DuPont™ Vespel® CR-6110 PFA/Carbon Fiber Composite for Semiconductor Wet Processing and Wafer Handling Applications

DuPont™ Vespel® CR-6110 is a high performance thermoplastic composite used for semiconductor wet processing and wafer handling applications. This article describes some of the many benefits of this innovative material for semiconductor manufacturing equipment.

Acid Resistance, Mechanical Properties, and Thermal Properties

The electronics industry uses a variety of aggressive acids including hydrofluoric acid and sulfuric acid for cleaning and etching semiconductor wafers. These strong acids will attack most plastic materials including acetal and PEEK (polyetheretherketone). Fluoropolymers such as PFA (perfluoroalkoxy) and FEP (fluorinated ethylene propylene) are often used in semiconductor wet processing and wafer handling applications since these plastics are generally resistant to strong acids.

That being said, unfilled fluoropolymers such as PFA and FEP tend to have low strength, low modulus, and high rates of thermal expansion. These limitations become more problematic at elevated temperatures since these materials become soft in high temperature environments. This makes many fluoropolymers and fluoropolymer composites unsuitable for applications that require high strength, dimensional stability, and the ability to operate at elevated temperatures.

DuPont™ Vespel® CR-6110 is a PFA/carbon fiber composite that has excellent resistance to strong acids due to the PFA base polymer. The carbon fiber reinforcement provides the composite with high strength, high modulus, and a low rate of thermal expansion. It also enhances the material’s mechanical strength at elevated temperatures. Users of Vespel® CR-6110 have reported that it demonstrates excellent thermal resistance at 260ºC (500°F) in their applications.

These performance attributes make DuPont™ Vespel® CR-6110 an excellent choice for semiconductor wet process and wafer handling applications where load bearing properties, dimensional stability, chemical resistance, and high service temperatures are required. The graphs below illustrate the high strength, high modulus, and low thermal expansion rate of DuPont™ Vespel® CR-6110 compared with several other fluoropolymers and fluoropolymer composites.

Typical Tensile Strength Values for DuPont™ Vespel® CR-6110 and
Other Fluoropolymers and Composites per ASTM D638 (psi)

Typical Flexural Modulus Values for DuPont™ Vespel® CR-6110 and
Other Fluoropolymers and Composites per ASTM D790 (kpsi)

Typical Coefficient of Thermal Expansion Values for DuPont™ Vespel® CR-6110 and
Other Fluoropolymers and Composites (in/in/°Fx10^-5)

Chemical Resistance and Purity

DuPont™ Vespel® CR-6110 is resistant to a wide range of chemicals that are used for cleaning and etching semiconductor wafers including solvents, bases, and certain concentrations of hydrofluoric acid and sulfuric acid/hydrogen peroxide mixtures.

DuPont™ Vespel® CR-6110 has outstanding purity characteristics, with low levels of metallic ion extractables when immersed in high purity semiconductor fluids.

Protection from Scratching and Electrostatic Discharge

Semiconductor wafers can become damaged during handling due to electrostatic discharge or mechanical scratching. DuPont™ Vespel® CR-6110 has low surface resistivity and low volume resistivity to reduce the likelihood of damage due to ESD. The material also has low abrasion on semiconductor wafer surfaces, which minimizes scratching during handling. 

Friction and Wear Performance

Long wear life is essential for semiconductor machinery components such as wafer chucks that repeatedly contact wafers during handling. As shown in the graph below, DuPont™ Vespel® CR-6110 has an extremely low wear rate compared with other fluoropolymers and fluoropolymer composites. This reduces maintenance downtime for semiconductor machinery.

Typical Values for Wear Rate of DuPont™ Vespel® CR-6110, PTFE, and PTFE Composites
Against SU316 Stainless Steel in Petroleum Jelly /Al₂O₃ Slurry (mm)
Based on a Proprietary Internal Test Method

Applications for DuPont™ Vespel® CR-6110

Because of its chemical resistance, purity, superior mechanical properties, high temperature capability, and dimensional stability, DuPont™ Vespel® CR-6110 is widely used for semiconductor wet processing and wafer handling applications including:

• Spin chucks
• Vacuum chucks
• Wafer handling devices
• End effectors
• Valve seats and seals
• Clamps
• Fasteners

For more information about DuPont™ Vespel® CR-6110 or for specific application questions Ask a Plastics Expert, or call 1-800-553-0335.