over time lubricant had heavily contaminated the chamber and images of defects had to be obtained on first pass. After cleaning with Evactron A-C contamination problems disappeared. Paper presented at 1999 M&M conference: The Removal of Contamination Deposits From Defects in Thin Film Magnetic Disks By Oxidative Cleaning Inside The SEM, by Sharon Meyers and Ronald Vane. User now cleans chamber with Evactron every 2 to 4 weeks as needed. System also has EDS system and oily window problems have stopped.

Hitachi S-4500 Applied Materials
Evactron system installed on this system when new to prevent contamination. Operated daily by automatic system for 2 minutes. No contamination problems have ever been noted on this SEM.

User has older SEM-CLEAN N2 purge system on their other SEMs. The new Evactron system makes this unit available for use over 23 hours per day versus on 17 hours per day for older system on the other SEMs.

Hitachi S-4700: NIST Gaithersburg MD
NIST borrowed and later purchased Evactron for controlling contamination in Hitachi S-4700. Their research on contamination control resulted in the paper "Active Monitoring and Control of Electron Beam Induced Contamination" Proc. SPIE Vol. 4344 (2001), 835. By András E. Vladár, Michael T. Postek and Ronald Vane. This paper found that the Evactron device was "effective in cleaning the vacuum of the specimen chamber of laboratory, and production metrology SEMs."

Hitachi S-4700 Oak Ridge National Laboratory, High Temperature Materials Lab.
Roughing pump oil backstreaming through sample exchange chamber was causing dirty specimens and chamber contamination that could not be controlled with LN cold finger. Contamination is controlled by use of both the Nitrogen purge feature and the plasma cleaning feature of the automatic Evactron SEM-CLEAN system.

Hitachi S-4700: University of Illinois, Champaign-Urbana Ill.
Three year old S-4700 had constant contamination problems since installed. User had added turbomolecular pump and heated micromaze foreline trap per Hitachi sales organization recommendations. They made little change because chamber was dirty and dirty samples continued to be introduced into the system. LN traps, top and bottom, had been keep in service constantly but failed to stop contamination problems.

User purchased Evactron SEM-CLEAN system with automation package. The automation package operates the Hitachi evacuation system with the proper delays to allow for the cooling of the heated aperture before venting chamber to Evactron operating pressure. The automatic package then operates the plasma clean cycle for the recommended 2 minutes. The system is ready to image specimen again 40 minutes after Evactron cleaning cycle.

Multiple cleaning cycles were done during installation for testing and demonstration purposes over two days. After installation was completed, an old gold on carbon specimen was imaged. This specimen had shown chronic contamination problems in the past with black squares forming quickly. After Evactron cleaning of the chamber, the specimen showed no black square formation even with dry LN traps during this first test. Cleanliness is maintained by operating Evactron SEM-CLEAN on a weekly maintenance cycle.

Leo 1550 and JEOL 6400: University of California Berkeley, Microfabrication Laboratory
The student used SEMs were heavily contaminated by student use on dirty specimens. SEM maintenance technician does not have time to watch over every user. LEO 1550 SEM has valveless turbopump pumping system and no load lock. After loading specimen turbo pump spins up during pump down causing variable pumping speed. SEM technician did not want to teach users how to clean with Evactron and did not want to spend time doing cleaning himself.

The Evactron was set up to operate during every pump down cycle for 100 seconds. By adjusting the gas leak and the vacuum set points for plasma operation the cleaning takes place while the SEM chambers pumps down through the .9 Torr to .4 torr pressure zone where Evactron cleaning is done. Operating the Evactron adds less than one minute to pump down time and is not notice by most users. Pump down to high vacuum is speeded up because UV light generated by plasma is effective at desorbing water vapor from walls during the cleaning cycle in the roughing mode.

Results: Cross contamination between specimens has disappeared. Higher resolutions are being seen. UCB Physics Department orders third Evactron A-C for new Sirion SEM in 2003 for use at LBL.

LEO 1525: NIST Boulder Colorado
NIST purchased Evactron to allow backscatter electron diffraction to be measured. The slightest layer of carbon interferes with these measurements. Evactron cleaning of the specimen and chamber before measurement insures the cleanest possible measurements By adjusting leak rate pressure can be maintained in the Evactron cleaning zone for up to five minutes if needed.

Leo 1550 Intel Sacramento.
Microscope is staying clean and pump-down speeds are increased. UV light from Evactron desorbs water from chamber walls during pump-down with Evactron cleaning. This system has no sample airlock so the Evactron in used remove both hydrocarbons and water vapor from the chamber.

Wright Patterson AFB, Dayton Ohio.
WPAFB purchased two Evactrons Anti-Contaminators in 2002 for use on two Lieca S360s. In 2003 they purchased 4 more Evactron units for use on two FEI FIBs and two FEI SEMs, an XL30 and a new Sirion.