污染是一個非常嚴重的問題，可以引起:
腐蝕
對MFC的破壞
破壞閥門波紋管
污染物生成
污染過濾器
調節器控制的損壞
傳感器的損壞
多種多樣引起污染的原因包括:
空氣混合在系統中
水分混合在系統中
連接錯誤的氣瓶
氣路有外漏
氣路加熱不正確
氣路安裝不正確
氣路中的組件有污染
硅烷或硅烷氣路
在一個清潔不當污染系統中安裝 新的流量計。
正常使用也會導致很多氣體殘留污染。
注意事項:
更換氣瓶時,CGA裝置會暴露出來，殘余的氣體將與空氣反應，這個污染將進入氣路中并污染工藝腔體。
如果一個閥或流量計被拆下時發現有污染腐蝕跡象，那么氣路中其它組件很可能也以同樣的方式被污染腐蝕。
如果新的流量計安裝到這個系統中，那么將馬上會被污染，之前的工作將白費。
舊的過濾器常常有污染物，當清洗污染系時請更換過濾器。
如果你有一個系統清洗后仍有問題,你需要考慮更換過濾器
你總是需要仔細檢查氣瓶安裝以確保它是正確的。
供氣之前需要檢漏 ，工作中也需檢漏。
在打開氣體之前，需要先吹掃整個從氣瓶到工藝腔體的氣路系統。
使用密封圈需要符合氣體特性
使用MFC需要匹配氣體
CONTAMINATION:
Contamination is a very serious issue and can cause:
Process problems
Corrosion
Damage to the MFC
Perforation of valve bellows and diaphragms
Particle generation
Destruction of filters
Loss of regulator control
Loss of sensors
Causes of contamination can be varied but may include:
Air in the gas system
Moisture in the gas system
Inadvertent connection of the wrong type of gas bottle
Corrupted gas in the bottle
Leaking fittings
Pinholes or micro cracks in valve diaphragms or bellows
Inadvertent opening of the gas system to atmosphere
Incorrect gas line heating
Incorrect gas line installation
Installation of components that were either improperly cleaned or not cleaned
Dusting of Silane or Silane based gas systems
Perforated flex lines
Installing new components in an improperly cleaned, contaminated system.
Normal use can also cause contamination as many gases leave residues.
Things to remember to prevent contamination:
When changing a gas bottle, the CGA fitting will be exposed to air and any
residual gas in that fitting will react and form a contaminate which will stay in
the system unless cleaned out or prevented. This contaminate will then enter
the gas stream and travel to the process chamber. The CGA fitting has a
bottle side as well.
If a component such as a valve or MFC is removed and it shows signs of
contamination, corrosion, etc. then the rest of the system is most likely also
contaminated the same way.
If new or refurbished components are installed in this system then they will
immediately become re-contaminated. Your work will be wasted.
Filters will trap contamination, when cleaning a contaminated
system…replace the filter .
If you have a system that is having flow problems after cleaning, did you
replace the filter ?
Always double check the gas bottle you are installing to ensure it is correct.
Never assume someone else has done something that was supposed to be
done, always check. Verify, Verify, Verify.
Always leak check a system prior to turning on the gas supply.
Always leak check a system after work is performed on the system.
Always purge and evacuate a gas system from the gas bottle to the chamber
prior to turning on the gas.
Use O-rings and seals that are compatible with the gas and the process.
Use MFC’s that are calibrated for the gas in use