Application of Perfluoroelastomer (FFKM) in the Vacuum Industry

FFKM is a top-tier elastomer sealing material for the vacuum industry. Its core values lie in ultra-low outgassing rate, ultra-low permeability, superior chemical resistance and high temperature resistance, which enable it to meet the stringent sealing requirements of high vacuum/ultra-high vacuum (UHV) conditions as well as harsh working environments with strong corrosion and high temperatures. It plays an indispensable role in the vacuum industry, especially in high-cleanliness and extreme-condition applications such as semiconductor manufacturing and aerospace, serving as a critical sealing material.

I. Core Advantages for Vacuum Applications (Why Choose FFKM)

1. Ultra-low Outgassing Rate

- Dense molecular structure and minimal extractables result in an outgassing rate far lower than that of conventional rubbers and fluoroelastomers (FKM).

- Semiconductor-grade FFKM meets the requirements of ultra-high vacuum and high cleanliness, preventing contamination of vacuum chambers and process products.

- It can reach Class 10 cleanliness standards after special clean processes and vacuum baking.

2. Ultra-low Gas Permeability

- The permeability coefficient to helium (the smallest molecule) is less than 1×10⁻¹⁰ cm³·cm/(cm²·s·Pa), 1-2 orders of magnitude lower than that of conventional FKM. It effectively prevents vacuum leakage, maintains long-term high vacuum levels, and reduces pump load and energy consumption.

3. Ultra-wide Temperature and Chemical Resistance

- Continuous operating temperature range: -50℃ to +290℃, up to 316℃ for short-term use, and an instantaneous maximum of 350℃.

- Resistant to almost all strong acids, strong alkalis, strong oxidants, organic solvents, plasmas and corrosive process gases (e.g., HF, Cl₂, F₂, NF₃, etc.). With plasma etching resistance, it is the only elastomeric sealing choice for semiconductor vacuum processes.

4. Long-term Sealing Reliability

- Retains excellent elasticity even under vacuum and high-temperature conditions, and maintains reliable rebound performance after long-term compression. For example, the compression set can be kept below 50% at 300℃, and the permanent compression set is ≤25% after 1000 hours.

- No particle shedding and low adsorptivity, which extend maintenance cycles and improve equipment utilization rate.

II. Main Vacuum Application Scenarios

1. Semiconductor Manufacturing

This is the core application of FFKM in the vacuum field. Many steps in the front-end semiconductor manufacturing process must be carried out in high-vacuum and plasma environments, and FFKM seals are the key to maintaining the vacuum level of these process chambers.

2. Vacuum Coating and Surface Treatment

- Optical coating, decorative coating and hard coating equipment: Sealing for chamber doors, rotating shafts and gas inlets.

- Ion plating, magnetron sputtering and electron beam evaporation: Withstands high temperatures and corrosion from process gases.

3. Aerospace Vacuum

- Satellite and rocket propulsion systems: Sealing for oxidizer/fuel pipelines, valves and thrust chambers, resistant to propellants such as hydrazine and dinitrogen tetroxide.

- Space simulators and thermal vacuum chambers: Long-term sealing under extreme temperature and high-vacuum environments.

III. Material Grade Selection

- General-grade FFKM: Suitable for high vacuum (10⁻⁴～10⁻⁷ Pa) and general corrosive working conditions.

- Semiconductor-grade/Clean-grade FFKM: Features ultra-low outgassing and low metal ion leaching, for use in UHV and advanced manufacturing processes.

- Plasma-resistant special FFKM: Optimized for etching processes with a longer service life against plasma corrosion.

IV. Sealing Structure and Installation

- Prioritize the use of O-rings, X-rings and rectangular rings, matched with metal flanges (ISO/KF/CF).

- Groove design: Follow vacuum sealing standards to ensure a 7%–20% compression ratio.

- Perform vacuum baking before installation (150–200℃ for several hours) to reduce the outgassing rate.