Plasma resistance of elastomers
How do you choose the right O-ring seal material?
Plasma resistance for common process chemistries
In order to provide accurate material recommendations for specific semiconductor plasma processes, PPE has tested a variety of elastomer materials, including those from other material suppliers.
The compounds were exposed to a number of different plasma chemistries commonly used in etch processes and deposition chamber cleaning processes. Elastomer materials can have different resistance to specific process chemistries and are generically improved by using a specific type of reinforcement or filler system and increased amounts of filler materials. The choice of material can also depend on several other factors such as, mechanical property requirements, device sensitivity to trace metal contaminants and filler particle size and type.
Accurate data will provide the following benefits:-
- Relative material performance and life-time comparison to base your selection decision on,
- Save time and effort in researching and qualifying new materials,
- Reduce the risk of choosing the wrong material.
The table below is a summary of PPE material erosion rates in four basic plasma chemistries.
|Filler system||Inorganic||Organic self reinforcing||Organic nano||Carbon black||Inorganic||Organic self reinforcing||Inorganic||Organic nano||Organic nano||Organic nano|
|O2||Parallel plate capacitive|
| Cl2 + BCl3|
|Remote inductively coupled plasma||3||6||5||7||2||4||1||9||10||8|
|SF6 + O2||Remote inductively coupled plasma||4||5||6||1||2||7||3||8||9||10|
|F - radical||Remote inductively coupled plasma||5||9||10||1||3||4||2||6||7||8|
|Trace metal level||H||F||D||J||I||E||G||A||B||C|
1 = Best (lowest erosion rate), 10 = Worst (highest trace metal level (ppb))
A = Best (lowest trace metal level (ppb)), J = Worst (highest trace metal level (ppb))
Materials are listed in order of relative price, lowest on the left to highest on the right.
- Remote source tests were carried out in several Oxford Instruments Plasma Technology process tools. Two different source types were used depending on the chemistry.
- The F-radical process was carried out in a much smaller inductively coupled plasma (ICP) source leading to higher loss of ions to the walls and a resulting higher radical to ion ratio.
- No bias was applied to any of the test samples in order to closely mimic the conditions that an O-ring or seal would be exposed to in a groove such as a chamber lid seal.
Want to see the results in more detail or learn more?
Contact our experts who will be happy to share the results of the testing.
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