Teflon® AF provides effective circuit protection, improved dielectrics, and easy application

Application Description
Superconductor films based on metal oxides are protected against acids in the atmosphere by solution application of 2 mm passivation coatings of DuPont Teflon® AF amorphous fluoropolymer resin.
Unlike conventional niobium superconductors, films pioneered by DuPont function effectively at temperatures readily achieved by cooling with liquid nitrogen or mechanical refrigeration equipment. The photo shows a sapphire wafer with a superconductive film that functions as the entire front end of a two-channel microwave receiver.
Reason for choosing Teflon® AF
Teflon® AF provided effective circuit protection, improved dielectrics and easy application.
Benefits Gained
- Effective Protection
Teflon® AF provides more protection against atmospheric acids and better adhesion than typical polyimide passivation coatings.
- Durability
Tests show the coating has good resistance to boiling water, and there has been no breakage of brittle oxide films during thermal cycling tests.
- Easy Application
Solutions of Teflon® AF are applied by conventional spin coating techniques to controlled thickness down to 1 Rm. They dry at 100°C (212°F) by solvent evaporation.
- Higher Electrical Performance
Superconductorbased devices under development gain increased velocity of propagation and reduced crosstalk, thanks to the very low dielectric constant (1.89-1.93) of Teflon® AF.