Fluorosilicate glass (FSG) is a low-k dielectric used in between copper metal layers during silicon integrated circuit fabrication process. It has a low dielectric constant (k) and is now widely adopted by semiconductor foundries on geometries sub 0.25μ. Fluorosilicate glass is effectively a fluorine-containing silicon dioxide (k=3.5, while k of undoped silicon dioxide is 3.9).
Fluorosilicate glass is used by IBM. Intel started using Cu metal layers and FSG on its 1.2 GHz Pentium processor at 130 nm CMOS. TSMC (Taiwan Semiconductor Manufacturing Company) brought in FSG and copper together in the Altera APEX.
Fluorosilicate glass-ceramics have good mechanical properties. Potassium fluorrichterite based materials are composed from tiny interlocked rod-shaped amphibole crystals; they have good resistance to chemicals and can be used in microwave ovens. Richterite glass-ceramics are used for high-performance tableware.
Fluorosilicate glass-ceramics with sheet structure, derived from mica, are strong and machinable. They find a number of uses and can be used in high vacuum and as dielectrics and precision ceramic components. A number of mica and mica-fluoroapatite glass-ceramics were studied as biomaterials.