XEI Scientific, Inc.
The EVACTRON® Anti-Contaminator and De-Contaminator Updated January 2010
RF Plasma Cleaning Systems for Electron Microscopes
and High Vacuum Systems
Stops Artifacts and Removes Hydrocarbons and Organics.
Scientific Papers, Patents, and Abstracts
Publications about contamination and the EVACTRON® system and its effectiveness:
BACKGROUND
In SEMs, FIBs, and TEMs, contamination is a serious problem for specimen analysis and producing high-resolution images. Beam-induced carbonaceous material is deposited on the region under study, causing loss of resolution. Hydrocarbon contamination causes the image darkening or "Black Square" in a typical SEM image. The Evactron® De-Contaminator (D-C) removes hydrocarbon contamination from electron microscopes. A radio frequency (RF) generated plasma is attached to the microscope vacuum chamber. Room air or other oxygen containing gas passes through the plasma, producing oxygen radicals in situ. These radicals clean organic contaminants from the interior of vacuum systems and sample surfaces. The oxygen radicals decompose carbon-containing material into H2O, CO, and CO2, which are evacuated from the system.
Contamination Removal Rates Improved by New Impedance Matching Network for the Evactron® De-Contaminator.pdf
Poster Presentation at Microscopy & Microanalysis (M&M) Meeting, July 2009, Richmond, VA.
Christopher G. Morgan, Ross Bernheim, and Ronald Vane, XEI Scientific, Inc., Redwood City, CA
In the Evactron D-C, an impedance matching network (match) is used to maximize the power delivered to the plasma. Data from various experiments done in this study clearly illustrate that the new design of the impedance match creates more oxygen radicals. Improving the efficiency of the match has been shown to increase the cleaning efficiency of the Evactron D-C.
Poster Presentation at Microscopy & Microanalysis (M&M) Meeting, July 2009, Richmond, VA.
Christopher G. Morgan and Ronald Vane, XEI Scientific,Inc., Redwood City, CA
The goal of the research program at XEI Scientific is to understand the downstream cleaning process. The program investigates the following questions to better understand the downstream cleaning process: (1) what chemistry is occurring in the plasma to create or remove oxygen radicals; (2) how many oxygen radicals are created, and what is their distribution in a vacuum chamber; and (3) what chemistry occurs when the oxygen radicals ash hydrocarbons. By placing an adaptive vacuum fixture with a fiber optic coupler between the Evactron® plasma system and the vacuum chamber, the plasma can be probed using emission spectroscopy. The use of a silver-coated Quartz Crystal Microbalance (QCM) directly measures oxygen radical concentrations from the plasma source.
Contamination-Free Transmission Electron Microscopy for High-Resolution Carbon Elemental Mapping of Polymers. Link to abstract/paper.
ACS Nano, 2009, 3(5), pp 1297-1304
M&M Meeting Aug 2007
Shin Horiuchi*, Takeshi Hanada**, Masaharu Ebisawa**, Yasuhiro Matsuda***, Motoyasu Kobayashi***, and Atsushi Takahara***,*AIST, Ibaraki, Japan, **Consulting Zero Loss Imaging, Tokyo, Japan ***Institute for Materials Chemistry and Engineering, Fukuoka, Japan
This study utilizes the Evactron® D-C for TEMs. The "contamination-free TEM" allowed researchers to accomplish high-resolution carbon elemental mapping by energy-filtered transmission electron microscopy (EFTEM) on the nanostructure of soft materials. In addition, this study illustrates that although TEM cryo-observation is known to be effective in reducing specimen damage, it was not observed to help in carbon mapping, suggesting that the cooling of the specimen may actually increase the contamination deposition rate. In the case of polymers, the detection of carbon is much simpler than those of other light elements because of its high content. Being able to do carbon analysis by elemental mapping and EELS with high spatial resolution without problematic contamination could lead to improvements for various soft-material nanoanalyses by EFTEM. This study suggests that the analytical technique utilizing the "contamination-free TEM" also offers possibilities in studies requiring extended exposure time of the electron beam, such as EELS, nanobeam diffraction and electron tomography.
Comparing the Effects of Different Gas Mixtures and Vacuum Chamber Geometries on the Evactron Cleaning Process.pdf
Poster Presentation at Microscopy & Microanalysis (M&M) Meeting, August 2008, Albuquerque, NM.
Christopher G. Morgan and Ronald Vane, XEI Scientific, Inc., Redwood City, CA
Using a quartz crystal microbalance (QCM), the effectiveness of the Evactron® process has been quantified in this study, as a function of cleaning parameters such as chamber pressure during cleaning, RF power, and distance from the plasma source. The QCM measurements can now be extended in order to consider the effect of different gas mixtures and chamber geometries on cleaning.
