Removing Hydrocarbons and Decontaminating Vacuum Chambers with the Evactron De-Contaminator


Plasma ashing and glow discharge cleaning of samples have long been cleaning methods available for sample preparation for SEMs and TEMs, but they require expensive auxiliary equipment. Argon and oxygen plasmas are nor- mally used. Argon cleans via a sputter etching mechanism. However, sputter etch should be avoided because of possible damage to com- ponents within the chamber.


The Evactron Decontaminator, on the other hand, is a small device which is attached to any vac- uum chamber allowing for direct in situ cleaning of the vacuum chamber. The Evactron Deconta- minator has a valve manifold which introduces a small stream of gas such as room air, oxygen or hydrogen into the vacuum chamber. An attached pressure sensor is used to control the amount of gas flow. The gas flows past an electrode ener- gized by a low power (5-20 W) radio frequency (RF) generator. This will create RF plasma local- ized in the region around the electrode.


The Evactron RF plasma creates radicals that chemically etch and remove hydrocarbons, or- ganics, and surface carbon from SEMs and other vacuum systems. Contaminants are ashed into volatile products which are removed through the roughing pump. As seen in the fig- ure below left, the radicals are carried out of the plasma into the main chamber by convec- tion. In the chamber they react with all exposed surfaces including the specimen if present. The plasma itself is confined to the Plasma Radical Source (PRS), which prevents ion bombardment damage to the instrument or specimen.


Radical Source (PRS) Evactron Plasma


Electron Column


EDX Plasma


Evactron Series ® Decontaminators and Cleaning Systems


Evactron® System


CombiClean™


• Cleans SEM/TEM samples and SEM chambers from one desktop controller


• Stores samples and parts after cleaning • Uses patented Safar TEM side loaders


Decontaminate specimens and columns of SEMs and FIBs. The Evactron®


CombiClean™ System


combines onboard vacuum cleaning chamber and external PRS (Plasma Radical Source) control in one unified system.


• Cleans SEM/TEM samples and SEM chambers from one desktop controller


• Stores samples and parts after cleaning • Uses patented Safar TEM side loaders


Innovative Design


Designed as a complete cleaning solution, the Evactron®


CombiClean System features an


integrated vacuum chamber for desktop cleaning samples and vacuum parts, as well as an external Plasma Radical Source (PRS) for Evactron®


in-situ


cleaning of E-beam instruments such as SEMs, FIBs, and other analytic instruments, by removing carbon contamination.


The system monitors operation of either PRS unit, has internal memory, and is designed for routine operation with minimal operator training. Onboard control allows for changing the cleaning modes between external and internal PRS with just the flip of a switch.


Reactive Gas Radicals


High Vacuum Pump


Vacuum Exhaust


Cross-section of SEM chamber illustrates how the Evactron De-Contaminator removes hydrocarbons from the system.


SEM chamber with Evactron De-Contaminator Plasma Radical Source (PRS) attached. An adaptor flange is used to mount the Evactron De- Contaminator to the SEM.


This system is compatible with rotary vane pumps without the worry of oil backstreaming. A dry nitrogen purge feature keeps specimens clean after a plasma cleaning, and a storage mode allows you to


Ordering Information Cat. No.


91000-17


Description Evactron®


CombiClean™ System


continue dry nitrogen purging a sample while the external PRS is in use.


Specifications


The system features a microprocessor with embedded software to regulate a leak valve and control the chamber pressure by a MicroPirani gauge.


The microprocessor also regulates the RF power, has a clock to time the downstream plasma cleaning and nitrogen purging cycles, and records the operational and fault log.


Cleaning with the Evactron® CombiClean System


may be setup from either the front panel or a remote computer.


VentDetect™ Technology


Compatible with rotary vane pumps without the worry of oil backstreaming Dry Nitrogen purge feature keeps specimens clean after plasma cleaning Storage mode allows continued dry nitrogen purging of samples while external PRS is in use System monitors operation of either PRS unit Onboard control allows for cleaning modes between internal and external PRS with just the flip of a switch Wide Pressure Range


Qty. each


Electron Microscopy Sciences P.O. Box 550 • 1560 Industry Rd. Hatfield, Pa 19440 Tel: (215) 412-8400 Fax: (215) 412-8450 email: sgkcck@aol.com or stacie@ems-secure.com


www.emsdiasum.com


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