Chemours in the Semicon Manufacturing Industry
Extractable fluirode ions
Extractions from resin samples do not tell the whole story of contamination potential. Published studies have shown differences in the contamination potential for components manufactured from different types of "PFA" resins.
As shown in this table, the ion contribution from Teflon™ PFA HP is extremely low, and stays low in this heating cycle which represents processing the polymer into components. Nonstable end groups contained in other PFA's readily interact and are then available to react with the metals in component fabrication equipment.
The predominant differentiation of high performance fluoropolymers in terms of extractables is fluoride ions. They are fatally undesirable in semiconductor processing because they etch silicone wafers.
The secondary differentiation is metal content of components, which is determined both by the "as manufactured" content, plus the contribution pulled into the system by reactive end groups.
The typically very low metal content of Teflon™ PFA HP and now Teflon™ PFA HP Plus fluoropolymers is an important consideration for their suitability for use in Semicon manufacturing processes. These polymers are manufactured to very high levels of purity.
This is an analysis of two lots of recent production Teflon™ PFA HP and HP Plus, which are manufactured in the same equipment. The samples were extruded into tubing using standard industry conditions. Samples of the tubing were sent to an outside laboratory where the metal content in parts per billion was determined by using a severe extraction in 49% hydrofluoric acid solution.
The total metal content of the polymer samples is extremely low, even after extrusion. The results obtained in the Semicon industry categories of "Very Critical" and "Critical" ions are shown, with many ion types below the detectable level.