Contamination Specification for Dimensional Metrology SEMs.pdf
Presented at SPIE Advanced Microlithograpy Feb 2008, San Jose, CA
András E. Vladár, K. P. Purushotham and Michael T. Postek, NIST, Gaithersburg, MD
Electron beam-induced contamination is becoming one of the most bothersome problems of the scanning electron microscopes. Even in clean-vacuum instruments it is possible that the image gradually darkens because a polymerized hydrocarbon layer with low secondary electron yield is deposited. This contamination layer can get so thick that it changes the size and shape of the small structures of current and future state-of-the art ICs. This greatly disturbs the measurement process and the erroneous results can lead to wrong process control decisions. NIST has developed cleaning procedures and a viable contamination specification that offer an effective solution for this problem.
Measuring Contamination with a Quartz Crystal Thickness Monitor
Quantification of Contamination Using Quartz Crystal Thickness
Monitors .pdf
Poster Presentations at Microscopy & Microanalysis (M&M) Meeting, August, 2007, Ft. Lauderdale, FL
Christopher G. Morgan, Mark M. Gleason and Ronald Vane, XEI Scientific, Inc., Redwood City, CA
Quartz crystal microbalances (QCMs) are a standard tool for vacuum deposition measurements. They can also be adapted to measure contamination removal by plasma cleaning. Here, they are used to record a thickness loss rate of an oil layer previously deposited on their surface; this loss rate is a measure of the cleaning effectiveness of the Evactron D-C.
The Effect of Collimators on Evactron® Cleaning of EDS Windows .pdf
Poster Presentation at Microscopy & Microanalysis (M&M) Meeting, August, 2007, Ft. Lauderdale, FL
Christopher G. Morgan, Mark M. Gleason and Ronald Vane, XEI Scientific, Inc., Redwood City, CA
XEI Scientific, Inc. has developed a quantitative technique to determine the efficiency of the Evactron® process under various conditions; using a collimator to measure the loss rate of an oil layer. To measure the loss rate the collimator is placed over a thickness meter prior to pump down. The rate of thickness loss with the collimator covering the monitor is compared to the loss rate when the monitor is completely exposed to the oxygen radicals produced by the Evactron® process.
Effect of Cleaning Parameters on Cleaning Effectiveness in a SEM Equipped with an Oxygen Plasma Etching Device .pdf Poster Presentation at Microscopy & Microanalysis (M&M) Meeting, August, 2007, Ft. Lauderdale, FL
R. Garcia*, A.D. Batchelor*, C.B. Mooney*, A.D. Garetto*, V.L. Carlino**, R. Vane**, and D.P. Griffiths
*Materials Science and Engineering Department and Analytical Instrumentation Facility, North Carolina State University, Raleigh, NC; **XEI Scientific, Redwood City, CA 94063; *Materials Science and Engineering Department and Analytical Instrumentation Facility, North Carolina State University, Raleigh, NC; **XEI Scientific, Redwood City, CA 94063
The Use of Oxygen in SEM Plasma Cleaning Equipment .pdf
Poster Presentation at Microscopy & Microanalysis (M&M) Meeting, August, 2007, Ft. Lauderdale, FL
Thomas O. Mueller, J. Cowan, and E. Swanson
ON Semiconductor, Gresham Failure Analysis Laboratory, Gresham, OR
Effect of Evactron® Cleaning on EBSD Detector Phosphor Screens .pdf
March 28, 2007
Mark Nave and Andrew Sullivan*
*Microanalysis Consulting Pty. Ltd., St Albans Park, Victoria, Australia
**Centre for Material and Fibre Innovation, Deakin University, Geelong, Victoria, Australia
Immobilization and Removal of Hydrocarbon Contamination Using the Evactron® De-Contaminator .pdf
Presentation at Microscopy & Microanalysis (M&M) Meeting, July-August, 2006, Chicago, IL
Ronald Vane, XEI Scientific, Inc., Redwood City, CA
Comparison of Residual Gas Analysis results on the removal of volatile components and visual observance of the removal of Hydrocarbon films indicates that the immobilization of Hydrocarbons on surfaces by polymerization using the Evactron De-Contaminator is also an important mechanism for reducing contamination interference with imaging in electron microscopy.
Environmental Contamination Sources and Control in High Resolution Scanning Electron Microscopy .pdf
Presentation at Microscopy & Microanalysis (M&M) Meeting, August, 2005, Honolulu, HI
Ronald Vane and Vince Carlino, XEI Scientific, Inc., Redwood City, CA
Hydrocarbon (HC) background and contamination is hard to avoid in our carbon based world. Even with the most careful handling carbon contamination artifacts from Airborne Molecular Contamination (AMC) can creep in and interfere with imaging and measurement in e-beam instruments. The Evactron De-Contaminator made by XEI Scientific is a tool that actively removes HC from the vacuum system and specimens within it to prevent these problems.
