by Sara McCaslin, PhD Sara McCaslin, PhD No Comments

O-rings are a circular seal that is seated within a groove and compressed between two or more parts during assembly to form a seal at the interface. While they may look simple, their importance cannot be overstated–especially when it comes to o-rings for semiconductor manufacturing applications.

Semiconductor Operating Environments

In the semiconductor manufacturing industry, it can be difficult to find an o-ring solution that can handle the harsh operating conditions that can involve factors such as aggressive media, extreme temperatures, and vacuum pressures. Chemicals such as bases, acids, solvents, amine-based strippers, and chlorinated gases may be involved depending on the application. Extended exposure to oxygen and fluorine plasmas are common

The performance requirements of o-rings for semiconductor manufacturing are challenging to meet as well, often requiring thermal, dimensional, and chemical stability at high temperatures as well as low outgassing and high purity. Requirements may also include extremely low levels of anionic and cationic impurities, low levels of TOC (Total Organic Carbon), reduced IR (Infrared Absorption), and low permeation rates.

What to Look for in an O-Ring for Semiconductor Applications

The key properties of an o-ring material for the semiconductor industry vary with the type of application involved. For example, track and lithography equipment and processes often require an o-ring that is very resistant to solvents, while CVD (Chemical Vapor Deposition) needs thermal stability and excellent performance in the presence of vacuum pressures. 

Other applications, such as CMP (Chemical Mechanical Polishing), must have o-rings made from a material that is both abrasion resistant and resistant to high pH chemical exposure. Wet etch demands an o-ring made from a high purity material that will cause no elemental contamination (i.e., low particle generation) and dry etch requires that the material be resistant to plasma. Resist stripping not only requires general chemical resistance but outstanding performance in the presence of ozone. 

O-ring materials may have to meet other requirements as well, such as resistance to poisonous doping agents and reactive fluids, low outgassing, and low trace metal content. Almost all semiconductor o-rings involve a low compression set, excellent dimensional stability, and a wide range of operating temperatures.

Is there a material that can handle the operating environments just described? Yes, there is: FFKM, which provides the resiliency and sealing force of an elastomer with the thermal stability and chemical compatibility of PTFE (trade name Teflon).

FFKM O-Rings

FFKM (perfluoroelastomer) possesses many of the key properties needed in an o-ring for semiconductor manufacturing operations. Key characteristics of FFKM include a very broad range of chemicals with which it is compatible (including acids, ozone, and other aggressive chemicals), thermal stability, high purity, low outgassing, and plasma resistance. O-rings made from FFKM can handle a range of pressures as well, including vacuum conditions, and are very low friction.

FFKM is known for its wide operating temperature range, excellent dimensional stability, critical mechanical properties, and low compression set. And FFKM o-rings can be used for static and some dynamic applications. In fact, it is considered the highest temperature-resistant elastomeric material available with an operating temperature range of -51 F to 620 F. And from a manufacturing standpoint, FFKM can easily be molded into o-rings as well as a wide variety of customized shapes.

Furthermore, there are grades of FFKM that offer key properties such as UHP (Ultra High Purity), exceptional plasma resistance, minimal extractable ion content, improved O2 plasma resistance, abrasion resistance, and minimal metallic ion content. Grades are also available that achieve a balance of chemical plasma and mechanical erosion resistance. In addition, there are FFKM options that work extremely well for processes that involve water vapor, ozone, and ammonia (e.g., CVD, strip process chemistry).

Where Are FFKM O-Rings Used in the Semiconductor Industry?

There are several areas where FFKM o-rings are already being used in the semiconductor industry, including …

  • Chemical Vapor Deposition (CVD)
  • Chemical Mechanical Polishing (CMP)
  • Cleaning (Wet and Dry)
  • Etching (Wet and Dry)
  • Resist stripping (Wet and Dry)
  • Track and lithography
  • Thermal (LPCVD) nitride
  • Plasma and gas deposition
  • Photolithography

This list, however, is far from exhaustive but provides an idea of the many ways that FFKM o-rings can be implemented in the various harsh environments of semiconductor manufacturing.

Benefits of FFKM O-Rings for Semiconductor Manufacturing

There are a host of benefits when using FFKM o-rings in the semiconductor industry. FFKM leads to a more reliable, long-lasting o-ring life, which also reduces maintenance requirements and reduces equipment downtime. The use of FFKM, in particular, reduces process contamination which results in better product quality and greater yield. Combined, such benefits also mean overall cost reduction. 

Conclusion

At Advanced EMC, we have access to the facilities required for providing UHP FFKM o-rings, both in terms of material and manufacturing processes. We will work with you to find the right o-ring sealing solution, whether it requires a standard o-ring or a customized design. Contact us today to find out what our Sealing Solutions Team has to offer you.

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