Non-Destructive Cleaning of Carbon Nanotube Surfaces: Removal of Organic Contaminants and Chemical Residue with Oxygen Radicals.pdf
Presentation at Microscopy & Microanalysis (M&M) Meeting, August, 2004, Savannah, GA
Mihail P. Petkov, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA
Oxygen radicals (OR) have been used as a surface cleaning method for a diverse range of materials. However, the application of OR cleaning to graphite and carbon nanotubes is not straightforward, as oxygen plasma is known to ash both forms of carbon. This work demonstrates a successful OR cleaning of surface organic contaminants (most likely hydrocarbons from the air), as well as chemical residue from the fabrication process, without inducing microstructural changes visible by SEM. An Evactron De-Contaminator was used for the study.
A
Study of the Effects of Evactron® Plasma Cleaning on X-ray Windows .pdf
Presentation at Microscopy & Microanalysis (M&M) Meeting, August, 2004, Savannah, GA
Ronald Vane*, Christine Roberts**, and Vince Carlino* *XEI Scientific, Inc., Redwood City, CA 94063
**Formerly with MOXTEK, Inc., Orem, UT 84057
A complete paper showing that long term cleaning of UTW does not cause window failure.
Improved Carbon Analysis with Evactron Plasma Cleaning .pdf
Presentation at Microscopy & Microanalysis (M&M) Meeting, August, 2004, Savannah, GA
Pierre
Rolland*, Vincent L. Carlino**, and Ronald Vane**
*Alprimage, 11 rue de Savoie, 91940 Les Ulis, France
**XEI Scientific, 1735 East Bayshore Rd., Suite 29A, Redwood City, CA 94063, USA
A complete paper on EDS analysis of carbon.
A
Study of the Effectiveness of the Removal of Hydrocarbon Contamination by Oxidative Cleaning Inside the SEM
Presentation at Microscopy & Microanalysis (M&M) Meeting, August, 2002, Quebec City, Canada
Neal Sullivan*, Tung Mai*, Scott Bowdoin*, and Ronald Vane**
Microscopy& Microscroanalysis Vol. 8, Supplement 2, 720CD
*Schlumberger Technologies, 45 Winthrop St., Concord, MA **XEI Scientific, Inc., Redwood City, CA
A complete paper with CD SEM Data
Active Monitoring and Control of Electron Beam Induced Contamination
András E. Vladár*, Michael T. Postek* and Ronald Vane**
Presentation at SPIE Microlilthography Conference Feb 27-28, 2001; Proc SPIE, Vol. 4344(2001): 835.
*National Institute of Standards and Technology, Gaithersburg, MD
**XEI Scientific, Inc., Redwood City, CA
EVACTRON® Cleaning of SEM Specimens Using an In-Situ RF Plasma on the SEM Chamber
By R.
Vane*, and G. Strossman**
Presentation at Microscopy & Microanalysis (M&M) Meeting, August, 2001, Long Beach, CA
*XEI Scientific, Inc., Redwood City, CA
**Charles Evans and Associates, Sunnyvale, CA
A complete paper with XPS results.
XPS Evaluation of Sample Surface Cleaned by the XEI Evactron®
Scott D. Walck**, Brian R. Strohmeier**, Edward G. Goralski**, and Ronald A. Vane*
Presentation at Microscopy & Microanalysis (M&M) Meeting, August, 2001, Long Beach, CA
*XEI Scientific, Inc., Redwood City, CA
**PPG Industries, Inc., Pittsburgh, PA
US Patent 6,610,257: "Low RF Power Electrode for Plasma Generation of Oxygen Radicals from Air"
Inventor Ronald A. Vane Issued Aug 26, 2003
US Patent 6,105,589: "Oxidative Cleaning Method and Apparatus for Electron Microscope Using an Air Plasma and an Oxygen radical Source "
Inventor Ronald A. Vane Issued Aug 22, 2002
US Patent 6,452,315: " Compact RF Plasma Device For Cleaning Electron Microscopes and Vacuum Chambers"
Inventor Ronald A. Vane Issued Sept. 17, 2002
Oxidative Cleaning in SEMS
By
Ronald Vane,
President XEI Scientific
Jan 15, 1999 revised 4/20/2003
Evactron ® Plasma Ashing
by Ronald Vane XEI Scientific
Aug 31, 2000
Low Pressure Nitrogen Purge Stops Oil Contamination in SEMs
Ronald A. Vane
President, XEI Scientific June 15, 1992